盐地碱蓬高亲和性K<sup>+</sup>转运蛋白基因<em> SsHAK</em>2的克隆与表达模式分析

引用本文

段慧荣, 王锁民. .盐地碱蓬高亲和性K⁺转运蛋白基因 SsHAK2的克隆与表达模式分析 . 草业学报, 2016,25(2): 114-123
DUAN Hui-Rong, WANG Suo-Min. .Cloning and expression analysis of a high-affinity K⁺ transporter gene SsHAK2 in Suaeda salsa . Acta Prataculturae Sinica,2016,25(2): 114-123 复制到剪切板

Permissions

本文属于开放获取期刊。

盐地碱蓬高亲和性K⁺转运蛋白基因 SsHAK2的克隆与表达模式分析

段慧荣, 王锁民^*

兰州大学草地农业科技学院,草地农业生态系统国家重点实验室,甘肃兰州730020

*通信作者Corresponding author. E-mail: smwang@lzu.edu.cn

作者简介:段慧荣(1987-),女,山西长治人,在读博士。E-mail:duanhuirong514@163.com

收稿日期: 2015-04-08

基金项目:基金项目:教育部博士点基金优先发展领域项目(20130211130001)和国家自然科学基金项目(31072073)资助

摘要

盐地碱蓬在高盐生境中可以有效吸收K⁺,并维持细胞内K⁺浓度的相对稳定。高亲和性K⁺转运蛋白KT/HAK/KUP家族成员在植物K⁺吸收过程中发挥重要作用。本研究从盐地碱蓬中克隆到一个KT/HAK/KUP家族成员 HAK2的同源基因 SsHAK2,并对其进行生物信息学分析和表达模式分析。SsHAK2编码788个氨基酸,与不同植物的HAK2类蛋白具有较高的同源性(80%92%)。系统进化分析表明,SsHAK2属于KT/HAK/KUP家族亚族Ⅱ成员,与拟南芥AtKUP2位于同一进化分枝。实时定量qPCR分析显示, SsHAK2在盐地碱蓬的根和叶中均有高丰度表达,且叶中的表达丰度显著高于根中。 SsHAK2的表达受外界不同浓度K⁺ (2.5和0.01 mmol/L)的诱导。2.5 mmol/L K⁺处理下,根和叶中 SsHAK2的表达受25 mmol/L NaCl的显著诱导;0.01 mmol/L K⁺处理下,25和150 mmol/L NaCl的添加抑制根中 SsHAK2的表达,却显著促进其在叶中的表达。以上研究结果表明,SsHAK2可能参与盐地碱蓬K⁺吸收及转运过程,在根和叶中发挥不同的功能。

关键词: 盐地碱蓬; SsHAK2; 克隆; 表达分析

Cloning and expression analysis of a high-affinity K⁺ transporter gene SsHAK2 in Suaeda salsa

DUAN Hui-Rong, WANG Suo-Min^*

State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China

Abstract

Suaeda salsa, a typical salt-accumulating halophyte, is capable of absorbing K⁺ with high efficiency, and thus maintains a relatively stable K⁺ level in cells, and grows well, even in highly saline soil. Members of the KT/HAK/KUP gene family have an important role in K⁺ uptake in plants. In this study, we cloned SsHAK2 in S. salsa and analyzed the expression patterns of SsHAK2 when the plants were exposed to different concentrations of KCl and NaCl. Results revealed that SsHAK2 coded for 788 amino acid residues and shared a high homology (80%-92%) with the identified members of KT/HAK/KUP family from other plants. Phylogenetic analysis showed that SsHAK2 belonged to a sub-group of the family known as group II, and formed a clade with AtKUP2 of Arabidopsis thaliana, indicating close relationship. SsHAK2 was highly expressed in roots and leaves, and was induced by widely differing K⁺ concentrations (2.5 and 0.01 mmol/L). Under 2.5 mmol/L K⁺ conditions, the expression of SsHAK2 in roots and leaves was induced by 25 mmol/L Na⁺ application. However, in the medium containing 0.01 mmol/L K⁺, the expression of SsHAK2 in roots was down-regulated by Na⁺ (25 and 150 mmol/L) application, but up-regulated in leaves. The results therefore indicate that SsHAK2 might mediate K⁺ uptake and transport in S. salsa, and functioned differently in roots and leaves.

Keyword: Suaeda salsa; SsHAK2; clone; expression analysis

Show Figures

K⁺是植物中含量最为丰富的阳离子, 也是植物生长发育所必需的营养元素, 占植物总干重的2%10%^[1]。作为重要的无机渗透调节剂和酶促剂, K⁺在细胞渗透调节、膨压维持、细胞伸长、气孔运动、氮代谢、脂肪代谢、蛋白质合成及细胞膜的极化等过程中均发挥着重要作用^[2]。土壤盐碱化是引起植物体内K⁺亏缺现象的主要非生物因素之一, 土壤中高浓度的Na⁺会限制植物体内K⁺的吸收和转运, 使植物生长受抑, 甚至死亡^[3]。盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^{[4, 5, 6]}, 例如维持细胞内K⁺浓度的稳定。

盐地碱蓬(Suaeda salsa)又名蓬子菜、盐蒿, 是藜科碱蓬属一年生多汁草本盐生植物, 生于盐渍化土壤、湖滨、河岸和沿海地带^[7]。盐地碱蓬的幼嫩茎叶营养丰富, 是很好的绿色蔬菜, 也可用作动物饲料, 其种子中富含不饱和脂肪酸和亚油酸等, 可压榨食用油, 具有很好的经济价值; 盐地碱蓬在盐碱地的改良、污染地的植被修复和有毒金属的吸附方面效果显著, 具有很好的生态价值^[8]。盐地碱蓬可在400 mmol/L的盐浓度下完成其生活史, 是典型的盐碱地指示植物, 它通过将根部吸收的大量Na⁺运输至地上部并区域化进液泡以减轻Na⁺毒害, 也是极具代表性的积盐型植物^[9]。Mori等^[10]的研究发现, 盐地碱蓬K⁺、Na⁺选择性吸收能力(SA_k)随外界NaCl浓度(550 mmol/L)的增加显著提高, 且植株体内K⁺吸收速率和K⁺浓度能维持相对稳定。可见, 有效吸收K⁺并维持体内K⁺浓度的相对稳定可能是盐地碱蓬适应高盐生境的重要策略之一。

大量研究表明, KT/HAK/KUP转运蛋白、HKT转运蛋白和Shaker K⁺通道主要参与植物根系K⁺吸收过程^[11]。Shao等^[12]研究发现, 盐地碱蓬HKT转运蛋白家族成员SsHKT1; 1参与根系K⁺吸收过程, 在盐胁迫下维持植株体内K⁺营养稳态, 从而提高植物耐盐性。此外, Duan等^[13]克隆并鉴定了盐地碱蓬Shaker K⁺通道成员SsAKT1, 推测其可能参与盐地碱蓬根中的K⁺吸收过程, 并在耐盐性中发挥重要作用。可见, 盐地碱蓬体内存在多基因网络调控的K⁺吸收途径, 然而, KT/HAK/KUP家族成员的相关研究尚未见报道。

植物KT/HAK/KUP家族蛋白具有高亲和转运K⁺的特性, 与细菌中的K⁺吸收透性酶KUP及真菌中的高亲和性K⁺转运蛋白HAKs的同源性极高, 最早从大麦(Hordeum vulgare)中克隆到了该家族成员HvHAK1^[14]。在植物中, KT/HAK/KUP家族成员能够恢复酵母或细菌K⁺吸收缺陷突变体的K⁺吸收, 在植物根和地上部K⁺稳态平衡中发挥重要作用^[15]。此外, 亦有研究表明, KT/HAK/KUP家族部分成员可以介导Na⁺从土壤进入植物根部^{[16, 17]}。Wang等^[16]的研究发现, 拟南芥根中仅存在AtHKT1; 1和AtHAK5两条主要的低亲和性Na⁺吸收途径, 且当AtHKT1; 1功能丧失后, AtHAK5成为唯一主要的低亲和性Na⁺吸收途径, 并且在低K⁺条件下, 其作用更为重要。Zhang等^[17]对海滨碱蓬(Suaeda maritima)的研究发现, KT/HAK/KUP家族可能参与95200 mmol/L Na⁺条件下的植株根系低亲和性Na⁺吸收过程。可见, KT/HAK/KUP家族成员在植物K⁺、Na⁺吸收及转运过程中可能发挥重要作用。

本研究以盐地碱蓬为材料, 克隆KT/HAK/KUP家族成员基因SsHAK2的cDNA全长并对其进行生物信息学分析, 采用实时定量qPCR的方法分析SsHAK2在不同浓度K⁺ (0.01和2.5 mmol/L)和NaCl (25和150 mmol/L)处理下的表达模式, 以期为进一步研究SsHAK2的功能提供分子基础。

1 材料与方法

1.1 材料培养

2013年3月, 挑选籽粒饱满无缺损的盐地碱蓬种子, 用蒸馏水冲洗23遍, 在直径9 cm的培养皿上铺滤纸润湿后播种于其上, 种子密度约为4粒/cm², 28℃下催芽, 待发芽后, 挑选均匀一致的幼苗移至装有灭菌红沙的塑料穴盘(5 cm× 5 cm× 5 cm)中, 4株/穴, 在温室中浇灌调整后的Hoagland营养液进行植物材料培养。调整后的Hoagland营养液(pH=5.7)包括2 mmol/L KNO₃, 0.5 mmol/L KH₂PO₄, 0.5 mmol/L MgSO₄· 7H₂O, 0.25 mmol/L Ca(NO₃)₂· 4H₂O, 1.25 mmol/L CaCl₂· 2H₂O, 0.06 mmol/L Fe-citrate, 50 μ mol/L H₃BO₃, 10 μ mol/L MnCl₂· 4H₂O, 1.6 μ mol/L ZnSO₄· 7H₂O, 0.6 μ mol/L CuSO₄· 5H₂O, 0.05 μ mol/L Na₂MoO₄· 2H₂O。温室的昼夜温度为(28± 2)℃/(23± 2)℃, 光照16 h/d, 光强度约600 μ mol/(m²· s), 相对湿度60%80%。

1.2 SsHAK2的全长克隆

3周龄盐地碱蓬幼苗用0.01 mmol/L KCl处理6 h后取样, 参照Trizol试剂盒说明书(上海生工)从根中提取总RNA, 按照PrimeScript^TM 1st strand cDNA Synthesis Kit反转录试剂盒说明书(大连宝生物)合成cDNA第1链。通过对已知植物的HAK2类核苷酸序列进行同源性比较, 找出高度保守区域, 根据同源性高和简并性低的原则, 利用DNAMAN和Primer 6.0软件设计1对简并引物P₁和P₂ (表1), 用于扩增盐地碱蓬HAK2基因核心片段, 推测目的片段的长度为474 bp。根据已测得的核心片段序列设计5'端特异引物P₃ (外侧引物)、P₄(巢式引物) (表1)及3'端特异引物P₅ (外侧引物)、P₆ (巢式引物) (表1), 分别与GeneRacer^TM试剂盒(Invitrogen, USA)提供的5' Primer (5' P)、5' Nested Primer (5' NP)及3' Primer (3' P)、3' Nested Primer (3' NP)配对, 用于外侧和巢式PCR扩增, 推测5'cDNA和3'cDNA碱基序列的长度约为801 bp和1250 bp左右。引物由上海生工生物工程有限公司合成。PCR扩增反应体系:在200 μ L PCR管中依次加入10× PCR Buffer 5 μ L、25 mmol/L MgCl₂ 3.5 μ L、10 mmol/L dNTP 1 μ L、10 μ mol/L P₁ 1 μ L、10 μ mol/L P₂ 1 μ L、Taq DNA polymerase (5 U/μ L) 0.5 μ L、cDNA 2 μ L, 加纯水至50 μ L。核心片段PCR反应条件:94℃预变性2 min; 94℃变性30 s、56℃退火50 s、72℃延伸50 s, 30个循环; 最后72℃延伸10 min; 5'-RACE的PCR反应条件:94℃预变性2 min; 94℃变性30 s、58℃退火50 s、72℃延伸80 s, 30个循环; 最后72℃延伸10 min; 3'-RACE的PCR反应条件:94℃预变性2 min; 94℃变性30 s、58℃退火50 s、72℃延伸130 s, 30个循环; 最后72℃延伸10 min; PCR扩增产物用1.2%的琼脂糖凝胶检测, 目的片段的回收和纯化按照UNIQ-10柱式DNA胶回收试剂盒(上海生工)操作说明进行。回收的PCR产物连接到Trans^TM T5载体, 转化Trans^TM 1-T1感受态细胞, 送至上海生工测序。将这些片段拼接得到了SsHAK2的全长cDNA。

表1 引物序列 Table 1 The sequences of primers

1.3 生物信息学分析

在NCBI (www.ncbi.nlm.nih.gov/BLAST)网站上, 将测序得到的SsHAK2基因序列和氨基酸序列与GenBank数据库中序列进行Blastn和Blastp分析; 序列的翻译、开放阅读框分析在DNAMAN 6.0生物软件上进行, 氨基酸序列与其他序列的同源比较用Bioedit软件进行, 氨基酸的跨膜区预测用在线生物学软件TMHMM (http://www.cbs.dtu.dk/services/TMHMM/)进行。系统进化树用MEGA 6.0软件的最大似然法(Maximum likelihood method)进行构建。

1.4 SsHAK2的表达模式分析

采用实时定量qPCR方法分析盐地碱蓬SsHAK2的表达模式。材料处理方案如下:(1) 正常K⁺加盐处理:待盐地碱蓬幼苗生长至30 d, 向Hoagland营养液中加25或150 mmol/L NaCl处理0, 6, 24 h。(2) 低K⁺ (0.01 mmol/L)加盐处理:待盐地碱蓬幼苗生长至23 d时, 转入低K⁺ (0.01 mmol/L) (2 mmol/L KNO₃用2 mmol/L HNO₃代替, 0.5 mmol/L KH₂PO₄用0.5 mmol/L H₃PO₄代替, 加入0.01 mmol/L KCl, 用1 mol/L Tris调整营养液pH值为5.7)营养液中处理7 d, 随后向低K⁺ Hoagland营养液中加入25或150 mmol/L NaCl处理0, 6, 24 h。处理液每天更换。处理结束后, 分别收集根和叶, 经无菌水冲洗后, 置于消毒滤纸上迅速吸干表面水分, 于液氮中快速冷冻用于RNA的提取。不同处理下盐地碱蓬根和叶总RNA的提取参照Trizol试剂盒说明书(上海生工)进行, 按照PrimeScript^TM RT Master Mix (Perfect Real Time)试剂盒操作说明(大连宝生物)合成cDNA第1链。荧光定量qPCR反应在ABI 7500荧光定量PCR仪(ABI, America)中进行, 用于表达分析的特异性引物由大连宝生物工程有限公司设计, 分别为P₇和P₈ (表1), 待扩增目的片段长度为155 bp, 以SsACTIN (GenBank登录号为EU429457)为内参基因, 引物为A₁和A₂ (表1), 待扩增目的片段长度为111 bp。PCR反应条件如下:95℃ 30 s, 40个循环(95℃ 5 s, 60℃ 34 s)。采用2^{-△ △ ct}法^[18]计算SsHAK2的相对表达量, 以无处理的根样作为对照。每个处理设3个重复, 每个样品重复3次。

1.5 数据分析

采用SPSS 17.0对数据进行分析, 运用Duncan多重比较进行差异显著性分析, 最小差异显著性水平为P< 0.05。用Excel 2010、MEGA 6.0等软件作图。

2 结果与分析

2.1 盐地碱蓬SsHAK2全长cDNA的克隆及生物信息学分析

以总RNA反转录所得到的第1链cDNA为模板, 利用简并性引物P₁和P₂进行RT-PCR扩增。扩增产物经凝胶电泳检测发现约在474 bp处有1条亮带, 且上下无杂带(图1a), 测序结果经BLAST检测表明该cDNA片段与其他高等植物的HAK2序列具有较高的同源性(78%88%), 其中与空心莲子草(Alternanthera philoxeroides) ApKUP2基因(GenBank登录号:JN635515)核苷酸序列的同源性高达88%, 可见该片段是盐地碱蓬HAK2类基因片段。根据此核心片段进一步设计了特异引物进行5'端和3'端的RT-PCR扩增, 分别得到801 bp的5'RACE产物和1250 bp的3'RACE产物(图1b和c), 将5'端、核心片段和3'端的序列进行拼接, 得到全长2890 bp的cDNA (图2)。该cDNA包含一个228 bp的5'非翻译区(5'UTR)、2367 bp的开放阅读框(ORF)以及296 bp的3'非翻译区(3'UTR), 有12个高度保守的跨膜区 (图3), 编码788个氨基酸, 推测其分子量为107.3 kDa。本研究将其命名为SsHAK2。

	Figure Option View Download New Window
	图1 盐地碱蓬SsHAK2基因RT-PCR产物电泳检测图Fig.1 Agarose gel electrophoresis analysis of RT-PCR products of SsHAK2 in S. salsa

	Figure Option View Download New Window
	图2 盐地碱蓬K⁺转运蛋白SsHAK2的cDNA核酸序列及其推测的氨基酸序列Fig.2 Nucleotide sequences and deduced amino acid residues of SsHAK2 in S. salsa

	Figure Option View Download New Window
	图3 SsHAK2的跨膜区预测Fig.3 Transmembrane domains prediction of SsHAK2 in S. salsa

多重比较分析结果表明, 盐地碱蓬SsHAK2与其他植物的HAK2类转运蛋白具有很高的同源性(图4), 其中与甜菜(Beta vulgaris)、空心莲子草、冰叶日中花(Mesembryanthemum crystallinum)和葡萄(Vitis vinifera) HAK2的同源性分别为92%, 87%, 86%和80%。系统进化分析进一步表明, SsHAK2属于KT/HAK/KUP家族的亚族Ⅱ 成员, 与拟南芥AtKUP2、AtKUP6和AtKUP8的进化关系较近, 而与其他亚族成员的进化关系较远(图5)。

	Figure Option View Download New Window
	图4 盐地碱蓬SsHAK2与其他植物HAK2类氨基酸的多重比较Fig.4 Sequence alignment of SsHAK2 in S. salsa with HAK2-like proteins from higher plants

	Figure Option View Download New Window
	图5 盐地碱蓬SsHAK2与拟南芥和水稻KT/HAK/KUP家族成员的系统进化分析Fig.5 Phylogenetic analysis of SsHAK2 in S. salsa and members of KT/HAK/KUP family from Arabidopsis thaliana and Oryza sativa

2.2 盐地碱蓬SsHAK2的表达分析

将合成的盐地碱蓬cDNA用特异性表达引物P₇和P₈、A₁和A₂进行实时定量qPCR, 得到SsHAK2和SsACTIN的qPCR反应产物, 经电泳检测, 条带单一, 无引物二聚体(图6), 表明引物的特异性较高, 反应条件较好, 可用于SsHAK2的表达模式分析。

	Figure Option View Download New Window
	图6 实时定量qPCR产物电泳检测图Fig.6 Agarose gel electrophoresis analysis of real-time qPCR products

组织特异性分析结果表明, SsHAK2在盐地碱蓬根和叶中均有高丰度表达, 在不同浓度K⁺条件下, 叶中的表达量显著高于根中(图7)。此外, 不同浓度K⁺ (0.01和2.5 mmol/L)处理均诱导SsHAK2的表达, 但2.5 mmol/L K⁺处理下SsHAK2的表达显著高于低K处理(0.01 mmol/L) (图7)。

	Figure Option View Download New Window
	图7 SsHAK2的组织特异性分析Fig.7 Tissue specificity of SsHAK2 expression in S. salsa

进一步分析不同浓度K⁺下添加NaCl对SsHAK2表达的影响, 结果见图8。在含有2.5 mmol/L K⁺的介质中, 根和叶中SsHAK2的表达受25 mmol/L NaCl处理的显著诱导, 且随处理时间延长, 分别在24和6 h处表达量达到最高, 较各自对照(0 h)增加了25%和169%; 高Na⁺ (150 mmol/L)处理对根中SsHAK2的表达无影响, 但抑制了叶中的表达(图8A和B)。0.01 mmol/L K⁺条件下, 25和150 mmol/L NaCl的加入均抑制根中SsHAK2的表达, 且随处理时间延长, 在24 h处表达量较对照(0 h)分别降低38%和58%; 然而, 25和150 mmol/L NaCl的加入使叶中SsHAK2的表达显著增加, 且在处理6 h后, 较对照(0 h)分别增加了80%和51% (图8C和D)。以上结果表明, SsHAK2的表达受介质中K⁺和Na⁺的共同调节。

	Figure Option View Download New Window
	图8 不同浓度K⁺和Na⁺处理0、6和24 h后SsHAK2的相对表达量Fig. 8 Expression analysis of SsHAK2 in S. salsa under different K⁺ plus different Na⁺ concentrations for 0, 6 and 24 h

3 讨论

迄今为止, 已经从很多植物如大麦^[14]、玉米(Zea mays)^[19]、胡椒(Piper nigrum)^[20]、冰叶日中花^[21]、葡萄^[22]、番茄(Solanum lycopersicum)^[23]等中克隆到KT/HAK/KUP家族部分成员基因, 然而, 该家族的结构仍未研究清楚。虽然KT/HAK/KUP家族并不具备完全相同的功能保守域, 但在氨基酸序列上都含有1个明显的特征GVVYGDLGTSPLY (加粗字母为在所有基因中都十分保守)^[24]。本研究得到的SsHAK2氨基酸序列中同样包含这一保守序列(图4)。此外, Gupta等^[25]的研究发现, 水稻KT/HAK/KUP家族成员(除OsHAK22外)中都含有3个很保守的区域, 经过对比, 在盐地碱蓬中, 同样有这样的保守区域存在(图2), 表明SsHAK2与水稻中这些蛋白的结构和功能可能存在相似之处。研究表明, 高等植物中KT/HAK/KUP家族蛋白成员含有1014个跨膜区域^[26]。经过TMHMM在线软件分析可见, SsHAK2含有12个跨膜区(图3), 与大麦和水稻等中的研究结果一致。KT/HAK/KUP家族根据系统发生分析可划分为4个亚族:亚族Ⅰ 包括拟南芥AtHAK5、水稻OsHAK1和大麦HvHAK1等, 主要介导高亲和性K⁺转运过程; 大麦HvHAK2、拟南芥AtKUP1和AtKUP2属于亚族Ⅱ 成员, 在单子叶植物中经常转运低亲和性K⁺吸收, 而在双子叶植物中表现出不同的转运活性^[24]; 亚族Ⅲ 和Ⅳ 成员的研究相对较少。本研究中, 我们将拟南芥13个和水稻27个KT/HAK/KUP家族成员与盐地碱蓬SsHAK2进行了系统进化分析(图5), 结果显示, SsHAK2属于亚族Ⅱ 成员, 与拟南芥AtKUP2、水稻OsHAK8和OsHAK9位于同一进化分枝, 表明SsHAK2可能具有与AtKUP2等类似的K⁺转运功能和特征。以上结果均表明, 本研究克隆到的SsHAK2编码KT/HAK/KUP家族K⁺转运蛋白。

Ahn等^[27]对拟南芥KT/HAK/KUP家族13个成员进行组织表达特异性分析发现, 亚族Ⅱ 基因成员AtKUP1、AtKUP2、AtKUP4、AtKUP6和AtKUP8在根和叶中均有高丰度表达。Su等^[21]发现, 亚族Ⅱ 基因成员McHAK1和McHAK4在冰叶日中花根、茎叶中有高丰度表达。与这些结果相一致, 本研究中, SsHAK2在盐地碱蓬的根和叶中均表达(图7), 表明其可能在根和叶中发挥重要的作用。研究表明, KT/HAK/KUP家族的亚族Ⅱ 成员在不同的双子叶植物中表现出不同的转运活性。Rigas等^[28]发现, AtKUP4介导拟南芥高亲和性K⁺吸收过程。然而, AtKUP6和AtKUP2则被证实介导拟南芥低亲和性K⁺吸收过程^{[27, 29]}。更有趣的是, AtKUP1介导兼性K⁺吸收过程, 在酵母K⁺吸收缺陷突变株中表达时, 于不同K⁺浓度条件下均增加菌株的K⁺吸收能力, 当外部K⁺浓度在100200 μ mol/L之间时发生从高亲和性到低亲和性K⁺吸收的相变^[30]。然而, Osakabe等^[31]对拟南芥三突变体atkup2/6/8的研究发现, KT/HAK/KUP家族的亚族Ⅱ 成员AtKUP2、AtKUP6和AtKUP8可能参与拟南芥的K⁺外流过程。本研究中, 0.01和2.50 mmol/L K⁺处理均诱导根和叶中SsHAK2的表达(图7), 表明SsHAK2在盐地碱蓬体内K⁺吸收及转运过程中可能发挥重要作用。

Li等^[32]在研究K⁺营养对盐胁迫下盐地碱蓬幼苗生长影响的过程中, 发现100和400 mmol/L NaCl处理下, 提高介质中K⁺浓度可明显增加植株的水分、干鲜重、生长速率, 表明K⁺对盐地碱蓬的耐盐性至关重要。本研究初步分析了不同浓度K⁺和Na⁺处理下盐地碱蓬SsHAK2表达模式的变化(图8)。不同浓度Na⁺处理对盐地碱蓬SsHAK2表达的影响受介质中K⁺浓度的调节(图8), 表明SsHAK2可能参与盐处理下的盐地碱蓬体内K⁺吸收及转运过程。Rubio等^[33]对拟南芥的研究发现, K⁺缺失引起根中AtHAK5的表达下调, 却显著增加其在叶中的表达, 可见, AtHAK5可能在不同的组织部位中发挥不同的作用, 但是具体的原因尚不清楚。Su等^[21]研究发现, 高盐处理(400 mmol/L Na⁺)显著诱导冰叶日中花McHAK1和McHAK4的表达, 利用原位杂交在成熟根和叶的脉管组织中观测到极强的McHAK1和McHAK4的杂交信号, 推测它们可能会通过脉管组织中的装载/卸载影响植物K⁺的长距离运输, 从而调节根中的K⁺吸收过程。本研究中, 低K⁺ (0.01 mmol/L)条件下, 不同浓度Na⁺ (25和150 mmol/L)的添加抑制盐地碱蓬根中SsHAK2的表达, 却显著诱导叶中SsHAK2的表达; 2.5 mmol/L K⁺处理下, 不同浓度Na⁺ (25和150 mmol/L)的添加也引起根和叶中SsHAK2表达的变化不同。我们推测, 盐处理下, SsHAK2在盐地碱蓬根和叶中发挥不同的功能, 且可能在叶中发挥的作用更大, 具体机制有待更深一步研究。

综上所述, SsHAK2编码KT/HAK/KUP家族K⁺转运蛋白, 在根和叶中均有高丰度表达, 转录丰度受外界K⁺和Na⁺浓度的调节, 可能参与盐地碱蓬体内K⁺的吸收和转运过程, 且根和叶中可能发挥不同的功能。该研究为进一步分析SsHAK2在盐地碱蓬中的功能提供了分子基础。

The authors have declared that no competing interests exist.

参考文献

View Option

[1]	Clarkson D T, Hanson J B. The mineral nutrition of higher plants. Annual Review of Plant Physiology, 1980, 31(1): 239-298. [本文引用:1]
[2]	Maathuis F J. Physiological functions of mineral macronutrients. Current Opinion in Plant Biology, 2009, 12(3): 250-258. [本文引用:1]
[3]	Kronzucker H J, Coskun D, Schulze L M, et al. Sodium as nutrient and toxicant. Plant and Soil, 2013, 369(1-2): 1-23. [本文引用:1]
[4]	Zhou X R, Yue L J, Wang S M. Sodium compound fertilizer improved growth and drought tolerance of Zygophyllum xanthoxylum seedlings under drought stress. Acta Prataculturae Sinica, 2014, 23(6): 142-147. [本文引用:1]
[5]	Chong P F, Li H Y, Li Y. Physiological responses of seedling roots of the desert plant Reaumuria soongorica to drought stress. Acta Prataculturae Sinica, 2015, 24(1): 72-80. [本文引用:1]
[6]	Li Y, Liu S K. Cloing of a TPS gene and analysis of its function in stress tolerance in Puccinellia tenuiflora. Acta Prataculturae Sinica, 2015, 24(1): 99-106. [本文引用:1]
[7]	Kefu Z, Hai F, Ungar I. Survey of halophyte species in China. Plant Science, 2002, 163(3): 491-498. [本文引用:1]
[8]	Song J, Wang B S. Using euhalophytes to understand salt tolerance and to develop saline agriculture: Suaeda salsa as a promising model. Annals of Botany, 2015, 115(3): 541-553. [本文引用:1]
[9]	Wang S M, Zhang J L, Flowers T J. Low-affinity Na+ uptake in the halophyte Suaeda maritima. Plant Physiology, 2007, 145(2): 559-571. [本文引用:1]
[10]	Mori S, Suzuki K, Oda R, et al. Characteristics of Na+ and K+ absorption in Suaeda salsa (L. ) Pall. Soil Science and Plant Nutrition, 2011, 57(3): 377-386. [本文引用:1]
[11]	Nieves-Cordones M, Alemán F, Martínez V, et al. K+ uptake in plant roots. The systems involved, their regulation and parallels in other organisms. Journal of Plant Physiology, 2014, 171(9): 688-695. [本文引用:1]
[12]	Shao Q, Han N, Ding T, et al. SsHKT1;1 is a potassium transporter of the C₃ halophyte Suaeda salsa that is involved in salt tolerance. Functional Plant Biology, 2014, 41(8): 790-802. [本文引用:1]
[13]	Duan H R, Ma Q, Zhang J L, et al. The inward-rectifying K+ channel SsAKT1 is a cand idate involved in K+ uptake in the halophyte Suaeda salsa under saline condition. Plant and Soil, DOI: DOI:10.1007/S11104-015-2539-9. [本文引用:1]
[14]	Santa-Maria G E, Rubio F, Dubcovsky J, et al. The HAK1 gene of barley is a member of a large gene family and encodes a high-affinity potassium transporter. Plant Cell, 1997, 9(12): 2281-2289. [本文引用:2]
[15]	Nieves-Cordones M, Alemán F, Martínez V, et al. The Arabidopsis thaliana HAK5 K+ transporter is required for plant growth and K+ acquisition from low K+ solutions under saline conditions. Molecular Plant, 2010, 3(2): 326-333. [本文引用:1]
[16]	Wang Q, Guan C, Wang P, et al. AtHKT1;1 and AtHAK5 mediate low-affinity Na+ uptake in Arabidopsis thaliana under mild salt stress. Plant Growth Regulation, 2015, 75: 615-623. [本文引用:2]
[17]	Zhang J L, Flowers T J, Wang S M. Differentiation of low-affinity Na+ uptake pathways and kinetics of the effects of K+ on Na+ uptake in the halophyte Suaeda maritima. Plant and Soil, 2012, 368(1-2): 629-640. [本文引用:2]
[18]	Livak K J, Schmittgen T D. Analysis of relative gene expression data using real-time quantitative PCR and the 2^-ΔΔCT method. Methods, 2001, 25(4): 402-408. [本文引用:1]
[19]	Zhang Z, Zhang J, Chen Y, et al. Genome-wide analysis and identification of HAK potassium transporter gene family in maize (Zea mays L. ). Molecular Biology Reports, 2012, 39(8): 8465-8473. [本文引用:1]
[20]	Martinez-Cordero M A, Martinez V, Rubio F. Cloning and functional characterization of the high-affinity K+ transporter HAK1 of pepper. Plant Molecular Biology, 2004, 56(3): 413-421. [本文引用:1]
[21]	Su H, Golldack D, Zhao C S, et al. The expression of HAK-type K+ transporters is regulated in response to salinity stress in common ice plant. Plant Physiology, 2002, 129(4): 1482-1493. [本文引用:3]
[22]	Davies C, Shin R, Liu W, et al. Transporters expressed during grape berry (Vitis vinifera L. ) development are associated with an increase in berry size and berry potassium accumulation. Journal of Experimental Botany, 2006, 57(12): 3209-3216. [本文引用:1]
[23]	Nieves-Cordones M, Martinez-Cordero M A, Martinez V, et al. An NH₄⁺-sensitive component dominates high-affinity K⁺ uptake in tomato plants. Plant Science, 2007, 172(2): 273-280. [本文引用:1]
[24]	Véry A A, Nieves-Cordones M, Daly M, et al. Molecular biology of K+ transport across the plant cell membrane: What do we learn from comparison between plant species? Journal of Plant Physiology, 2014, 171(9): 748-769. [本文引用:2]
[25]	Gupta M, Qiu X, Wang L, et al. KT/HAK/KUP potassium transporters gene family and their whole-life cycle expression profile in rice (Oryza sativa). Molecular Genetics and Genomics, 2008, 280(5): 437-452. [本文引用:1]
[26]	Gierth M, Mäser P. Potassium transporters in plants——involvement in K+ acquisition, redistribution and homeostasis. FEBS Letters, 2007, 581(12): 2348-2356. [本文引用:1]
[27]	Ahn S J, Shin R, Schachtman D P. Expression of KT/KUP genes in Arabidopsis and the role of root hairs in K+ uptake. Plant Physiology, 2004, 134(3): 1135-1145. [本文引用:2]
[28]	Rigas S, Debrosses G, Haralampidis K, et al. TRH1 encodes a potassium transporter required for tip growth in Arabidopsis root hairs. Plant Cell, 2001, 13(1): 139-151. [本文引用:1]
[29]	Quintero F J, Blatt M R. A new family of K+ transporters from Arabidopsis that are conserved across phyla. FEBS Letters, 1997, 415(2): 206-211. [本文引用:1]
[30]	Fu H H, Luan S. AtKUP1: a dual-affinity K+ transporter from Arabidopsis. Plant Cell, 1998, 10(1): 63-73. [本文引用:1]
[31]	Osakabe Y, Arinaga N, Umezawa T, et al. Osmotic stress responses and plant growth controlled by potassium transporters in Arabidopsis. Plant Cell, 2013, 25: 609-624. [本文引用:1]
[32]	Li P H, Chen M, Wang B S. Effect of K+ nutrition on growth and activity of leaf tonoplast V-H+-ATPase and V-H+-PPase of Suaeda salsa under NaCl stress. Acta Botanica Sinica, 2002, 44(4): 433-440. [本文引用:1]
[33]	Rubio F, Santa-Maria G E, Rodriguez-Navarro A. Cloning of Arabidopsis and barley cDNAs encoding HAK potassium transporters in root and shoot cells. Physiologia Plantarum, 2000, 109(1): 34-43. [本文引用:1]
[4]	周向睿, 岳利军, 王锁民. 钠复合肥提高多浆旱生植物霸王幼苗生长及抗旱性. 草业学报, 2014, 23(6): 142-147. [本文引用:1]
[5]	种培芳, 李航逸, 李毅. 荒漠植物红砂根系对干旱胁迫的生理响应. 草业学报, 2015, 24(1): 72-80. [本文引用:1]
[6]	李莹, 柳参奎. 碱茅6-磷酸海藻糖合成酶基因的克隆及其耐逆性分析. 草业学报, 2015, 24(1): 99-106. [本文引用:1]
[32]	李平华, 陈敏, 王宝山. K+营养对NaCl胁迫下盐地碱蓬生长及叶片液泡膜V-H+-ATPase和V-H+-PPase活性的影响. 植物学报, 2002, 44(4): 433-440. [本文引用:1]

1980

0.0

... K⁺是植物中含量最为丰富的阳离子,也是植物生长发育所必需的营养元素,占植物总干重的2%10%^[1] ...

2009

0.0

. 2009, 12(3):250-258 DOI:10.1016/j.pbi.2009.04.003

Physiological functions of mineral macronutrients.

Maathuis F J.

University of York, Biology Department Area 9, York, United Kingdom. fjm3@york.ac.uk

Plants require calcium, magnesium, nitrogen, phosphorous, potassium and sulfur in relatively large amounts (>0.1% of dry mass) and each of these so-called macronutrients is essential for a plant to complete its life cycle. Normally, these minerals are taken up by plant roots from the soil solution in ionic form with the metals Ca(2+), Mg(2+) and K(+) present as free cations, P and S as their oxyanions phosphate (PO(4)(3-)) and sulfate (SO(4)(2-)) and N as anionic nitrate (NO(3)(-)) or cation ammonium (NH(4)(+)). Recently, important progress has been made in identifying transport and regulatory mechanisms for macronutrients and the mechanisms of uptake and distribution. These and the main physiological roles of each nutrient will be discussed.

PMID: 19473870

... 作为重要的无机渗透调节剂和酶促剂,K⁺在细胞渗透调节、膨压维持、细胞伸长、气孔运动、氮代谢、脂肪代谢、蛋白质合成及细胞膜的极化等过程中均发挥着重要作用^[2] ...

2013

0.0

... 土壤盐碱化是引起植物体内K⁺亏缺现象的主要非生物因素之一,土壤中高浓度的Na⁺会限制植物体内K⁺的吸收和转运,使植物生长受抑,甚至死亡^[3] ...

2014

0.0

. 2014, 23(6):142-147 DOI:doi:10.11686/cyxb20140618

钠复合肥提高多浆旱生植物霸王幼苗生长及抗旱性

周向睿, 岳利军, 王锁民

In this study, the effect on growth and drought tolerance of the succulent xerophyte Zygophyllum xanthoxylum under drought stress of a Na compound fertilizer that contains appropriate amounts of nitrogen, phosphorous and sodium was studied in a pot experiment. Compared with control and diammonium phosphate treatments, the application of Na compound fertiliser increased plant height by 30% and 12%, leaf area by 97% and 40%, leaf relative organic weight by 10% and 7%, dry weight by 57% and 38%, water content by 347% and 55%, net photosynthetic rate ( P n ) by 145% and 24%, primary light energy conversion of PSⅡ by 6% and 4%, photosynthetic electron transport rate by 16% and 8%, quantum yield by 14% and 5%, but decreased leaf malondialdehyde concentration by 58% and 18%, and penetrability of membranes by 50% and 26% respectively under drought stress. Meanwhile, the application of Na compound fertilizer significantly increased water use efficiency by 4%, compared with control pots. These results suggested that Na compound fertilizer could promote growth and enhance drought tolerance of Z. xanthoxylum , and the effectiveness was greater than diammonium phosphate.

本研究采用室内盆栽实验,探讨了一种由适量的氮、磷和钠等元素组成的钠复合肥对多浆旱生植物霸王幼苗生长及抗旱性的影响。结果表明,干旱胁迫下施钠复合肥后,与对照和磷酸二铵肥相比,霸王幼苗的株高增加了30%和12%、叶面积增加了97%和40%、叶相对有机干重增加了10%和7%、叶干重增加了57%和38%、叶含水量增加了347%和55%,净光合速率增加了145%和24%、PSⅡ原初光能转换效率增加了6%和4%、电子传递速率增加了16%和8%、量子产额增加了14%和5%,而叶MDA含量下降了58%和18%、相对质膜透性下降了50%和26%。另外,与对照相比,施钠复合肥后霸王幼苗水分利用效率提高了4%。这些结果说明,钠复合肥能够促进干旱胁迫下霸王幼苗的生长、提高其抗旱性,并且效果优于磷酸二铵肥。

... 盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^[4,5,6],例如维持细胞内K⁺浓度的稳定 ...

2015

0.0

. 2015, 24(1):72-80 DOI:doi:10.11686/cyxb20150110

荒漠植物红砂根系对干旱胁迫的生理响应

种培芳, 李航逸, 李毅

The physiological responses of seedling roots to drought stress were investigated in the desert plant Reaumuria soongorica from two provenances: highly drought resistant (Wuwei) and weakly drought resistant (Lanzhou). Under drought stress, root vigor, relative permeability of plasma (RPP), contents of proline (Pro),soluble sugars (SS),soluble protein (SP),malondialdehyde (MAD) and activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)were measured with two-year nursery stocks. Grey correlative analysis was used to analyse drought resistance and its correlation with indexes of roots. Root vigor decreased significantly under drought stress, while RPP and the contents of MDA, Pro, SS and SP, the activities of SOD, POD and CAT of roots increased significantly. Germplasm of highly drought-resistant provenance (Wuwei) was more sensitive to drought stress than germplasm of weakly drought-resistant provenance (Lanzhou). The grey correlative degrees for root vigor, RPP and Pro and drought resistance were greater than 0.9. However, R. soongorica enhanced drought resistance through a wider series of physiological variations, beyond these three.

以抗旱性不同的红砂2个种源2年生苗木为试材,通过盆栽实验,测定干旱胁迫后红砂苗木根系的活力、膜透性(RPP)、脯氨酸 (Pro)、可溶性糖 (SS)、可溶性蛋白 (SP)、丙二醛(MDA)含量和抗氧化物酶系(SOD、POD、CAT)的活性变化,并通过灰色关联度法分析了各指标与红砂根系抗旱性的关系。结果表明,水分胁迫导致红砂根系活力下降,膜透性RPP和膜质过氧化产物MDA 含量增加,渗透调节物质Pro含量、SS含量和SP含量明显增加,抗衰老酶SOD、POD和CAT活性显著升高,且抗性强的种源比抗性弱的种源对干旱胁迫的生理生化反应更明显。红砂根系的RPP、Pro和根系活力的关联度虽然都大于0.9,但红砂根系并不是完全通过这几种机理适应干旱,而是发生了一系列适应性的生理变化,以提高其根系的抗旱性。

... 盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^[4,5,6],例如维持细胞内K⁺浓度的稳定 ...

2015

0.0

. 2015, 24(1):99-106 DOI:doi:10.11686/cyxb20150113

碱茅6-磷酸海藻糖合成酶基因的克隆及其耐逆性分析

李莹, 柳参奎

In this study, a 6-trehalose phosphate synthase gene ( TPS ) fragment, 1153 bp in length, was isolated through NaCl and NaHCO 3 screening from Puccinellia tenuiflora yeast cDNA library. A 3'-end cDNA amplification technique was used to clone PutTPS . The full-length cDNA is 3358 bp containing an open reading frame (ORF) of 882 amino acids. Multiple alignment analysis based on amino acids of TPS proteins of rice, Arabidopsis , maize, and other higher plants revealed that the amino acid homologies were about 60% to 90%.The tissue expression patterns of P. tenuiflora PutTPS and the expression under NaCl and NaHCO 3 stress were further investigated by northern blot. Also the recombinant yeast INVScI (pYES 2 - PutTPS ) and control INVScI (pYES 2 ) were subjected to salt, drought, osmotic and oxidative stresses. PutTPS was highly expressed in roots and flowers; in roots and leaves, NaCl and NaHCO 3 induced up-regulated expression of PutTPS genes and the recombinant yeast cells showed higher stress resistance than control cells. It was also found that the TPS from alkali grass contributes to salt, drought, osmotic and oxidative resistance.The present study indicated that there was a relationship between PutTPS expression and multiple stresses, and PutTPS may play an important role for P. tenuiflora during adaption to environmental abiotic stress.

从碱茅酵母cDNA文库中经过NaCl、NaHCO 3 筛选,均得到长为1153 bp碱茅6-磷酸海藻糖合成酶基因( PutTPS )片段。通过3'End cDNA amplification方法获得基因缺失的3'序列,该基因全长3358 bp,编码882个氨基酸。氨基酸序列比较结果表明, PutTPS 氨基酸序列与水稻、拟南芥、玉米等多种高等植物的TPS蛋白的同源性高达60%90%。利用Northern blot技术,研究该基因的组织表达模式及NaCl、NaHCO 3 胁迫处理下基因的表达模式变化;同时对转pYES 2 - PutTPS 基因酵母菌株进行盐、碱、氧化胁迫、渗透胁迫处理,观察其在逆境下的生存表现。结果表明, PutTPS 具有组织表达特异性,其中在根和花中表达量最大;NaCl、NaHCO 3 会诱导 PutTPS 基因在根和叶中的上调表达;同时重组酵母菌株对盐碱、氧化、渗透胁迫及干旱等逆境的适应能力显著增强。以上研究结果表明,碱茅 PutTPS 基因与逆境之间具有一定的应答关系,并在植物适应环境逆境过程中起着重要的作用。

... 盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^[4,5,6],例如维持细胞内K⁺浓度的稳定 ...

2002

0.0

... 盐地碱蓬(Suaeda salsa)又名蓬子菜、盐蒿,是藜科碱蓬属一年生多汁草本盐生植物,生于盐渍化土壤、湖滨、河岸和沿海地带^[7] ...

2015

0.0

. 2015, 115(3):541-553 DOI:10.1093/aob/mcu194

Using euhalophytes to understand salt tolerance and to develop saline agriculture: Suaeda salsa as a promising model.

Song J , Wang B S.

Key Laboratory of Plant Stress, College of Life Science, Shandong Normal University, Jinan 250014, PR China songjieever@163.com.

As important components in saline agriculture, halophytes can help to provide food for a growing world population. In addition to being potential crops in their own right, halophytes are also potential sources of salt-resistance genes that might help plant breeders and molecular biologists increase the salt tolerance of conventional crop plants. One especially promising halophyte is Suaeda salsa, a euhalophytic herb that occurs both on inland saline soils and in the intertidal zone. The species produces dimorphic seeds: black seeds are sensitive to salinity and remain dormant in light under high salt concentrations, while brown seeds can germinate under high salinity (e.g. 600 mm NaCl) regardless of light. Consequently, the species is useful for studying the mechanisms by which dimorphic seeds are adapted to saline environments. S. salsa has succulent leaves and is highly salt tolerant (e.g. its optimal NaCl concentration for growth is 200 mm). A series of S. salsa genes related to salt tolerance have been cloned and their functions tested: these include SsNHX1, SsHKT1, SsAPX, SsCAT1, SsP5CS and SsBADH. The species is economically important because its fresh branches have high value as a vegetable, and its seed oil is edible and rich in unsaturated fatty acids. Because it can remove salts and heavy metals from saline soils, S. salsa can also be used in the restoration of salinized or contaminated saline land.

PMID: 25288631

... 盐地碱蓬在盐碱地的改良、污染地的植被修复和有毒金属的吸附方面效果显著,具有很好的生态价值^[8] ...

2007

0.0

. 2007, 145(2):559-571

Low-affinity Na+ uptake in the halophyte Suaeda maritima.

Wang S M , Zhang J L , Flowers T J.

School of Pastoral Agriculture Science and Technology, Key Laboratory of Grassland Agro-ecosystem, Ministry of Agriculture, Lanzhou University, Lanzhou 730000, People's Republic of China.

Na(+) uptake by plant roots has largely been explored using species that accumulate little Na(+) into their shoots. By way of contrast, the halophyte Suaeda maritima accumulates, without injury, concentrations of the order of 400 mM NaCl in its leaves. Here we report that cAMP and Ca(2+) (blockers of nonselective cation channels) and Li(+) (a competitive inhibitor of Na(+) uptake) did not have any significant effect on the uptake of Na(+) by the halophyte S. maritima when plants were in 25 or 150 mM NaCl (150 mM NaCl is near optimal for growth). However, the inhibitors of K(+) channels, TEA(+) (10 mM), Cs(+) (3 mM), and Ba(2+) (5 mM), significantly reduced the net uptake of Na(+) from 150 mM NaCl over 48 h, by 54%, 24%, and 29%, respectively. TEA(+) (10 mM), Cs(+) (3 mM), and Ba(2+) (1 mm) also significantly reduced (22)Na(+) influx (measured over 2 min in 150 mM external NaCl) by 47%, 30%, and 31%, respectively. In contrast to the situation in 150 mm NaCl, neither TEA(+) (1-10 mM) nor Cs(+) (0.5-10 mM) significantly reduced net Na(+) uptake or (22)Na(+) influx in 25 mM NaCl. Ba(2+) (at 5 mm) did significantly decrease net Na(+) uptake (by 47%) and (22)Na(+) influx (by 36% with 1 mM Ba(2+)) in 25 mM NaCl. K(+) (10 or 50 mM) had no effect on (22)Na(+) influx at concentrations below 75 mM NaCl, but the influx of (22)Na(+) was inhibited by 50 mM K(+) when the external concentration of NaCl was above 75 mM. The data suggest that neither nonselective cation channels nor a low-affinity cation transporter are major pathways for Na(+) entry into root cells. We propose that two distinct low-affinity Na(+) uptake pathways exist in S. maritima: Pathway 1 is insensitive to TEA(+) or Cs(+), but sensitive to Ba(2+) and mediates Na(+) uptake under low salinities (25 mM NaCl); pathway 2 is sensitive to TEA(+), Cs(+), and Ba(2+) and mediates Na(+) uptake under higher external salt concentrations (150 mM NaCl). Pathway 1 might be mediated by a high-affinity K transporter-type transporter and pathway 2 by an AKT1-type channel.

PMID: 17766398

... 盐地碱蓬可在400 mmol/L的盐浓度下完成其生活史,是典型的盐碱地指示植物,它通过将根部吸收的大量Na⁺运输至地上部并区域化进液泡以减轻Na⁺毒害,也是极具代表性的积盐型植物^[9] ...

2011

0.0

... Mori等^[10]的研究发现,盐地碱蓬K⁺、Na⁺选择性吸收能力(SA_k)随外界NaCl浓度(550 mmol/L)的增加显著提高,且植株体内K⁺吸收速率和K⁺浓度能维持相对稳定 ...

2014

0.0

. 2014, 171(9):688-695 DOI:10.1016/j.jplph.2013.09.021

K+ uptake in plant roots. The systems involved, their regulation and parallels in other organisms.

Nieves-Cordones M , Alem#cod#x000e1;n F , Mart#cod#x000ed;nez V

Departamento de Nutrición Vegetal, CEBAS-CSIC, Campus de Espinardo, Murcia 30100, Spain.

Potassium (K(+)) is an essential macronutrient for plants. It is taken into the plant by the transport systems present in the plasma membranes of root epidermal and cortical cells. The identity of these systems and their regulation is beginning to be understood and the systems of K(+) transport in the model species Arabidopsis thaliana remain far better characterized than in any other plant species. Roots can activate different K(+) uptake systems to adapt to their environment, important to a sessile organism that needs to cope with a highly variable environment. The mechanisms of K(+) acquisition in the model species A. thaliana are the best characterized at the molecular level so far. According to the current model, non-selective channels are probably the main pathways for K(+) uptake at high concentrations (>10mM), while at intermediate concentrations (1mM), the inward rectifying channel AKT1 dominates K(+) uptake. Under lower concentrations of external K(+) (100μM), AKT1 channels, together with the high-affinity K(+) uptake system HAK5 contribute to K(+) acquisition, and at extremely low concentrations (<10μM) the only system capable of taking up K(+) is HAK5. Depending on the species the high-affinity system has been named HAK5 or HAK1, but in all cases it fulfills the same functions. The activation of these systems as a function of the K(+) availability is achieved by different mechanisms that include phosphorylation of AKT1 or induction of HAK5 transcription. Some of the characteristics of the systems for root K(+) uptake are shared by other organisms, whilst others are specific to plants. This indicates that some crucial properties of the ancestral of K(+) transport systems have been conserved through evolution while others have diverged among different kingdoms.

PMID: 24810767

... 大量研究表明,KT/HAK/KUP转运蛋白、HKT转运蛋白和Shaker K⁺通道主要参与植物根系K⁺吸收过程^[11] ...

2014

0.0

... Shao等^[12]研究发现,盐地碱蓬HKT转运蛋白家族成员SsHKT1 ...

0.0

... 此外,Duan等^[13]克隆并鉴定了盐地碱蓬Shaker K⁺通道成员SsAKT1,推测其可能参与盐地碱蓬根中的K⁺吸收过程,并在耐盐性中发挥重要作用 ...

1997

0.0

. 1997, 9(12):2281-2289

The HAK1 gene of barley is a member of a large gene family and encodes a high-affinity potassium transporter.

Santa-Maria G E , Rubio F , Dubcovsky J

Departamento de Biotecnología, Escuela Técnica Superior de Ingenieros Agrónomos, Madrid, Spain.

The high-affinity K+ uptake system of plants plays a crucial role in nutrition and has been the subject of extensive kinetic studies. However, major components of this system remain to be identified. We isolated a cDNA from barley roots, HvHAK1, whose translated sequence shows homology to the Escherichia coli Kup and Schwanniomyces occidentalis HAK1 K+ transporters. HvHAK1 conferred high-affinity K+ uptake to a K(+)-uptake-deficient yeast mutant exhibiting the hallmark characteristics of the high-affinity K+ uptake described for barley roots. HvHAK1 also mediated low-affinity Na+ uptake. Another cDNA (HvHAK2) encoding a polypeptide 42% identical to HvHAK1 was also isolated. Analysis of several genomes of Triticeae indicates that HvHAK1 belongs to a multigene family. Translated sequences from bacterial DNAs and Arabidopsis, rice, and possibly human cDNAs show homology to the Kup-HAK1-HvHAK1 family of K+ transporters.

PMID: 9437867

... 植物KT/HAK/KUP家族蛋白具有高亲和转运K⁺的特性,与细菌中的K⁺吸收透性酶KUP及真菌中的高亲和性K⁺转运蛋白HAKs的同源性极高,最早从大麦(Hordeum vulgare)中克隆到了该家族成员HvHAK1^[14] ...

... 3 讨论迄今为止,已经从很多植物如大麦^[14]、玉米(Zea mays)^[19]、胡椒(Piper nigrum)^[20]、冰叶日中花^[21]、葡萄^[22]、番茄(Solanum lycopersicum)^[23]等中克隆到KT/HAK/KUP家族部分成员基因,然而,该家族的结构仍未研究清楚 ...

2010

0.0

. 2010, 3(2):326-333 DOI:10.1093/mp/ssp102

The Arabidopsis thaliana HAK5 K+ transporter is required for plant growth and K+ acquisition from low K+ solutions under saline conditions.

Nieves-Cordones M , Alem#cod#x000e1;n F , Mart#cod#x000ed;nez V

Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, CSIC, Campus de Espinardo, 30100 Murcia, Spain.

K(+) uptake in the high-affinity range of concentrations and its components have been widely studied. In Arabidposis thaliana, the AtHAK5 transporter and the AtAKT1 channel have been shown to be the main transport proteins involved in this process. Here, we study the role of these two systems under two important stress conditions: low K(+) supply or the presence of salinity. T-DNA insertion lines disrupting AtHAK5 and AtAKT1 are employed for long-term experiments that allow physiological characterization of the mutant lines. We found that AtHAK5 is required for K(+) absorption necessary to sustain plant growth at low K(+) in the absence as well as in the presence of salinity. Salinity greatly reduced AtHAK5 transcript levels and promoted AtAKT1-mediated K(+) efflux, resulting in an important impairment of K(+) nutrition. Although having a limited capacity, AtHAK5 plays a major role for K(+) acquisition from low K(+) concentrations in the presence of salinity.

PMID: 20028724

... 在植物中,KT/HAK/KUP家族成员能够恢复酵母或细菌K⁺吸收缺陷突变体的K⁺吸收,在植物根和地上部K⁺稳态平衡中发挥重要作用^[15] ...

2015

0.0

... 此外,亦有研究表明,KT/HAK/KUP家族部分成员可以介导Na⁺从土壤进入植物根部^[16,17] ...

... Wang等^[16]的研究发现,拟南芥根中仅存在AtHKT1 ...

2012

0.0

... 此外,亦有研究表明,KT/HAK/KUP家族部分成员可以介导Na⁺从土壤进入植物根部^[16,17] ...

... Zhang等^[17]对海滨碱蓬(Suaeda maritima)的研究发现,KT/HAK/KUP家族可能参与95200 mmol/L Na⁺条件下的植株根系低亲和性Na⁺吸收过程 ...

2001

0.0

. 2001, 25(4):402-408

Analysis of relative gene expression data using real-time quantitative PCR and the 2^{-#cod#x00394;#cod#x00394;CT} method.

Livak K J , Schmittgen T D.

Applied Biosystems, Foster City, California 94404, USA.

The two most commonly used methods to analyze data from real-time, quantitative PCR experiments are absolute quantification and relative quantification. Absolute quantification determines the input copy number, usually by relating the PCR signal to a standard curve. Relative quantification relates the PCR signal of the target transcript in a treatment group to that of another sample such as an untreated control. The 2(-Delta Delta C(T)) method is a convenient way to analyze the relative changes in gene expression from real-time quantitative PCR experiments. The purpose of this report is to present the derivation, assumptions, and applications of the 2(-Delta Delta C(T)) method. In addition, we present the derivation and applications of two variations of the 2(-Delta Delta C(T)) method that may be useful in the analysis of real-time, quantitative PCR data.

PMID: 11846609

... ct法^[18]计算SsHAK2的相对表达量,以无处理的根样作为对照 ...

2012

0.0

. 2012, 39(8):8465-8473 DOI:10.1007/s11033-012-1700-2

Genome-wide analysis and identification of HAK potassium transporter gene family in maize (Zea mays L.).

Zhang Z , Zhang J , Chen Y

Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China. happyzzb@126.com

The high-affinity K(+) (HAK) transporter gene family constitutes the largest family that functions as potassium transporter in plant and is important for various cellular processes of plant life. In spite of their physiological importance, systematic analyses of ZmHAK genes have not yet been investigated. In this paper, we indicated the isolation and characterization of ZmHAK genes in whole-genome wide by using bioinformatics methods. A total of 27 members (ZmHAK1-ZmHAK27) of this family were identified in maize genome. ZmHAK genes were distributed in all the maize 10 chromosomes. These genes expanded in the maize genome partly due to tandem and segmental duplication events. Multiple alignment and motif display results revealed major maize ZmHAK proteins share all the three conserved domains. Phylogenetic analysis indicated ZmHAK family can be divided into six subfamilies. Putative cis-elements involved in Ca(2+) response, abiotic stress adaption, light and circadian rhythms regulation and seed development were observed in the promoters of ZmHAK genes. Expression data mining suggested maize ZmHAK genes have temporal and spatial expression pattern. In all, these results will provide molecular insights into the potassium transporter research in maize.

PMID: 22711305

2004

0.0

. 2004, 56(3):413-421

Cloning and functional characterization of the high-affinity K+ transporter HAK1 of pepper.

Martinez-Cordero M A , Martinez V , Rubio F

Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del, Segura-CSIC, Apartado de Correos 164, Murcia, 30100, Spain.

High-affinity K+ uptake in plants plays a crucial role in K+ nutrition and different systems have been postulated to contribute to the high-affinity K+ uptake. The results presented here with pepper (Capsicum annum) demonstrate that a HAK1-type transporter greatly contributes to the high-affinity K+ uptake observed in roots. Pepper plants starved of K+ for 3 d showed high-affinity K+ uptake (Km of 6 microM K+) that was very sensitive to NH and their roots expressed a high-affinity K+ transporter, CaHAK1, which clusters in group I of the KT/HAK/KUP family of transporters. When expressed in yeast ( Saccharomyces cerevisiae ), CaHAK1 mediated high-affinity K+ and Rb+ uptake with Km values of 3.3 and 1.9 microM, respectively. Rb+ uptake was competitively inhibited by micromolar concentrations of NH and Cs+, and by millimolar concentrations of Na+.

PMID: 15604753

2002

0.0

. 2002, 129(4):1482-1493

The expression of HAK-type K+ transporters is regulated in response to salinity stress in common ice plant.

Su H , Golldack D , Zhao C S

Department of Plant Sciences, University of Arizona, Tucson, 85721, USA.

Four transcripts homologous to K(+) transporters of the HAK/KT/KUP family have been characterized from the common ice plant (Mesembryanthemum crystallinum). We report tissue-specific expression of McHAK1 and McHAK4 transcripts abundant in roots, leaves, and stems. McHAK2 was predominantly present in stems and McHAK3 in root tissues. By in situ hybridizations, the McHAKs showed signals in the leaf vascular bundles, mesophyll, and epidermal cells as well as in epidermal bladder cells. In mature roots, transcripts were mainly localized to the vasculature, and in differentiated root tips, the strongest signals were obtained from the epidermis. Expression of McHAK1, McHAK2, and McHAK4 complemented a yeast mutant defective in low- and high-affinity K(+) uptake. Growth of the yeast mutant was restored at low-millimolar K(+) concentrations and was inhibited by Rb(+) and Cs(+) but was not affected by Na(+). Transcript levels of McHAK1 and McHAK4 increased by K(+) starvation and by salt stress of 400 mM NaCl in leaves and roots. Expression of McHAK2 and McHAK3 was stimulated in leaves and was transiently induced in roots in response to high salinity with prestress transcript levels restored in salt-adapted plants. We discuss possible roles for such transporters in ion homeostasis at high salinity.

PMID: 12177462

... Su等^[21]发现,亚族#cod#x02161 ...

... Su等^[21]研究发现,高盐处理(400 mmol/L Na⁺)显著诱导冰叶日中花McHAK1和McHAK4的表达,利用原位杂交在成熟根和叶的脉管组织中观测到极强的McHAK1和McHAK4的杂交信号,推测它们可能会通过脉管组织中的装载/卸载影响植物K⁺的长距离运输,从而调节根中的K⁺吸收过程 ...

2006

0.0

. 2006, 57(12):3209-3216

Transporters expressed during grape berry (Vitis vinifera L.) development are associated with an increase in berry size and berry potassium accumulation.

Davies C , Shin R , Liu W

CSIRO Plant Industry and Cooperative Research Centre for Viticulture, PO Box 350, Glen Osmond, SA 5064, Australia. Christopher.Davies@csiro.au

Potassium accumulation is essential for grapevine (Vitis vinifera L.) growth and development, but excessive levels in berries at harvest may reduce wine quality particularly for red wines. In addition to decreasing the free acid levels, potassium also combines with tartaric acid to form largely insoluble potassium bitartrate. This precipitates during winemaking and storage, resulting in an increase in wine pH that is associated with negative impacts on wine colour, flavour, and microbiological stability. For these reasons, a better understanding of potassium transport and accumulation within the vine and berries is important for producing fruit with improved winemaking characteristics. Here two genes encoding KUP/KT/HAK-type potassium transporters that are expressed in grape berries are described. Their function as potassium transporters was demonstrated by complementation of an Escherichia coli mutant. The two transporters are expressed most highly in the berry skin during the first phase of berry development (pre-veraison), with similar patterns in two grapevine varieties. The timing and location of expression of these transporters are consistent with an involvement in potassium accumulation in grape berries.

PMID: 16936223

2007

0.0

2014

0.0

. 2014, 171(9):748-769 DOI:10.1016/j.jplph.2014.01.011

Molecular biology of K+ transport across the plant cell membrane: What do we learn from comparison between plant species?

V#cod#x000e9;ry A A , Nieves-Cordones M , Daly M

Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France. Electronic address: very@supagro.inra.fr.

Cloning and characterizations of plant K(+) transport systems aside from Arabidopsis have been increasing over the past decade, favored by the availability of more and more plant genome sequences. Information now available enables the comparison of some of these systems between species. In this review, we focus on three families of plant K(+) transport systems that are active at the plasma membrane: the Shaker K(+) channel family, comprised of voltage-gated channels that dominate the plasma membrane conductance to K(+) in most environmental conditions, and two families of transporters, the HAK/KUP/KT K(+) transporter family, which includes some high-affinity transporters, and the HKT K(+) and/or Na(+) transporter family, in which K(+)-permeable members seem to be present in monocots only. The three families are briefly described, giving insights into the structure of their members and on functional properties and their roles in Arabidopsis or rice. The structure of the three families is then compared between plant species through phylogenic analyses. Within clusters of ortologues/paralogues, similarities and differences in terms of expression pattern, functional properties and, when known, regulatory interacting partners, are highlighted. The question of the physiological significance of highlighted differences is also addressed.

PMID: 24666983

... 虽然KT/HAK/KUP家族并不具备完全相同的功能保守域,但在氨基酸序列上都含有1个明显的特征GVVYGDLGTSPLY (加粗字母为在所有基因中都十分保守)^[24] ...

... 成员,在单子叶植物中经常转运低亲和性K⁺吸收,而在双子叶植物中表现出不同的转运活性^[24] ...

2008

0.0

. 2008, 280(5):437-452 DOI:10.1007/s00438-008-0377-7

KT/HAK/KUP potassium transporters gene family and their whole-life cycle expression profile in rice (Oryza sativa).

Gupta M , Qiu X , Wang L

National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China.

KT/HAK/KUP potassium transporter protein-encoding genes constitute a large family in the plant kingdom. The KT/HAK/KUP family is important for various physiological processes of plant life. In this study, we identified 27 potential KT/HAK/KUP family genes in rice (Oryza sativa) by database searching. Analysis of these KT/HAK/KUP family members identified three conserved motifs with unknown functions, and 11-15 trans-membrane segments, most of which are conserved. A total of 144 putative cis-elements were found in the 2 kb upstream region of these genes, of which a Ca2+-responsive cis-element, two light-responsive cis-elements, and a circadian-regulated cis-element were identified in the majority of the members, suggesting regulation of these genes by these signals. A comprehensive expression analysis of these genes was performed using data from microarrays hybridized with RNA samples of 27 tissues covering the entire life cycle from three rice genotypes, Minghui 63, Zhenshan 97, and Shanyou 63. We identified preferential expression of two OsHAK genes in stamen at 1 day before flowering compared with all the other tissues. OsHAK genes were also found to be differentially upregulated or downregulated in rice seedlings subjected to treatments with three hormones. These results would be very useful for elucidating the roles of these genes in growth, development, and stress response of the rice plant.

PMID: 18810495

... 此外,Gupta等^[25]的研究发现,水稻KT/HAK/KUP家族成员(除OsHAK22外)中都含有3个很保守的区域,经过对比,在盐地碱蓬中,同样有这样的保守区域存在(图2),表明SsHAK2与水稻中这些蛋白的结构和功能可能存在相似之处 ...

2007

0.0

. 2007, 581(12):2348-2356

Potassium transporters in plants#cod#x02014;#cod#x02014;involvement in K+ acquisition, redistribution and homeostasis.

Gierth M , M#cod#x000e4;ser P.

Universität zu Köln, Institut für Botanik II, Gyrhofstrasse 15, 50931 Köln, Germany. markus.gierth@uni-koeln.de

Potassium is a major plant nutrient which has to be accumulated in great quantity by roots and distributed throughout the plant and within plant cells. Membrane transport of potassium can be mediated by potassium channels and secondary potassium transporters. Plant potassium transporters are present in three families of membrane proteins: the K(+) uptake permeases (KT/HAK/KUP), the K(+) transporter (Trk/HKT) family and the cation proton antiporters (CPA). This review will discuss the contribution of members of each family to potassium acquisition, redistribution and homeostasis.

PMID: 17397836

... 研究表明,高等植物中KT/HAK/KUP家族蛋白成员含有1014个跨膜区域^[26] ...

2004

0.0

. 2004, 134(3):1135-1145

Expression of KT/KUP genes in Arabidopsis and the role of root hairs in K+ uptake.

Ahn S J , Shin R , Schachtman D P.

Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, Missouri 63132, USA.

Potassium (K(+)) is the most abundant cation in plants and is required for plant growth. To ensure an adequate supply of K(+), plants have multiple mechanisms for uptake and translocation. However, relatively little is known about the physiological role of proteins encoded by a family of 13 genes, named AtKT/KUP, that are involved in K(+) transport and translocation. To begin to understand where and under what conditions these transporters function, we used reverse transcription-PCR to determine the spatial and temporal expression patterns of each AtKT/KUP gene across a range of organs and tested whether selected AtKT/KUP cDNAs function as K(+) transporters in Escherichia coli. Many AtKT/KUPs were expressed in roots, leaves, siliques, and flowers of plants grown under K(+)-sufficient conditions (1.75 mm KCl) in hydroponic culture. AtHAK5 was the only gene in this family that was up-regulated upon K(+) deprivation and rapidly down-regulated with resupply of K(+). Ten AtKT/KUPs were expressed in root hairs, but only five were expressed in root tip cells. This suggests an important role for root hairs in K(+) uptake. The growth and rubidium (Rb(+)) uptake of two root hair mutants, trh1-1 (tiny root hairs) and rhd6 (root hair defective), were studied to determine the contribution of root hairs to whole-plant K(+) status. Whole-plant biomass decreased in the root hair mutants only when K(+) concentrations were low; Rb(+) (used as a tracer for K(+)) uptake rates were lower in the mutants at all Rb(+) concentrations. Seven genes encoding AtKUP transporters were expressed in E. coli (AtKT3/KUP4, AtKT/KUP5, AtKT/KUP6, AtKT/KUP7, AtKT/KUP10, AtKT/KUP11, and AtHAK5), and their K(+) transport function was demonstrated.

PMID: 14988478

... Ahn等^[27]对拟南芥KT/HAK/KUP家族13个成员进行组织表达特异性分析发现,亚族#cod#x02161 ...

... 然而,AtKUP6和AtKUP2则被证实介导拟南芥低亲和性K⁺吸收过程^{[27, 29]} ...

2001

0.0

. 2001, 13(1):139-151

TRH1 encodes a potassium transporter required for tip growth in Arabidopsis root hairs.

Rigas S , Debrosses G , Haralampidis K

Laboratory of Molecular Biology, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.

Root hair initiation involves the formation of a bulge at the basal end of the trichoblast by localized diffuse growth. Tip growth occurs subsequently at this initiation site and is accompanied by the establishment of a polarized cytoplasmic organization. Arabidopsis plants homozygous for a complete loss-of-function tiny root hair 1 (trh1) mutation were generated by means of the T-DNA-tagging method. Trichoblasts of trh1 plants form initiation sites but fail to undergo tip growth. A predicted primary structure of TRH1 indicates that it belongs to the AtKT/AtKUP/HAK K(+) transporter family. The proposed function of TRH1 as a K(+) transporter was confirmed in (86)Rb uptake experiments, which demonstrated that trh1 plants are partially impaired in K(+) transport. In line with these results, TRH1 was able to complement the trk1 potassium transporter mutant of Saccharomyces, which is defective in high-affinity K(+) uptake. Surprisingly, the trh1 phenotype was not restored when mutant seedlings were grown at high external potassium concentrations. These data demonstrate that TRH1 mediates K(+) transport in Arabidopsis roots and is responsible for specific K(+) translocation, which is essential for root hair elongation.

PMID: 11158535

... Rigas等^[28]发现,AtKUP4介导拟南芥高亲和性K⁺吸收过程 ...

1997

0.0

. 1997, 415(2):206-211

A new family of K+ transporters from Arabidopsis that are conserved across phyla.

Quintero F J , Blatt M R.

Laboratory of Plant Physiology and Biophysics, University of London, Wye College, UK. Quintero@wye.ac.uk

Transport of K+ in higher plants, as in bacteria and fungi, is mediated by two broad classes of transport proteins that operate in the millimolar and micromolar K+ concentration ranges. A search of the Expressed Sequence Tag database using amino acid consensus sequences for the K+ transporters HAK1 from Schwanniomyces and Kup of Escherichia coli yielded two homologous sequences for Arabidopsis. Cloning and sequencing of these genes gave single open reading frames for the putative transporters, AtKT1 and AtKT2, with predicted molecular weights of 79 and 88 kDa. The predicted gene products showed a high degree of homology at the amino acid level (56% identity) and exhibited significant hydrophobic stretches in their N-terminal halves, consistent with 12 membrane-spanning, alpha-helical domains. Database searches using AtKT1 and AtKT2 identified 10 additional sequences in Arabidopsis as well as additional homologous sequences in the plant species Oryza and Allium, the bacterium Lactococcus lactis, and in Homo sapiens. Expression of AtKT2 rescued growth on low millimolar [K+] in Saccharomyces cerevisiae carrying deletions for the genes encoding the K+ transporters TRK1 and TRK2. Rescue was associated with a 2-fold stimulation of Rb+ uptake and was sensitive to competition with external Na+ but not to extracellular pH, indicating that the gene encodes a low-affinity K+ transporter. These and additional results suggest that AtKT1 and AtKT2 belong to a superfamily of cation transporters that have been conserved through evolution.

PMID: 9350997

... 然而,AtKUP6和AtKUP2则被证实介导拟南芥低亲和性K⁺吸收过程^{[27, 29]} ...

1998

0.0

... mol/L之间时发生从高亲和性到低亲和性K⁺吸收的相变^[30] ...

2013

0.0

. 2013, 25:609-624 DOI:10.1105/tpc.112.105700

Osmotic stress responses and plant growth controlled by potassium transporters in Arabidopsis.

Osakabe Y , Arinaga N , Umezawa T

Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.

Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K(+) uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K(+) channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using (86)radioactive rubidium ion ((86)Rb(+)) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses.

PMID: 23396830

... 然而,Osakabe等^[31]对拟南芥三突变体atkup2/6/8的研究发现,KT/HAK/KUP家族的亚族#cod#x02161 ...

2002

0.0

... Li等^[32]在研究K⁺营养对盐胁迫下盐地碱蓬幼苗生长影响的过程中,发现100和400 mmol/L NaCl处理下,提高介质中K⁺浓度可明显增加植株的水分、干鲜重、生长速率,表明K⁺对盐地碱蓬的耐盐性至关重要 ...

2000

0.0

... Rubio等^[33]对拟南芥的研究发现,K⁺缺失引起根中AtHAK5的表达下调,却显著增加其在叶中的表达,可见,AtHAK5可能在不同的组织部位中发挥不同的作用,但是具体的原因尚不清楚 ...

2014

0.0

. 2014, 23(6):142-147 DOI:doi:10.11686/cyxb20140618

钠复合肥提高多浆旱生植物霸王幼苗生长及抗旱性

周向睿, 岳利军, 王锁民

... 盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^[4,5,6],例如维持细胞内K⁺浓度的稳定 ...

2015

0.0

. 2015, 24(1):72-80 DOI:doi:10.11686/cyxb20150110

荒漠植物红砂根系对干旱胁迫的生理响应

种培芳, 李航逸, 李毅

... 盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^[4,5,6],例如维持细胞内K⁺浓度的稳定 ...

2015

0.0

. 2015, 24(1):99-106 DOI:doi:10.11686/cyxb20150113

碱茅6-磷酸海藻糖合成酶基因的克隆及其耐逆性分析

李莹, 柳参奎

... 盐生植物在长期进化过程中形成了多种有效机制来抵御盐胁迫^[4,5,6],例如维持细胞内K⁺浓度的稳定 ...

2002

0.0