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草业学报 ›› 2025, Vol. 34 ›› Issue (6): 139-153.DOI: 10.11686/cyxb2024303

• 研究论文 • 上一篇    

蒺藜苜蓿MtBMI1基因克隆及抗旱性分析

赵媛媛1,2(), 蒲小剑1,2, 徐成体1,2, 王伟1,2, 傅云洁1,2   

  1. 1.青海大学畜牧兽医科学院,青海 西宁 810016
    2.农业农村部西北耕地保育及边际土地改良企业重点实验室,青海 德令哈 817000
  • 收稿日期:2024-07-31 修回日期:2024-09-20 出版日期:2025-06-20 发布日期:2025-04-03
  • 通讯作者: 赵媛媛
  • 作者简介:赵媛媛(1991-),女,山东威海人,助理研究员,博士。E-mail: 18893147262@163.com
    赵媛媛(1991-),女,山东威海人,助理研究员,博士。E-mail: 18893147262@163.com
  • 基金资助:
    省部共建三江源生态与高原农牧业国家重点实验室自主课题(2024-ZZ-16);青海省重大科技专项(2023-NK-A3);青海大学青年科研基金(2023-QNY-6)

Cloning of the MtBMI1 gene from Medicago truncatula and its role in drought tolerance

Yuan-yuan ZHAO1,2(), Xiao-jian PU1,2, Cheng-ti XU1,2, Wei WANG1,2, Yun-jie FU1,2   

  1. 1.Academy of Animal Science and Veterinary Medicine,Qinghai University,Xining 810016,China
    2.Northwest Key Laboratory of Cultivated Land Conservation and Marginal Land Improvement,Ministry of Agriculture and Rural Affairs,Delingha 817000,China
  • Received:2024-07-31 Revised:2024-09-20 Online:2025-06-20 Published:2025-04-03
  • Contact: Yuan-yuan ZHAO

摘要:

干旱不利于植物的正常生长、发育及繁殖,是造成农作物及饲草产量降低的重要因素之一。BMI1蛋白作为PcG蛋白复合体中唯一介导组蛋白泛素化的成员,在参与植物对外界非生物胁迫响应的表观遗传调控中发挥重要的作用。以蒺藜苜蓿为材料,克隆得到PcG家族成员MtBMI1,该基因全长5386 bp,编码429个氨基酸,具有zf-C3HC4和RAWUL两个保守的功能结构域。系统进化树分析表明该基因与菜豆PvBMI1-1和大豆GmBMI1-1亲缘关系更接近。烟草表皮亚细胞定位结果表明该基因编码的蛋白定位在细胞核上。GUS化学染色结果表明在成熟的拟南芥花序及柱头、花茎和果柄中具有较强的MtBMI1启动子表达活性。将MtBMI1在拟南芥中过表达进行功能分析,结果表明转基因拟南芥H2AK119ub组蛋白含量相比野生型显著(P<0.05)升高,同时干旱处理后的转基因株系相比野生型产生明显的失水表型,且根长、根鲜重和地上鲜重显著(P<0.05)低于野生型,丙二醛含量显著(P<0.05)高于野生型。以上结果表明MtBMI1在蒺藜苜蓿干旱胁迫响应中发挥负调控作用,该研究可为进一步揭示蒺藜苜蓿响应干旱胁迫的表观遗传调控机制提供理论依据。

关键词: 蒺藜苜蓿, MtBMI1, 基因克隆, 抗旱性

Abstract:

Drought significantly impedes the normal growth, development, and reproduction of plants, and has emerged as a pivotal factor contributing to the decline in crop and forage yields. The BMI1 protein, a key component of the Polycomb Group (PcG) protein complex that mediates histone ubiquitination, is crucial for the epigenetic regulation of plant responses to abiotic stresses. This study reports the cloning of MtBMI1, which encodes a member of the PcG family, from Medicago truncatula. Our analyses showed that the MtBMI1 gene sequence spans 5386 base pairs and encodes a protein comprising 429 amino acids, featuring two functional domains: zf-C3HC4 and RAWUL. Phylogenetic analyses revealed close relationships between MtBMI1 and PvBMI1-1 of Phaseolus vulgaris and GmBMI1-1 of Glycine max. A subcellular localization analysis in tobacco epidermal cells confirmed the nuclear localization of the MtBMI1 protein. Moreover, GUS staining analyses revealed robust activity of the MtBMI1 promoter in the mature inflorescence, stigma, flower, stem, and pedicel of Arabidopsis. Functional analysis via overexpression in Arabidopsis demonstrated that the histone H2AK119ub content was significantly higher (P<0.05) in transgenic lines than in wild type. Under drought stress, transgenic lines exhibited pronounced water-loss phenotypes, with reduced root length, root fresh weight, and aboveground fresh weight (P<0.05), and elevated levels of malondialdehyde (P<0.05), compared with the wild type. These findings suggest that MtBMI1 exerts a negative regulatory effect on M. truncatula’s response to drought stress. The results of this study offer insights into the epigenetic mechanisms underlying drought stress tolerance in this model legume species.

Key words: Medicago truncatula, MtBMI1, gene cloning, drought resistance