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草业学报 ›› 2021, Vol. 30 ›› Issue (5): 42-51.DOI: 10.11686/cyxb2020220

• 研究论文 • 上一篇    下一篇

硼对根瘤菌胞外多糖和吲哚乙酸分泌的调控研究

陈永岗(), 康文娟, 吴芳, 阿芸, 师尚礼(), 张翠梅, 李自立   

  1. 甘肃农业大学草业学院,甘肃 兰州 730070
  • 收稿日期:2020-05-13 修回日期:2020-06-29 出版日期:2021-05-20 发布日期:2021-04-16
  • 通讯作者: 师尚礼
  • 作者简介:Corresponding author. E-mail: shishl@ gsau.edu.cn
    陈永岗(1988-),男,甘肃定西人,在读硕士。E-mail: 1547558857@qq.com
  • 基金资助:
    国家农业产业技术体系项目(CARS-34)

Boron promotes secretion of extracellular polysaccharides and indole-3-acetic acid by Rhizobium

Yong-gang CHEN(), Wen-juan KANG, Fang WU, Yun A, Shang-li SHI(), Cui-mei ZHANG, Zi-li LI   

  1. College of Grassland Science,Gansu Agricultural University,Lanzhou 730070,China
  • Received:2020-05-13 Revised:2020-06-29 Online:2021-05-20 Published:2021-04-16
  • Contact: Shang-li SHI

摘要:

为探究硼促进根瘤菌gn5f产胞外多糖和吲哚乙酸的调控机制,采用Label free蛋白质定量技术,分析硼对根瘤菌gn5f差异蛋白表达的影响。结果表明,最适硼浓度为100 mg?L-1,该浓度可以显著促进根瘤菌gn5f胞外多糖和吲哚乙酸(IAA)的分泌,同时最适浓度处理根瘤菌gn5f共鉴定到54个差异表达蛋白,其中7个上调蛋白,47个下调蛋白。生物信息学分析表明,这些差异蛋白与能量产生及转化,脂肪酸β氧化、糖异生、氨基酸代谢及各种代谢酶类等有关。100 mg?L-1硼促进根瘤菌gn5f产胞外多糖和IAA的机制为:硼通过促进烟酰胺腺嘌呤二核苷酸(NAD)依赖性琥珀酸半醛脱氢酶、乙酰辅酶A合成酶、琥珀酸半醛脱氢酶(NADP+)等差异蛋白上调,继而促进丙酮酸代谢、γ-氨基丁酸(GABA)旁路代谢,谷氨酸代谢等与三羧酸循环有关的代谢通路,为胞外多糖合成提供能量及所需要的各种前体物质(D-半乳糖残基,D-葡萄糖残基以及D-葡萄糖醛酸等),进而促进胞外多糖的合成;硼促进色氨酸合成,色氨酸在相关酶的作用下经吲哚-3-乙酰胺(IAM)或吲哚-3-丙酮酸途径合成IAA,继而促进IAA的合成。

关键词: 硼, 根瘤菌, 胞外多糖, IAA, 蛋白质组学

Abstract:

The aim of this study was to determine how boron promotes the production of extracellular polysaccharides and indole-3-acetic acid (IAA) by the Rhizobium strain gn5f. A label-free protein quantitative technique was used to analyze the effect of boron on the protein expression of Rhizobium strain gn5f. The results showed that 100 mg?L-1 was the optimum boron concentration for inducing polysaccharide and IAA production by Rhizobium strain gn5f. A comparison between the control (no boron) and the 100 mg?L-1 boron treatment identified 54 differentially expressed proteins; 7 up-regulated proteins and 47 down-regulated proteins. Bioinformatics analysis showed that these differentially expressed proteins were related to energy production and conversion, fatty acid β-oxidation, gluconeogenesis, amino acid metabolism, and various metabolic processes. The proposed mechanism by which boron promotes the production of extracellular polysaccharides and IAA by Rhizobium gn5f is as follows: boron up-regulates NAD-dependent succinate-semialdehyde dehydrogenase, acetyl-coenzyme A synthetase, and succinate-semialdehyde dehydrogenase (NADP+), which promote metabolic pathways related to the tricarboxylic acid cycle such as pyruvate metabolism, γ-aminobutyric acid (GABA) bypass metabolism, and glutamate metabolism. The energy and various carbohydrates (D-galactose and D-glucose residues, D-glucuronic acid) provided by these metabolic pathways promote the synthesis of extracellular polysaccharides. Finally, IAA is synthesized from tryptophan via indole-3-acetamide (IAM) or indole-3-pyruvate under the action of related enzymes, and boron contributes to this process by improving tryptophan synthesis.

Key words: boron, rhizobia, extracellular polysaccharides, IAA, proteomics