Functions of plant hormones involved in the formation of nodules on the roots of legumes

植物激素在豆科植物根部根瘤形成中的作用

• 批准号: 10660105
• 负责人: YAMANE Hisakazu
• 金额: $ 2.3万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660105/
• 关键词: Glycine max L.; Bradyrhizobium elkanii; transposon; indole-3-acetic acid; indole-3-pyruvate decarboxylase; jasmonic acid; flavonoids; phenylalanine ammonia-lyase; 共生; 生合成; インドールピルビン酸デカルボキシラー

We have isolated the 11 low-indole-3-acetic acid (IAA)-producing mutants of Bradyrhizobium elkanii by Tn5 mutagenesis. The amounts of IAA produced by the respective mutants were 2.2 to 13.6 % of that in the wild type. It was also shown by resting cell reactions that biosynthetic step to convert indole-3-pyrubic acid to indole-3-acetaldehyde was blocked in all the mutants. This suggests that indole-3-pyruvate decarboxylase (IPDC) functions as a key enzyme in the IAA biosynthesis of B. elkanii. When some of the low-IAA-producing mutants were applied to the leguminous plant siratro, the number of noduration on the roots reduced 10 to 60% of that when the wild type was applied, indicating that IAA produced by B. elkanii plays impotant roles on the formation of root nodules. On the other hand, it has been shown that flavonoids secreted from the roots of host plants induced the expression of nod genes in the nodule bacteria. We speculated that nod factors causes promotion of flavonoid biosynthesis via jasmonate biosynthesisas as well as the early events of nodulation in the host plants. To investigate this hypothesis, we developed a bioassay system using suspension-cultured cells of Glycine max to examine the effect of jasmonic acid or nod factors on phenylalanine ammonia-lyase (PAL) activity, which is a key enzyme in the flavonoid biosynthesis.

通过Tn5诱变，筛选出11株低产吲哚-3-乙酸(IAA)的伊氏慢生根瘤菌。各突变体产生的IAA量是野生型的2.2~13.6%。静息细胞反应也表明，所有突变株都阻止了将吲哚-3-丙酮酸转化为吲哚-3-乙醛的生物合成步骤。这表明吲哚-3-丙酮酸脱羧酶(IPDC)是黑曲霉IAA生物合成过程中的一个关键酶。将一些IAA产量低的突变体应用于豆科植物siratro时，根部无持续时间的数量比使用野生型时减少了10%~60%，表明B.elkanii产生的IAA在根瘤的形成中起着重要作用。另一方面，从寄主植物根中分泌的黄酮类化合物诱导了结瘤细菌中nod基因的表达。我们推测结瘤因子通过茉莉酸的生物合成促进了类黄酮的生物合成，并导致了寄主植物结瘤的早期事件。为了验证这一假设，我们建立了一个生物测定系统，利用悬浮培养的大豆细胞来检测茉莉酸或结节因子对苯丙氨酸解氨酶(PAL)活性的影响，苯丙氨酸解氨酶(PAL)是类黄酮生物合成中的一个关键酶。

项目成果

Ken Yagi 他7名: "Isolation and characterization of low-indole-3-acetic acid-producing mutants from Bradyrhizobium elkanii"Bioscience,Biotechnology and Biochemistry. 64(印刷中). (2000)

Ken Yagi 和其他 7 人：“来自 Bradyrhizobium elkanii 的低吲哚 3-乙酸生产突变体的分离和表征”《生物科学、生物技术和生物化学》64（出版中）。

Ken Yagi 他7名: "Isolation and characterization of low-indole-3-acetic acid-producing mutants from Bradyrhizobium elkanil"Bioscience, Tiotechnology, and Biochemistry. 64(印刷中). (2000)

Ken Yagi 和其他 7 人：“Bradyrhizobium elkanil 低吲哚 3-乙酸产生突变体的分离和表征”Bioscience、Tiotechnology 和 Biochemistry 64（出版中）。

Ken Yagi, Taku Matsumoto, Tetsuya Chujo, Hideaki Nojiri, Toshio Omori, Kiwamu Minamisawa, Makoto Nishiyama, and Hisakazu Yamane: "Isolation and characterization of low-indole-3-acetic acid-producing mutants of Bradyrhizobium elkanii"Bioscience, Biotechnol

Ken Yagi、Taku Matsumoto、Tetsuya Chujo、Hideaki Nojiri、Toshio Omori、Kiwamu Minamisawa、Makoto Nishiyama 和 Hisakazu Yamane：“Bradyrhizobium elkanii 低吲哚 3-乙酸生产突变体的分离和表征”生物科学、生物技术