OsJAR1 Contributes Mainly to Biosynthesis of the Stress-Induced Jasmonoyl-Isoleucine Involved in Defense Responses in Rice
OsJAR1 Contributes Mainly to Biosynthesis of the Stress-Induced Jasmonoyl-Isoleucine Involved in Defense Responses in Rice
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DOI：
10.1271/bbb.130272
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发表时间：
2013-07-01
影响因子：
1.6
通讯作者：
Okada, Kazunori
中科院分区：
文献类型：
--
作者：
Shimizu, Takafumi;Miyamoto, Koji;Okada, Kazunori
茉莉酸在植物生长和逆境反应中起着关键作用，如防御病原体的攻击。jasmonoyl -异亮氨酸（JA-Ile）是茉莉酸盐的一种主要活性形式，被认为在植物防御反应中起关键作用，但JA-Ile在水稻防御反应中的作用，包括植物抗毒素的产生，在很大程度上仍然未知。在这里，我们发现OsJAR1主要通过使用OsJAR1 Tos17突变体来促进应激诱导的JA-Ile产生。osjar1突变体在ja诱导的ja应答基因表达和植物抗毒素产生中受损，这些缺陷在遗传上得到恢复。在重金属胁迫和稻瘟病菌胁迫下，内源JA-Ile对黄酮类植物抗菌素sakururetin的产生是必需的，而对二萜类植物抗菌素的产生则不是必需的。osjar1突变体也被发现比亲本野生型更容易受到爆炸真菌的影响。这些结果表明，JA-Ile的产生对水稻的防御反应有贡献，对胁迫诱导的樱花素的产生有很大影响。
Jasmonate plays key roles in plant growth and stress responses, as in defense against pathogen attack. Jasmonoyl-isoleucine (JA-Ile), a major active form of jasmonates, is thought to play a pivotal role in plant defense responses, but the involvement of JA-Ile in rice defense responses, including phytoalexin production, remains largely unknown. Here we found that OsJAR1 contributes mainly to stress-induced JA-Ile production by the use of an osjar1 Tos17 mutant. The osjar1 mutant was impaired in JA-induced expression of JA-responsive genes and phytoalexin production, and these defects were restored genetically. Endogenous JA-Ile was indispensable to the production of a flavonoid phytoalexin, sakuranetin, but not to that of diterpenoid phytoalexins in response to heavy metal stress and the rice blast fungus. The osjar1 mutant was also found to be more susceptible to the blast fungus than the parental wild type. These results suggest that JA-Ile production makes a contribution to rice defense responses with a great impact on stress-induced sakuranetin production.