Development of marker genes for jasmonic acid signaling in shoots and roots of wheat

The jasmonic acid (JA) signaling pathway plays key roles in a diverse array of plant development, reproduction, and responses to biotic and abiotic stresses. Most of our understanding of the JA signaling pathway derives from the dicot model plant Arabidopsis thaliana, while corresponding knowledge in wheat is somewhat limited. In this study, the expression of 41 genes implicated in the JA signaling pathway has been assessed on 10 day-old bread wheat seedlings, 24 h, 48 h, and 72 h after methyl-jasmonate (MeJA) treatment using quantitative real-time PCR. The examined genes have been previously reported to be involved in JA biosynthesis and catabolism, JA perception and signaling, and pathogen defense in wheat shoots and roots. This study provides evidence to suggest that the effect of MeJA treatment is more prominent in shoots than roots of wheat seedlings, and substantial regulation of the JA pathway-dependent defense genes occurs at 72 h after MeJA treatment. Results show that the expression of 22 genes was significantly affected by MeJA treatment in wheat shoots. However, only PR1.1 and PR3 were significantly differentially expressed in wheat roots, both at 24 h post-MeJA treatment, with other genes showing large variation in their gene expression in roots. While providing marker genes on JA signaling in wheat, future work may focus on elucidating the regulatory function of JA-modulated transcription factors, some of which have well-studied potential orthologs in Arabidopsis.茉莉酸（jasmonic acid, JA）信号通路在植物多样的生长发育、繁殖过程以及对生物和非生物胁迫的响应中发挥关键调控作用。目前学界对JA信号通路的认知大多来源于双子叶模式植物拟南芥（Arabidopsis thaliana），而小麦中的相关研究认知则相对有限。本研究以10日龄普通小麦幼苗为实验材料，采用定量实时PCR（quantitative real-time PCR）技术，检测了茉莉酸甲酯（methyl-jasmonate, MeJA）处理后24 h、48 h和72 h时，41个与JA信号通路相关基因的表达水平。本次检测的基因此前已被报道参与小麦地上部与根系的JA生物合成与代谢、JA感知与信号转导以及病原体防御过程。本研究结果显示，MeJA处理对小麦幼苗地上部的调控效果显著优于根系，且JA通路依赖的防御基因在处理72 h后出现显著表达调控。数据分析表明，小麦地上部中有22个基因的表达受MeJA处理的显著影响。然而，小麦根系中仅PR1.1和PR3两个基因在MeJA处理后24 h出现显著差异表达，其余基因在根系中的表达波动幅度较大。本研究不仅为小麦JA信号通路提供了候选标记基因，后续相关研究可聚焦于解析JA调控的转录因子的调控功能，其中部分转录因子在拟南芥中已有研究较为深入的潜在直系同源基因（orthologs）。