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 <i>Arabidopsis thaliana</i>, 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 <i>PR1.1</i> and <i>PR3</i> 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 <i>Arabidopsis</i>.

茉莉酸（jasmonic acid，JA）信号通路在植物生长发育、繁殖以及应对生物与非生物胁迫的多样过程中发挥关键作用。目前学界对JA信号通路的认知大多源自双子叶模式植物拟南芥（Arabidopsis thaliana），而小麦中的相关研究认知仍较为有限。本研究以10日龄面包小麦幼苗为材料，采用实时定量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及72 h时，41个与JA信号通路相关的基因的表达量。本次检测的基因此前已被报道参与小麦地上部与根部的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。本研究结果表明，MeJA处理对小麦幼苗地上部的调控效果显著强于根部，且JA通路依赖的防御基因的显著表达调控多发生于MeJA处理后72 h。数据显示，小麦地上部中有22个基因的表达受MeJA处理的显著影响；然而小麦根部仅PR1.1与PR3两个基因在MeJA处理后24 h出现显著差异表达，其余基因在根部的表达量波动幅度较大。本研究不仅为小麦JA信号通路提供了标记基因，未来的研究可聚焦于解析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同源基因。