Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
New Phytol. 2010 Apr;186(2):471-83. doi: 10.1111/j.1469-8137.2010.03183.x. Epub 2010 Feb 8.
*The Arabidopsis MYB96 transcription factor plays a role in abscisic acid (ABA)-mediated drought response. Notably, anthocyanins accumulate in the activation-tagging myb96-1d line, suggesting a role of MYB96 in biotic and abiotic stress responses in plants. Here, we investigate the role of MYB96 in salicylic acid (SA) biosynthesis and plant defense and explore the mechanisms underlying the ABA-SA interaction. *myb96-1d and myb96-1 were subject to pathogen infection assays, and expression of SA biosynthetic and defense genes was examined. myb96-1d was crossed with the NahG transgenic plants to investigate the role of MYB96 in ABA regulation of SA biosynthesis. *Whereas myb96-1d exhibited an enhanced disease resistance, myb96-1 was susceptible to pathogen infection. A subset of pathogenesis-related (PR) genes was up-regulated in myb96-1d. However, PR transcript abundances were reduced in myb96-1d X NahG. Interestingly, a SA biosynthetic gene SALICYLIC ACID INDUCTION DEFICIENT2 (SID2) was up-regulated, and concentrations of SA and SA-beta-glucoside (SAG) were elevated in myb96-1d. In addition, the inductive effects of abiotic stresses on SID2 were reduced in aba3-1. *Our observations indicate that MYB96-mediated ABA signals enhance plant disease resistance by inducing SA biosynthesis. It is envisioned that MYB96 is a molecular link that mediates ABA-SA crosstalks.
拟南芥 MYB96 转录因子在脱落酸（ABA）介导的干旱响应中发挥作用。值得注意的是，在激活标签 myb96-1d 系中积累了花色素苷，这表明 MYB96 在植物的生物和非生物胁迫反应中起作用。在这里，我们研究了 MYB96 在水杨酸（SA）生物合成和植物防御中的作用，并探讨了 ABA-SA 相互作用的机制。对 myb96-1d 和 myb96-1 进行了病原体感染分析，并检查了 SA 生物合成和防御基因的表达。myb96-1d 与 NahG 转基因植物杂交，以研究 MYB96 在 ABA 调节 SA 生物合成中的作用。myb96-1d 表现出增强的抗病性，而 myb96-1 对病原体感染敏感。myb96-1d 中一组与发病相关（PR）基因被上调。然而，myb96-1d X NahG 中 PR 转录物丰度降低。有趣的是，水杨酸合成基因 SALICYLIC ACID INDUCTION DEFICIENT2（SID2）上调，myb96-1d 中 SA 和 SA-β-葡萄糖苷（SAG）的浓度升高。此外，在 aba3-1 中，非生物胁迫对 SID2 的诱导作用降低。我们的观察表明，MYB96 介导的 ABA 信号通过诱导 SA 生物合成增强植物的抗病性。可以预见，MYB96 是一种分子连接，介导 ABA-SA 串扰。
