National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Graduate School of Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
Mol Plant. 2010 May;3(3):539-48. doi: 10.1093/mp/ssp107. Epub 2010 Jan 6.
Plants have evolved complex mechanisms to defend themselves against pathogens. It has been shown that several defense responses are influenced by light, and the red/far-red light photoreceptor phytochromes (PHY) modulate plant defense responses in Arabidopsis. Blue light receptor cryptochromes (CRY) work together with PHY to regulate many light-controlled responses, including photomorphogenesis, floral induction, and entrainment of the circadian clock. We report here that the Arabidopsis blue light photoreceptor CRY1 positively regulates inducible resistance to Pseudomonas syringae under continuous light conditions. By challenging plants with P. syringae pv. tomato (Pst.) DC3000 carrying avrRpt2, we demonstrate that effector-triggered local resistance is down-regulated in the cry1 mutant, leading to more pathogen multiplication. In plants overexpressing CRY1 (CRY1-ovx), however, local resistance is significantly up-regulated. We also show that systemic acquired resistance (SAR) is positively regulated by CRY1, and that salicylic acid (SA)-induced pathogenesis-related gene PR-1 expression is reduced in the cry1 mutant, but enhanced in CRY1-ovx plants. However, our results indicate that CRY1 only modestly influences SA accumulation and has no effect on hypersensitive cell death. These results suggest that CRY1 may positively regulate R protein-mediated resistance to P. syringae with increased PR gene expression.
植物已经进化出复杂的机制来抵御病原体。已经表明，几种防御反应受光的影响，红光/远红光光受体光敏色素（PHY）调节拟南芥的植物防御反应。蓝光受体隐花色素（CRY）与 PHY 一起工作，调节许多光控反应，包括光形态发生、花诱导和生物钟的驯化。我们在这里报告，拟南芥蓝光受体 CRY1 在连续光照条件下正向调节对丁香假单胞菌 pv.番茄（Pst.）DC3000 的诱导抗性。通过用携带 avrRpt2 的丁香假单胞菌 pv.番茄（Pst.）DC3000 挑战植物，我们证明效应子触发的局部抗性在 cry1 突变体中下调，导致更多的病原体繁殖。然而，在过表达 CRY1（CRY1-ovx）的植物中，局部抗性显著上调。我们还表明，系统获得性抗性（SAR）受 CRY1 正向调节，并且在 cry1 突变体中，水杨酸（SA）诱导的病程相关基因 PR-1 的表达减少，但在 CRY1-ovx 植物中增强。然而，我们的结果表明，CRY1 仅适度影响 SA 积累，并且对过敏细胞死亡没有影响。这些结果表明，CRY1 可能通过增加 PR 基因表达正向调节 R 蛋白介导的对丁香假单胞菌的抗性。
