Molecular Plant Pathology, University of Amsterdam, Amsterdam, The Netherlands.
RNA Biology and Applied Bioinformatics, University of Amsterdam, Amsterdam, The Netherlands.
PLoS Genet. 2018 Jan 22;14(1):e1007157. doi: 10.1371/journal.pgen.1007157. eCollection 2018 Jan.
Increased ambient temperature is inhibitory to plant immunity including auto-immunity. SNC1-dependent auto-immunity is, for example, fully suppressed at 28°C. We found that the Arabidopsis sumoylation mutant siz1 displays SNC1-dependent auto-immunity at 22°C but also at 28°C, which was EDS1 dependent at both temperatures. This siz1 auto-immune phenotype provided enhanced resistance to Pseudomonas at both temperatures. Moreover, the rosette size of siz1 recovered only weakly at 28°C, while this temperature fully rescues the growth defects of other SNC1-dependent auto-immune mutants. This thermo-insensitivity of siz1 correlated with a compromised thermosensory growth response, which was independent of the immune regulators PAD4 or SNC1. Our data reveal that this high temperature induced growth response strongly depends on COP1, while SIZ1 controls the amplitude of this growth response. This latter notion is supported by transcriptomics data, i.e. SIZ1 controls the amplitude and timing of high temperature transcriptional changes including a subset of the PIF4/BZR1 gene targets. Combined our data signify that SIZ1 suppresses an SNC1-dependent resistance response at both normal and high temperatures. At the same time, SIZ1 amplifies the dark and high temperature growth response, likely via COP1 and upstream of gene regulation by PIF4 and BRZ1.
环境温度升高会抑制植物的免疫，包括自身免疫。例如，在 28°C 时，SNC1 依赖性自身免疫完全受到抑制。我们发现，拟南芥 SUMOylation 突变体 siz1 在 22°C 时表现出 SNC1 依赖性自身免疫，但在 28°C 时也表现出这种现象，这在两个温度下都依赖于 EDS1。这种 siz1 自身免疫表型在两个温度下都增强了对 Pseudomonas 的抗性。此外，siz1 的莲座叶尺寸在 28°C 时仅微弱恢复，而该温度完全挽救了其他 SNC1 依赖性自身免疫突变体的生长缺陷。siz1 的这种耐热性不敏感性与热感觉生长反应受损有关，该反应独立于免疫调节剂 PAD4 或 SNC1。我们的数据表明，这种高温诱导的生长反应强烈依赖于 COP1，而 SIZ1 控制着该生长反应的幅度。这一观点得到了转录组学数据的支持，即 SIZ1 控制着高温转录变化的幅度和时间，包括 PIF4/BZR1 基因靶标的一部分。综合我们的数据表明，SIZ1 在正常和高温下均抑制 SNC1 依赖性抗性反应。同时，SIZ1 放大了暗和高温生长反应，可能通过 COP1 以及 PIF4 和 BRZ1 对基因调控的上游。
