Low temperature enhances plant immunity via salicylic acid pathway genes that are repressed by ethylene

First author: Zhan Li; Affiliations: Zhejiang University (浙江大学): Hangzhou, China

Corresponding author: Jian Hua

Temperature has a large impact on plant immune responses. Earlier studies identified intracellular immune receptor nucleotide-binding leucine-rich repeat (NLR) genes and salicylic acid (SA) as targets of high temperature inhibition of plant immunity. Here we report that moderately low temperature enhances immunity to the bacterial pathogen Pseudomonas syringae in Arabidopsis thaliana. This enhancement is dependent on SA signaling and is accompanied by upregulation of multiple SA biosynthesis and signaling genes at lower temperature. SA signaling is repressed by jasmonic acid and ethylene at both normal and low temperatures. The inhibition of SA biosynthesis by ethylene, while mainly through ISOCHORISMATE SYNTHASE 1/SALICYLIC ACID-INDUCTION DEFICIENT 2 (ICS1/SID2) at normal temperature, is through ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5)/SID1, ICS2, and ICS1/SID2 at lower temperature. The repression by ethylene is mediated by a direct regulation of the ethylene response transcription factor Ethylene Insensitive 3 (EIN3) on multiple SA biosynthesis and signaling genes. Thus, low temperature enhances the SA pathway to promote immunity and at the same time uses ethylene to repress multiple SA regulators to achieve fine-tuned immune responses.

温度对于植物的免疫响应具有非常大的影响。早先的研究鉴定了细胞内的免疫受体核苷酸结合富含亮氨酸重复序列NLR基因和水杨酸SA作为高温抑制植物免疫的靶标。本文中，作者报道了适度的低温会增强拟南芥对于细菌病原菌丁香假单胞菌的免疫。这种增强效应依赖于SA信号转导，并且伴随着多个SA合成和信号转导基因在低温时的表达上调。无论是在正常温度或是低温条件下，SA信号转导都会受到茉莉酸和乙烯的抑制。常温条件下，乙烯抑制SA信号转导主要是通过ICS1/SID2，而低温条件下则通过EDS5/SID1、ICS2和ICS1/SID2。乙烯介导的SA信号转导抑制是由乙烯响应转录因子EIN3对于多个SA生物合成和信号转导基因的直接调控所介导的。因此，低温增强了SA通路以促进植物免疫，同时低温通过乙烯抑制多个SA调控因子以精确调控免疫响应。

通讯：Jian Hua (https://plantbio.cals.cornell.edu/people/jian-hua/)

个人简介：1998年，加州理工学院，博士。

研究方向：植物响应于温度变化以调节自身发育和免疫的分子机制。

doi: https://doi.org/10.1104/pp.19.01130

Journal: Plant Physiology

Published date: November 06, 2019