The transcription factor FcWRKY40 of Fortunella crassifolia functions positively in salt tolerance through modulation of ion homeostasis and proline biosynthesis by directly regulating SOS2 and P5CS1 homologs
The transcription factor FcWRKY40 of Fortunella crassifolia functions positively in salt tolerance through modulation of ion homeostasis and proline biosynthesis by directly regulating SOS2 and P5CS1 homologs
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金柑转录因子 FcWRKY40 通过直接调节 SOS2 和 P5CS1 同源物来调节离子稳态和脯氨酸生物合成，从而在耐盐性中发挥积极作用
DOI：
10.1111/nph.15240
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发表时间：
2018-08-01
期刊：
影响因子：
9.4
通讯作者：
Liu, Ji-Hong
中科院分区：
文献类型：
--
作者：
Dai, Wenshan;Wang, Min;Liu, Ji-Hong
本研究通过过量表达和病毒诱导的基因沉默（virus-induced gene silencing，VIGS）两种途径，阐明了FcWRKY 40基因在烟草和柠檬中的耐盐性，并阐明了其靶基因，结果表明：FcWRKY 40基因的过量表达增强了烟草和柠檬的耐盐性，而FcWRKY 40基因的沉默增强了柠檬的耐盐性。盐过度敏感2（SOS 2）和δ-1-吡咯啉-5-羧酸合成酶1（P5 CS 1）的同源基因在转基因柠檬中表达显著上调，而在VIGS中表达下调。转基因柠檬表现出较低的Na+和较高的脯氨酸浓度，而沉默系积累更多的Na+，但脯氨酸较少。用24-表油菜素处理转基因柠檬损害耐盐性，而外源脯氨酸的供应部分恢复VIGS线的耐盐性。FcWRKY 40特异性结合并激活FcSOS 2和FcP 5CS 1的启动子。FcWRKY 40被阿坝和盐上调，并被证实是ABA反应元件结合因子2（FcABF 2）的靶点。盐处理上调了FcABF 2和FcP 5CS 1的表达，提高了脯氨酸的含量，表明FcWRKY 40参与了阿坝信号转导途径，并通过调节离子稳态和脯氨酸生物合成相关基因的表达而发挥正调控作用。
Although some WRKYs have been characterized, regulatory roles of most WRKYs remain poorly understood.Herein, we elucidated function of FcWRKY40 from Fortunella crassifolia in salt tolerance via overexpression and virus-induced gene silencing (VIGS) and unraveled its target genes.Overexpression of FcWRKY40 enhanced salt tolerance in transgenic tobacco and lemon, while silencing of FcWRKY40 increased salt susceptibility. Homolog genes of Salt Overly Sensitive 2 (SOS2) and Delta-1-pyrroline-5-carboxylate synthetase 1 (P5CS1) were dramatically up-regulated in transgenic lemon but down-regulated in VIGS line. Consistently, transgenic lemon displayed lower Na+ and higher proline concentrations, whereas the silenced line accumulated more Na+ but less proline. Treatment of transgenic lemon with 24-epi-brassinolide compromised salt tolerance, while supply of exogenous proline partially restored salt tolerance of the VIGS line. FcWRKY40 specifically binds to and activates promoters of FcSOS2 and FcP5CS1. FcWRKY40 was up-regulated by ABA and salt, and confirmed as a target of ABA-responsive element binding factor 2 (FcABF2). Moreover, salt treatment up-regulated FcABF2 and FcP5CS1, and elevated proline concentrations.Taken together, our findings demonstrate that FcWRKY40 participates in the ABA signaling pathway and as a positive regulator functions in salt tolerance by regulating genes involved in ion homeostasis and proline biosynthesis.