Investigating the mechanisms of isochorismate synthase:An approach to improve salicylic acid synthesis and increase resistance to Fusarium head blight in wheat  

作　　者：Ya-Zhou Zhang Jie Man Dan Xu Lan Wen Yinghui Li Mei Deng Qian-Tao Jiang Qiang Xu Guo-Yue Chen Yu-Ming Wei 

机构地区：[1]State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China,Sichuan Agricultural University,Chengdu 611130,Sichuan,China [2]Triticeae Research Institute,Sichuan Agricultural University,Chengdu 611130,Sichuan,China

出　　处：《The Crop Journal》2024年第4期1054-1063,共10页作物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(3210170116);the Science and Technology Department of Sichuan Province(2022YFSY0035).

摘　　要：Salicylic acid(SA),a vital endogenous hormone,plays a crucial role in plant growth and the response to abiotic and biotic stress.Isochorismate synthase(ICS)and phenylalanine ammonia lyase(PAL)are critical rate-limiting enzymes for SA synthesis.Fusarium head blight(FHB)seriously threatens the safety of wheat production,but increasing the content of SA can enhance FHB resistance.However,the pathway of SA synthesis and regulation in wheat remains unknown.In this study,three wheat ICS(TaICSA,TaICSB,and TaICSD)were identified,and their functions were validated in vitro for isomerizing chorismate to isochorismate.The mutation of one or two homoeoalleles of TaICSA,TaICSB,and TaICSD in the wheat variety‘Cadenza’reduced SA levels under ultraviolet treatment and Fusarium graminearum infection,further enhancing sensitivity to FHB.Overexpression of TaICSA can significantly enhance SA levels and resistance to FHB.To further study SA synthesis pathways in wheat and avoid interference with pathogenicity related genes,the leaves of wild-type Cadenza and different TaICS mutant lines were subjected to ultraviolet treatment for transcriptomic analysis.The results showed that 37 PALs might be involved in endogenous SA synthesis,and 82 WRKY and MYB family transcription factors may regulate the expression of ICS and PAL.These results were further confirmed by RT-PCR.In conclusion,this study expands our knowledge of SA biosynthesis and identifies TaICSA,as well as several additional candidate genes that encode transcription factors for regulating endogenous SA levels,as part of an efficient strategy for enhancing FHB resistance in wheat.

关 键 词：Salicylic acid Chorismate Isochorismate RNA-SEQ Phenylalamine ammonia lyase 

分 类 号：S435.121.45[农业科学—农业昆虫与害虫防治]