Cloning of the key genes in maize oxylipins pathways and their roles in herbivore induced defense  

作　　者：XU Tao WANG Jianwu LUO Shiming 

机构地区：[1]Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou 510642, China

出　　处：《Chinese Science Bulletin》2005年第21期2457-2466,共10页

基　　金：supported by the National Natural Science Foundation of China(Grant No.30000114,30270137);Natural Science Foundation of Guangdong Province(Grant No.039254,04020569&21043)

摘　　要：To gain an understanding of the molecular ba-sis of signaling pathways in herbivore-induced maize plant defense, three key genes, ZmAOS, ZmAOC and ZmHPL, which are involved in the biosynthesis of oxylipin signals, have been cloned using RT-PCR in this study. Beet army-worm (BAW) infestation induced the systemic expression of the key genes involved in the biosynthesis of oxylipin signals similar to exogenous methyl jasmonate (MeJA). Moreover, the systemic expression patterns of maize defense-related genes were similar between maize leaves induced by jas-monic acid (JA) and damaged by BAW. Previous treatment with salicyhydroxamic acid (SHAM), an inhibitor of jas-monates (JAs) signal pathway followed by BAW infestation did not induce the systemic expression of the defense-related genes. Exposure to the vapors of green leafy volatiles (GLVs, (Z)-3-hexen-1-ol, (E)-2-hexenal, (E)-3-hexenal) and β-oci- mene induced the expression of the defense-related genes, as well as the key genes involved in biosynthesis of JAs. How-ever, previous treatment with SHAM clearly decreased the transcript levels of the defense genes induced by (Z)-3-hexen-1-ol, (E)-2-hexenal and (E)-3- hexenal. These results demonstrate the major role of oxylipin signal path-way in herbivore-induced maize chemical defense. JA was the endogenous signal in the process of herbivore-induced maize systemic defense. GLVs, another group of oxylipin, played an important role in the process of herbivore-induced systemic defense outside the plant. Furthermore, the expres-sion of defense-related genes induced by GLVs was partially dependent on JAs signal pathway, while β-ocimene induction was independent of JAs signal pathway.To gain an understanding of the molecular basis of signaling pathways in herbivore-induced maize plant defense, three key genes, ZmAOS, ZmAOC and ZmHPL, which are involved in the biosynthesis of oxylipin signals, have been cloned using RT-PCR in this study. Beet armyworm （BAW） infestation induced the systemic expression of the key genes involved in the biosynthesis of oxylipin signals similar to exogenous methyl jasmonate （MeJA）. Moreover, the systemic expression patterns of maize defense-related genes were similar between maize leaves induced by jasmonic acid （JA） and damaged by BAW. Previous treatment with salicyhydroxamic acid （SHAM）, an inhibitor of jasmonates （JAs） signal pathway followed by BAW infestation did not induce the systemic expression of the defense-related genes. Exposure to the vapors of green leafy volatiles （GLVs, （Z）-3-hexen-l-ol, （E）-2-hexenal, （E）-3-hexenal） and β-ocimene induced the expression of the defense-related genes, as well as the key genes involved in biosynthesis of JAs. However, previous treatment with SHAM clearly decreased the transcript levels of the defense genes induced by （Z）-3-hexen-l-ol, （E）-2-hexenal and （E）-3- hexenal. These results demonstrate the major role of oxylipin signal pathway in herbivore-induced maize chemical defense. JA was the endogenous signal in the process of herbivore-induced maize systemic defense. GLVs, another group of oxylipin, played an important role in the process of herbivore-induced systemic defense outside the plant. Furthermore, the expres- sion of defense-related genes induced by GLVs was partially dependent on JAs signal pathway, while β-ocimene induction was independent of JAs signal pathway.

关 键 词：玉米 繁殖技术 基因表达 茉莉酮 

分 类 号：S513[农业科学—作物学]