香豆素合成途径关键酶基因Ghpal、Ghc4h和Gh4cl在棉花抗链格孢菌中的作用

发布时间：2018-04-02 10:54

本文选题：棉花　切入点：链格孢菌　出处：《植物病理学报》2017年02期

【摘要】：链格孢菌Alternaria alternata引起的棉花轮纹斑病,是导致棉花早衰发生的主要成因之一,严重危害棉花生产。香豆素合成途径作为合成植保素的一条代谢支路,其产物能够抑制病原菌,增强植物的抗病性。为了揭示该途径在棉花抗链格孢菌中的作用,本文利用棉花皱缩病毒介导的基因沉默技术,通过对棉花香豆素合成途径中编码关键酶基因的沉默抑制,来解析其在棉花抗链格孢菌中的作用,所选择的基因有编码苯丙氨酸解氨酶(PAL)的基因Ghpal、肉桂-4-羟化酶(C4H)基因Ghc4h和4香豆酸-辅酶-A(4CL)的基因Gh4cl。结果显示,Ghpal、Ghc4h和Gh4cl基因受链格孢菌诱导转录,表明这些基因可能参与了棉花对链格孢菌的抗性反应。Ghpal、Ghc4h和Gh4cl基因分别被沉默后,结果显示各基因沉默植株对链格孢菌的抗性下降,表现为接种链格孢菌后,基因沉默植株的病情指数分别为43.36、38.27和44.78,显著高于野生型和VIGS空载体对照植株。这表明,Ghpal、Ghc4h和Gh4cl参与了棉花对链格孢菌的抗性反应。此外,离体条件下给Ghpal、Ghc4h和Gh4cl基因沉默植株叶片饲喂外源香豆素,结果发现基因沉默植株对链格孢菌的抗性得到恢复。这一结果进一步表明香豆素合成途径在棉花抗链格孢菌中起着重要作用。
[Abstract]:Cotton root-spot disease caused by Alternaria alternata is one of the main causes of cotton premature senescence, which seriously harms cotton production. Coumarin synthesis pathway is a metabolic branch of phytin-synthesizing, and its products can inhibit pathogenic bacteria. In order to reveal the role of this pathway in cotton resistance to Alternaria, the silencing technique of cotton wrinkle virus mediated gene silencing was used to suppress the key enzyme genes in cotton coumarin biosynthesis pathway. To analyze its role in the resistance of cotton to Alternaria spp. The selected genes were Ghpall, Ghc4h and Gh4cl. the results showed that the genes of Ghpal4 and Gh4cl were induced by Alternaria albicans, and the results showed that the genes encoding phenylalanine ammonia-lyase (pal), cinnamon-4-hydroxylase (C4H) and 4-coumaric acid-coenzyme (AH4CLL) were transcribed by Alternaria. The results indicated that these genes might be involved in cotton resistance response to Alternaria. After the silencing of Ghc4 and Gh4cl genes, the results showed that the resistance of the silenced plants to Alternaria was decreased, which was shown by inoculation of Alternaria spp. The disease index of gene silencing plants was 43.36 and 44.78 respectively, which was significantly higher than that of wild type and VIGS blank vector control plants, which indicated that Ghc4 h and Gh4cl were involved in the resistance of cotton to Alternaria. In vitro, the leaves of Ghpalus Ghc4 and Gh4cl gene silencing plants were fed with exogenous coumarin. The results showed that the resistance of gene silencing plants to Alternaria was recovered, which further indicated that coumarin biosynthesis plays an important role in the resistance of cotton to Alternaria.
【作者单位】：中国农业科学院植物保护研究所植物病虫害生物学国家重点实验室;
【基金】：国家自然科学基金资助项目(31371898) 转基因生物新品种培育重大专项(2012ZX08009001)
【分类号】：S435.621.2

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