荔枝霜疫霉果胶乙酰酯酶PAE4和PAE5的功能与作用机制研究

荔枝霜疫霉(Peronophythora litchii)引起的霜疫霉病是荔枝上最严重的病害。病原菌的效应子通常在与植物互作过程中发挥重要作用。申请者在荔枝霜疫霉中鉴定了一类具有果胶乙酰酯酶功能域的效应子，且查明是植物病原卵菌中保守的分泌蛋白，在植物上瞬时表达可增强感病性，但具体的生化功能和作用机制尚不清楚。本项目将构建荔枝霜疫霉具有果胶乙酰酯酶功能域效应子PAE4和PAE5 (pectin acetylesterase 4 and 5)的突变体和互补体，然后通过分子生物学、植物病理学、生物化学等实验方法，阐明该类效应子的时空表达、生化活性和毒性功能；还将通过Co-IP技术筛选PAE4和PAE5在植物中的互作蛋白并研究它们之间相互作用的分子机制。本项目的实施不仅可阐明荔枝霜疫霉PAE类效应子在植物与病原菌互作过程中的生物学功能，而且也为设计和改良荔枝对荔枝霜疫霉抗性的分子育种提供理论依据。

Peronophythora litchii induced litchi downy blight is the most destructive disease on litchi. Effectors always play a key role in plant-pathogen interaction. Here, We identified a class of effectors containing pectin acetylesterase (PAE) domain in Peronophythora litchii, which is conserved secreted proteins in oomycete and can enhance plant susceptibility; however the the function and mechanism of action of these effectors are unknown. This project will constructs knockout and complement mutants of P. litchii pectin acetylesterase 4 and 5（PAE4 and PAE5）, and analysis the functions of these genes by pathogenic, molecular and biochemical methods, to demonstrate the localization, biochemical activity and virulence functions. This project also will screen the interacting proteins of PAE4 and PAE5 by Co-IP and analysis the molecular mechanism of interaction between them. This project will not only reveal the biological functions of PAEs in litchi-P. litchii interaction, but also provide research bases for genetic engineering of litchi with improved resistance to P. litchii.