霜疫霉诱导的荔枝果皮几丁质酶活性及其基因表达分析

Enzyme Activity and Gene Expression Analysis of Chitinase Induced by Peronophythora litchii in Litchi Pericarp

为探究荔枝果皮几丁质酶对霜疫霉病抗性中的功能,本研究以抗病品种‘黑叶’和感病品种‘桂味’为试验材料,分析荔枝果皮中的几丁质酶活性和基因表达情况。结果表明,果皮中几丁质酶活性不同,其与品种的抗病性正相关,霜疫霉菌侵染提高了果皮中酶活性。基于转录组数据,共检测到75条几丁质酶基因,在系统进化树上分为3枝。接种霜疫霉的抗病和感病品种果皮中差异表达基因有58条,表明几丁质酶基因响应霜疫霉入侵表达。不同进化分枝上的3个基因的表达水平因抗病性和接种时间的差异表达模式不同。LcChi3-1基因在抗病品种‘黑叶’中的表达水平远远高于感病品种‘桂味’,‘黑叶’果皮中LcChi3-1基因的表达水平与酶活性具有显著的相关性,表明其参与了对霜疫霉菌的抗病过程,并发挥主要作用。

In order to explore the resistance function of chitinase to Peronophythora litchii in litchi pericarp,the enzyme activity and gene expression were analyzed with disease-resistant cultivar’Heiye’and susceptible cultivar’Guiwei’as experimental materials.The results showed that chitinase activity had positive correlation with resistance of litchi varieties.The activity of chitinase was enhanced after inoculation with P.litchii.In our transcriptome,there were 75 genes were identified and classified into 3 subfamilies and 58 genes had up-or down-relative expression between different treatments.All these results indicated the expression of chitinase gene was response to the infection of P.litchii and different subfamilies had different expression profile.LcChi3-1 had the highest expression level in’Heiye’,but had the lowest expression level in’Guiwei’.Moreover,the expression of LcChi3-1 has significant positive correlation with the enzyme activity in resistance varieties.We speculated that LcChi3-1 play an important role in the process of resistance against P.litchii in litchi.