油茶果生刺盘孢组蛋白乙酰化转移酶Rtt109生物学功能

Function of the histone acetyltransferase Rtt109 in Colletotrichum fructicola,the causal organism of Camellia oleifera anthracnose

炭疽病是油茶的主要病害,造成巨大经济损失。果生刺盘孢是油茶炭疽病优势致病菌。本研究旨在探讨果生刺盘孢中组蛋白乙酰化转移酶Rtt109的生物学功能,为油茶炭疽病防治提供理论依据。通过构建基因敲除载体,根据同源重组原理,敲除目标基因CfRTT109,进一步筛选获得突变体ΔCfrtt109;构建CfRTT109基因回补质粒,转化至突变体ΔCfrtt109,通过荧光筛选回补菌株。生物学表型测定结果显示:相比于野生型,突变体ΔCfrtt109生长速率下降了51.23%,分生孢子的形成率下降了71.89%;在含有5.0mmol/L内质网胁迫剂二硫苏糖醇的PDA培养基中,突变体ΔCfrtt109的生长抑制率为50.75%,显著高于野生型和回补菌株;荧光定量PCR结果表明,与野生型和回补菌株相比,内质网相关的基因HAC1、SCJ1与PDI1基因在突变体中显著上调表达;在含有DNA损伤试剂甲基磺酸甲酯的PDA培养基中,突变体ΔCfrtt109停止生长;进一步研究发现,在甲基磺酸甲酯胁迫下,突变体ΔCfrtt109中的DNA损伤修复基因RHM52、RHM54与REV1表达量上调幅度显著低于野生型;致病力测定结果显示,突变体ΔCfrtt109在油茶叶上形成的病斑面积减小了77.60%,在苹果上减少了89.91%。综上所述,组蛋白乙酰化转移酶CfRtt109参与调控果生刺盘孢营养生长、分生孢子形成、内质网胁迫和DNA损伤胁迫应答以及致病力。

Anthracnose is one of the most important diseases of Camellia oleifera,caused by Colletotrichum fructicola.As an important epigenetic modification,histone acetylation plays an important role in the regulation of a variety of biological processes,which is currently unclear in C.fructicola.The research aims at exploring the biological function of histone acetyltransferase Rtt109 in C.fructicola in order to elucidate the molecular mechanism of CfRtt109 and provide theoretical basis for the prevention and control of oil-tea tree anthracnose.Based on homologous recombination principle and the PEG-mediated transformation method,the mutant strain ofΔCfrtt109 and the complemented strains were obtained.It was found that the vegetative growth and conidiation of mutant was significantly lower than that of wild type and the complemented strain.Compared with the wild type and the complemented strain,ΔCfrtt109 was more sensitive to 5.0 mmol/L DTT and 0.01%MMS,additives to PDA medium.The expression levels of HAC1,SCJ1 and PDI1 were significantly upregulated inΔCfrtt109.RNA-seq combined with RT-qPCR analysis showed that loss of CfRTT109 would alter the expression of genes involved in DNA damage repair.Furthermore,the pathogenicity of theΔCfrtt109 was significantly reduced on the wounded oil-tea leaf and apple.To sum up,our results revealed the critical roles of Rtt109 in growth,conidiation,tolerance to ER stress and DNA damage stress and pathogenicity of C.fructicola.