重寄生枝孢菌SYC63中MYB转录因子鉴定及分析

Genome-wide identification and analysis of the MYB transcription factor family in mycoparasite Cladosporium SYC63 strain

摘要:

【背景】V-myb禽成髓细胞瘤病毒癌基因同源物(v-myb avian myeloblastosis viral oncogene homolog, MYB)转录因子广泛存在于真菌中，在真菌的胁迫响应与致病性中发挥重要功能。枝孢菌(Cladosporium sp.)作为一类对锈菌有重寄生作用的真菌，具有极高的生防潜力，然而有关其MYB转录因子尚未见报道，对其MYB家族转录因子进行鉴定和表达分析，有助于理解枝孢菌在重寄生过程中发挥的作用。【目的】了解重寄生枝孢菌(Cladosporium cladosporioides) SYC63菌株中MYB转录因子家族种类数目及在重寄生过程中发挥的作用。【方法】利用生物信息学方法对其基本特性进行预测，并结合锈孢子诱导下的表达情况进行分析。【结果】枝孢菌SYC63中包含22个MYB转录因子家族基因，所有MYB转录因子均含有SANT结构域，分子量为28.26-239.05 kDa，等电点(isoelectric point, pI)为4.57-10.15，均为亲水蛋白；大多定位在细胞核，共有1R-MYB和2R-MYB两类，均含有响应病原菌的启动子结合位点。经锈孢子诱导后，大多SycMYBs下调表达，只有6个基因上调表达，筛选出8个表达量或差异倍数较高的基因进行RT-qPCR，验证结果显示不同时间处理下出现不同的表达变化趋势，其中SycMYB6基因在侵染过程的表达水平持续升高。【结论】MYB转录因子可能在枝孢菌SYC63重寄生过程的初期发挥响应侵染和抗逆的作用，这为深入探究MYB转录因子在真菌中发挥的作用和枝孢菌重寄生机制提供理论依据。

Abstract:

[Background] V-myb avian myeloblastosis viral oncogene homolog (MYB) transcription factors, which are ubiquitous in fungi, are vital in stress response and pathogenicity of the microbes. Cladosporium sp., parasitizing rust fungi, is a potential candidate for biocontrol. However, no report of its MYB transcription factors is available. The identification and expression analysis of its MYB transcription factor family are of great significance for understanding role of Cladosporium sp. in mycoparasitism. [Objective] To clarify the number of MYB transcription factors in Cladosporium cladosporioides SYC63 strain and the roles in the mycoparasitism. [Methods] We predicated fundamental characteristics of the MYB transcription factors with bioinformatics methods and analyzed the expression of them in the presence of aecidiospores. [Results] C. cladosporioides SYC63 harbors 22 MYB transcription factor genes and all the MYB transcription factors contain the SANT domain with molecular weight of 28.26–239.05 kDa and pI of 4.57–10.15. They are all hydrophilic proteins and mostly located in the nucleus. These genes can be classified to 1R-MYB and 2R-MYBs, which contain promoter binding sites for the response to pathogens. After rust spore induction, most SycMYBs were down-regulated, and only six genes were up-regulated. Eight genes with high expression or great fold change were selected for RT-qPCR, and the results suggested different change trends of expression after the induction for different time. Among the eight genes, SycMYB6 kept at a high level during the infestation. [Conclusion] MYB transcription factors play a role in the response to infestation and stress resistance of strain SYC63 during the mycoparasitism. The result is expected to lay a theoretical basis for further exploring the role of MYB transcription factor family in fungi and the mycoparasitim mechanism of Cladosporium sp..