目的 从全基因组水平挖掘茯苓Poria cocos MYB转录因子基因家族成员，并分析其在菌丝、菌核等部位及茉莉酸甲酯(methyl jasmonate，MeJA)诱导后菌丝中的表达模式，以期发现与茯苓发育及次生代谢物生物合成调控相关的MYB转录因子。方法 基于茯苓基因组数据，通过序列比对及保守结构域分析挖掘MYB转录因子基因，利用ExPASy在线工具预测分析MYB蛋白质理化性质，利用MEGA 7.0软件构建茯苓MYB蛋白进化树，利用MEME在线工具分析保守基序，利用Plant CARE进行启动子区顺式作用元件分析，通过MeJA诱导菌丝并采用qRT-PCR方法检测基因相对表达量。结果 在茯苓基因组中共鉴定到10个含有特征性保守结构域的MYB转录因子，其中4个属于1R类型，4个属于2R类型，2个属于4R类型。进化树及保守基序显示，相同进化枝的MYB蛋白所含基序类型相似。启动子区预测分析发现了多类激素及逆境响应顺式作用元件。基因表达谱分析显示有2个基因(PcMYB7和PcMYB8)在菌丝中的表达量高于菌核中的表达量，而PcMYB9则是在菌核中表达量相对较高。MeJA诱导后，有3个基因(PcMYB5、PcMYB6和PcMYB7)在诱导3 h时表达量明显上调。结论 从茯苓全基因组中系统鉴定MYB转录因子基因家族，为进一步研究MYB基因在调控茯苓发育及次生代谢物合成方面的生物学功能奠定基础。

Objective To discover the MYB transcription factors which related to the regulation on fungal development and secondary metabolsome in Poria cocos, the MYB transcription factor gene family have been mined and identified in the genome of P. cocos. In this study, the expression patterns of these genes in different tissues (sclerotium and mycelium) and the relative expression level in the mycelium after treatment by methyl jasmonate (MeJA) were analyzed. Methods Based on the P. cocos genome, the MYB gene were identified by Blast and the identification of the conserved domains. The ExPASy protparam tool was used to predict the physicochemical properties of these MYB proteins. The phylogenetictree was constructed by MEGA7.0 software, and the conserved motifs were identified by MEME method. Plant CARE was used to analyze the cis-acting elements in the promoter regions of these genes. The relative expression levels of these genes were detected by RT-qPCR method. Results A total of 10 MYB transcription factors with conserved domains were identified in the P. cocos genome, among which, four genes belonged to 1R type and 2R type, respectively, and the remaining two genes belonged to 4R type. The phylogenetic analysis and the conserved motif identification showed that the similar conserved motifs were existed in the MYB proteins belonging to the same evolutionary branch. A large number of cis-elements related to hormones and stress response have been discovered in the promoter regions of these MYB genes. The gene expressional profiles showed that two genes (PcMYB7 and PcMYB8) were more highly expressed in mycelium than that in sclerotium, based on the transcriptome data generated from these two tissues. On the contrary, PcMYB9 was expressed more abundantly in sclerotium. Furthermore, the expression of PcMYB5、PcMYB6和PcMYB7 was up-regulated by MeJA induction for 3 h. Conclusion The MYB transcription factor gene family of P. cocos was systematically identified in P. cocos genome in this study. This study provides foundation for further identification of the biological functions of MYB genes in regulating the development and secondary metabolite biosynthesis in P. cocos.

国家自然科学基金资助项目(81973422)；中国医学科学院医学与健康科技创新工程(2021-I2M-1-071)