Genome-Wide Identification, Evolution and Functional Divergence of MYB Transcription Factors in Chinese White Pear (Pyrus bretschneideri)
Genome-Wide Identification, Evolution and Functional Divergence of MYB Transcription Factors in Chinese White Pear (Pyrus bretschneideri)
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中国白梨 (Pyrus bretschneideri) MYB 转录因子的全基因组鉴定、进化和功能分化
DOI：
10.1093/pcp/pcw029
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发表时间：
2016-04-01
影响因子：
4.9
通讯作者：
Wu, Jun
中科院分区：
文献类型：
--
作者：
Li, Xiaolong;Xue, Cheng;Wu, Jun
MYB超家族在植物中很大，功能也很多样化。到目前为止，MYB家族基因在中国白梨中还没有被鉴定出来，其功能也尚不清楚。在本研究中，我们确定了231个候选MYB基因，并将其分为四个亚家族。R2R3-MYB(PbrMYB)家族共有一个R2R3结构域，共有104个氨基酸残基，其中包括5个保守的色氨酸残基。PbrMYB家族分为37个功能亚组，其中33个亚组同时含有蔷薇科植物的MYB基因和AtMYB基因，4个亚组仅含有蔷薇科植物的MYB基因或AtMYB基因。具有相似功能的PbrMYB基因聚为同一亚群，表明功能保守。我们还发现，全基因组复制(WGD)和分散复制在MYB家族的扩大中起着关键作用。这87对PbrMYB重复基因可以追溯到两次WGD事件。纯化选择是PbrMYB基因进化的主要驱动力。在正选择条件下，15对基因呈现1~7个密码子位置。从果实的RNA测序数据中共鉴定出147个表达基因，通过实时荧光定量PCR分析，确定其中6个PbrMYB亚群成员是调控木质素合成的重要候选基因。进一步的相关分析表明，6个PbrMYB与木质素途径中的5个结构基因家族(F5H、Hct、Ccr、POD和C3‘H)显著相关。中国白梨MYB基因家族的系统发育、进化和表达分析为今后对PbrMYB基因进行全面的功能分析奠定了坚实的基础。
The MYB superfamily is large and functionally diverse in plants. To date, MYB family genes have not yet been identified in Chinese white pear (Pyrus bretschneideri), and their functions remain unclear. In this study, we identified 231 genes as candidate MYB genes and divided them into four subfamilies. The R2R3-MYB (PbrMYB) family shared an R2R3 domain with 104 amino acid residues, including five conserved tryptophan residues. The PbrMYB family was divided into 37 functional subgroups including 33 subgroups which contained both MYB genesof Rosaceae plants and AtMYB genes, and four subgroups which included only Rosaceae MYB genes or AtMYB genes. PbrMYB genes with similar functions clustered into the same subgroup, indicating functional conservation. We also found that whole-genome duplication (WGD) and dispersed duplications played critical roles in the expansion of the MYB family. The 87 PbrMYB duplicated gene pairs dated back to the two WGD events. Purifying selection was the primary force driving PbrMYB gene evolution. The 15 gene pairs presented 1-7 codon sites under positive selection. A total of 147 expressed genes were identified from RNA-sequencing data of fruit, and six PbrMYB members in subgroup C1 were identified as important candidate genes in the regulation of lignin synthesis by quantitative real-time PCR analysis. Further correlation analysis revealed that six PbrMYBs were significantly correlated with five structural gene families (F5H, HCT, CCR, POD and C3'H) in the lignin pathway. The phylogenetic, evolution and expression analyses of the MYB gene family in Chinese white pear establish a solid foundation for future comprehensive functional analysis of PbrMYB genes.