茶树MYC转录因子家族的全基因组鉴定及表达分析

Genome-wide Analysis and Expression Pattern of MYC Family in Camellia sinensis

【目的】髓细胞组织增生蛋白(Myelocytomatosis proteins,MYC)是植物茉莉酸信号转导途径中的重要转录因子。鉴定并分析茶树MYC转录因子有助于了解其潜在的分子机制。【方法】采用生物信息学方法,对茶树CsMYC转录因子进行全基因组范围内的鉴定与分析。【结果】从茶树基因组中总共鉴定出9个CsMYC成员,分布在茶树的5条染色体上。系统进化分析表明植物MYC家族可能起源于陆生植物并发生了谱系特异性分化事件。结构分析表明该家族内含子数目为0~3个,说明该家族在进化过程中发生内含子丢失事件。茶树8个MYC成员能在双子叶植物葡萄中找到同源基因。茶树不同组织转录组分析表明,除了CsMYC2和CsMYC9外,其他成员在芽和叶中表达量较高;荧光定量结果表明,所有成员均响应茉莉酸胁迫处理,同时个别成员也响应干旱、低温和赤霉素处理。使用皮尔森相关系数对与CsMYCs各成员表达量显著相关的基因集进行KEGG功能富集分析表明CsMYCs广泛参与了茶树次级代谢相关途径。【结论】本研究共鉴定出9个CsMYC成员,分析并预测了其结构及潜在分子功能。结合实时荧光定量和功能富集分析表明CsMYC家族在茶树非生物胁迫响应中扮演了重要角色。

【Objective】 Myelocytomatosis proteins(MYCs), the key transcription factor in the jasmonic acid signal transduction pathway, in Camellia sinensis were identified and analyzed to help understand the underlying molecular mechanism associated with resistance of tea plants to abiotic stress.【Method】 A genome-wide analysis on the MYC family in tea plant(CsMYC) was conducted using bioinformatics methods.【Result】 Nine CsMYC members were identified in the tea plant genome which distributed unevenly in 5 chromosomes. The phylogenetic analysis suggested that the CsMYCs might originate from terrestrial plants and have undergone lineage specific differentiation. Structurally, the family had only 0 to 3 introns indicating a deletion might have occurred in evolution. Eight of the 9 CsMYCs had homologous genes of dicotyledonous plants like grape, but not of monocotyledonous plants like rice. The transcriptome data showed that, except for CsMYC 2 and CsMYC 9, all members were highly expressed in the buds and leaves. On the fluorescence quantitative tests, all members responded to MeJA stress and some also to drought, low temperature, and/or GA treatments. It indicated a likely close association of tea plants to abiotic stress played by CsMYCs. The KEGG enrichment of the CsMYCs suggested its wide involvement in the secondary metabolism pathways in tea plants. 【Conclusion】 Nine CsMYCs in C. sinensis were identified in this study. The structures and potential molecular functions of the members were analyzed and predicted. Combining the results obtained by the real-time fluorescence quantification and functional enrichment analyses, it appeared that the CsMYC family might be closely associated with the response of tea plants to abiotic stress.