干旱处理下2个梨品种转录组差异表达基因分析

Analysis of differentially expressed genes in transcriptomes of two pear genotypes under drought stress

【目的】以转录组数据为基础挖掘梨抗旱关键基因,为培育梨抗旱品种提供理论基础。【方法】以正常浇水和干旱处理下黄冠梨Pyrus bretschneideri‘Xuehuali’×P.pyrifolia‘Shinsseiki’和黄金梨P.pyrifolia‘Niitaka’×P.pyrifolia‘Nijisseiki’的叶片进行Illumina Hi Seq TM 2000高通量转录组测序分析,利用基因本体(GO)和京都基因与基因组百科全书(KEGG)数据库分析2个梨品种中的差异表达基因(DEGs)。【结果】2个梨品种间在正常浇水和干旱处理下分别发现了4 377和3 841个DEGs,其中只在干旱处理下的DEGs有1 340个。这些DEGs在GO数据库的3个本体生物过程、分子功能和细胞成分中富集到的数量分别是1 387、922和1 253个,与植物抗旱相关的代谢过程、应激反应和生物膜等条目分别富集到349、139和151个DEGs。仅在干旱处理下的1 340个DEGs被比对到102个KEGG代谢通路上,其中与植物内源激素相关的代谢通路有3个。将1 340个DEGs进行转录因子分析发现,被注释为转录因子的有37个,分布在17个转录因子家族中,其中乙烯应答转录因子(ERF)家族所拥有的DEGs最多,为11个。【结论】本研究发现了与梨抗旱相关的内源激素代谢基因和转录因子,干旱胁迫下这些基因在2个梨品种中差异表达,这可能与2个品种的抗旱性差异存在密切关系,为下一步梨抗旱分子机理研究奠定了基础。

【Object】To discover key genes related to drought resistance of pear plants based on transcriptome data, and provide a theoretical foundation for the breeding of drought resistant pear varieties.【Method】High through-put transcriptome sequencing by illumina Hi Seq TM 2000 was performed using leaves of ‘Huangguan＇pear（Pyrus bretschneideri ‘Xuehuali＇×P. pyrifolia ‘Shinsseiki＇） and ‘Hwangkumbae＇ pear（P. pyrifolia‘Niitaka＇×P. pyrifolia ‘Nijisseiki＇） under normal irrigation and drought stress treatments. Gene ontology（GO） and Kyoto encyclopedia of genes and genomes（KEGG） databases were used to analyze the differentially expressed genes（DEGs） in two pear genotypes.【Result】There were 4 377 and 3 841 DEGs comparing two pear genotypes under control irrigation and drought stress, respectively. Among these DEGs, 1 340 DEGs were only found under drought stress. There were 1 387, 922 and 1 235 DEGs in three ontologies including biologicalprocess, molecular function and cellular component, respectively. There were 349, 139 and 151 DEGs enriched in terms related to drought response of plant including metabolic process, stress response and biomembrane,respectively. The 1 340 DEGs only found under drought stress were matched to 102 KEGG pathways, and three of the pathways were related to phytohormone biosynthesis. Furthermore, among the 1 340 DEGs, 37 genes were annotated as transcription factors which belonged to 17 transcription factor families, and the ethylene responsive factor（ERF） family had 11 DEGs.【Conclusion】In this study, some genes related to endogenous hormone metabolism and transcription factors are found to express differentially in two pear genotypes under drought stress. These genes are probably closely related to the genotypic differences in drought resistance. Our results provide a basis for future study of the molecular mechanism of drought resistance of pear plant.