谷子DGAT基因家族分析及基于WGCNA发掘甘油三酯合成与调控相关基因

Analysis of millet DGAT gene family and discovery of genes related to triglyceride synthesis and its regulation based on WGCNA

[目的]二酰甘油酰基转移酶(Diacylglycerol acyltransferase,DGAT)是甘油三酯合成途径中的限速酶,对植物甘油三酯和脂肪酸的积累至关重要。[方法]本研究利用生物信息学方法对谷子DGAT基因家族进行了鉴定和分类,对其进化模式、序列特性、基因结构、亚细胞定位、启动子序列和表达模式进行了分析,并利用名优品种晋谷21的15个组织转录组数据构建了加权基因共表达网络。[结果]谷子基因组中有14个DGAT基因,分为DGAT1、DGAT2和WSD 3个类群,分别含有相应的特征结构域(MBOAT、DGAT和WS_DGAT),同类群的DGAT具有相似的结构和功能;启动子区包含逆境响应、生长发育相关的多种顺式作用元件,表明这些基因可能受多种因子调控;不同基因在谷子组织中的表达具有特异性,其中,SiDGAT2.1和SiDGAT2.2在灌浆期籽粒中表达量较高,可能是籽粒中甘油三酯积累的关键酶;利用WGCNA挖掘了与甘油三酯合成相关的基因和转录因子。[结论]本研究为进一步研究谷子油脂代谢途径和小米品质改良提供理论依据。

[Objective]Diacylglycerol acyltransferase(DGAT)is a rate-limiting enzyme in the triglyceride synthesis pathway and is essential for the accumulation of triacylglycerol and fatty acids in plants.[Methods]In this study,the bioinformatics methods were used to identify and classify the millet DGAT gene family;its evolutionary pattern,sequence features,gene structure,subcellular location,promoter region sequence and expression patterns were analyzed based on the transcriptome data which were collected from 15 different tissues of elite variety Jingu 21,and also were used to construct a co-expression network by weighted gene co-expression network analysis(WGCNA).[Results]The result showed that a total of 14 DGAT genes in the genome of foxtail millet were identified and were divided into three subgroups,named as DGAT1,DGAT2 and WSD,which contained corresponding characteristic domains(MBOAT,DGAT and WS_DGAT domains,respectively).DGAT genes of the same subgroup showed similar structure and might perform the similar functions.The promoter regions contained the cis-acting elements which related to stress response,growth and development,suggesting that these genes might be regulated by a variety of factors.The expression of different genes in millet tissues was specific.Among them,SiDGAT2.1 and SiDGAT2.2 showed a high expression level at grain filling stage,which indicated that they might be the key enzymes for triglyceride accumulation.The genes and transcription factors related to triglyceride synthesis were predicted using WGCNA.[Conclusion]This study provided theoretical basis for further study on lipid metabolism pathway and quality improvement in foxtail millet.