黄秋葵MYB转录因子的鉴定及与果实老化关系分析

Identification of MYB Family Genes and Its Relationship With Fruit Aging Mechanism of Hibiscus esculentus L.

黄秋葵(Hibiscus esculentus L.)纤维素和木质素的大量积累极易引起果实老化,而植物MYB转录因子参与纤维素和木质素等生物合成与沉积,在次生细胞壁形成中起着重要的调控作用。为研究MYB转录因子在黄秋葵老化中的作用,从黄秋葵果实转录组测序数据库中筛选得到10条功能注释为MYB基因的片段序列,克隆获得了HeMYB4、HeMYB6、HeMYB26、HeMYB28、HeMYB44、HeMYB46、HeMYB59、HeMYB86、HeMY108和HeMYB113的基因全长,分析其核苷酸及编码氨基酸序列特征,同时进行了亚细胞定位、磷酸化位点、功能域、进化等生物信息学分析。结果显示,10个MYB基因均定位于细胞质膜上,具有丰富的磷酸化位点和功能域,与拟南芥等物种中参与纤维素和木质素合成的MYB蛋白亲缘关系较近。通过实时荧光定量PCR分析黄秋葵MYB基因家族的10个基因在果实发育过程、采后常温贮藏期间的表达,结果发现,HeMYB46、HeMYB86、HeMY108的表达量与纤维素含量呈极显著正相关,推测上述基因在黄秋葵果实衰老过程纤维素合成中起重要作用;HeMYB46、HeMYB59的表达量与木质素含量呈极显著正相关,推测其在木质素合成中起到重要调控作用。本研究结果初步明确了黄秋葵MYB转录因子在黄秋葵老化过程中的作用,为黄秋葵的生产、分子育种等提供了理论基础。

Studies have found that aging of Hibiscus esculentus L.is caused by the massive accumulation of cellulose and lignin,and plant MYB transcription factors,which are involved in the biosynthesis and deposition of cellulose and lignin,play important regulatory roles in the formation of secondary cell wall.To investigate the roles of the MYB transcription factor in the aging of Hibiscus esculentus L.,ten fragments annotated as MYB gene family were screened from the RNA-seq database of Hibiscus esculentus L.fruit,then the full-length cDNA sequences of HeMYB4,HeMYB6,HeMYB26,HeMYB28,HeMYB44,HeMYB46,HeMYB59,HeMYB86,HeMY108,HeMYB113 genes were cloned.Expression of these ten genes of cellulose synthase gene family in Hibiscus esculentus L.were estimated.The nucleotide sequence and encoded amino acid sequences were analyzed for subcellular localization,phosphorylation site,functional domain,and evolution using bioinformatics methods.The ten MYB genes were all located at the Plasma membrane,with abundant phosphorylation sites and functional domains similar to MYB involved in lignin and cellulose synthesis in Arabidopsis and other species.Expressions of these ten genes of the MYB gene family in Hibiscus esculentus L.during fruit development and postharvest normothermic storage were analyzed by reverse transcript quantitative PCR.The results showed that HeMYB46、HeMYB86 and HeMYB108 were significantly positively correlated with the contents of cellulose,HeMYB46 and HeMY59 were significantly positively correlated with the content of lignin,which led to the speculation that they play important roles in the synthesis of cellulose during aging of Hibiscus esculentus L.fruits,while the expression levels of HeMYB46 and HeMY59 showed a highly significants positive correlation with lignin content,it was speculated that these two genes play an important regulatory role in lignin synthesis.It is important to initially define the function of the Hibiscus esculentus L.MYB transcription factors during aging,which may provide a rational basis for okra production,molecular breeding.