Identification and Bioinformatics Analysis of the bHLH Transcription Factor Family in Citrus sinensis

Fuxuan Meng , Yujiao Yang , Yuanjie Duan , Zhiyuan Lv , Xiaoying Lu , Shuping Guo , Haigang Liu bHLH转录因子家族是第2大转录因子家族，广泛存在于微生物、植物以及动物中。以甜橙为试验材料，通过全基因组数据库搜索鉴定，对 bHLH 基因进行了理化性质、系统发育、染色体分布、保守基序、蛋白互作生物信息学分析，探讨它们在不同组织的表达情况。结果表明：共鉴定出126个 bHLH 基因，其中112个不均匀的分布于9条染色体上，14个分布位置尚未确定；系统发育分析表明甜橙 bHLH 基因家族可分为16个亚家族，并且给定亚家族中的大多数基因具有相似的基因结构和保守基序。在甜橙中，多个 bHLH 基因相互作用共同调控其开花、光的形态发生和花色素苷合成等过程；大多数的 CsbHLH 基因在愈伤组织、叶、花和果实中均有表达。本研究为 CsbHLH 基因的功能研究奠定了基础，并有助于 bHLH 基因在其他植物物种中的功能研究。 Abstract: The bHLH TFs (basic Helix-Loop-Helix transcription factors) family is widely found in microorganisms, plants and animals, and is the second largest family of transcription factors. In this study, Citrus sinensis was used as the experimental material, the physicochemical properties, phylogeny, chromosome distribution, conserved motif and protein interaction bioinformatics of bHLH gene were analyzed by genome-wide database search, and their expression in different tissues was discussed. Studies have shown that 126 bHLH genes were identified. Among them, 112 bHLH genes are distributed on 9 chromosomes, 14 bHLH genes are located in uncertain locations. Phylogenetic analysis indicated that the C. sinensis bHLH gene family can be divided into 16 subfamilies, and most genes in a given subfamily have similar gene structures and conserved motifs. Multiple bHLH gene interactions in C. sinensis regulate the development of flower organogenesis, light morphogenesis and anthocyanin synthesis. The tissue expression pattern of CsbHLH gene indicates that most members are in callus, leaves, flowers and fruits are expressed. This study laid the foundation for the functional study of the CsbHLH gene and contributed to the functional study of the bHLH gene in other plant species.