Li Jianzhong, Li Guoliang, Zhu Caishuo, Wang Shaoxing, Zhang Shifan, Li Fei, Zhang Hui, Sun Rifei, Yuan Lingyun, Chen Guohu, Tang Xiaoyan, Wang Chenggang, Zhang Shujiang
College of Horticulture, Anhui Agricultural University, Hefei 230036, China.
State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Plants (Basel). 2025 Jan 18;14(2):268. doi: 10.3390/plants14020268.
The trichomes of mustard leaves have significance due to their ability to combat unfavorable external conditions and enhance disease resistance. It was demonstrated that the MYB-bHLH-WD40 (MBW) ternary complex consists of MYB, basic Helix-Loop-Helix (bHLH), and WD40-repeat (WD40) family proteins and plays a key role in regulating trichome formation and density. The bHLH gene family, particularly the Myelocytomatosis (MYC) proteins that possess the structural bHLH domain (termed bHLH-MYC), are crucial to the formation and development of leaf trichomes in plants. bHLH constitutes one of the largest families of transcription factors in eukaryotes, of which MYC is a subfamily member. However, studies on bHLH-MYC transcription factors in mustard have yet to be reported. In this study, a total of 45 bHLH-MYC transcription factors were identified within the genome, and a comprehensive series of bioinformatic analyses were conducted on their structures and properties: an examination of protein physicochemical properties, an exploration of conserved structural domains, an assessment of chromosomal positional distributions, an analysis of the conserved motifs, an evaluation of the gene structures, microsynteny analyses, three-dimensional structure prediction, and an analysis of sequence signatures. Finally, transcriptome analyses and a subcellular localization examination were performed. The results revealed that these transcription factors were unevenly distributed across 18 chromosomes, showing relatively consistent conserved motifs and gene structures and high homology. The final results of the transcriptome analysis and gene annotation showed a high degree of variability in the expression of bHLH-MYC transcription factors. Five genes that may be associated with trichome development (, , , , and ) were identified. The subcellular localization results indicated that the transcription and translation products of these five genes were expressed in the same organelle: the nucleus. This finding provides a basis for elucidating the roles of bHLH-MYC family members in plant growth and development, and the molecular mechanisms underlying trichome development in mustard leaves.
芥菜叶的表皮毛因其具有抵御不利外部条件和增强抗病性的能力而具有重要意义。研究表明，MYB-bHLH-WD40（MBW）三元复合物由MYB、基本螺旋-环-螺旋（bHLH）和WD40重复（WD40）家族蛋白组成，在调节表皮毛的形成和密度方面起关键作用。bHLH基因家族，特别是具有结构bHLH结构域的髓细胞瘤（MYC）蛋白（称为bHLH-MYC），对植物叶片表皮毛的形成和发育至关重要。bHLH是真核生物中最大的转录因子家族之一，其中MYC是一个亚家族成员。然而，关于芥菜中bHLH-MYC转录因子的研究尚未见报道。在本研究中，在基因组中总共鉴定出45个bHLH-MYC转录因子，并对其结构和性质进行了一系列全面的生物信息学分析：蛋白质理化性质检测、保守结构域探索、染色体位置分布评估、保守基序分析、基因结构评估、微共线性分析、三维结构预测以及序列特征分析。最后，进行了转录组分析和亚细胞定位检测。结果表明，这些转录因子在18条染色体上分布不均，具有相对一致的保守基序和基因结构以及高度同源性。转录组分析和基因注释的最终结果显示，bHLH-MYC转录因子的表达具有高度变异性。鉴定出五个可能与表皮毛发育相关的基因（、、、和）。亚细胞定位结果表明，这五个基因的转录和翻译产物在同一细胞器——细胞核中表达。这一发现为阐明bHLH-MYC家族成员在植物生长发育中的作用以及芥菜叶表皮毛发育的分子机制提供了依据。
