马缨杜鹃bHLH转录因子家族的鉴定与表达分析

Identification and expression analysis of bHLH transcription factors family in Rhododendron delavayi

关键词:  马缨杜鹃, bHLH, 生物信息学, 干旱胁迫, 表达模式

Key words:   Rhododendron delavayi, bHLH, bioinformatics, drought stress, expression patterns

摘要:

水分亏缺是制约马缨杜鹃(Rhododendron delavayi)园林应用的关键因子,bHLH转录因子在植物生长发育和胁迫响应过程中发挥重要调控作用。该文以马缨杜鹃基因组文件和转录表达数据为材料,运用生物信息学方法鉴定马缨杜鹃bHLH转录因子(RdbHLH)家族成员,并分析了基因结构、保守基序、系统发育、蛋白理化性质、顺式作用元件、蛋白互作网络及表达模式等特征。结果表明:(1)共鉴定出116个RdbHLH基因,不同蛋白氨基酸数目和分子量大小差异较大,总体为弱酸性亲水蛋白,主要在细胞核行使功能。(2)RdbHLH共划分为17个亚家族,各亚家族基因基序结构保守,但在不同亚家族间差异较大,绝大多数RdbHLH蛋白同时含有Motif 1和Motif 2,启动子区域含大量与植物生长发育、激素响应、光响应和胁迫响应相关的顺式作用元件。(3)马缨杜鹃响应干旱胁迫主要通过激发信号传导通路与渗透调节和黄酮类化合物合成系统,以缓解胁迫损伤; 干旱胁迫影响了36个RdbHLH基因的表达,强烈诱导了12个RdbHLH基因的表达,其中RdbHLH49和RdbHLH95可能在植株抗干旱胁迫过程中发挥重要调控作用。研究结果为进一步研究RdbHLH基因的生物学功能提供了理论依据,也为培育马缨杜鹃优良园艺品种提供了靶向基因资源。

Abstract:

Water deficiency is a critical factor that restricts the utilization of Rhododendron delavayi in landscaping. bHLH transcription factors are pivotal regulators of plant growth, development, and stress responses. This study aimed to identify members of the R. delavayi bHLH transcription factor(RdbHLH)family by utilizing the R. delavayi genome file and transcriptome data. Through bioinformatics methods, we analyzed various aspects, including gene structure, conserved motifs, phylogenetic relationships, protein physicochemical properties, cis-acting elements, protein interaction networks, and expression patterns. The results were as follows:(1)A total of 116 RdbHLH genes were identified, exhibiting significant variations in terms of amino acid composition and molecular weight of proteins. These genes were primarily weakly acidic hydrophilic proteins that function predominantly within the cell nucleus.(2)The RdbHLH family was categorized into 17 subfamilies, where motif structures were conserved within each subfamily but displayed noticeable differences between different subfamilies. Most RdbHLH proteins contained both Motif 1 and Motif 2 at the same time. The promoter region of these genes contained a substantial number of cis-acting elements associated with plant growth and development, hormone response, light response, and stress response.(3)R. delavayi responds to drought stress by activating signal transduction pathways and regulating osmotic pressure and flavonoid biosynthesis systems, leading to stress damage mitigation. Drought stress exerted an impact on the expression of 36 RdbHLH genes, with 12 genes displaying robust induction. Notably, RdbHLH49 and RdbHLH95 might play pivotal regulatory roles in enhancing plant resistance to drought stress. These research findings provide a theoretical basis for further investigations into the biological functions of RdbHLH genes and establish target gene resources for the breeding of superior horticultural varieties of R. delavayi.