天麻茎色形成相关bHLH基因的鉴定与分析OA

Objective:Gastrodia elata has evolved ecological types with shortened rhizome internodes and diversified flower and fruit coloration in response to different altitudes.Studying the genetic mechanisms of different ecotype germplasm is significant for guiding variety breeding in different cultivation areas.Methods:The bHLH gene family was identified based on the whole-genome datasets of G.elata f.elata and G.elata f.glauca.Subsequently,the gene family members were subject to analysis,including gene structure,chromosomal localization,cis-acting elements,gene synteny,and phylogeny.Combined with transcriptome data and quantitative Real-time PCR,the expression patterns of bHLH genes in the stems of the different G.elata ecotype germplasm were analyzed.Finally,correlation analysis was conducted between gene expression patterns and color to obtain the key bHLH genes regulating the color formation of stem.Results:A total of 63 bHLH genes were identified in both G elata f.elata and G.elata f.glauca,unevenly distributed across 17 chromosomes and clustered into 16 subfamilies,with significant expansion in some family members.Obvious inversions of bHLH genes on the same chromosome and interchromosomal translocations were detected in the two ecotype germplasm.Among these genes,12 bHLH genes(such as bHLH62-3 and bH LH 7 4)were associated with the bright yellow color of G elata f.elata stem,while 9 bHLH genes(such as PIL13,UNE12,and bHLH130)were correlated with the red color of G.elata f.glauca stem.Compared to G.elata f.glauca,the bHLH48 expression level was significantly higher in flowers and scale leaves of G elata f.elata,and the bH LH62-3 expression level was significantly higher in all organs of G elata f.elata.Conclusions:Functional pathway divergence of the bHLH family members has occurred across different chromosomes in G elata f.elata and G.elata f.glauca.Through synergism or antagonism with other genes,21 bHLH genes participate in the coloration metabolic pathway regulation of stems,flowers,and fruits.Specifically,bHLH62-3 is involved in regulating stem color differentiation in the anthocyanin biosynthesis pathway of G.elata,thus relevant to the color formation of stem.Additionally,GebHLH48 positively regulates flowering-related pathways to promote the early-flowering phenotype of G.elata f.elata.These findings have laid the foundation for analyzing the genetic regulatory mechanisms underlying the color formation of the G.elata stem.