Basic helix-loop-helix(bHLH)transcription factors regulate diverse plant processes,particularly anthocyanin biosynthesis through the MYB-bHLH-WD40 complex.Despite snapdragon(Antirrhinum majus)serving as a classical mo...Basic helix-loop-helix(bHLH)transcription factors regulate diverse plant processes,particularly anthocyanin biosynthesis through the MYB-bHLH-WD40 complex.Despite snapdragon(Antirrhinum majus)serving as a classical model for studying flower pigmentation genetics,its bHLH gene family has rarely been comprehensively characterized.Here,we performed a genome-wide identification and systematic characterization of the bHLH gene family in A.majus,with a focus on candidates involved in anthocyanin biosynthesis.A total of 150 AmbHLH genes were identified and subjected to in-silico analyses,including phylogenetic classification,structural analysis,and promoter cis-element characterization.Comparative transcriptomic profiling between anthocyanin-poor(“SIPPE50”,Green)and anthocyanin-rich(“JI2R”,Red)snapdragon lines highlighted eight differentially expressed AmbHLHs.AmbHLH001,AmbHLH002,and AmbHLH042 showed significant upregulation in the anthocyanin-rich line and showed positive correlations with the expression of key anthocyanin biosynthetic genes.Among these,AmbHLH002 was prioritized as a candidate and was assessed via heterologous overexpression in tomatoes.Notably,AmbHLH002 is a newly identified regulator whose overexpression in tomato resulted in visible purple pigmentation and increased anthocyanin accumulation.These findings support the view that AmbHLH002 acts as a positive regulator,with phylogenetic evidence for conservation of anthocyanin biosynthesis,presenting valuable potential for engineering pigmentation traits in ornamental plants and serving as a candidate visible marker for plant genetic transformation.展开更多
基金funded by the USDANIFA grant 2019-67013-29236the USDA HATCH program FLA-MFC-006387,awarded to Heqiang Huo.
文摘Basic helix-loop-helix(bHLH)transcription factors regulate diverse plant processes,particularly anthocyanin biosynthesis through the MYB-bHLH-WD40 complex.Despite snapdragon(Antirrhinum majus)serving as a classical model for studying flower pigmentation genetics,its bHLH gene family has rarely been comprehensively characterized.Here,we performed a genome-wide identification and systematic characterization of the bHLH gene family in A.majus,with a focus on candidates involved in anthocyanin biosynthesis.A total of 150 AmbHLH genes were identified and subjected to in-silico analyses,including phylogenetic classification,structural analysis,and promoter cis-element characterization.Comparative transcriptomic profiling between anthocyanin-poor(“SIPPE50”,Green)and anthocyanin-rich(“JI2R”,Red)snapdragon lines highlighted eight differentially expressed AmbHLHs.AmbHLH001,AmbHLH002,and AmbHLH042 showed significant upregulation in the anthocyanin-rich line and showed positive correlations with the expression of key anthocyanin biosynthetic genes.Among these,AmbHLH002 was prioritized as a candidate and was assessed via heterologous overexpression in tomatoes.Notably,AmbHLH002 is a newly identified regulator whose overexpression in tomato resulted in visible purple pigmentation and increased anthocyanin accumulation.These findings support the view that AmbHLH002 acts as a positive regulator,with phylogenetic evidence for conservation of anthocyanin biosynthesis,presenting valuable potential for engineering pigmentation traits in ornamental plants and serving as a candidate visible marker for plant genetic transformation.
