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兰州百合LdGRAS基因家族的鉴定和表达分析

Genome-wide identification and expression analysis of the LdGRAS gene family

  • 摘要: 百合(Lilium)鳞茎需要经过低温打破休眠,实现正常生长和开花。本研究通过兰州百合(L. davidii var. unicolor (Hoog) Cotton)全基因组序列分析,鉴定该物种的LdGRAS 基因家族,结合生物信息学、转录组数据和RT-qPCR分析结果,筛选可能参与百合鳞茎休眠解除过程的候选基因。结果显示,在兰州百合中共鉴定出52个LdGRAS基因,可分为9个进化分支,各亚族内基因结构和保守基序具有高度的一致性;LdGRAS基因家族与油棕(Elaeis guineensis Jacq.)、海枣(Phoenix dactylifera L.)分别存在29和38对共线性基因对;LdGRAS基因启动子区包含与光响应、组织发育和胁迫响应相关的多种顺式作用元件,其中只有LdGRAS25启动子含有细胞周期相关调控元件。转录组数据分析结果表明,LdGRAS基因家族在兰州百合的根系和子房中高表达基因最丰富。RT-qPCR分析结果显示,LdGRAS25基因在低温贮藏鳞茎茎尖中的表达量显著高于常温处理组,其编码的蛋白定位于细胞核中。综上,LdGRAS家族基因在兰州百合不同组织的表达具有一定特异性,其中LdGRAS25在休眠解除过程中响应低温上调表达,可作为休眠解除研究的候选基因。

     

    Abstract: Low-temperature exposure is critical for dormancy release and subsequent growth and flowering in Lilium species. Using the Lanzhou lily (L. davidii var. unicolor (Hoog) Cotton) as a model, a genome-wide analysis was conducted to identify and characterize members of the GRAS gene family and to screen potential candidate genes involved in bulb dormancy release. A total of 52 LdGRAS genes were identified and classified into nine evolutionary subgroups exhibiting conserved structural features and motif compositions. Comparative synteny analysis revealed 29 and 38 collinear gene pairs between the LdGRAS family and the genomes of Elaeis guineensis Jacq. and Phoenix dactylifera L., respectively. Promoter analysis indicated that LdGRAS genes harbored numerous cis-regulatory elements associated with light responsiveness, growth and development regulation, and stress adaptation, while only LdGRAS25 contained elements associated with cell cycle regulation. Transcriptomic analysis revealed that LdGRAS genes exhibited tissue-specific expression patterns, with the highest expression levels observed in roots and ovaries. RT-qPCR analysis further demonstrated that LdGRAS25 expression in bulb apical meristems under cold treatment was significantly elevated compared with that under normal temperature conditions. Collectively, these findings indicate that the LdGRAS gene family exhibits tissue-specific expression in Lanzhou lily and participates in stress responses. Notably, LdGRAS25 was identified as a low-temperature-induced gene upregulated during dormancy release, representing a promising candidate for elucidating the molecular mechanisms underlying temperature-mediated dormancy regulation in lilies.

     

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