Abstract: MYB transcription factors play a crucial role in various physiological and biochemical processes, including the regulation of plant secondary metabolism,hormone signal transduction,and stress resistance. To investigate the response of MYB transcription factors in kentucky bluegrass (Poa pratensis L.) to stress conditions,we cloned and bioinformatically analyzed the PpMYB44 gene. We also examined the gene’s expression specificity in different tissues and under abiotic stress treatments using qRT-PCR technology. Our results showed that PpMYB44 contains the typical domain PLN03091 superfamily and has a higher degree of similarity to its homologous gene in ryegrass. The expression of the PpMYB44 gene is specific to different tissues,with the highest relative expression in roots,followed by stems and leaves. PpMYB44 significantly responds to drought,salt,phosphorus,and nitrogen stress,with drought and nitrogen stress inhibiting its expression,while salt and phosphorus significantly promoting its expression. Moreover,treatments with the plant hormones SA and GA down-regulated the relative expression of PpMYB44,whereas IAA and GABA promoted its expression. This study provides a theoretical basis for enhancing our understanding of the regulatory mechanism of MYB transcription factors in bluegrass under abiotic stress.

Key words: Kentucky Bluegrass, Transcription factor, PpMYB44, Abiotic stress, Expression analysis

摘要： MYB转录因子在植物次生代谢调节、激素信号转导和抗逆等生理生化过程中发挥重要作用。为揭示MYB转录因子对草地早熟禾(Poa pratensis L.)逆境胁迫条件下的响应，本研究克隆了PpMYB44基因，并进行了生物信息学分析，应用qRT-PCR技术对该基因在组织中的表达特异性及非生物胁迫处理下的表达进行了检测。结果显示，PpMYB44包含典型结构域PLN03091超家族，与其在黑麦草(Lolium perenne)中的同源基因相似度较高。草地早熟禾PpMYB44基因存在组织特异性，其相对表达量由高到低依次为根＞茎＞叶；PpMYB44显著响应干旱、盐、磷和氮胁迫，干旱、氮胁迫抑制PpMYB44基因表达；盐和磷显著促进其表达；经植物激素SA、GA处理后， PpMYB44相对表达量下调，而IAA及GABA促进该基因表达。本研究为丰富草地早熟禾转录因子MYB家族在非生物胁迫下的调节机制提供了理论基础。

关键词: 草地早熟禾, 转录因子, PpMYB44, 非生物胁迫, 表达分析