草地早熟禾光敏色素作用因子基因PpPIFs的鉴定与表达分析

Identification and expression patterns analysis of phytochrome interaction factor gene PpPIFs in Poa pratensis

摘要:

草地早熟禾(Poa pratensis)是世界上应用广泛的草坪草种，其优异基因的挖掘对新品种的选育具有重要意义。光敏色素作用因子(PIF)基因是植物特有的转录因子之一，在植物生长发育和逆境胁迫中起到重要作用。本研究从草地早熟禾转录组数据库序列中比对分析得到 4 个 PpPIFs 基因的 cDNA 全长序列，具有完整的开放阅读框。运用生物信息学方法预测 PpPIFs 家族成员的理化性质和保守结构域，发现 4 个 PpPIFs 转录因子都是酸性蛋白，亚细胞定位都在细胞核中，通过聚类分析可将 4 个 PpPIFs成员分为 3 类。对干旱胁迫下不同时间点叶片中的 PpPIFs进行实时荧光定量 PCR。结果显示，PpPIF1、PpPIF3 和 PpPIF4 在干旱胁迫 8 h 时均显著上调表达，而在干旱胁迫 96 h 时 PpPIF1、PpPIF3 和 PpPIF5 均表现为上调。对草地早熟禾不同组织的 PpPIFs 基因进行表达分析发现，分蘖枝中 PpPIF1、PpPIF3 和 PpPIF4 的相对表达量显著高于叶片中的相对表达量，而 4 个 PpPIFs 基因在根系中的相对表达量均显著低于叶片中的相对表达量。PpPIF1 和 PpPIF3 可能参与调控草地早熟禾分蘖芽伸长生长和抗旱性。研究结果可为草坪草生物育种提供优异的基因资源。

Abstract:

Poa pratensis is a widely used turfgrass species in the world. It is of great importance to explore excellent genes for the breeding of new cultivars in turfgrass. Phytochrome interaction factor(PIF)gene family is one of the plant specific transcription factors，which plays an important role in plant growth and the response to environmen‐ tal stresses. In this study，the full‐length cDNA sequences of four PpPIF genes with complete open reading frame were obtained from the transcriptome database sequences of P. pratensis. Bioinformatics method was used to predict the physicochemical properties and conserved domains in all PpPIFs. It was found that four PpPIFs were acidic pro‐ teins with subcellular localization in the nucleus. They were classified into three categories by cluster analysis. Real‐ time quantitative PCR results showed that PpPIF1，PpPIF3 and PpPIF4 were significantly up‐regulated in leaves at 8 h after drought stress，while PpPIF1，PpPIF3 and PpPIF5 were up‐regulated in leaves at 96 h after drought stress. The expression of PpPIFs genes in different tissues of Poa pratensis were further determined. The relative expres‐ sion levels of PpPIF1，PpPIF3 and PpPIF4 were significantly higher in tillers than those in leaves，while the relative expression levels of four PpPIF genes were significantly lower in roots than those in leaves. PpPIF1 and PpPIF3 play a potential role in regulating tiller outgrowth and drought resistance. These genes provide excellent gene resources for the breeding of turfgrass.