PhPIF4在矮牵牛分枝发育中的功能分析

Functional analysis of PhPIF4 in Petunia hybrida branching development

摘要:

PIF4作为光信号转导核心调控元件，参与植物的多个发育过程。为在观赏植物中分析该基因的功能及作用机理，本研究通过遗传转化和转录组测序(RNA sequencing, RNA-seq)解析了PhPIF4在矮牵牛分枝发育中的功能及其下游调控路径。结果表明，PhPIF4过表达拟南芥转基因株系分枝数目减少，而PhPIF4-RNAi矮牵牛转基因株系则呈现分枝数显著增加的表型；RNA-seq揭示PhPIF4过表达株系中591个差异基因显著富集于激素代谢通路，细胞分裂素合成基因IPT3/5、CYP735A1及LOG2显著下调。进一步验证发现，PhPIF4通过激活分枝抑制因子BRC1和SPL9，及远红光伴侣蛋白基因FHL，最终影响分枝发育。本研究为进一步解析PhPIF4调控矮牵牛分枝发育的分子机制提供了理论依据。

Abstract:

As a core regulatory component of photomorphogenic signaling, phytochrome interacting factor 4 (PIF4) participates in multiple developmental processes in plants. To analyze the function and mechanism of this gene in ornamental plants, this study elucidated the role of PhPIF4 in the branching development of Petunia hybrida and its downstream regulatory pathways through genetic transformation and RNA sequencing (RNA-seq). The results showed that Arabidopsis transgenic lines overexpressing PhPIF4 exhibited reduced branches, whereas PhPIF4-RNAi transgenic lines of P. hybrida displayed significantly increased branches. RNA-seq results revealed that 591 differentially expressed genes in PhPIF4-overexpressing lines were significantly enriched in phytohormone metabolic pathways, and the expression levels of cytokinin biosynthesis-related genes IPT3/5, CYP735A1, and LOG2 were markedly downregulated. Further verification demonstrated that PhPIF4 affected branching by activating the branching inhibitor genes BRC1 and SPL9 and the far-red light chaperone gene FHL. This study provides a theoretical basis for further elucidating the molecular mechanisms by which PhPIF4 regulates the branching of P. hybrida.