Abstract: Ethylene response factors （ERFs） are key regulatory proteins involved in plant responses to abiotic stresses. In this study， based on the genome data of Pennisetum purpureum， 53 members of the PpERF gene family were identified. The encoded proteins ranged from 191 to 1145 amino acids in length， with predicted isoelectric points ranging from 4.75 to 11.79 and molecular weights ranging from 20 536.11 to 124 866.3 Da. Among these genes， three were not mapped to the chromosomes， whereas the remaining genes were unevenly distributed across eight chromosomes. Phylogenetic analysis classified the PpERF genes into three evolutionary clades. Most PpERF proteins contained highly conserved Motifs 1， 2， and 4， and multiple stress-responsive cis-acting elements were identified in their promoter regions. Expression analysis showed that 11 PpERF genes exhibited spatiotemporal expression specificity under low-temperature stress， among which PpERF17， PpERF21， and PpERF32 were significantly upregulated after 24 h of cold treatment. Transient overexpression assays in tobacco further demonstrated that these three genes significantly enhanced plant tolerance to low-temperature stress. This study provides a theoretical basis for elucidating the molecular mechanisms underlying low-temperature responses in Pennisetum purpureum and offers potential candidate genes for the breeding of cold-tolerant forage grasses.

Key words: Pennisetum purpureum, ERF transcription factor, Low-temperature stress, Gene expression analysis

摘要： 乙烯响应因子（ERF）是植物响应非生物胁迫的核心调控蛋白，本研究基于象草基因组数据，鉴定出53个PpERF基因家族成员，其编码的氨基酸数量、等电点和分子量范围分别为 191~1145 aa、4.75~11.79和20 536.11~124 866.3 Da，其中3个基因未定位到染色体，其余分布于8条染色体上。系统发育分析将其分为3个进化分支，多数蛋白包含高度保守的Motif 1，2，4，启动子区域存在多种胁迫响应相关顺式作用元件。表达分析显示，11个PpERF基因在低温胁迫下具有时空表达特异性，PpERF17， PpERF21， PpERF32在24 h显著上调，烟草瞬时过表达实验进一步证实这3个基因可显著增强植物低温耐受性。本研究为解析象草低温响应机制及抗寒牧草育种提供了理论依据与基因靶点。

关键词: 象草, ERF转录因子, 低温胁迫, 基因表达分析