Abstract:

Phytochrome （PHY） in plants not only receives light signals as a photoreceptor， but also responds to environmental temperature changes as a temperature sensor. To identify PHY genes in wheat， the bioinformatics methods was used， and their physical and chemical properties， phylogenetic evolution， gene structure， protein conserved domain， promoter cis-acting element and gene expression characteristics were comprehensively analyzed. The results showed that 9 TaPHY genes were identified， which randomly distributed on 6 chromosomes of wheat. And the subcellular localization prediction showed that these proteins were located in the nucleus. Phylogenetic analysis showed that these genes were classified into 3 subclasses， the genes of same subclass had high similarity of gene structure and protein conserved domain， which suggested similar function. Cis-element analysis revealed that the promoter of TaPHY genes had a variety of light and hormone response elements. In addition， tissue expression analysis identified significant differences in the expression abundance of TaPHY genes. Combined with the screening results of heat tolerant and fluorescence quantitative analysis， the expression levels of TaPHYA1 and TaPHYC2 were first down-regulated and then up-regulated under heat stress condition， while other genes showed different degrees of down-regulation， it showed that TaPHY genes induced by heat stress and participated in the regulation of heat resistance of wheat. Correlation analysis showed that the expression of TaPHYA3 was significantly negatively correlated with H₂O₂ content in the heat-resistant material 1-2-3， TaPHYC1 was positively correlated with superoxide dismutase （SOD） activity， TaPHYC3 expression was significantly correlated with SOD activity. Above results provided an experimental basis for further understanding the mechanism of TaPHY involved in heat stress response， and also provided important genetic resources for the screening of heat tolerant wheat lines.

Key words: wheat, PHY gene family, gene identification, heat stress, correlation analysis

摘要：

植物光敏色素（phytochrome， PHY）不仅是光感受器接收光信号，还能够作为温度传感器响应环境温度的变化。为鉴定小麦PHY基因，采用生物信息学方法在小麦全基因组中进行鉴定，并对其理化性质、系统进化、基因结构、蛋白保守结构域、启动子顺式作用元件和基因表达特性等进行综合分析。结果表明，在小麦全基因组中共鉴定出9个TaPHY基因，随机分布在小麦6条染色体上；亚细胞定位预测这些蛋白均定位于细胞核内。系统进化分析将这9个TaPHY基因划分成3个亚类，同一亚类基因的结构和蛋白保守结构域相似度较高，推测其功能相似。顺式作用元件分析显示，TaPHY基因启动子区域存在多种光响应、激素响应顺式作用元件。此外，组织表达分析发现，不同TaPHY基因的表达丰度存在显著差异。结合耐热筛选和荧光定量检测发现，在热胁迫诱导下TaPHYA1和TaPHYC2的表达量先下调后上调，其他基因则呈现不同程度的下调表达趋势，推断TaPHY基因可能参与调控小麦耐热性。相关性分析表明，在耐热材料1-2-3中，TaPHYA3的表达与H₂O₂含量呈显著负相关；TaPHYC1的表达与超氧化物歧化酶（superoxide dismutase，SOD）活性呈极显著正相关；TaPHYC3的表达与SOD活性呈显著正相关。上述研究结果为深入解析TaPHY参与热胁迫响应机制提供了试验依据，也为小麦耐热品系筛选提供了重要功能基因资源。

关键词: 小麦, PHY基因家族, 基因鉴定, 热胁迫, 相关分析