Abstract: Late embryogenesis abundant (LEA) proteins are a class of proteins accumulating in seeds during the late stage of embryonic development in higher plant, and they play  important roles in plant resistance to adversity stress. LEA3, the third group of the LEA proteins, is the major member of this family and has been extensively studied for its excellent performance in drought and salt tolerance in plants. In previous study, a differential accumulation protein Wrab17 (TaLEA3 gene family) associated with Fusarium head blight (FHB) resistance was screened from wheat cobs inoculated with Fusarium graminearum   by high-throughput proteomics strategy. In order to reveal the sequence characteristics of TaLEA3 gene family in wheat and its response mechanism to biological stress, bioinformatics method was used to systematically study the gene family. The results showed that a total of 26 TaLEA3 genes were present in wheat genome named TaG3LEA-1~TaG3LEA-26, which were distributed on nine chromosomes of wheat. Tandem duplication and segmental duplication were probably the main expansion ways of this gene family. And MEME analysis showed that the members of this family contained either motif 2 or motif 5, which is the typical feature of LEA3 family. Through expression profiling analysis and qRT-PCR verification, TaG3LEA-25 was highly expressed under both drought and high temperature stresses, and there was also a significant difference in FHB inoculation test, suggesting that it might be involved in FHB resistance. The results of this study provided valuable information for elucidation of the evolutionary relationships of TaLEA3 gene family in wheat and laid a theoretical foundation for further exploration of their functional mechanisms.

Key words: wheat, LEA3, gene family, Fusarium head blight, expression profile

摘要： 胚胎晚期丰富（late embryogenesis abundant，LEA）蛋白是高等植物胚胎发育后期种子中大量积累的一类蛋白质，在植物逆境胁迫方面具有重要作用。其中第三组的LEA蛋白（LEA3）是该类蛋白家族的主要成员，因其在植物抗旱耐盐性方面的卓越表现而被广泛研究。在前期研究中，通过高通量蛋白质组学的方法，在禾谷镰刀菌接种的小麦穗轴中筛选到1个与抗病相关的差异积累蛋白Wrab17（LEA3基因家族）。为了揭示小麦中TaLEA3基因家族的序列特征及其对生物胁迫的响应机制，采用生物信息学方法对该基因家族进行了系统研究。结果表明，在小麦全基因组中共鉴定到26个TaLEA3基因，命名为TaG3LEA-1~TaG3LEA-26，分布于小麦的9条染色体上。串联重复和片段复制是该基因家族扩张的主要方式；MEME分析表明该家族成员含有motif 2或motif 5，是LEA3家族的典型特征。通过基因表达分析和qRT-PCR验证，发现TaG3LEA-25在干旱和高温胁迫下均高表达，并且在不同赤霉病抗感材料间存在显著差异，推测其可能参与了小麦赤霉病抗性调控。研究结果为阐明小麦TaLEA3家族基因的进化关系提供了有价值的信息，并且为进一步探究其功能机制奠定了理论基础。

关键词: 小麦, LEA3, 基因家族, 赤霉病, 表达谱