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第3组LEA蛋白(late embryogenesis abundant protein)介导干旱、高温、高盐等非生物胁迫响应,关于普通小麦LEA基因的研究鲜有报道。利用噬菌体原位杂交技术,从小麦苗期干旱胁迫条件构建的cDNA文库中筛选出LEA蛋白基因TaLEAL3,其全长750bp,编码区长501bp,编码166个氨基酸,含有一个明显的核定位信号区。氨基酸同源性分析发现,TaLEAL3属于第3组LEA蛋白,序列中含有由11个氨基酸组成的3个不完全重复的基序和α-螺旋的LEA结构。电子定位结果显示,TaLEAL3基因位于4BL、4DL和5AL染色体上,主要在茎中表达,而在根中几乎无表达。实时荧光定量PCR分析表明,在干旱、低温和ABA诱导下,TaLEAL3基因表达量明显增加。在该基因上游1.7kb序列处,预测具有启动子的核心序列和增强子序列,及与干旱和低温等多种逆境胁迫相关的调控序列。本研究为深入分析小麦LEA蛋白基因的功能,初步解析LEA蛋白的作用机制提供了数据。
Group 3 LEA (late embryogenesis abundant protein) mediates abiotic stress responses such as drought, high temperature and high salt. There are few reports about the LEA gene in common wheat. Using phage in situ hybridization, the LEA gene TaLEAL3 was screened from cDNA library constructed under the drought stress conditions of wheat seedlings. The full-length cDNA of TaLEAL3 was 750bp in length with a coding region of 501bp encoding a polypeptide of 166 amino acids with a clear nuclear localization signal. Amino acid homology analysis revealed that TaLEAL3 belonged to the third group of LEA proteins and contained three incompletely repeated motifs composed of 11 amino acids and the α-helix LEA structure. The electronic localization results showed that the TaLEAL3 gene is located on the chromosomes 4BL, 4DL and 5AL, mainly expressed in the stems but scarcely expressed in the roots. Real-time PCR analysis showed that TaLEAL3 gene expression was significantly increased under drought, hypothermia and ABA induction. At the 1.7kb sequence upstream of the gene, the core sequence and enhancer sequence with promoter and the regulatory sequences related to various stresses such as drought and low temperature are predicted. This study provides the data for further analysis of the function of LEA protein in wheat and preliminary analysis of the mechanism of action of LEA protein.