中国农业科学Issue(19)：3736-3745,10.DOI:10.3864/j.issn.0578-1752.2014.19.002
两个小麦LEA基因的特征及其对非生物胁迫的响应
Characterization of Two LEA Genes and Their Response to Abiotic Stresses in Wheat
摘要
Abstract
[Objective] Drought is one of the major factors significantly affecting the growth and yield of wheat crop. In this study, two LEA genes were characterized and their response to abiotic stresses, such as drought, salt, heat and cold, were investigated. The biological functions of these two LEA genes during the stress tolerance of wheat plant were also discussed, which would provide important information for the application of these two LEA genes in wheat molecular breeding for the improvement of stress tolerance. [Method]RT-PCR technology was used in the cloning of LEA genes and proper bioinformatic methods were applied for characterizing the LEA genes and their deduced proteins. The gene expression patterns responding to various abiotic stresses were analyzed by using the real time qRT-PCR.[Result]Two wheat LEA genes TaLEA4 and TaLEA5, with complete coding sequences, were cloned and sequencing analysis showed that these two LEA genes encode 180 and 163 amino acids, with a predicted molecular weight of about 18.8 and 16.9, pI of 5.6 and 7.2, respectively. Genomic structuring showed that one intron with 100 bp in length was detected in both of the cloned genes. Amino acid sequence analysis indicated that both of the wheat LEA proteins were rich in polar amino acids, which accounted for about 71%, and so they showed high hydrophilic. Conserved domain analysis indicated that both of TaLEA4 and TaLEA5 included a typical LEA_4 (pfam:02978) domain and belong to LEA_4 subfamily of LEA proteins. Protein structural analysis demonstrated that the region of helixes accounted for 96.7%and 96.3%of TaLEA4 and TaLEA5, respectively. Both of these LEA proteins can form a bow shape structure, and one binding site of ligand PEV (C39H78NO8P) was found in TaLEA4, while two of that were detected in TaLEA5. The expression profiling revealed that both of the wheat LEA genes were induced by plant hormone ABA, and the expression level of TaLEA4 was significantly higher than that of TaLEA5. Under the abiotic stresses of drought, salt and heat, TaLEA4 was greatly up-regulated, while TaLEA5 was only induced by drought-stress and its expression level was significantly lower than that of TaLEA4. Both of these LEA genes did not response to cold-stress. Interestingly, the expression level of TaLEA4 was obviously higher in root tissues than that in leaf tissues under drought- and salt-stresses, while that was higher in leaves under heat-stress, which might be due to that the osmotic stresses were directly sensed by roots, but leaf tissues were more sensitive to heat-stress. [Conclusion] Both of the wheat LEA genes TaLEA4 and TaLEA5 belonged to the LEA_4 subclass LEA family, they showed high hydrophilic and were involved in the ABA dependent stress-responding gene network. It was deduced that TaLEA4 might play important roles during the processes of responding to the drought, salt and heat stresses, while the TaLEA5 was only involved in the drought-stress responding and its function might be weaker than that of TaLEA4.关键词
普通小麦/LEA基因/非生物胁迫/表达模式Key words
common wheat/LEA gene/abiotic stresses/expression patterns引用本文复制引用
刘露露,陈雷,张春艳,石瑞杰,任江萍,孟凡荣,尹钧,李永春..两个小麦LEA基因的特征及其对非生物胁迫的响应[J].中国农业科学,2014,(19):3736-3745,10.基金项目
农业部转基因生物新品种培育科技重大专项 （）
