小麦质膜蛋白基因TaPM19-1的克隆及其对非生物胁迫的响应

Cloning of a Plasma Membrane Protein Gene TaPM19-1 and Its Response to Abiotic Stresses in Wheat

【目的】分析小麦质膜蛋白基因TaPM19-1的特征及其对非生物胁迫的响应,并探讨其在小麦抗逆调控过程中的生物学功能。【方法】利用RACE技术克隆了该基因cDNA全长,采用生物信息学方法分析克隆基因编码蛋白的特性,并通过半定量RT-PCR分析该基因在非生物胁迫条件下的表达特性。【结果】TaPM19-1的cDNA全长1 090 bp,无内含子,编码蛋白包含182个氨基酸,分子量为19.02 kD,包含有典型的AWPM19保守域;依据氨基酸序列将来源于不同植物的16个AWPM19类蛋白分为3组,TaPM19-1与2个来源于大麦及1个二穗短柄草的AWPM19类蛋白亲源关系最近,同属于第三组。高级结构分析显示,TaPM19-1可形成4个由α-螺旋组成的跨膜域,N端位于膜内,包含由27个氨基酸组成的信号肽,C端近40个氨基酸位于膜内。表达分析显示,TaPM19-1除在发育后期的种子中有较高水平表达外,其它组织中未检测到表达;在所检测的2个小麦品种根系中,TaPM19-1的表达受ABA诱导,但在叶片中的表达量极低;水分胁迫条件下,该基因在根系和叶片中均呈现较强的诱导表达特性;在高盐和高温胁迫条件下,该基因在洛旱2号小麦中均可诱导表达,而在中国春小麦中未检测到该基因表达;在低温胁迫条件下,未检测到TaPM19-1的表达。【结论】获得了小麦质膜蛋白基因TaPM19-1的cDNA全长,其编码蛋白可形成典型的跨膜结构特征;该基因受植物激素ABA的诱导,在洛旱2号中也可被干旱、高盐和高温胁迫诱导,但在中国春中对高盐和高温胁迫无响应。推测TaPM19-1在洛旱2号和中国春中存在不同的转录调控机制。

【Objective】 The characteristics of a plasma membrane protein gene TaPM19-1 and its response to abiotic stresses in wheat were studied,which will provide an insight into its biological roles involved in the molecular mechanisms of abiotic-sterss response in wheat.【Method】 RACE technology was used in full-length cDNA cloning and proper bioinformatics software was applied for characterizing the cloned gene and its deduced protein.Semi-quantitative RT-PCR was performed to study the expression patterns of TaPM19-1 under abiotic stresses.【Result】 The full-length cDNA of TaPM19-1 is 1 090 bp and no introns were included.TaPM19-1 consists of 182 amino acids with a molecular weight of 19.02 kD,and an typical AWPM19 conserved domain was found in it.Based on the amino acid sequences,16 AWPM19-like proteins of different plant species were sorted into 3 categories,TaPM19-1 and 3 others,2 AWMP19-like proteins of Hordeum vulgare and 1 of Brachypodium distachyon,were highly similar and included in the third category.The structural prediction of TaPM19-1 revealed that 4 transmembrane regions with alpha helixes could be formed,the N-terminal（including a signal peptide consists of 27 amino acids） was located inside the membrane,while the C-terminus（about 40 amino acids） located inside.The RT-PCR analysis showed that the expression of TaPM19-1 was not detected in all tissues except in later period of developing seeds.The expression of TaPM19-1 was greatly induced by ABA in roots of two detected wheat cultivars,while its expression in leaves was very low.Under the water stress,the gene was immediately and highly induced both in roots and leaves.The expression of TaPM19-1 can be induced by salt-and heat-stress in Luohan 2,while not induced in Chinese Spring.Under lower temperature treatment,no expression of TaPM19-1 was detected in both wheat varieties.【Conclusion】 The full-length cDNA of TaPM19-1 was obtained and some typical transmembrane structural features were found in its deduced protein.The expression of TaPM19-1 can be induced by plant hormone ABA.TaPM19-1 can also be induced by drought-,salt-and heat-stress in Luohan 2,while not response to salt-and heat-stress in Chinese Spring.The results suggested that TaPM10-1 might have different transcriptional regulating mechanisms in Luohan 2 and Chinese Spring.