陆地棉NAC转录因子基因GhSNAC1的克隆及其抗旱耐盐分析  

Cloning of NAC Transcription Factor Gene GhSNAC1 and Its Drought and Salt Resistance in Upland Cotton(Gossypium hirsutum)

作　　者：王立国[1] 傅明川 李浩[1] 刘任重[1] 柳展基[1] WANG Li-Guo;FU Ming-Chuan;LI Hao;LIU Ren-Zhong;LIU Zhan-Ji(Key Laboratory of Cotton Breeding and Cultivation in Huang-Huai-Hai Plain, Ministry of Agriculture/Shandong Cotton Research Center, Jinan 250100, China)

机构地区：[1]农业部黄淮海棉花遗传改良与栽培生理重点实验室/山东棉花研究中心,济南250100

出　　处：《农业生物技术学报》2019年第4期571-580,共10页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金(No.31571755);山东省农业科学院农业科技创新工程项目(No.CXGC2018E06和No.CXGC2018B01)

摘　　要：NAC (NAM/ATAF/CUC)家族是植物中特有的一类转录因子,其功能涉及植物生长发育调控、激素信号转导、逆境胁迫响应等重要生理过程。本研究利用反转录PCR (reverse transcription PCR, RT-PCR)技术从陆地棉(Gossypium hirsutum)中克隆了1个逆境胁迫响应(stress-responsive) NAC类转录因子基因,命名为GhSNAC1 (GenBank No. KU759894)。该基因长度为1 104 bp,预测编码蛋白含有299个氨基酸,分子量为33.9 kD,等电点为6.18。蛋白序列分析表明,GhSNAC1具有典型的NAC转录因子特征,N端含有保守的NAC结构域。进化分析表明,GhSNAC1与拟南芥(Arabidopsis thaliana) ATAF1 (Arabidopsis transcription activation factor 1)高度相似。qRT-PCR结果显示,GhSNAC1受到干旱、高盐、低温和黄萎病菌(Verticillium dahliae)胁迫诱导,提示该基因可能参与生物和非生物胁迫响应。在烟草(Nicotiana tabacum)中过表达GhSNAC1,分析干旱或盐胁迫条件下转基因和野生型烟草株系种子的萌发率和幼苗生长差异,实验结果显示,在100 mmol/L NaCl或200 mmol/L甘露醇胁迫下,野生型烟草的种子萌发受到明显抑制,萌发率低于50%,而转基因株系显著优于野生型,其种子萌发率均在80%以上;野生型烟草幼苗弱小,而转基因株系长势强,其单株鲜重和根长分别是野生型的2倍和1.5倍以上。上述结果表明,过表达GhSNAC1可显著提高转基因烟草的抗旱耐盐能力。本研究为深入探究GhSNAC1抗旱耐盐的分子机制提供了基础资料。NAC(NAM/ATAF/CUC) family is a class of transcription factors unique to plants, and plays crucial roles on developmental regulation, hormone signal transduction, biotic and abiotic stress responses. In the present study, a stress-responsive NAC gene, named as GhSNAC1(GenBank No. KU759894), was isolated from upland cotton(Gossypium hirsutum) via reverse transcription PCR(RT-PCR). The sequence analysis indicated that GhSNAC1 was 1 104 bp in length and encoded a protein of 299 amino acids with a relative molecular mass of 33.9 kD and an isoelectric point of 6.18. GhSNAC1 contained a conserved NAC domain in the N-terminus, indicating that it was a typical NAC transcription factor. The phylogenetic analysis indicated that GhSNAC1 had extremely high similarity with ATAF1(Arabidopsis transcription activation factor 1) from Arabidopsis thaliana. qRT-PCR anaylsis showed that GhSNAC1 was induced by treatments of drought, salt,cold and Verticillium dahliae which suggested that GhSNAC1 might be involved in responses to biotic and abiotic stresses. GhSNAC1 was then overexpressed in transgenic tobacco(Nicotiana tabacum) plants.Transgenic lines and wild type(WT) were used to evaluate the germination and seedling growth under either salt(100 mmol/L NaCl) or drought(200 mmol/L mannitol) stress. The results indicated that drought and salt stresses significantly inhibited the germination of WT seeds, and the germination rate of WT was below 50%,while the germination of transgenic lines was above 80%. The WT seedlings were small and weak. However,the transgenic lines were vigorous. The fresh weight per plant and root length of transgenic lines were more than twice and 1.5 times of those of wild type, respectively. Collectively, the above results suggested that overexpression of GhSNAC1 in tobacco could improve tolerance to drought and salt stresses. The present study laid a foundation for further exploring the molecular mechanism of drought and salt tolerance of GhSNAC1.

关 键 词：棉花 NAC转录因子 干旱 盐胁迫 过表达分析 

分 类 号：S562[农业科学—作物学]