《植物生理学报》 2018, 54(6): 1085-1094

烟草NtNAC1基因的克隆及其在烟草中的抗旱功能分析

徐小艳¹, 姚新转¹, 吕立堂^1,2,*, 赵德刚^1,3,*

¹贵州大学生命科学学院/农业生物工程研究院, 山地植物资源保护与种质创新省部共建教育部重点实验室, 贵阳550025; ²贵州大学茶学院, 贵阳550025; ³贵州省农业科学院, 贵阳550006

通信作者：吕立堂；E-mail: lvlitang@163.com, dgzhao@gzu.edu.cn

摘　要：

NAC转录因子在植物信号转导及非生物损伤过程中起重要作用。本实验从烟草cDNA文库中克隆了Nt-NAC1基因, cDNA编码区全长861 bp, 编码286个氨基酸。进化树分析结果显示, NtNAC1基因编码的氨基酸序列与马铃薯同源性最高。农杆菌介导的遗传转化获得37株转基因烟草, 用20% PEG6000处理转基因和野生型植株7 d。结果显示, 转基因植株的超氧化物歧化酶(SOD)、过氧化物酶(POD)的酶活性都高于野生型, 丙二醛(MDA)和脯氨酸(Pro)含量都低于野生型。RT-PCR分析结果显示, NtNAC1基因以及NtNAC基因表达高于野生型, 脯氨酸合成的2个关键酶吡咯啉-5-羧酸合成酶(P5CS)和鸟氨酸-δ-氨基转移酶(δ-OAT)基因表达低于野生型。选取T₀代转基因和野生型种子, 对苗期根系进行耐旱性分析。结果发现, 在300 mmol·L^-1甘露醇胁迫下, 转基因根系比野生型长, 野生型根系的生长明显受到抑制。这表明转NtNAC1基因的表达可能提高了植株的抗旱能力。

关键词：NtNAC1基因; 克隆; 抗氧化酶; 抗旱性

收稿：2017-11-09   修定：2018-05-16

资助：国家转基因生物新品种培育科技重大专项子课题任务(2014ZX08010-003)、国家自然科学基金(31160149)和贵州茶产业技术创新中心(黔科中引地[2017]4005)。

Cloning of NtNAC1 gene from Nicotiana tabacum and its analysis of drought-resistant function

XU Xiao-Yan¹, YAO Xin-Zhuan¹, LÜ Li-Tang^1,2,*, ZHAO De-Gang^1,3,*

¹College of Life Sciences and Institute of Agro-Bioengineering, the Key Laboratory of Plant Resources Conservation and Germplasm Innovationin Mountainous Region (Ministry of Education), Guizhou University, Guiyang 550025, China; ²College of Tea Sciences, Guizhou University, Guiyang 550025, China; ³Guizhou Academy of Agricultural Science, Guiyang 550006, China

Corresponding author: ; E-mail: lvlitang@163.com, dgzhao@gzu.edu.cn

Abstract:

NAC transcription factor plays an important role in plant signal transduction and abiotic damage. In this study, the NtNAC1 gene was cloned from the cDNA library of tobacco, and the coding region was 861 bp in length, encoding 286 amino acids. The phylogenetic tree analysis showed that the amino acid sequence encoded by NtNAC1 gene was the highest homologous to potato and 37 strains of transgenic tobacco obtained by Agrobacterium tumefaciens were treated with 20% PEG6000 for 7 days. The results showed that the activities of superoxide dismutase (SOD) and peroxidase (POD) in transgenic plants were higher than those in wild type. The contents of MDA and proline were lower than those of wild type. The results showed that the expression of NtNAC1 and NtNAC gene were higher than wild type by RT-PCR analysis, and the pyrroline-5-carboxylic acid synthase (P5CS) and ornithine-δ-aminotransferase (δ-OAT) were lower than wild type. The T₀ transgenic and wild type seeds were selected to analyze the drought tolerance of seedling roots. The results showed that under the condition of 300 mmol·L^-1 mannitol, the transgenic plant roots were more inhibited than wild type roots. The results showed that the expression of NtNAC1 gene could increase the drought tolerance of plant.

Key words: NtNAC1 gene; cloning; enzyme activity; drought resistance