甘薯抗旱相关基因IbNAC72的克隆与功能分析  

Cloning and functional analysis of a drought tolerance-related gene IbNAC72 in sweet potato

作　　者：张欢[1] 杨乃科 商丽丽[2] 高晓茹 刘庆昌[1] 翟红[1] 高少培 何绍贞[1] ZHANG Huan;YANG Nai-Ke;SHANG Li-Li;GAO Xiao-Ru;LIU Qing-Chang;ZHAI Hong;GAO Shao-Pei;HE Shao-Zhen(Key Laboratory of Sweet Potato Biology and Biotechnology,Ministry of Agriculture and Rural Affairs/Laboratory of Crop Heterosis&Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding,Ministry of Education,China Agricultural University,Beijing 100193,China;Yantai Academy of Agricultural Sciences,Yantai 265500,Shandong,China)

机构地区：[1]中国农业大学农业农村部甘薯生物学与生物技术重点实验室/教育部作物杂种优势研究与利用重点实验室,北京100193 [2]山东省烟台市农业科学研究院,山东烟台265500

出　　处：《作物学报》2020年第11期1649-1658,共10页Acta Agronomica Sinica

基　　金：国家重点研发计划项目(2018YFD1000700,2018YFD1000704);北京粮经创新团队项目(BAIC09-2020);国家现代产业技术体系建设专项(CARS-10,甘薯)资助。

摘　　要：NAC(NAM/ATAF/CUC,NAC)转录因子是植物中特有的转录调控因子,在植物体的生长发育与逆境胁迫响应等多种生理过程中起着重要的调控作用。本研究利用cDNA末端快速扩增技术(rapid amplification of cDNA ends,RACE)从甘薯品种栗子香中克隆到甘薯抗旱相关基因IbNAC72,该基因cDNA长为1319 bp,开放阅读框(open reading frame,ORF)为1008 bp,编码335个氨基酸,分子量为37.4 kD,等电点为8.76,基因组全长为1199 bp,含有3个外显子、2个内含子。多重序列比对和系统进化树分析显示,IbNAC72基因与牵牛花中同源基因的亲缘关系最近。实时荧光定量PCR分析表明,IbNAC72基因在甘薯叶片中的表达量显著高于在茎段和根系中;同时IbNAC72基因受到干旱和盐胁迫显著诱导表达。利用农杆菌介导法转化烟草,获得过表达IbNAC72基因的转基因烟草植株。对IbNAC72转基因烟草植株的抗旱性分析表明,在长时间干旱条件下,转基因植株的根系更加发达,SOD活性显著提高,MDA的含量显著降低,抗旱性显著提高。本研究表明,IbNAC72是与抗旱性密切相关的基因,为深入探究IbNAC72抗旱的分子机制提供了基础。NAC(NAM/ATAF/CUC)is a plant-specific transcription factor family,which plays an important role in plant growth,development and stress responses.In this study,we cloned IbNAC72,a drought tolerance-related gene from sweet potato[Ipomoea batatas(L.)Lam.]variety Lizixiang by RACE method.The IbNAC72 cDNA of 1319 bp in length,had an open reading frame(ORF)of 1008 bp,and encoded a 335 amino acids polypeptide,with a molecular weight of 37.4 kD and an isoelectric point(pI)of 8.76.The genomic DNA of IbNAC72 gene was 1199 bp and was deduced to contain 3 exons and 2 introns.Sequence alignment and phylogenetic analysis revealed that IbNAC72 had a close relationship with the predicted protein products of Ipomoea nil.RT-qPCR analysis showed that IbNAC72 was expressed at the highest level in the leaves of sweet potato,and it was strongly induced by PEG-6000 and NaCl,respectively.IbNAC72 was transformed into tobacco via Agrobacterium-mediated transformation.Its overexpression significantly enhanced drought tolerance in the transgenic tobacco plants.Under drought stress,transgenic plants developed stronger root system;the SOD activity was significantly increased whereas the MDA content was significantly decreased in transgenic plants compared to those of wild type plants.This study showed that IbNAC72 gene was closely related to drought tolerance,providing a basis for in-depth study on the drought tolerance molecular mechanism of Ib-NAC72 in sweet potato.

关 键 词：甘薯 NAC转录因子 IbNAC72 过表达 抗旱 

分 类 号：S531[农业科学—作物学]