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大豆根系中应答镉胁迫的R2R3-MYB基因分析

丁杰1,2,张晓娜1,2,朴春兰1,崔敏龙1,高振蕊1*   

  1. 1中国科学院沈阳应用生态研究所污染生态与环境工程重点实验室, 沈阳 110016;2中国科学院大学, 北京 100049)
  • 出版日期:2018-07-10 发布日期:2018-07-10

Analysis of the R2R3-MYB genes in soybean roots in response to Cd stress.

DING Jie1,2, ZHANG Xiao-na1,2, PIAO Chun-lan1, CUI Min-long1, GAO Zhen-ri1*   

  1. (1Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; 2University of Chinese Academy of Sciences, Beijing 100049, China).
  • Online:2018-07-10 Published:2018-07-10

摘要: 非生命活动所需的重金属镉(Cd),在土壤中以低浓度存在时,便可以产生极强的毒性,影响植物的生长发育。MYB转录因子是植物中最大的转录因子家族之一,近年的研究表明其广泛参与多种生物学过程。为了解大豆根系中应答镉胁迫的MYB基因,本研究将发芽7天的大豆苗在镉浓度为75 μmol·L-1的培养基中处理0、4、8、12和48 h,采用Illumina HiSeq高通量测序平台对大豆根系进行转录组测序分析,获得16个与镉胁迫应答息息相关的R2R3-MYB基因。氨基酸序列分析表明,这16个MYB转录因子均含有4个保守元件,且均含有R2、R3保守结构域。参考拟南芥R2R3-MYB亚组分类进行系统发生学分析,发现它们分为S1、S2、S8、S15、S17、S20和S22 7个亚组。大豆根系中MYB基因差异表达分析结果显示,镉胁迫条件下,16个R2R3-MYB基因的表达量均发生变化,且表达量变化均在2倍以上,其中6个基因表达下调,最大下调倍数达17倍,10个基因表达上调,最大上调倍数为11倍。进一步分析发现,大豆根系中的MYB基因主要通过调控重金属镉的吸收、转运、解毒过程来缓解镉的毒害作用。本研究通过对大豆根系中应答镉胁迫的R2R3-MYB基因分析,为大豆抗重金属镉育种提供基因资源和理论基础。

关键词: 坡向, 土壤, 铁杆蒿, 化学计量, 黄土丘陵区

Abstract: Low concentrations of the non-essential heavy metal cadmium (Cd) generate an extremely high level of toxicity, which affects the growth and development of plants. The MYB  family is one of the largest families of transcription factors in plants. Related studies in recent years have highlighted its role in a wide range of biological processes. In this study, to gain a better understanding of the role of MYB genes in Cd stress responses in soybean roots, 7-day-old soybean seedlings were treated with a culture medium containing 75 μmol·L-1 of Cd for 0, 4, 8, 12, and 48 h, respectively. Transcriptome sequencing and analysis of the soybean roots were subsequently performed using the Illumina HiSeq high-throughput sequencing system. We identified 16 R2R3-MYB genes closely linked to Cd stress responses. An amino acid sequence analysis showed that all 16 MYB transcription factors composed of four conserved elements and contained the conserved R2 and R3 domains. A phylogenetic analysis was conducted using the subgroup classification of R2R3-MYBgenes in Arabidopsis thaliana as reference; the genes belonged to seven subgroups, namely S1, S2, S8, S15, S17, S20, and S22. Under Cd stress, changes in expression levels of at least twofold occurred in all the 16 R2R3-MYB genes. In particular, expression was downregulated in six genes, with the highest degree of downregulation being 17-fold, and upregulated in the other 10 genes, with the highest degree of upregulation being 11 old. Further analysis revealed that MYB genes in soybean roots primarily alleviated Cd toxicity through regulating Cd absorption, transport, and detoxification. Our results will provide both genetic resources and a theoretical basis for the breeding of Cdresistant soybeans.

Key words: loess hilly region, soil, stoichiometry, aspect, Artemisia sacrorum