大麦HvMYB2分子特性及响应干旱胁迫的功能分析  

Molecular characteristics and functional analysis of HvMYB2 in response to drought stress in barley

作　　者：王林 陈晓雨 张文梦龙 汪思琦 程冰云 程靖秋 潘锐 张文英[1] WANG Lin;CHEN Xiao-Yu;ZHANG Wen-Meng-Long;WANG Si-Qi;CHENG Bing-Yun;CHENG Jing-Qiu;PAN Rui;ZHANG Wen-Ying(College of Agriculture,Yangtze University,Jingzhou 434025,Hubei,China)

机构地区：[1]长江大学农学院,湖北荆州434025

出　　处：《作物学报》2025年第4期873-887,共15页Acta Agronomica Sinica

基　　金：国家自然科学基金面上项目(32372052);长江大学大学生创新创业项目(Yz2023206)资助。

摘　　要：干旱是全球农业生产中最主要的环境胁迫之一,严重影响作物的生长发育和产量形成。挖掘野生大麦优异的抗旱基因对于我国干旱、半干旱区域抗旱大麦品种的选育与利用具有重要意义。为阐明HvMYB2基因的分子特性及其响应干旱胁迫的功能,本研究从抗旱野生大麦EC_S1中扩增HvMYB2编码序列(CDS),获得了912 bp长的CDS序列,编码303个氨基酸。保守结构分析显示,HvMYB2为R2R3型MYB转录因子,含有2个HTH_MYB结构域,其编码蛋白定位于细胞核。系统发育分析表明,HvMYB2与小麦PIMP1蛋白同源性最高(87.5%)。表达模式分析显示,HvMYB2在苗期地上部分表达水平最高。在干旱胁迫条件下,HvMYB2在抗旱野生大麦EC_S1中表达水平显著升高。过表达HvMYB2的拟南芥株系在干旱条件下表现出更强的抗旱性,干旱胁迫下叶片相对含水量、叶绿素a和叶绿素b含量显著高于野生型拟南芥,相对电导率则显著降低,叶片气孔导度显著低于野生型植株。反之,沉默HvMYB2导致了大麦植株在干旱胁迫下的抗旱性显著降低,表现为更高的水分损失和细胞损伤,以及更大的气孔导度。由此推测HvMYB2通过调节叶片气孔导度正调控大麦的抗旱性。互作蛋白预测结果显示,HvMYB2可能与HvMYB27和HvMYB29转录因子形成复合物以调节下游基因表达。此外,HvMYB2启动子分析揭示其包含多个干旱诱导和激素响应元件,野生大麦HvMYB2启动子中181 bp特异性片段插入导致其转录水平受干旱显著诱导,可能提高了野生大麦EC_S1的抗旱性。本研究为全面解析HvMYB2抗旱分子调控机制奠定了基础,为大麦品种抗旱遗传改良提供了新的基因资源。Drought is one of the most critical environmental stresses affecting global agricultural production,severely impairing crop growth and yield.Identifying drought-resistant genes in wild barley holds significant potential for the utilization of arid and semi-arid lands in northwest China.This study focused on the molecular characterization of the HvMYB2 gene and its functional role under drought stress.A 912 bp coding sequence(CDS)of HvMYB2 was amplified from the drought-tolerant wild barley EC_S1,encoding a protein of 303 amino acids.Conserved structure analysis revealed that HvMYB2 is an R2R3-type MYB transcription factor containing two HTH_MYB domains,and it was predicted to localize in the nucleus.Phylogenetic analysis showed that HvMYB2 shares the highest homology(87.5%)with wheat PIMP1.Expression pattern analysis indicated that HvMYB2 is most highly expressed in the shoots at the seedling stage.Under drought stress,HvMYB2 expression was significantly upregulated in the drought-tolerant wild barley EC_S1.Arabidopsis thaliana plants overexpressing HvMYB2 exhibited enhanced drought tolerance,characterized by higher relative water content,increased chlorophyll a and b levels,and reduced relative electrical conductivity.Additionally,these plants displayed lower stomatal conductance under drought conditions compared to wild-type plants.Conversely,silencing HvMYB2 in barley significantly reduced drought tolerance,resulting in greater water loss,increased cell damage,and higher stomatal conductance.These results suggest that HvMYB2 positively regulates drought tolerance in barley by modulating stomatal closure.Protein interaction predictions indicated that HvMYB2 may form a complex with the transcription factors HvMYB27 and HvMYB29 to regulate downstream gene expression.Promoter analysis of HvMYB2 revealed the presence of multiple drought-responsive and hormone-regulated elements.Notably,the insertion of a 181 bp specific fragment in the HvMYB2 promoter of wild barley significantly enhanced its transcription under dr

关 键 词：野生大麦 MYB转录因子 干旱胁迫 基因克隆 VIGS沉默 

分 类 号：S51[农业科学—作物学]