热诱导转录因子ZmNF-YC13调控热胁迫应答基因提高玉米耐热性

Heat-inducible transcription factor ZmNF-YC13 regulates heat stress response genes to improve heat tolerance in maize

热胁迫是影响玉米生长发育和产量形成的重要因素,相关抗性基因的挖掘和机制解析是进行玉米耐热品种培育的重要分子基础,而目前这方面的研究仍是缺乏。本研究鉴定到一个与热胁迫应答相关的核因子ZmNF-YC13,该基因受高温和渗透胁迫快速诱导表达。用拟南芥热胁迫诱导表达基因AtHSP70的启动子驱动ZmNF-YC13基因,转化玉米筛选出了热诱导表达的转基因材料HSP21Pro:ZmNF-YC13-myc。高温处理后的表型鉴定表明,叶长、叶宽、地上部粗、地上部分和地下部分的鲜重和干重均显著高于野生型。表达分析表明, ZmNF-YC13能增强下游热胁迫应答基因响应热胁迫的程度。荧光素酶报告基因实验和ChIP-qPCR实验表明,ZmNF-YC13可调控热应激转录因子ZmHsfA2c的表达。这些结果初步证实了ZmNF-YC13可通过调控下游热胁迫应答基因来提高玉米的耐热能力,可为利用该位点的多态性进行分子标记辅助选择和种质资源鉴定提供理论依据。

Heat stress is an essential factor affecting maize growth and yield formation.The exploration and mechanism analysis of related tolerance genes is an important field for breeding maize heat stress tolerant varieties.However,there is few study in this aspect.In this study,we identified a nuclear factor ZmNF-YC13 associated with heat stress response,and its encoding gene expression was rapidly induced by high temperature and osmotic stress.The promoter of Arabidopsis thaliana heat stress-inducible expression gene AtHSP70 was used to drive ZmNF-YC13 and the heat-inducible expression maize material of ZmNF-YC13(HSP21Pro:ZmNF-YC13-myc)was successfully screened.Phenotypic analysis after high temperature treatment demonstrated that leaf length,leaf width,shoot thickness,fresh and dry weight of shoot and root were significantly higher than wild type.The relative expression level showed that ZmNF-YC13 could enhance the inducible level of downstream heat stress response genes in response to heat stress.Luciferase reporter assay and ChIP-qPCR assay also revealed that ZmNF-YC13 could regulate the expression of heat stress transcription factor ZmHsfA2c.These results confirmed preliminarily that ZmNF-YC13 could improve the heat tolerance of maize by regulating downstream heat stress response genes,which could provide a theoretical basis for marker-assisted selection and germplasm identification using the polymorphism of this locus.