【作者】 吴泽； 李婷； 向均； 滕人达； 张德花； 丁利平； 章茵艺； 王雨欣； 滕年军；

【Author】 WU Ze;LI Ting;XIANG Jun;TENG Renda;ZHANG Dehua;DING Liping;ZHANG Yinyi;WANG Yuxin;TENG Nianjun;College of Horticulture/Key Laboratory of Landscaping Agriculture,Ministry of Agriculture and Rural Affairs,Nanjing Agricultural University;Nanjing Agricultural University-Nanjing Oriole Island Modern Agricultural Development Co.,Ltd.Jiangsu Graduate Workstation/Nanjing Agricultural University Baguazhou Modern Horticultural Industry Science and Technology Innovation Center;College of Agriculture,Nanjing Agricultural University;

【机构】 南京农业大学园艺学院/农业农村部景观农业重点实验； 南京农业大学—南京鹂岛现代农业发展有限公司江苏省研究生工作站/南京农业大学八卦洲现代园艺产业科技创新中心； 南京农业大学农学院；

【摘要】 NAC转录因子广泛参与植物的逆境胁迫调控,而其在百合(Lilium spp.)耐热性中的研究鲜有报道。我们发现LlNAC014是百合中一个膜结合的NAC家族转录因子,其基因在百合叶片中的表达受长期高温胁迫抑制,但高温可以迅速激活其蛋白功能LlNAC014蛋白的C末端具有一个典型的跨膜结构域(TM)。在常温下,其定位于膜系统上,但在高温条件中,LlNAC014发生蛋白加工形成定位于细胞核的活性形式蛋白LlNAC14ΔC。LlNAC14AC在其C端具有转录激活结构域,可以在酵母和植物细胞中发挥转录激活子的作用。在百合和拟南芥中过表达LlNAC014ΔC可增加其耐热性,但在百合中沉默LlNAC014会降低耐热性。基因表达分析表明LlNAC014AC可以通过诱导依赖于或不依赖于热激转录因子(HSF)途径的高温响应基因的表达来组成型地激活热激反应。进一步地研究表明,LINAC014是DREB2-HSFA3耐热核心模块的直接调节因子,其活性形式LlNAC14ΔC可直接与LIHSFA3A、LlHSFA3B和LlDREB2B启动子中的CTT(N7) AAG元件结合以激活其表达。因此,该研究发现LlNAC014通过感受高温胁迫发生蛋白加工后转移至细胞核中以激活DREB2-HSFA3模块来提高植物的耐热性。该研究通过解析LlNAC014在百合高温响应中的调控机理,为培育耐热的百合种质提供了有效的基因储备和良好的理论基础。更多还原

【Abstract】 The NTL(NAC with transmembrane motif 1-like) transcription factors with a conserved transmembrane motif are members of the NAC family and are important in plant development and in response to stress.However,knowledge of their regulatory pathways is scarce,especially under heat stress.Here,we cloned and identified a novel lily(Lilium longiflorum) NTL gene,LlNAC014, that increases thermotolerance.High temperature repressed LlNAC014 expression but activated its protein.LlNAC014 contained a typical transmembrane motif at its far C-terminus and was normally located on membranes,but under heat stress it entered the nucleus as a transcription factor.LlNAC014 also has a transactivation domain at its C-terminus,and its active form,LINAC014ΔC,could function as a trans-activator in both yeast and plant cells.LlNAC014ΔC overexpression in lily and Arabidopsis increased thermotolerance,and also caused growth defects;silencing LlNAC014 in lily decreased thermotolerance.LlNAC014 AC could constitutively activate the heat stress response by inducing the expression of heat-responsive genes,some of which were dependent on the HSF(heat stress transcription factor) pathway.Further analysis showed that LlNAC014 was a direct regulator of the DREB2-HSFA3 module,and bound to the CTT(N7) AAG element in the promoters of LlSFA3 A,LlHSFA3 B,and LlDREB2 B to activate their expression.Thus,LlNAC014 increased thermotolerance by-sensing high temperature and translocating to the nucleus to activate the DREB2-HSFA3 module.更多还原