HEAT-INDUCED TAS1 TARGET1 Mediates Thermotolerance via HEAT STRESS TRANSCRIPTION FACTOR A1a-Directed Pathways in Arabidopsis
HEAT-INDUCED TAS1 TARGET1 Mediates Thermotolerance via HEAT STRESS TRANSCRIPTION FACTOR A1a-Directed Pathways in Arabidopsis
复制标题
DOI：
10.1105/tpc.114.124883
复制
发表时间：
2014-04-01
期刊：
影响因子：
11.6
通讯作者：
He, Yuke
中科院分区：
文献类型：
--
作者：
Li, Shuxia;Liu, Jinxin;He, Yuke
许多热胁迫转录因子（Hsfs）和热激蛋白（Hsps）在植物的耐热性中起重要作用。然而，许多介导热反应途径的关键因素仍然未知。在这里，我们报告了两个基因，这是目标的TAS 1（反式作用siRNA前体1）衍生的小干扰RNA，我们命名为热诱导TAS 1目标1（HTT 1）和HTT 2，参与耐热性。基因芯片分析表明，HTT 1和HTT 2基因在拟南芥幼苗中高度上调热休克反应。TAS 1a的反式作用小干扰RNA靶向HTT基因，其过表达增加了TAS 1-siRNA的积累并降低了HTT基因的表达水平，导致较弱的耐热性。相反，HTT 1和HTT 2的过表达上调了几个Hsf基因，导致更强的耐热性。在过表达HsfA 1a的耐热植物中，HTT基因被上调，特别是在高温下。同时，HsfA 1a通过与HTT 1和HTT 2的启动子结合直接激活HTT 1和HTT 2。HTT 1与热休克蛋白Hsp 70 -14和Hsp 40以及核因子Y C2亚单位相互作用。综上所述，这些结果表明，HTT 1介导的耐热性途径，因为它是由TAS 1a的目标，主要由HsfA 1a激活，并作为热休克蛋白70 -14复合物的辅因子。
Many heat stress transcription factors (Hsfs) and heat shock proteins (Hsps) have been identified to play important roles in the heat tolerance of plants. However, many of the key factors mediating the heat response pathways remain unknown. Here, we report that two genes, which are targets of TAS1 (trans-acting siRNA precursor 1)-derived small interfering RNAs that we named HEAT-INDUCED TAS1 TARGET1 (HTT1) and HTT2, are involved in thermotolerance. Microarray analysis revealed that the HTT1 and HTT2 genes were highly upregulated in Arabidopsis thaliana seedlings in response to heat shock. Overexpression of TAS1a, whose trans-acting small interfering RNAs target the HTT genes, elevated accumulation of TAS1-siRNAs and reduced expression levels of the HTT genes, causing weaker thermotolerance. By contrast, overexpression of HTT1 and HTT2 upregulated several Hsf genes, leading to stronger thermotolerance. In heat-tolerant plants overexpressing HsfA1a, the HTT genes were upregulated, especially at high temperatures. Meanwhile, HsfA1a directly activated HTT1 and HTT2 through binding to their promoters. HTT1 interacted with the heat shock proteins Hsp70-14 and Hsp40 and NUCLEAR FACTOR Y, SUBUNIT C2. Taken together, these results suggest that HTT1 mediates thermotolerance pathways because it is targeted by TAS1a, mainly activated by HsfA1a, and acts as cofactor of Hsp70-14 complexes.