The Mediator subunit SFR6/MED16 controls defence gene expression mediated by salicylic acid and jasmonate responsive pathways
The Mediator subunit SFR6/MED16 controls defence gene expression mediated by salicylic acid and jasmonate responsive pathways
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DOI：
10.1111/j.1469-8137.2012.04138.x
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发表时间：
2012-07-01
期刊：
影响因子：
9.4
通讯作者：
Knight, Heather
中科院分区：
文献类型：
--
作者：
Wathugala, Deepthi L.;Hemsley, Piers A.;Knight, Heather
拟南芥对冷冻敏感6 (SFR6) 控制寒冷和干旱诱导的基因表达以及冷冻和渗透胁迫耐受性。它被鉴定为 MEDIATOR 转录共激活因子复合物的一个组成部分，使我们能够解决它在其他转录反应中的参与问题。通过实时定量 PCR 研究了三个 sfr6 突变等位基因对丁香假单胞菌、紫外线 C (UV-C) 照射、水杨酸 (SA) 和茉莉酸 (JA) 的基因表达反应，并评估了对 UV-C 照射和假单胞菌感染的敏感性。 sfr6 突变体对丁香假单胞菌感染和 UV-C 照射更敏感。经过这些处理或直接施用 SA 后，它们表现出比野生型拟南芥相应更弱的 PR（发病机制相关）基因表达，参与对 UV-C 和假单胞菌感染的反应。然而，这些处理在突变体中正常诱导了其他基因。 sfr6 突变体在响应 JA 的植物防御素基因表达方面存在严重缺陷； ERF5 的过表达会在野生型中引发防御素基因的异位表达，但在 sfr6 中则不会。 SFR6/MED16 控制 SA 和 JA 介导的防御基因表达，并且对于耐受丁香假单胞菌感染和 UV-C 照射是必需的。然而，它不是应激基因转录的通用调节因子，并且可能仅介导特定调节子的转录激活。
Arabidopsis SENSITIVE TO FREEZING6 (SFR6) controls cold- and drought-inducible gene expression and freezing- and osmotic-stress tolerance. Its identification as a component of the MEDIATOR transcriptional co-activator complex led us to address its involvement in other transcriptional responses. Gene expression responses to Pseudomonas syringae, ultraviolet-C (UV-C) irradiation, salicylic acid (SA) and jasmonic acid (JA) were investigated in three sfr6 mutant alleles by quantitative real-time PCR and susceptibility to UV-C irradiation and Pseudomonas infection were assessed. sfr6 mutants were more susceptible to both Pseudomonas syringae infection and UV-C irradiation. They exhibited correspondingly weaker PR (pathogenesis-related) gene expression than wild-type Arabidopsis following these treatments or after direct application of SA, involved in response to both UV-C and Pseudomonas infection. Other genes, however, were induced normally in the mutants by these treatments. sfr6 mutants were severely defective in expression of plant defensin genes in response to JA; ectopic expression of defensin genes was provoked in wild-type but not sfr6 by overexpression of ERF5. SFR6/MED16 controls both SA- and JA-mediated defence gene expression and is necessary for tolerance of Pseudomonas syringae infection and UV-C irradiation. It is not, however, a universal regulator of stress gene transcription and is likely to mediate transcriptional activation of specific regulons only.