Department of Nematology, University of California, 2107A Genomics Building, Riverside, CA 92521, USA.
Planta. 2012 Feb;235(2):299-309. doi: 10.1007/s00425-011-1509-6. Epub 2011 Sep 7.
Plant resistance (R) gene-mediated defense responses against biotic stresses include vast transcriptional reprogramming. In several plant-pathogen systems, members of the WRKY family of transcription factors have been demonstrated to act as both positive and negative regulators of plant defense transcriptional networks. To identify the possible roles of tomato (Solanum lycopersicum) WRKY transcription factors in defense mediated by the R gene Mi-1 against potato aphid, Macrosiphum euphorbiae, and root-knot nematode (RKN), Meloidogyne javanica, we used tobacco rattle virus (TRV)-based virus-induced gene silencing and transcriptionally suppressed SlWRKY70, a tomato ortholog of the Arabidopsis thaliana WRKY70 gene. Silencing SlWRKY70 attenuated Mi-1-mediated resistance against both potato aphid and RKN showing that SlWRKY70 is required for Mi-1 function. Furthermore, we found SlWRKY70 transcripts to be inducible in response to aphid infestation and RKN inoculation. Mi-1-mediated recognition of these pests modulates this transcriptional response. As previously described for AtWRKY70, we found SlWRKY70 transcript levels to be up-regulated by salicylic acid and suppressed by methyl jasmonate. This indicates that some aspects of WRKY70 regulation are conserved among distantly related eudicots.
植物抗性（R）基因介导的生物胁迫防御反应包括广泛的转录重编程。在几种植物-病原体系统中，WRKY 家族转录因子的成员已被证明是植物防御转录网络的正、负调节剂。为了确定番茄（Solanum lycopersicum）WRKY 转录因子在 Mi-1 基因介导的防御中的可能作用，Mi-1 基因可以抵抗马铃薯蚜和根结线虫（RKN），Meloidogyne javanica，我们使用烟草脆裂病毒（TRV）基于病毒诱导的基因沉默和转录抑制 SlWRKY70，拟南芥 WRKY70 基因的番茄同源物。沉默 SlWRKY70 减弱了 Mi-1 对马铃薯蚜和 RKN 的抗性，表明 SlWRKY70 是 Mi-1 功能所必需的。此外，我们发现 SlWRKY70 转录物可响应蚜虫侵害和 RKN 接种而诱导。Mi-1 介导的这些害虫的识别调节这种转录反应。如先前对 AtWRKY70 的描述，我们发现 SlWRKY70 转录物水平被水杨酸上调，被茉莉酸甲酯抑制。这表明 WRKY70 调节的某些方面在远缘真双子叶植物中是保守的。
