Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, People's Republic of China.
Mol Genet Genomics. 2012 Jun;287(6):495-513. doi: 10.1007/s00438-012-0696-6. Epub 2012 May 9.
The WRKY transcription factors have been implicated in multiple biological processes in plants, especially in regulating defense against biotic and abiotic stresses. However, little information is available about the WRKYs in tomato (Solanum lycopersicum). The recent release of the whole-genome sequence of tomato allowed us to perform a genome-wide investigation for tomato WRKY proteins, and to compare these positively identified proteins with their orthologs in model plants, such as Arabidopsis and rice. In the present study, based on the recently released tomato whole-genome sequences, we identified 81 SlWRKY genes that were classified into three main groups, with the second group further divided into five subgroups. Depending on WRKY domains' sequences derived from tomato, Arabidopsis and rice, construction of a phylogenetic tree demonstrated distinct clustering and unique gene expansion of WRKY genes among the three species. Genome mapping analysis revealed that tomato WRKY genes were enriched on several chromosomes, especially on chromosome 5, and 16 % of the family members were tandemly duplicated genes. The tomato WRKYs from each group were shown to share similar motif compositions. Furthermore, tomato WRKY genes showed distinct temporal and spatial expression patterns in different developmental processes and in response to various biotic and abiotic stresses. The expression of 18 selected tomato WRKY genes in response to drought and salt stresses and Pseudomonas syringae invasion, respectively, was validated by quantitative RT-PCR. Our results will provide a platform for functional identification and molecular breeding study of WRKY genes in tomato and probably other Solanaceae plants.
WRKY 转录因子参与植物的多种生物学过程，特别是在调节生物和非生物胁迫的防御中。然而，关于番茄（Solanum lycopersicum）中的 WRKY 知之甚少。番茄全基因组序列的最新发布，使我们能够对番茄 WRKY 蛋白进行全基因组研究，并将这些鉴定出的蛋白与拟南芥和水稻等模式植物的同源蛋白进行比较。在本研究中，基于最近发布的番茄全基因组序列，我们鉴定了 81 个 SlWRKY 基因，它们分为三个主要组，第二组进一步分为五个亚组。根据番茄、拟南芥和水稻的 WRKY 结构域序列，构建的系统发育树表明，三个物种的 WRKY 基因聚类明显，基因扩展独特。基因组图谱分析表明，番茄 WRKY 基因富集在几条染色体上，特别是在第 5 号和第 16 号染色体上，有 16%的家族成员是串联重复基因。每个亚组的番茄 WRKY 都具有相似的基序组成。此外，番茄 WRKY 基因在不同的发育过程和对各种生物和非生物胁迫的反应中表现出不同的时空表达模式。通过定量 RT-PCR 验证了 18 个选定的番茄 WRKY 基因对干旱和盐胁迫以及丁香假单胞菌入侵的响应。我们的研究结果将为番茄和其他茄科植物 WRKY 基因的功能鉴定和分子育种研究提供一个平台。
