title: Tomato RAV transcription factor is a pivotal modulator involved in the AP2/EREBP-mediated defense pathway.
abstract: Ralstonia solanacearum is the causal agent of bacterial wilt (BW), one of the most important bacterial diseases worldwide. We used cDNA microarray to survey the gene expression profile in transgenic tomato (Solanum lycopersicum) overexpressing Arabidopsis (Arabidopsis thaliana) CBF1 (AtCBF1), which confers tolerance to BW. The disease-resistant phenotype is correlated with constitutive expression of the Related-to-ABI3/VP1 (RAV) transcription factor, ethylene-responsive factor (ERF) family genes, and several pathogenesis-related (PR) genes. Using a transient assay system, we show that tomato RAV2 (SlRAV2) can transactivate the reporter gene driven by the SlERF5 promoter. Virus-induced gene silencing of SlERF5 and SlRAV2 in AtCBF1 transgenic and BW-resistant cultivar Hawaii 7996 plants gave rise to plants with enhanced susceptibility to BW. Constitutive overexpression of SlRAV2 in transgenic tomato plants induced the expression of SlERF5 and PR5 genes and increased BW tolerance, while knockdown of expression of SlRAV2 inhibited SlERF5 and PR5 gene expression under pathogen infection and significantly decreased BW tolerance. In addition, transgenic tomato overexpressing SlERF5 also accumulated higher levels of PR5 transcripts and displayed better tolerance to pathogen than wild-type plants. From these results, we conclude that SlERFs may act as intermediate transcription factors between AtCBF1 and PR genes via SlRAV in tomato, which results in enhanced tolerance to BW.
authors.affiliation: Academia Sinica Biotechnology Center in Southern Taiwan, Tainan 741, Taiwan.
authors.forename: Chia-Wen
authors.initials: CW
authors.lastname: Li
authors.forename: Ruey-Chih
authors.initials: RC
authors.lastname: Su
authors.forename: Chiu-Ping
authors.initials: CP
authors.lastname: Cheng
authors.lastname: Sanjaya
authors.forename: Su-Juan
authors.initials: SJ
authors.lastname: You
authors.forename: Tsai-Hung
authors.initials: TH
authors.lastname: Hsieh
authors.forename: To-Chun
authors.initials: TC
authors.lastname: Chao
authors.forename: Ming-Tsair
authors.initials: MT
authors.lastname: Chan
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D002734:Chlorophyll / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D060467:Disease Resistance; D015870:Gene Expression; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017930:Genes, Reporter; D018551:Solanum lycopersicum / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D043368:Ralstonia solanacearum / Q000502:physiology*; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C104387:CBF1 protein, Arabidopsis; D018076:DNA, Complementary; D010940:Plant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C053376:pathogenesis-related proteins, plant; D002734:Chlorophyll