title: Phytoalexin biosynthesis genes are regulated and involved in plant response to Ralstonia solanacearum infection.
abstract: Genes encoding phytoalexin biosynthesis enzymes are transcriptionally regulated and are required for defense against fungi and oomycetes. Here, we studied the regulation of tobacco 5-epi-aristolochene synthase 4 (EAS4) promoters on bacterial infection and investigated the roles of tomato and Arabidopsis phytoalexin biosynthesis genes in defense against pathogenic bacteria. Our results showed that the Nicotiana glutinosa EAS4 (NgEAS4) promoter was significantly induced by treatments with several bacteria in treated and systemic leaves of transgenic plants. This promoter was also partially induced by treatments with type-III secretion-deficient mutants and total lysate of R. solanacearum (Rs), revealing that both bacterial pathogen-associated molecular patterns (PAMPs) and effectors are involved in R. solanacearum-induced local and systemic activation of the NgEAS4 promoter. Furthermore, the absence of a cis-element GT-1 box in the NgEAS4 promoter abolished systemic activation in non-treated leaves, whereas disruption of the GT-1 box of the N. tabacum EAS4 (NtEAS4) promoter led to constitutive expression. Moreover, silencing of tomato sesquiterpene synthase genes and disruption of the key gene PAD3 for Arabidopsis camalexin biosynthesis resulted in decreased tolerance to R. solanacearum. These results together, reveal the varied function of GT-1 boxes in regulating tobacco EAS4 promoters and the involvement of phytoalexin-biosythesis genes in plant defense against R. solanacearum.
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Lin
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Shu-Lein
authors.initials: SL
authors.lastname: Shih
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Wan-Chi
authors.initials: WC
authors.lastname: Lin
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Wu
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Ya-Ting
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Chi-Ying
authors.initials: CY
authors.lastname: Hsieh
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Li-Ching
authors.initials: LC
authors.lastname: Guan
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC.
authors.forename: Lu
authors.initials: L
authors.lastname: Lin
authors.affiliation: Graduate Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC; Department of Life Science, College of Life Science, National Taiwan University, Taipei 106, Taiwan, ROC. Electronic address: chiupingcheng@ntu.edu.tw.
authors.forename: Chiu-Ping
authors.initials: CP
authors.lastname: Cheng
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D018515:Plant Leaves; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D043368:Ralstonia solanacearum; D012717:Sesquiterpenes / Q000378:metabolism*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D000094162:Phytoalexins
chemical_list: D010940:Plant Proteins; D012717:Sesquiterpenes; D019883:Alkyl and Aryl Transferases; C078217:5-epi-aristolochene synthase; D000094162:Phytoalexins
keywords: EAS; GT-1; PAD; PAMP; TPS