title: Characterization of Cell-Death-Inducing Members of the Pectate Lyase Gene Family in Phytophthora capsici and Their Contributions to Infection of Pepper.
abstract: Pectate lyases (PL) play a critical role in pectin degradation. PL have been extensively studied in major bacterial and fungal pathogens of a wide range of plant species. However, the contribution of PL to infection by oomycete pathogens remains largely unknown. Here, we cloned 22 full-length pectate lyase (PcPL) genes from a highly aggressive strain of Phytophthora capsici SD33. Of these, PVX agroinfiltration revealed that 12 PcPL genes were found to be highly induced during infection of pepper by SD33 but the induction level was twofold less in a mildly aggressive strain, YN07. The four genes with the highest transcript levels as measured by by quantitative reverse-transcription polymerase chain reaction (PcPL1, PcPL15, PcPL16, and PcPL20) also produced a severe cell death response following transient expression in pepper leaves but the other eight PcPL genes did not. Overexpression of these four genes increased the virulence of SD33 on pepper slightly, and increased it more substantially during infection of tobacco. Overexpression of the genes in YN07 restored its aggressiveness to near that of SD33. Gene silencing experiments with the 12 PcPL genes produced diverse patterns of silencing of PcPL genes, from which it could be inferred from regression analysis that PcPL1, PcPL16, and PcPL20 could account for nearly all of the contributions of the PcPL genes to virulence.
authors.affiliation: 1 Department of Plant Pathology, Shandong Agricultural University, No. 61, Daizong Street, Taian, Shandong, 271018, China;
authors.forename: Li
authors.initials: L
authors.lastname: Fu
authors.affiliation: 1 Department of Plant Pathology, Shandong Agricultural University, No. 61, Daizong Street, Taian, Shandong, 271018, China;
authors.forename: Chunyuan
authors.initials: C
authors.lastname: Zhu
authors.affiliation: 1 Department of Plant Pathology, Shandong Agricultural University, No. 61, Daizong Street, Taian, Shandong, 271018, China;
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Ding
authors.affiliation: 1 Department of Plant Pathology, Shandong Agricultural University, No. 61, Daizong Street, Taian, Shandong, 271018, China;
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Yang
authors.affiliation: 2 Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403 U.S.A.;
authors.forename: Paul F
authors.initials: PF
authors.lastname: Morris
authors.affiliation: 3 Center for Genome Research and Biocomputing, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, 97331, U.S.A.
authors.forename: Brett M
authors.initials: BM
authors.lastname: Tyler
authors.affiliation: 1 Department of Plant Pathology, Shandong Agricultural University, No. 61, Daizong Street, Taian, Shandong, 271018, China;
authors.forename: Xiuguo
authors.initials: X
authors.lastname: Zhang
mesh_terms: D002212:Capsicum / Q000166:cytology / Q000382:microbiology*; D016923:Cell Death; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D054884:Host-Pathogen Interactions / Q000235:genetics*; D008969:Molecular Sequence Data; D010838:Phytophthora / Q000235:genetics / Q000472:pathogenicity*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D011133:Polysaccharide-Lyases / Q000235:genetics* / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D011133:Polysaccharide-Lyases; C023911:pectate lyase