title: A translationally controlled tumor protein negatively regulates the hypersensitive response in Nicotiana benthamiana.
abstract: We have been isolating and characterizing Ralstonia solanacearum-responsive genes (RsRGs) in Nicotiana plants. In this study we focused on RsRG308, which we renamed NbTCTP (N. benthamiana translationally controlled tumor protein) because it encodes a polypeptide showing similarity to translationally controlled tumor proteins. Induction of the hypersensitive response (HR) was accelerated in NbTCTP-silenced N. benthamiana plants challenged with R. solanacearum 8107 (Rs8107). The Rs8107 population decreased significantly, whereas hin1 gene expression was enhanced in the silenced plant. Accelerated induction of HR was observed in NbTCTP-silenced plants inoculated with Pseudomonas cichorii and P. syringae pv. syringae. Silencing of NbTCTP also accelerated the induction of HR cell death by Agrobacterium-mediated transient expression of HR inducers, such as AvrA, BAX, INF1 and NbMEK2(DD). NbTCTP silencing enhanced NbrbohB- and NbMEK2-mediated reactive oxygen species production, leading to HR. Transient expression of both the full-length sequence and the Bcl-xL domain of NbTCTP decreased HR cell death induced by Agrobacterium-mediated transient expression of HR inducers. NbTCTP-silenced plants also showed slightly dwarf phenotypes. Therefore, NbTCTP might have a role in cell death regulation during HR to fine-tune programmed cell death-associated plant defense responses.
authors.affiliation: Laboratory of Plant Pathology and Biotechnology, Faculty of Agriculture, Kochi University, Nankoku, Kochi 783-8502, Japan.
authors.forename: Meenu
authors.initials: M
authors.lastname: Gupta
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yoshioka
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mizumoto
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Hikichi
authors.forename: Akinori
authors.initials: A
authors.lastname: Kiba
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D016923:Cell Death; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D020868:Gene Silencing; D008969:Molecular Sequence Data; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011549:Pseudomonas / Q000502:physiology; D043368:Ralstonia solanacearum / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014026:Nicotiana / Q000235:genetics* / Q000276:immunology / Q000382:microbiology / Q000502:physiology
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D017382:Reactive Oxygen Species
keywords: Hypersensitive response; Nicotiana benthamiana; Translationally controlled tumor protein; Virus-induced gene silencing