Suppression of DS1 phosphatidic acid phosphatase confirms resistance to Ralstonia solanacearum in Nicotiana benthamiana

Masahito Nakano; Masahiro Nishihara; Hirofumi Yoshioka; Hirotaka Takahashi; Tatsuya Sawasaki; Kouhei Ohnishi; Yasufumi Hikichi; Akinori Kiba

doi:10.1371/journal.pone.0075124

Suppression of DS1 phosphatidic acid phosphatase confirms resistance to Ralstonia solanacearum in Nicotiana benthamiana

PLoS One. 2013 Sep 20;8(9):e75124. doi: 10.1371/journal.pone.0075124. eCollection 2013.

Authors

Masahito Nakano¹, Masahiro Nishihara, Hirofumi Yoshioka, Hirotaka Takahashi, Tatsuya Sawasaki, Kouhei Ohnishi, Yasufumi Hikichi, Akinori Kiba

Affiliation

¹ Laboratory of Plant Pathology and Biotechnology, Faculty of Agriculture, Kochi University, Nankoku, Kochi, Japan.

Abstract

Nicotianabenthamiana is susceptible to Ralstonia solanacearum. To analyze molecular mechanisms for disease susceptibility, we screened a gene-silenced plant showing resistance to R. solanacearum, designated as DS1 (Disease suppression 1). The deduced amino acid sequence of DS1 cDNA encoded a phosphatidic acid phosphatase (PAP) 2. DS1 expression was induced by infection with a virulent strain of R. solanacearum in an hrp-gene-dependent manner. DS1 rescued growth defects of the temperature-sensitive ∆lpp1∆dpp1∆pah1 mutant yeast. Recombinant DS1 protein showed Mg(2+)-independent PAP activity. DS1 plants showed reduced PAP activity and increased phosphatidic acid (PA) content. After inoculation with R. solanacearum, DS1 plants showed accelerated cell death, over-accumulation of reactive oxygen species (ROS), and hyper-induction of PR-4 expression. In contrast, DS1-overexpressing tobacco plants showed reduced PA content, greater susceptibility to R. solanacearum, and reduced ROS production and PR-4 expression. The DS1 phenotype was partially compromised in the plants in which both DS1 and NbCoi1 or DS1 and NbrbohB were silenced. These results show that DS1 PAP may affect plant immune responses related to ROS and JA cascades via regulation of PA levels. Suppression of DS1 function or DS1 expression could rapidly activate plant defenses to achieve effective resistance against Ralstonia solanacearum.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Apoptosis
Blotting, Western
Cell Proliferation
Gene Expression Regulation, Plant
Gene Silencing
Host-Pathogen Interactions
Lipids / analysis
Molecular Sequence Data
Nicotiana / enzymology
Nicotiana / immunology*
Nicotiana / microbiology*
Phosphatidate Phosphatase / antagonists & inhibitors*
Phosphatidate Phosphatase / metabolism
Phylogeny
Plant Diseases / immunology*
Plant Diseases / microbiology
Plant Immunity / immunology*
Plants, Genetically Modified / enzymology
Plants, Genetically Modified / immunology*
Plants, Genetically Modified / microbiology
RNA, Messenger / genetics
Ralstonia solanacearum / genetics
Ralstonia solanacearum / pathogenicity*
Reactive Oxygen Species / metabolism
Real-Time Polymerase Chain Reaction
Reverse Transcriptase Polymerase Chain Reaction
Sequence Homology, Amino Acid

Substances

Lipids
RNA, Messenger
Reactive Oxygen Species
Phosphatidate Phosphatase

Grants and funding

This work was supported by Grants in Aid for Scientific Research to AK (16780031 and 18780029) and YH (15028214 and 16380037) from the Ministry of Education, Culture, Sports, Science and Technology, Japan. AK is also grateful for financial support from the Asahi Glass Foundation. Grant-in-Aid for Japan Society for the Promotion of Science Fellows M. Nakano (25-7248). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.