Abstract
To analyze Nicotiana plants-Ralstonia solanacealum(Rs) interaction, we focused on the Rs responsive gene RsRG3-11, which expressed in N. tabacum inoculated with pathogenic strain of Rs (RsOE1-1). Deduced amino acid sequence of RsRG3-11 showed similarity to a phosphatidic acid pase (PAP) 2 from Vitis vinifera. Temperature-sensitive phenotype of the yeast mutant lacking major PAP activity was rescued by RsRG3-11. Then we designated RsRG3-11 as NtPAP2 and NbPAP2 (ortholog of N.benthamiana). In NbPAP2-silenced plants challenged with RsOE1-1, expression of PR-4 was enhanced compared with control plants. Growth of RsOE1-1 and the wilt symptom were reduced in silencing plants. Inversely, RsRG3-11 was not induced by inoculation with nonpathogenic strain of Rs(Rs8107). Furthermore, growth of Rs8107 and induction of hypersensitive response by Rs8107 were scarcely affected by NbPAP2-silencing. These results indicate that NtPAP2/NbPAP2 might act as a negative regulator of basal defense induced by pathogenic Rs in Nicotiana plants.
