Abstract
Most studies of plant-pathogen interactions have focused on establishment of plant immunity. On the other hands, little is known about host factors required for pathogen fitness and modified by the invading microorganism to avoid plant immunity.
To elucidate the molecular mechanisms of disease susceptibility in plants, we identified NbPAP (Nicotiana benthamiana phosphatidic acid phosphatase), which is specifically expressed in Nicotiana plants by inoculation with pathogenic strain of Ralstonia solanacearum.
Phosphatidic aicd, which is substrate for PAP, functions as an important signaling molecule involved in diverse physiological processes. To elucidate the role of PAP in plant-pathogen interactions, we created NbPAP-silenced plants using virus-induced gene silencing. Silencing of NbPAP reduced PAP activity leading to accumulation of PA. In the silenced plants, growth of R. solanacearum and the appearance of wilt symptom decreased. These results indicate that PAP negatively regulates plant immunity via accumulation of PA.
