Submitted to: Physiological and Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2001
Publication Date: N/A
Interpretive Summary: The goal of this project is to develop a means to improve crop resistance to bacterial pathogens. Here we report a bacterial response that occurs upon detection of plant components. This acts a detection/recognition mechanism for the pathogen and could be the first step in triggering various pathogen elicitors that could determine the outcome of the interaction susceptibility or resistance. Specifically we report that an oxygen uptake response can be detected within minutes of the bacteria detecting plant components. This work will benefit ARS and scientists by providing a means or tool for further investigation of the bacterial detection/recognition mechanisms and how they might improve our ability to either enhance or suppress the response to manipulate the interaction in the favor of the plant.
Within minutes after the addition of heat-killed bacteria, potato suspension cells responded with a rapid increase in oxygen uptake. The elicited cells continued to utilize oxygen at a steady but accelerated rate for several minutes before beginning a slow increase over the remaining few hours of the monitoring period. Calculation of the total oxygen consumption by the plant cells indicated that only a small fraction of the increased oxygen uptake was due to the concomitant production of reactive oxygen species. Pretreatment of cells with the NAD(P)H inhibitor, DPI, prohibited the production of reactive oxygen, and inhibited the total oxygen uptake response by approximately 60 %. The protein kinase inhibitor, K-252, inhibited the oxygen uptake response by more than 90%, suggesting the involvement of protein phosphorylation in the oxygen uptake response. The alternate oxidase inhibitor, SHAM, significantly inhibited the elicited oxygen uptake increase while a combination of SHAM and KCN almost completely blocked both the basal oxygen uptake and the elicited response. The data indicate that mitochondrial respiration and, in particular, the alternate oxidase, play a significant role in the elicited oxygen uptake response of potato cells.