|Zhu, Min Li|
Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2005
Publication Date: 10/1/2005
Citation: Zou, J., Rodriguez-Zas, S., Aldea, M., Zhu, Min Li, Gonzalez, D., Vodkin, L., Delucia, E., Clough, S.J. 2005. Expression profiling soybean response to pseudomonas syringae reveals new defense-related genes and rapid HR-specific down regulation of photosynthesis. Molecular Plant-Microbe Interactions. 18:1161-1174. Interpretive Summary: Maximum crop yields are restricted by disease. Therefore, improving resistance to disease is of major importance. Plants defend against pathogens by a variety of physical and chemical means. To identify genes involved in resistant soybean, we analyzed gene expression responses occurring during a resistant and a susceptible interaction. In this study, we screened 27,000 different soybean genes and identified nearly 4,000 as being significantly affected during these interactions. Most of the genes induced during the resistant response are also induced during the susceptible response. The difference seems to be mainly in the timing and strength of the response. In the resistant response, genes tended to be induced earlier and to a higher degree. In addition, the project identified many genes that were specific to the first 24 hours of the resistance reactioin. The genes identified provide biological information on resistance mechanisms, such as a role of photosynthetic machinery, and also provide candidate genes to be investigated further to determine if they are key genes that could act on their own to alter the disease outcome. This information will be useful to any scientist interested in breeding, genetics, gene structure, gene function to improve disease resistance in crop plants.
Technical Abstract: Transcript profiling during susceptible (S) and HR-associated resistance (R) responses was determined in soybean (Glycine max). Pseudomonas syringae pv. glycinea carrying or lacking the avirulence gene avrB, was infiltrated into cultivar Williams 82. Leaf RNA was sampled at 2, 8, and 24 hours post inoculation (hpi). Significant changes in transcript abundance were observed for 3,897 genes during the experiment at p ' 0.000005. Many of the genes showed a similar direction of increase or decrease abundance in both the S and R responses, but the R response generally showed a significantly greater degree of differential expression. More than 25% of these responsive genes had not been previously reported as being associated with pathogen interactions, as 704 had no functional annotation and 378 had no homolog in NCBI databases. The highest number of transcriptional changes was noted at 8 hpi including the down regulation of 94 chloroplast-associated genes specific to the R response. Photosynthetic measurements were consistent with an R-specific reduction in photosystem II operating efficiency ('PSII) that was apparent at 8 hpi for the R response with little effect in the S or control treatments. Imaging analyses suggest that the decreased 'PSII was a result of physical damage to PSII reaction centers.