ARS | Publication request: Cross comparison of soybean gene expression upon infection by pathogens and the symbiont Bradyrhizobium japonicum

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 11, 2008
Publication Date: July 26, 2008
Citation: Radwan, O., Zernova, O., Lozovaya, V., Clough, S.J. 2008. Cross comparison of soybean gene expression upon infection by pathogens and the symbiont Bradyrhizobium japonicum [abstract]. American Phytopathological Society Annual Meeting. 98:S129.

Technical Abstract: Pseudomonas syringae pv.glycinae and Fusarium virguliformi (formally known as F. solani f.sp glycines) are examples of bacterial and fungal pathogens which attack soybean and can cause significant damage under environmental conditions favorable to the pathogens. Bradyrhizobium japonicum is a nitrogen-fixing bacterium which develops a symbiotic relationship with soybean roots. Using genomic approaches, such as microarrays and real time PCR technologies, we are detecting global changes in gene expression during these interactions. Preliminary results from the cross comparison of gene expression data from these different interactions indicate that most genes show similar expression patterns in P. syringae challenged leaves as in F.virguliforme challenged roots, suggesting that many defense responses are shared between these two very different tissues, and two very different pathogens. For example, pathogenesis related proteins and WRKY transcription factors were clearly up regulated in the case of P. syringae incompatible versus compatible interactions, and were also up in roots challenged with F. virguliforme, whereas these genes were down regulated in the B. japonicum-soybean interaction. These results suggested that plants employ many similar defenses and signaling components regardless of tissue type, and that B. japonicum suppresses their expression while establishing a symbiotic relationship. Functional analysis of defense and signaling components that are shared, as well as a few that differ during pathogenic and symbiotic interactions, is currently being conducted.