Proteomics Based Study of Soybean and Phakopsora pachyrhizi Interaction

Abstract

Phakopsora pachyrhizi, the causal agent of Asian soybean rust (ASR), has the potential to cause severe yield losses as all currently grown U.S. commercial soybean varieties are susceptible. In this proteomics study, we compared two soybean sibling lines, a resistant line 10G18 and a susceptible line 10G21 derived from Recombinant Inbred Line (RIL) population RN06-32-2 to understand the compatible and incompatible host-pathogen interactions at the molecular level. We compared the protein profile differences between the two lines over a time-course of 14 days with or without P. pachyrhizi inoculation using differential in-gel electrophoresis (DIGE). Approximately 70 differentially expressed spots between 10G18 and 10G21 lines with and without P. pachyrhizi inoculation were identified. Some of these spots, which were up- and down-regulated in resistant line 10G18, were sequenced using LC-MS/MS. Of the 70 differentially expressed protein spots, 31 up-regulated and 6 down-regulated spots in resistant line 10G18 were sequenced. These sequenced proteins were mostly involved in photosynthesis based on homology searches. The involvement in disease resistance for some of these differentially up-regulated proteins has been reported, indicating their possible role in soybean defense against ASR. However, further studies are necessary. Accepted for publication 3 September 2013. Published 25 November 2013.