Asian soybean rust (ASR), caused by the obligate fungal pathogen Phakopsora pachyrhizi, often leads to significant yield losses and can only be managed through fungicide applications currently. In the present study, eight urediniospore germination or appressorium formation induced P. pachyrhizi genes were investigated for their feasibility to suppress ASR through a bean pod mottle virus (BPMV)‐based host‐induced gene silencing (HIGS) strategy. Soybean plants expressing three of these modified BPMV vectors suppressed the expression of their corresponding target gene by 45%–80%, fungal biomass accumulation by 58%–80%, and significantly reduced ASR symptom development in soybean leaves after the plants were inoculated with P. pachyrhizi, demonstrating that HIGS can be used to manage ASR. In addition, when the in vitro synthesized double‐stranded RNAs (dsRNAs) for three of the genes encoding an acetyl‐CoA acyltransferase, a 40S ribosomal protein S16, and glycine cleavage system H protein were sprayed directly onto detached soybean leaves prior to P. pachyrhizi inoculation, they also resulted in an average of over 73% reduction of pustule numbers and 75% reduction in P. pachyrhizi biomass accumulation on the detached leaves compared to the controls. To the best of our knowledge, this is the first report of suppressing P. pachyrhizi infection in soybean through both HIGS and spray‐induced gene silencing. It was demonstrated that either HIGS constructs targeting P. pachyrhizi genes or direct dsRNA spray application could be an effective strategy for reducing ASR development on soybean.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.