|Comparative analysis of differential gene expression in response to rust pathogens|
J. BRIGGS (1), J. Garbe (1), M. Rouse (2), J. Kurle (1). (1) University of Minnesota-Twin Cities, St. Paul, MN, U.S.A.; (2) USDA-ARS, St. Paul, MN, U.S.A.
The presence of plant pathogens alters the host transcriptome throughout the infection process. To gain an understanding of host-rust pathogen interactions, we examined susceptible host differential expression early in the infection process in barley, soybean, and maize with and without rust infection. Total RNA was extracted from 6-10 bulked plants at 6, 12, 24, and 72 hours post inoculation (hpi) and was sequenced using the Illumina HiSeq platform at 20 million 100 bp paired-end reads per sample. Two biological replicates were used per time point. Transcriptomes were assembled via genome-guided assembly using the Galaxy program. Peak differential expression was observed in Morex at 12 and 72 hpi with a reduction in differential expression occurring at 24 hpi and no differential expression at 6 hpi. Peak differential expression occurred in Williams 82 at 6, 12, and 72 hpi; a reduction in differential expression was also observed at 24 hpi. Currently the maize transcriptome is undergoing analysis. Sets of homologous and similarly differentially expressed genes were identified between Morex and Williams 82. Results from this study not only illuminate our understanding of host-rust pathogen interactions, but also provide candidate host (susceptibility) genes that are necessary for successful rust colonization. Manipulation of these ‘susceptibility’ genes may lead to novel and broad-spectrum rust resistance.