RNA-seq analysis reveals genetic response and tolerance mechanisms to ozone exposure in soybean

Oxidative stress caused by ground level ozone is a major contributor to yield loss in a number of important crop plants. Soybean (Glycine max) is especially ozone sensitive, and research into its response to oxidative stress is limited. To better understand the genetic response in soybean to oxidative stress, an RNA-seq analysis of two soybean cultivars was performed comparing an ozone intolerant cultivar and an ozone resistant cultivar after being exposed to ozone. A cursory analysis of the transcriptome data revealed differences between cultivars in the expression levels of genes previously implicated in oxidative stress responses, indicating unique cultivar-specific responses. An examination of the timing of gene responses over the course of ozone exposure showed expression of cuticle wax genes in the intolerant line over all sampled time points, whereas the tolerant line only expressed this pathway in the first time point. The ozone tolerant cultivar has a thicker leaf structure and we believe this lends a passive benefit to the plant which the intolerant cultivar is attempting to supplement via cuticle wax synthesis. These results suggest that differences in genetic responses work in concert with physiological differences to explain differences in ozone tolerance between soybean cultivars. Overall design: 16 total samples. 8 control, 8 at high ozone, 4 time points (30 minute increments starting 5 hours after introduction of ozone) . Replicates were pooled at extraction.

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Whaley A, Sheridan J, Safari S, Burton A, Burkey K, Schlueter J