|WHALEY, ADAM - University Of North Carolina|
|SHERIDAN, JAIME - University Of North Carolina|
|SAFARI, SAJEDEH - University Of North Carolina|
|BURTON, AMY - Former ARS Employee|
|SCHLUETER, JESSICA - University Of North Carolina|
Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2015
Publication Date: 6/1/2015
Citation: Whaley, A., Sheridan, J., Safari, S., Burton, A., Burkey, K.O., Schlueter, J. 2015. RNA-seq analysis reveals genetic response and tolerance mechanisms to ozone exposure in soybean. Biomed Central (BMC) Genomics. 16:426. doi: 10.1186/s12864-015-1637-7.
Interpretive Summary: Ground level ozone is formed by the action of sunlight on volatile hydrocarbons and nitrogen oxides produced during combustion of carbon based fuels. Although frequently considered an urban problem, ozone pollution is much broader in scope because weather systems transport the pollutants into agricultural areas. Ozone is an air pollutant that is toxic to plants, causing visible injury to foliage and a reduction in the growth and yield of sensitive crops such as soybean. Estimates suggest that current ambient ozone levels are sufficient to reduce soybean yield by 10-20% with greater yield losses anticipated if tropospheric ozone concentrations continue to rise. In the absence of successful efforts to control ozone pollution, future crop productivity may depend on the development of ozone-tolerant soybean varieties. In this study, USDA-ARS researchers and colleagues at the University of North Carolina at Charlotte conducted a comprehensive gene expression study that compared ozone-sensitive and tolerant soybean genotypes. The results are a first step in the identification of genes that could be manipulated to develop cultivars capable of maintaining yields under elevated ozone conditions.
Technical Abstract: 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 sensitive 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 sensitive 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.