Tropospheric ozone (O 3) is a secondary air pollutant and anthropogenic greenhouse gas. Concentrations of tropospheric O 3 ([O 3] have more than doubled since the Industrial Revolution, and are high enough to damage plant productivity. Soybean ( Glycine max L. Merr.) is the world’s most important legume crop and is sensitive to O 3. Current ground-level [O 3] are estimated to reduce global soybean yields by 6% to 16%. In order to understand transcriptional mechanisms of yield loss in soybean, we examined the transcriptome of soybean flower and pod tissues exposed to elevated [O 3] using RNA-Sequencing.
Elevated [O 3] elicited a strong transcriptional response in flower and pod tissues, with increased expression of genes involved in signaling in both tissues. Flower tissues also responded to elevated [O 3] by increasing expression of genes encoding matrix metalloproteinases (MMPs). MMPs are zinc- and calcium-dependent endopeptidases that have roles in programmed cell death, senescence and stress response in plants. Pod tissues responded to elevated [O 3] by increasing expression of xyloglucan endotransglucosylase/hydrolase genes, which may be involved with increased pod dehiscence in elevated [O 3].