Distinct transcriptional profiles of ozone stress in soybean ( Glycine max) flowers and pods

Abstract

Background

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.

Results

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].

Conclusions

This study established that gene expression in reproductive tissues of soybean are impacted by elevated [O ₃], and flowers and pods have distinct transcriptomic responses to elevated [O ₃].

Electronic supplementary material

The online version of this article (doi:10.1186/s12870-014-0335-y) contains supplementary material, which is available to authorized users.