Chromosome location contributing to ozone tolerance in wheat

Authors: MASHAHEET, ALSAYED - Damanhour University; Burkey, Kent; Marshall, David

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2019
Publication Date: 8/1/2019
Citation: Mashaheet, A., Burkey, K.O., Marshall, D.S. 2019. Chromosome location contributing to ozone tolerance in wheat. Plants. 8:261.
DOI: https://doi.org/10.3390/plants8080261

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 toxic to plants, causing visible injury to foliage and a reduction in the growth and yield of sensitive crops such as wheat. Estimates suggest that current ambient ozone levels are sufficient to reduce wheat yields by 7-12% with greater yield losses anticipated if tropospheric ozone concentrations continue to rise. In the absence of international efforts to control air pollution, future wheat productivity may depend on the development of ozone-tolerant varieties. A first step in cultivar improvement is identification of genes that can be utilized in plant breeding programs to develop ozone-tolerant varieties. In this study, an international team of researchers from Egypt and the USDA-ARS Plant Science Research Unit in Raleigh, North Carolina tested the ozone sensitivity of a set of wheat genotypes with a single missing chromosome in a common genetic background. The researchers identified chromosome 7A to be a major contributor to ozone tolerance in wheat. The results suggest that major ozone tolerance genes in wheat are located on this chromosome.

Technical Abstract: Breeding wheat for higher grain yield can contribute to global food security and sustainable production on less land. Tropospheric ozone can injure wheat plants and subsequently reduce grain yield. Identification of ozone tolerance in the wheat genome can assist plant breeders in developing new sources of tolerant germplasm. Our objective was to use the ‘Chinese Spring’ monosomic lines to screen for ozone response and identify the chromosomic locations contributing to ozone tolerance. Two methodologies, Continuous Stirred Tank Reactors, and Outdoor Plant Environment Chambers, were used to expose the wheat monosomic lines to varying concentrations and durations of ozone. Each wheat monosomic line in ‘Chinese Spring’ has a missing chromosome in each of the wheat subgenomes (A, B, or D). In both methodologies, we found significant and repeatable data to identify chromosome 7A as a major contributor to tolerance to ozone injury in ‘Chinese Spring’. In every experiment, the absence of chromosome 7A resulted in significant injury to wheat due to ozone. The absence of no other chromosome resulted in a significant ozone injury response.