Dissecting the Role of Metabolites in Drought Tolerance in Maize Under Hot and Dry Environments.

Development of drought and/or heat tolerant crop varieties is one of the most effective ways to mitigate the negative impacts associated with climate change on crop production. Drought and heat tolerance in plants are complex traits. A variety of metabolites is known to play critical roles in plant sensing and adaptation to abiotic stresses. We have taken a targeted metabolic profiling analysis approach to characterize germplasm collection and obtain information on the drought stress responses of plants at the metabolite level. Leaf samples were collected from field-grown maize plants of 537 inbred lines under well-watered and deficit irrigation conditions in 2012 and 2014. Three classes of metabolites were extracted and analyzed quantitatively. The amounts of soluble sugars, ABA, proline, and other related components and the changes of these compounds during drought stress treatment were analyzed in correlation with field drought stress tolerance ratings. Genome-wide association analyses will be performed to identify chromosome regions and/or genetic loci contributing to metabolite changes and/or drought tolerance in maize. The aim of this study was to identify metabolites that contribute to increased environmental stress tolerance and to select maize germplasm for superior drought stress tolerance under naturally hot and dry environments.