Respiratory burst oxidase‐D Expression and Biochemical Responses in Festuca arundinacea under Drought Stress

Abstract

ABSTRACTNicotinamide adenine dinucleotide phosphate (NADPH) oxidases catalyze the production of superoxide, a type of reactive oxygen species (ROS). In plants, the NADPH oxidase homologs have been identified as respiratory burst oxidase homologs (Rboh). They are involved in ROS production in response to drought stress. Three entries of tall fescue (Festuca arundinacea Schreb.) were used for analyses in the present study: tolerant (‘Isfahan’) and sensitive (‘Quchan’) accessions to drought during the germination stage, selected from 14 wild populations in Iran, as well as ‘Barvado’ as a control. Partial sequence of the Festuca respiratory burst oxidase‐D (FrbohD) gene was isolated from Barvado. We compared expression levels of the FrbohD gene as well as hydrogen peroxide (H2O2), catalase activity and some biochemical responses among the three entries. Gene expression was evaluated for leaf and shoot samples subjected to 3, 6, and 9 d without water. The transcript level of FrbohD, H2O2 content, and catalase activity increased in Quchan under drought stress. It appears that lower levels of FrbohD gene transcription and H2O2 concentration in F. arundinacea leaves contributed to drought stress tolerance in Isfahan. Total protein and total soluble carbohydrate content also increased significantly in Isfahan when it was subjected to drought stress. Isfahan exhibited drought resistance through various strategies, which could serve as selection criteria for improving drought resistance in turfgrass breeding programs.