申論題

 Drought stress often limits plant growth and global crop yields. Catalase (CAT)-mediated hydrogen peroxide (H₂O₂) scavenging plays an important role in the adaptation of plant stress responses, but the transcriptional regulation of the CAT gene in response to drought stress is not well understood. Here, we isolated an APETALA2/ETHYLENE-RESPONSIVE FACTOR (APZ/ERP) domin-containing transcription factor (TF), NiERF172, which was strongly induced by drought, abscisic acid (ABA) and H₂O₂, from tobacco (Nicotiana tabacum) by yeast one-hybrid screening. NERF172 localized to the nucleus and acted as a transcriptional activator. Chromatin immunoprecipitation, ycast one-hybrid assays, electrophoretic mobility shift assays and transient expression analysis assays showed that NHERF172 directly bound to the promoter region of the NICAT gene and positively regulated its expression. Transgenic
 plants overexpressing NIERF1 72 displayed enhanced tolerance to drought stress, whereas suppression of NrERF! 72 decreased drought tolerance. Under drought stress conditions, the NrERF1 72-0verexpressed lines showed higher catalase activity and lower accumulation of H₂O₂, compared with wild-type (Wi) plants, while the NERF172-silenced plants showed the inverse corre relation. Exogenous application of amnino-1,2.4-triazole (3-AT), an irreversible CAT inhibitor, to the NERF172-overexpression Iines showed decreased catalase activity and drought tolerance, and increased levels of cellular H₂O₂. Knockdown of NiCATin tho NERF172-overexpression Tines displayed a more drought stress-sensitive phenotype than MERF172-overexpression lines. We propose that MERF1 72 acts as a positive factor in drought stress tolerance, at least in part through the regulation of CAT-mediated H₂O₂ homcostasis. (Plant Biotechnology Journal, 2020, 18: 2444-2455)