Overexpression of OsTZF8 regulates drought stress resilience, senescence, and chlorophyll content in rice

Rice (Oryza sativa) is a water-dependent crop and is grown under flooded environments worldwide. Several biotic and abiotic stresses severely impact its yield. To improve our comprehension of abiotic stress management, we characterized the OsTZF8 gene for its role in rice drought stress resilience. Drought stress and abscisic acid (ABA) triggered the OsTZF8 gene expression. The putative OsTZF8 promoter region was observed to have many abiotic stress-related cis-acting elements. The β-glucuronidase histochemical response in transgenic rice plants having the OsTZF8 promoter combined with β-glucuronidase (POsTZF8: GUS) was detected in callus and young leaves. The OsTZF8-GFP localization was observed in the nucleus and the cell membrane. Upon ABA treatment, OsTZF8-GFP localization was predominantly observed in the nucleus. Transgenic rice plants with overexpression of OsTZF8 under the constitutive ubiquitin promoter of maize (Ubi: OsTZF8-OX) displayed a slight growth delay and showed greater survival under drought. These transgenic rice plants also displayed delayed leaf senescence as revealed by the content of chlorophyll in the top four leaves. Microarray examination showed that in Ubi: OsTZF8-OX rice plants, several genes linked to chlorophyll, homeostasis of reactive oxygen species and stress were regulated. The above results suggest that OsTZF8 could be utilized to enhance stress resilience in different crops.