OsBBP1, a newly identified protein containing DUF630 and DUF632 domains confers drought tolerance in rice

Domain of unknown function (DUF) protein families, which are uncharacterized and numerous within the Pfam database. Recently, studies have demonstrated that DUFs played crucial roles in plant development, but whether, or how, they function in drought resistance remain unclear. In this study, we identified the Os03g0321500 gene, encoding OsbZIP72 binding protein 1 (OsBBP1), as a target of OsbZIP72 using chromatin immunoprecipitation sequencing in rice. OsBBP1 is a novel member of DUFs, which localize both in the nuclei and cytoplasm of rice protoplasts. Furthermore, yeast one-hybrid and electrophoretic mobility shift assays confirmed the specific binding between OsbZIP72 and OsBBP1. Additionally, a luciferase reporter analysis illustrated that OsbZIP72 activated the expression of OsBBP1. Drought tolerance experiments demonstrate that the OsBBP1 CRISPER-CAS9 transgenic mutants were sensitive to drought stress, but the transgenic OsBBP1 over-expressing rice plants showed enhanced drought resistance. Moreover, drought tolerance experiments in a paddy field suggested that OsBBP1 contributed to less yield or yield-related losses under drought conditions. Mechanistically, OsBBP1 might confer drought resistance by inducing more efficient reactive oxygen species (ROS) scavenging. Several ROS scavenging-related genes showed increased expression levels in OsBBP1 overexpression lines and decreased expression levels in OsBBP1 CRISPER-CAS9 mutants under drought conditions. Thus, OsBBP1, acting downstream of OsbZIP72, contributes to drought resistance and causes less yield or yield-related losses under drought conditions. •We catch the Os03g0321500 gene, here identified as OsbZIP72 binding protein 1, OsBBP1 as one of the targets of OsbZIP72 by chromatin immunoprecipitation sequencing (Chip-seq) in rice.•The yeast one-hybrid and electrophoretic mobility shift assay confirm the specific binding between OsbZIP72 and its target OsBBP1. Additionally, the luciferase reporter analysis illustrate that OsbZIP72 activate the expression of OsBBP1.•The drought tolerance experiment demonstrate that the OsBBP1 CRISPER-CAS9 transgenic mutants are sensitive to drought stress, but the transgenic over-expression of OsBBP1 rice plants show enhanced drought resistance.•The OsBBP1 confers drought resistance by inducing more efficient reactive oxygen species scavenging. Several reactive oxygen species scavenging-related genes showed increased expression in OsBBP1 over-expression lines and dec