Impact of OsBadh2 Mutations on Salt Stress Response in Rice

Abstract

Mutations in the Betaine aldehyde dehydrogenase 2 (OsBadh2) gene resulted in aroma, which is a highly preferred grain quality attribute in rice. However, research on naturally occurring aromatic rice has revealed ambiguity and controversy regarding aroma emission, stress tolerance, and response to salinity. In this study, mutant lines of two non-aromatic varieties, Huaidao#5 (WT_HD) and Jiahua#1 (WT_JH), were generated by targeted mutagenesis of OsBadh2 using CRISPR/Cas9 technology. The mutant lines of both varieties became aromatic; however, WT_HD mutants exhibited an improved tolerance, while those of WT_JH showed a reduced tolerance to salt stress. To gain insight into the molecular mechanism leading to the opposite effects, comparative analyses of the physiological activities and expressions of aroma- and salinity-related genes were investigated. The WT_HD mutants had a lower mean increment rate of malondialdehyde, superoxide dismutase, glutamate, and proline content, with a higher mean increment rate of γ-aminobutyric acid, hydrogen peroxide, and catalase than the WT_JH mutants. Fluctuations were also detected in the salinity-related gene expression. Thus, the response mechanism of OsBadh2 mutants is complicated where the genetic makeup of the rice variety and interactions of several genes are involved, which requires more in-depth research to explore the possibility of producing highly tolerant aromatic rice genotypes.

CRISPR-Cas System, a Possible “Savior” of Rice Threatened by Climate Change: An Updated Review

“…Although gene disruption could contribute to stress tolerance, genotypic background largely affects the induction of stress tolerance. In this regard Prodhan et al ( 2022 ) have disrupted the betaine aldehyde dehydrogenase ( OsBadh2 ) gene with CRISPR-Cas9 simultaneously in Jiahua#1 (WT_JH) and Huaidao#5 (WT_HD) cultivars. Surprisingly mutation in OsBadh2 gene induced salinity tolerance in WT_HD lines only, indicating the significant effect of the genetic background to acquire the stress tolerance.…”

Untitled

“…These substances are said to have a crucial role in osmotic regulation, cellular macromolecule fortification, and nitrogen storage. They are necessary to detoxify cells, scavenge ROS species, and preserve cellular pH homeostasis 20 .…”