Impact of OsBadh2 Mutations on Salt Stress Response in Rice

Area of Science:

• Plant genetics
• Molecular biology
• Agricultural science

Background:

• Aroma in rice, a desirable grain quality, is linked to mutations in the Betaine aldehyde dehydrogenase 2 (OsBadh2) gene.
• Naturally occurring aromatic rice exhibits controversial traits regarding stress tolerance, particularly salinity response.
• Understanding the genetic basis of these variations is crucial for developing improved rice varieties.

Purpose of the Study:

• To investigate the contrasting effects of OsBadh2 gene mutations on salt tolerance in two non-aromatic rice varieties.
• To elucidate the molecular mechanisms underlying the differential responses to salinity stress in aromatic rice mutants.
• To explore the potential for breeding highly tolerant aromatic rice genotypes.

Main Methods:

• CRISPR/Cas9 technology was employed for targeted mutagenesis of the OsBadh2 gene in Huaidao#5 (WT_HD) and Jiahua#1 (WT_JH) rice varieties.
• Comparative physiological analyses were conducted, measuring levels of malondialdehyde, superoxide dismutase, glutamate, proline, γ-aminobutyric acid, hydrogen peroxide, and catalase.
• Gene expression analysis of salinity-related genes was performed in the generated aromatic rice mutant lines.

Main Results:

• Mutant lines of both WT_HD and WT_JH varieties successfully produced aroma.
• WT_HD mutants displayed enhanced salt tolerance, while WT_JH mutants showed reduced salt tolerance.
• Significant differences in physiological parameters and gene expression related to stress response were observed between the two mutant lines.

Conclusions:

• The OsBadh2 gene's impact on salt tolerance in rice is complex and depends on the variety's genetic background.
• Interactions between the OsBadh2 gene and other genetic factors significantly influence the physiological response to salinity stress.
• Further research is needed to develop strategies for producing aromatic rice with high salt tolerance.