OsABA45 Negatively Regulates Salt Stress Responses by Modulating Abscisic Acid Biosynthesis in Rice

Area of Science:

• Plant Biology
• Molecular Genetics
• Agricultural Science

Background:

• Salinity is a major abiotic stress limiting global rice (Oryza sativa L.) productivity.
• Understanding the molecular mechanisms of salt tolerance is crucial for crop improvement.

Purpose of the Study:

• To investigate the function and mechanism of the GRAM domain-containing gene OsABA45 in mediating rice salt stress responses.
• To determine OsABA45's role as a regulator of abscisic acid (ABA) biosynthesis and signaling.

Main Methods:

• Gene cloning and functional characterization of OsABA45 in rice.
• Analysis of salt tolerance in wild-type, knockout, overexpression, and complementation lines.
• Assessing physiological responses including survival rates, ABA levels, and gene expression.

Main Results:

• OsABA45 acts as a negative regulator of salt tolerance; knockout lines show enhanced tolerance, while overexpression lines exhibit reduced tolerance.
• OsABA45 influences abscisic acid (ABA) sensitivity during germination and post-germination stages.
• OsABA45 knockout lines upregulate ABA biosynthesis genes, increase endogenous ABA, and improve tolerance to ionic, osmotic, and oxidative stress.

Conclusions:

• OsABA45 plays a critical role in ABA-mediated salt stress responses in rice.
• OsABA45 functions as a negative regulator, and manipulating its pathway offers potential for developing salt-tolerant rice varieties.
• This study identifies OsABA45 as a novel molecular target for breeding strategies aimed at enhancing crop resilience to salinity.