SlWHY2 interacts with SlRECA2 to maintain mitochondrial function under drought stress in tomato

Area of Science:

• Plant Biology
• Molecular Biology
• Genetics

Background:

• Drought stress negatively impacts plant physiological processes, including photosynthesis and respiration.
• Reactive oxygen species (ROS) accumulate during drought, causing cellular damage.
• Mitochondrial function is critical for plant survival under abiotic stress.

Purpose of the Study:

• To investigate the role of the tomato WHIRLY2 (SlWHY2) gene in drought stress response.
• To elucidate the function of SlWHY2 in maintaining mitochondrial integrity and plant tolerance to drought.

Main Methods:

• Gene silencing using RNA interference (RNAi) to create SlWHY2 knockdown tomato lines.
• Phenotypic analysis of wild-type (WT) and SlWHY2 RNAi plants under drought conditions.
• Measurement of physiological parameters including chlorophyll content, photosystem efficiency, ROS levels, alternative oxidase (AOX) activity, and mitochondrial membrane potential (MMP).
• Analysis of mitochondrial gene expression and protein-protein interactions.

Main Results:

• SlWHY2 expression was significantly induced by drought stress in tomato.
• SlWHY2 RNAi plants exhibited increased wilting, reduced biomass, lower chlorophyll content, and impaired photosystem efficiency (YI and Fv/Fm) under drought.
• Drought-stressed SlWHY2 RNAi lines showed elevated ROS accumulation, decreased AOX activity, and unstable MMP compared to WT.
• Expression of key mitochondrial genes was further reduced in SlWHY2 RNAi lines under drought.
• SlWHY2 was found to interact with SlRECA2, a mitochondrial DNA repair protein.

Conclusions:

• SlWHY2 is essential for maintaining mitochondrial function and stability during drought stress in tomato.
• The SlWHY2 gene plays a critical role in enhancing drought tolerance by supporting mitochondrial integrity and potentially DNA repair mechanisms.