Targeting antioxidant pathways for improved tolerance to chromium exposure

Area of Science:

• Plant biotechnology
• Environmental science
• Genomics

Background:

• Functional genomics enables engineering plants for heavy metal tolerance.
• The ascorbate-glutathione (AsA-GSH) pathway is crucial for managing oxidative stress in plants.

Purpose of the Study:

• To evaluate chromium stress response in tomato transgenic plants overexpressing key genes of the AsA-GSH pathway.
• To assess the potential of these transgenic plants for phytoremediation.

Main Methods:

• Overexpression of ascorbate peroxidase (APX), MDHAR, DHAR, GR, and SOD genes in tomato.
• Exposure of transgenic and wild-type (WT) plants to 100 µM potassium dichromate (Cr stress).
• Analysis of physiological parameters, pigment content, osmolytes, MDA, ROS, gene expression, and chromium accumulation.

Main Results:

• Transgenic tomato plants exhibited higher carotenoid and anthocyanin levels, improved photosynthesis, transpiration, and stomatal conductance under chromium stress.
• Increased osmolytes and phenolics, reduced electrolyte leakage, MDA, and ROS were observed in transgenic lines.
• Transgenic plants showed higher chromium accumulation in leaves and roots with fewer deformities compared to WT.

Conclusions:

• Overexpression of the AsA-GSH pathway enhances chromium tolerance in tomato.
• Transgenic tomato lines are suitable candidates for phytoremediation of chromium-contaminated environments.