Ectopic expression of the Pseudomonas aeruginosa KatA gene in cotton improves its drought tolerance and yield under drought stress

Drought stress breaks the balance between the production and elimination of reactive oxygen species in plant cells, resulting in the accumulation of free radicals, which in turn affect plant growth, development, and yield. Antioxidant enzymes including catalase, can scavenge excessive free radicals and protect cells from oxidative damage. In this study, T-0 transgenic cotton expressing a catalase gene PaKatA from Pseudomonas aeruginosa was obtained by Agrobacterium-mediated method, and two seventh generation of transgenic cotton lines were obtained by continuous screening for kanamycin resistance and PCR-based genotyping. Ectopic expression of PaKatA in cotton resulted in significantly elevated catalase and peroxidase activities, proline and relative water content, as well as decreased H2O2 and malondialdehyde content under drought stress conditions, conferring on transgenic plants better tolerance to drought. Furthermore, the yield of transgenic cotton increased by 34% under drought stress in the field, probably as a result of relatively stronger net photosynthetic capacity (Pn) and better optimal quantum yield of PSII (Fv/Fm). Our results indicate that the PaKatA gene can be used to improve drought tolerance and yield of cotton varieties and might also be a promising drought-resistant gene for improving other crop varieties.