Co-overexpression of AVP1/PP2A-C5 in cotton to enhance cotton abiotic stress tolerance and fertilizer use efficiency
Food security is currently threatened by more challenges such as the increasing world population, climate change, and toxic metal contaminated arable land. To meet the demand of feeding and clothing the increasing world population, it is necessary to enhance crop yield in the world. Cotton is a major fiber crop for Texas Southern High Plains, as well as for US, unfortunately cotton production is facing a severe challenge imposed by those threats. Overuse of fertilizer in agricultural production has caused salinization in soils worldwide, leading to unbalanced nutrients in soils that caused huge yield losses in many semiarid regions in the world. In addition, toxic metal is another important threat limiting agriculture production and it affects plant, animal, and human health. This research uses Agrobacterium-mediated plant transformation to co-overexpress PP2A-C5, and AVP1 in cotton and aims at generating a cotton variety with high fertilizer use efficiency that can also functions as a metal hyperaccumulator to clean toxic metal contaminated arable land. AVP1 is a vacuolar membrane-bound H+ pyrophosphatase, and overexpression of AVP1 in plants could increase tolerance of toxic metals and fertilizer use efficiency. The PP2A-C5 is the catalytic subunit 5 of the Arabidopsis protein phosphatase 2A. Overexpression of PP2AC5 in Arabidopsis could increase tolerance to NaCl, KCl, LiCl, and KNO3. In this study, we found that AVP1/PP2AC5 co-overexpressing cotton performed better under low fertilizer conditions than AVP1-overexpressing cotton and wild-type cotton. In addition, we found that AVP1/PP2AC5 co-overexpressing cotton performed better and accumulated more lithium under high lithium condition than wild-type cotton. Interestingly, AVP1/PP2AC5 co-overexpressing cotton exhibited higher N, P, K use efficiency under high lithium conditions as well in comparison with wild-type cotton plants. Those data prove that AVP1/PP2AC5 co-overexpressing cotton could serve as a hyperaccumulator plant for lithium, and it could be used to clean fertilizer overused soils.