Co-overexpression of OsSIZ1 and LtRCA in Arabidopsis thaliana improves heat, drought, and salt tolerance

Abstract

Abiotic stresses such as heat and drought are major constraints to plant growth and development, which result in tremendous decline in agricultural productivity. The concomitant occurrence of these stresses is common in nature and can lead to bigger losses in crop yield. Hence, implementing a rigorous approach to enhance abiotic stress tolerance is urgently needed. Multi-gene stacking through genetic engineering is considered to be an effective method that could increase abiotic stress tolerance. Previously, it was shown that overexpression of OsSIZ1 increased heat, drought, and salt tolerance in transgenic plants. It was recently shown that overexpression of LtRCA, a Rubisco activase gene from Larrea tridentata, could increase heat tolerance in Arabidopsis. In this study, we demonstrated that co-overexpression of OsSIZ1 and LtRCA significantly enhances abiotic stress tolerance, particularly under combined drought and heat stress conditions. Notably, OsSIZ1/LtRCA co-overexpressing plants produced at least eight times more seeds and significantly greater biomass compared to wild-type plants, outperforming other transgenic plants. Under individual stress conditions, they yielded six times more seeds under drought stress and three times more under heat stress conditions than wild-type plants. These findings highlight the effectiveness of pyramiding beneficial genes as a powerful strategy to confer broad-spectrum stress resilience in plants.