Enhanced expression of the ScTpx2 gene confers tolerance to drought stress in transgenic sugarcane.

Abstract

Drought events can have a devastating impact on agriculture, and due to climate change, such extreme events are expected to become more frequent. Sugarcane plays a critical role in the Brazilian economy by producing sugar and bioethanol, contributing positively to the reduction of CO₂ emissions. Although sugarcane is considered resilient to drought, this stress remains the primary abiotic factor reducing sugar and biomass yields. Here, we describe the role of a sugarcane gene, ScTpx2, which is induced by drought in sugarcane leaves under field conditions. When overexpressed in Arabidopsis, ScTpx2 enhanced plant survival under extreme water deficit and improved performance under mild stress conditions, which better represent field scenarios. We subsequently overexpressed the ScTpx2 gene in sugarcane plants. After 10 days of water deficit at 30% field capacity in a greenhouse, net photosynthesis in ScTpx2-overexpressing lines (ScTpx2OE) was 12-23% higher than in wild-type plants. While malondialdehyde (MDA) content, a marker of oxidative stress, increased by 129% in wild-type plants under water deficit, in ScTpx2OE plants, the increase ranged from 20% to 107%. Additionally, the vascular bundles and xylem areas were larger in ScTpx2OE compared to WT. These findings suggest that the ScTpx2 protein influences the development of the vascular system, thereby improving water transport efficiency. Our results demonstrate that overexpression of the ScTpx2 gene mitigates the effects of water deficit in sugarcane, offering promising opportunities for biotechnological applications in developing drought-tolerant commercial cultivars.