Identification of the nsLTP gene family from sugar beet and functional analysis of BvnsLTP10 in drought tolerance

Non-specific lipid transfer proteins (nsLTPs) participate in lipid-related processes and plant responses to abiotic stress, yet their roles in drought tolerance in sugar beet remain largely unclear. In this study, a genome-wide analysis identified 15 nsLTP genes in sugar beet, distributed across six chromosomes, and promoter analysis revealed multiple cis-acting elements associated with abiotic stress responses. Among these genes, BvnsLTP10 exhibits sustained up-regulation in leaves and peak induction in roots and stems under PEG-induced drought. Subcellular localization analysis showed that BvnsLTP10 is a secreted protein localized to the cell wall/apoplast, suggesting a role in extracellular lipid transport. Functional characterization in transgenic Arabidopsis demonstrated that BvnsLTP10 overexpression enhanced drought tolerance, as evidenced by increased fresh weight (1.85-fold), relative water content (1.41-fold), chlorophyll content (+ 36%), and Fv/Fm (+ 19.6%), along with elevated antioxidant enzyme activities (POD + 65.1%, SOD + 37.5%, CAT + 54.3%) and reduced electrolyte leakage (− 17.63%). SEM observations indicated potential changes in leaf and stem surface structures, and coordinated upregulation of wax biosynthesis and transport genes ( KCS1 , CER1 , CER3 , WSD1 , FAR3 , ABCG11 ; ~ 20–40-fold) under drought stress, suggesting a possible involvement of wax-related pathways. These findings indicate that BvnsLTP10 enhances drought tolerance by improving plant water status, strengthening antioxidant defense systems, and promoting extracellular structural modifications. Notably, the functional validation was conducted in Arabidopsis thaliana rather than sugar beet, which may limit direct functional extrapolation to the crop species. Nevertheless, BvnsLTP10 represents a promising candidate gene for future studies aimed at enhancing drought resilience in sugar beet.