Bioinformatic Characterization and Functional Analysis of a Lipid Transfer Protein from Panax ginseng Involved in Biotic and Abiotic Stress Responses

Plant lipid transfer proteins (LTPs) are key components in defense against biotic and abiotic stresses, yet their functional diversity in Panax ginseng remains unclear. This study aimed to characterize LTP and evaluate its role in stress tolerance. The gene was identified from ginseng transcriptome data and analyzed using bioinformatics tools to determine its structural and physicochemical properties. Panax ginseng lipid transfer protein (PgLTP) was then heterologously expressed in Arabidopsis thaliana (A. thaliana). Transgenic lines were evaluated under fungal infection, drought, and salt stress conditions. Physiological and molecular responses, including reactive oxygen species(ROS) accumulation, malondialdehyde (MDA) content, proline levels, electrolyte leakage, and stomatal behavior under abscisic acid (ABA) treatment, were assessed. Bioinformatic analysis indicated that PgLTP encodes a small protein of approximately 12 kDa containing ten conserved cysteine residues, four α-helices, a signal peptide, and a transmembrane region, suggesting structural divergence from typical LTPs. Functional assays showed that transgenic plants exhibited significantly reduced disease indices under Fusarium oxysporum (F. oxysporum) and Cylindrocarpon destructans (C. destructans) infection. Under drought and salinity stress, transgenic lines demonstrated higher germination and survival rates, enhanced proline accumulation, reduced oxidative damage, and lower electrolyte leakage compared with the wild type. Additionally, PgLTP exhibited enhanced ABA-responsive stomatal closure, which was associated with reduced water loss. These findings indicate that PgLTP contributes to plant tolerance against both biotic and abiotic stresses, which is associated with changes in redox status, osmotic adjustment capacity, and stomatal responses.