Piriformospora indica Preserves Fruit Quality and Postharvest Shelf Life While Suppressing Tomato Leaf Curl Virus

Abstract

Tomato leaf curl virus (ToLCV) is one of the most destructive viral pathogens, limiting tomato productivity by impairing plant growth, fruit development, yield, and nutritional quality. Piriformospora indica is a beneficial root endophytic fungus known to enhance plant growth, yield, and tolerance to biotic and abiotic stresses in diverse crop species. This study examined the effects of pre- and post-colonisation by P. indica on tomato leaf curl disease, fruit productivity, nutritional quality, and shelf life following artificial inoculation with ToLCV. Pre-colonisation with P. indica significantly reduced disease severity by lowering the vulnerability index by 67.75%, whereas post-colonisation reduced it by 23.27% compared with virus-infected plants, and substantially improved fruit yield, locule development, and seed production. Virus infection significantly reduced yield and productivity, as well as fruit ascorbic acid, lycopene, β-carotene, total soluble solids, and shelf life. In contrast, P. indica colonisation significantly compensated for reductions in tomato fruit yield and productivity and restored quality attributes. Fruits from pre-colonised plants contained 18.72 mg 100 g⁻¹ fresh weight ascorbic acid, 4.31 mg 100 g⁻¹ lycopene, 0.69 mg 100 g⁻¹ β-carotene, and 4.48 °Brix soluble sugars, which were substantially higher than those of virus-inoculated plants. Furthermore, the shelf life of harvested fruits was extended from 6.8 to 10.4 days. Enhanced postharvest storage was associated with increased expression of the fruit shelf-life-associated gene SlFSR, indicating transcriptional regulation of postharvest longevity by the endophytic fungus. Overall, these findings indicate that P. indica mitigates ToLCV-induced disease severity, yield reduction, fruit-quality deterioration, and reduced fruit shelf life by modulating biochemical and fruit developmental processes. This highlights the potential of P. indica as a sustainable biological strategy for reducing disease severity and improving fruit yield, nutritional quality, and postharvest storage under ToLCV infection.