Heat stress and viral infection elicit a specific and differential gene response in thermo-tolerant and thermo-susceptible tomato plants

Abiotic and biotic factors can influence plant responses, yet the extent to which the combination of heat tolerance and viral infection can modulate common or exclusive signaling pathways remains unclear. Here, we examined the effects of temperature variations (20/14°C, 26/20°C, and 32/26°C) and <i>Potexvirus pepini</i> (pepino mosaic virus, PepMV) infection on viral accumulation and gene expression in two tomato cultivars with high- and low-temperature tolerance. Comparative 3´mRNA-seq analysis revealed that the combined effects of heat stress and viral infection had a greater impact on thermo-susceptible plants, where PepMV accumulation was higher. Among differentially expressed genes (DEGs), 64% and 45% were associated with abiotic and biotic stress, respectively. Furthermore, we identified five and 16 genes that were consistently expressed under both high- and low- temperature conditions in thermo-susceptible and thermo-tolerant plants, respectively, as potential candidates involved in the response to heat stress and PepMV accumulation. These findings underscore the significance of plant-pathogen-environment interactions and provide insights for enhancing crop resilience and productivity in response to shifting disease and climatic conditions.