Transcriptome analyses reveal Beauveria bassiana endophyte induced disruption of aphid physiology

Some strains of entomopathogenic fungi are known to colonize crops endophytically, providing systemic protection against insect pests. This colonization has been revealed to reduce aphid survival and reproductive potential. Understanding the molecular mechanisms underlying these effects could provide insight into what occurs to aphids when they feed on endophytically colonized plants. In this study, an RNA sequencing (RNA-Seq) was conducted for transcriptome analyses of the melon aphid Aphis gossypii and its symbiotic bacteria after feeding on Beauveria bassiana endophytically colonized melon plants. The fungal colonization triggers significant alterations in the aphid transcriptome, reflecting molecular responses to fungal propagules and/or plant-induced systemic resistance. Key changes include the up-regulation of genes involved in host plant recognition by the aphid pest, immune system activation, energy production, and defense mechanisms such as toxin adaptation, detoxification, and cell death markers. Genes associated with escape responses, including alarm pheromone production and wing bud differentiation, were also up-regulated. In contrast, down-regulated genes point to disruptions in homeostasis and neuronal function, further impacting aphid physiology and its symbiotic relationship with Buchnera. These molecular perturbations likely underlie the lethal and sublethal effects observed in aphids feeding on B. bassiana-colonized plants. This study identifies critical pathways involved in aphid-fungal-plant interactions, offering valuable insights into the potential of endophytic entomopathogenic fungi for aphid pest management.