Evaluation of cotton immune genes treated with Beauveria bassiana (GHA) as endophyte

Cotton (Gossypium hirsutum), a major cash crop in many countries, can be affected by a broad range of arthropod pests, resulting in significant economic losses. Identifying and evaluating pest management practices that can contribute to production sustainability remains a focus of many studies. Relatively recently, an endophytic strain of Beauveria bassiana (Ascomycota: Hypocerales) known as GHA has been identified, which can colonize host plants. The colonized plants have been reported to have faster and/or stronger induction of various defense responses to biotic and abiotic stresses compared to the non-colonized plants. The present laboratory study was conducted to quantify the expression of defense-related genes following plant colonization by B. bassiana GHA. The differential expression results showed that the four evaluated genes associated with Ethylene (ERF1, MPK2), Salicylic acid (WRKY40), and Jasmonic acid (JAZ) pathways were upregulated in cotton plants upon inoculation with B. bassiana GHA. The expression rate differed among different genes, with the highest expression observed in ERF1 and MPK2 genes (more than 30-fold change; P < 0.001) and the lowest expression observed in WRKY40 and JAZ genes (2-fold change). The findings add to our understanding of interactions between the endophytic B. bassiana and host plants and demonstrate its effectiveness in activating systemic immune responses in cotton.