Barley shows reduced Fusarium head blight under drought and modular expression of differentially expressed genes under combined stress.

The article focuses on the transcriptional and physiological responses of spring barley (Hordeum vulgare) to combined drought stress and Fusarium head blight (FHB) infection caused by Fusarium culmorum. Using three barley varieties with differing susceptibility to FHB, the study found that drought stress prior to infection reduced FHB severity, particularly in susceptible varieties, and that gene expression responses to combined stress largely reflected additive effects of single stresses rather than unique combined-stress responses. Weighted gene correlation network analysis (WGCNA) identified distinct gene modules associated with pathogen response, drought stress, and their physiological markers such as abscisic acid (ABA), fungal DNA content, and proline. The findings suggest that drought-induced ABA accumulation and accelerated seed maturation may contribute to reduced fungal infection, highlighting complex interactions between abiotic and biotic stress pathways relevant for breeding stress-tolerant and disease-resistant barley genotypes.