Mechanisms of Host Jumps in Pyricularia oryzae and Related Pyricularia Lineages: Interplay of Effectors and Climate Change

ABSTRACT Pyricularia species are filamentous fungi belonging to the phylum Ascomycota and are causal agents of blast disease in several Poaceae crops. The species can incite blast disease in a broad host range, including cereals, millets and weeds. Pyricularia species have arisen from multiple independent host jumps, facilitated by genomic plasticity and diversification of effector repertoires through mutation, recombination and hybridization. These processes, often intensified under changing climatic conditions, have enabled the pathogen to overcome host barriers and expand its epidemiological footprint. The emergence and global spread of wheat blast highlight the risks associated with hybridization‐driven host jumps. Therefore, understanding the role of effector repertoire and the influence of abiotic factors plays a pivotal role in understanding the behaviour of the organism, anticipating future host jumps and developing management strategies. Here we review the evolutionary plasticity that helps Pyricularia to cross host boundaries by highlighting how effector‐mediated modulation of plant immunity supports pathogenic success. In addition, we discuss the evolutionary dynamics of effector families and advances in computational tools for effector identification and characterization. Furthermore, we emphasize the role of abiotic factors, particularly climatic shifts, in shaping pathogen aggressiveness and outbreak potential. The wheat blast outbreak in Bangladesh serves as a compelling case study, illustrating how genetic innovation in the pathogen, coupled with favourable environmental conditions, can trigger devastating epidemics.