A comprehensive exploration of molecular aspects of rice-Ustilaginoidea virens interactions

Rice false smut (RFS) caused by Ustilaginoidea (U.) virens has become an emerging threat to global rice production, driven by complex host-pathogen interactions and stage-specific infection processes. We present a comprehensive review of the omics approach to delve into the interplay of genes and their functional validation in decoding the pathway of infection by U. virens and the resistance mechanism exhibited by rice. Firstly, the pathogenesis genes are discussed, which are triggered at spore germination, progressing to hyphal colonization of floral tissues and smut ball formation. Furthermore, these processes are a consequence of tightly regulated expression of genes of different pathways such as cAMP-MAPK signaling, transcriptional regulators, cell wall integrity factors, virulence determinants, secondary metabolites, and carbohydrate-active enzymes. The rice plants also respond by activating a plethora of defense genes such as phytoalexin biosynthesis, pathogenesis-related proteins, receptor-like kinases, transcription factors, anti-oxidation, etc. The mapping of these genes to related quantitative trait loci and short sequence repeat sequences may aid in gene pyramiding strategies for molecular-assisted breeding programs. The molecular manipulation of resistance genes using CRISPR-Cas9 may further facilitate targeted development of improved rice varieties. Overall, molecular insights of host-pathogen interactions offer decoding of sustainable strategies for developing resilient cultivars and effective management of false smut disease.