Quantitative proteomic analysis deciphers mechanisms of sheath blight resistance in novel rice landrace against Rhizoctonia solani.

Sheath blight (ShB) disease, caused by Rhizoctonia solani Kuhn, poses a significant economic threat to rice production world wide. Acknowledging the limited understanding of ShB resistance proteomics in highly resistant germplasm, our study aimed to unravel the proteomic intricacies underlying the interaction between resistant landrace Nizam Shait and R. solani. Utilizing Nizam Shait and BPT-5204 as representatives of ShB resistance and susceptibility, a comparative proteome analysis was performed using Orbitrap-Fusion mass spectrometry. The analysis unveiled 5133 differentially expressed proteins, with 118 significantly upregulated and 172 significantly downregulated at 0.05 p-value. Functional annotation revealed that the proteins associated with jasmonic acid-induced systemic resistance (JA-ISR), brassinosteroid (BR) signaling pathway, terpenoid biosynthesis, cell wall remodeling and carbohydrate metabolism showed significant upregulation in Nizam Shait upon ShB infection. The proteins associated with systemic acquired resistance (SAR), pathogenesis related proteins, cell redox homeostasis and cell death were downregulated, Notably, the 14-3-3 like protein GF-E exhibited highest upregulation, indicating its pivotal role in defense modulation through the brassinosteroid signaling pathway. The two key proteins of gamma-aminobutyric acid (GABA) shunt mediated defense, Succinate-semialdehyde dehydrogenase and Gamma-aminobutyrate transaminase were upregulated in Nizam Shait versus BPT-5204 and many other defense proteins were upregulated. Key signaling pathways involved in ShB resistance in Nizam Shait encompassed PTI via JA-ISR, cell wall strengthening, and brassinosteroid mediated resistance. Validation of the proteome data through RT-qPCR corroborated the findings, highlighting the significance of this research for future proteome assisted breeding efforts aimed at developing ShB resistant rice varieties.In conclusion, the current study deciphers pathways responsible for high resistance in landrace Nizam Shait against R. solani and identifies key proteins in Rice-R. solani interaction.