Bacterial leaf blight (BLB) disease is a rice disease caused by Xanthomonas oryzae pv.oryzae (Xoo). Under variable climate conditions, the new races of Xanthomonas oryzae pv. oryzae (Xoo) have a massive impact on rice crop yield. The focus of the study has been finding disease-resistant genes that will provide resistance against Xoo. Different strains of Xoo attack rice crops all over the world; the kinds that are resistant to these strains can differ depending on where in the world you live.
Currently, 45 Xa-genes have been identified that possess resistance against the Xoo pathogen and are being used in screening rice-diverse cultivars. In this project, amino acid sequences of Xa23, Xa23Ni, Xa10, and X10Ni were mined and used for their motif, domain identification, and chromosome localization. Almost 113 amino acids in both the Xa23 and Xa23-Ni were observed. However, 126 and 134 amino acids were identified in XaXa10 and X10-Ni. The amino acid-conserved regions of Xa23 contribute 50% of the identity to the known executor R protein of Xa10. In addition, trans-membrane helices of Xa23 were also present in Xa10. However, the activation of transcription in Xa23 observed by AvrXa23 was distinct from that in Xa10. During in-silico analysis, two novel Xa10-like genes (Xa10-Ni and Xa23-Ni) were recognized. The structural analysis (physical and chemical characterization) of the Xa23, Xa23Ni, Xa10, and X10Ni proteins showed that, except for all the genes, Xa10-Ni has α-helix and was slightly acidic in nature. Due to their hydrophobic attributes, all were found to be stable proteins. In Ramachandran plot analysis, over 90% of amino acid residues fall in the favored regions. In homology modeling, except for Xa10-Ni, the predicted models of Xa23, Xa23-Ni, and Xa10 possess the ligands. During chromosomal localization, all the genes were found on Chromosome No. 11. It is concluded that the project study will be helpful for the selection of R-genes to build resistance in rice varieties against particular isolates of the Xoo strain to achieve sustainable rice crop production under variable climate conditions.