Characterization of Atypical Protein Tyrosine Kinase (PTK) Genes and Their Role in Abiotic Stress Response in Rice.

Tyrosine phosphorylation constitutes up to 5% of the total phophoproteome. However, only limited studies are available on protein tyrosine kinases (PTKs) that catalyze protein tyrosine phosphorylation in plants. In this study, domain analysis of the 27 annotated genes in rice genome led to the identification of 18 PTKs with tyrosine kinase domain. The kinase domain of rice PTKs shared high homology with that of dual specificity kinase BRASSINOSTEROID- INSENSITIVE 1 (BRI1) of . In phylogenetic analysis, rice PTKs clustered with receptor-like cytoplasmic kinases-VII (RLCKs-VII) of . mRNAseq analysis using Genevestigator revealed that rice except and express at moderate to high level in most tissues. expression was highly abundant in panicle at flowering stage. mRNAseq data analysis led to the identification of drought, heat, salt, and submergence stress regulated genes in rice. was upregulated under all stresses. qRT-PCR analysis also showed that all except were significantly upregulated in root under osmotic stress. Tissue specificity and abiotic stress mediated differential regulation of suggest their potential role in development and stress response of rice. The candidate dual specificity identified in this study paves way for molecular analysis of tyrosine phosphorylation in rice.