The Rice Online Expression Profiles Array Database Version 2 (ROADv2): An Interactive Atlas for Rice Functional Genomics

The Rice Online expression profiles Array Database version 2 (ROADv2; https://roadv2.khu.ac.kr), an enhanced database for rice gene expression analysis, transitions from the previous microarray platforms to RNA-Seq data for improved accuracy. It encompasses 328 datasets from diverse experimental series, including anatomy, abiotic and biotic stress, hormone response, and nutrient starvation. Key updates include gene annotation (upgraded to RGAP version 7) and functional enrichment data (utilizing recent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) versions). ROADv2 debuts protein–protein interaction (PPI) network analysis and broadens interactive visualization across all features. Gene expression data are segmented into anatomy, biotic, abiotic, nutrient, and hormone categories, with user-interactive heatmaps displaying normalized log2 expression and log2 fold change data. Coexpression correlation analysis identifies genes with similar patterns, visualized through interactive network graphs. Functional enrichment tools display GO and KEGG analyses with significant terms emphasized in various formats. PPI network analysis integrates coexpression data to enhance prediction accuracy. Validation studies affirm the database’s reliability, demonstrating reproducible tissue/organ-specific expression patterns. ROADv2 provides a comprehensive resource for rice functional genomics studies.