PPRD: a comprehensive online database for expression analysis of ~45,000 plant public RNA-Seq libraries

High-throughput RNA-sequencing (RNA-seq) has become the most popular technology for profiling gene expression in the last decade due to its low cost and high coverage. As a result, the number of RNA-seq libraries from the plant community has been increasing exponentially in recent years. For major crops, such as maize, rice, soybean, wheat, and cotton, the plant community has collected a total of ~45,000 libraries by 2021. To take full advantage of the bigdata of RNA-seq libraries, an effort to integrate all publicly available libraries via a uniformed processing pipeline and curate them into an easy-to-use searchable database is urgently needed. To address this challenge, here we present a comprehensive web-based platform, Plant Public RNA-seq Database (PPRD, http://ipf.sustech.edu.cn/pub/plantrna/). PPRD consists of a large number of RNA-seq libraries of maize (11,726), rice (19,664), soybean (4,085), wheat (5,816), and cotton (3,483) from Gene Expression Omnibus (GEO), Sequence Read Archive (SRA), European Nucleotide Archive (ENA), and DNA Data Bank of Japan (DDBJ) databases.