PlantG4DB: A Database of G-Quadruplex Sequences in Plants

DNA can adopt different non-canonical three-dimensional conformations. Guanine-rich sequences can adopt a non-canonical four-stranded conformation known as G-quadruplex (G4). G-quadruplex is made up of multiple G-quartets (four guanine bases associated via Hoogsteen hydrogen bonding) stacked on top of each other. G-quadruplex forming sequences (GQSes) have been categorized into different types based on the number of guanine repeats (2-G2, 3-G3 or 4-G4) and number of nucleotides in the loops (loop length of 1–3 bp, 1–7 bp and so on). GQSes have been identified in many animals and have been shown to regulate several important cellular processes. However, a comprehensive resource for GQSes in plants is lacking. The Database of G-Quadruplex Sequences in Plants (PlantG4DB) has been developed with the view to provide a comprehensive information about the GQSes in plants. The database contains information about the genomic location and annotation of different types of GQSes in 25 sequenced plant (dicots, monocots and others) genomes. A tool for the prediction of GQSes in a given query sequence has also been implemented. The database is freely available resource, which provides plant biologists a portal to browse, search and query the data to facilitate GQS research in different plant species.