The Chloroplast Genome Sequence of Mungbean (Vigna radiata) Determined by High-throughput Pyrosequencing: Structural Organization and Phylogenetic Relationships

Mungbean is an economically important crop which is grown principally for its protein-rich dry seeds. However, genomic research of mungbean has lagged behind other species in the Fabaceae family. Here, we reported the complete chloroplast (cp) genome sequence of mungbean obtained by the 454 pyrosequencing technology. The mungbean cp genome is 151 271 bp in length which includes a pair of inverted repeats (IRs) of 26 474 bp separated by a small single-copy region of 17 427 bp and a large single-copy region of 80 896 bp. The genome contains 108 unique genes and 19 of these genes are duplicated in the IR. Of these, 75 are predicted protein-coding genes, 4 ribosomal RNA genes and 29 tRNA genes. Relative to other plant cp genomes, we observed two distinct rearrangements: a 50-kb inversion between accD/rps16 and rbcL/trnK-UUU, and a 78-kb rearrangement between trnH/rpl14 and rps19/rps8. We detected sequence length polymorphism in the cp homopolymeric regions at the intra- and inter-specific levels in the Vigna species. Phylogenetic analysis demonstrated a close relationship between Vigna and Phaseolus in the phaseolinae subtribe and provided a strong support for a monophyletic group of the eurosid I.