UVB radiation which causes dermatosis, cancroid, and necrosis in living organisms is mostly absorbed by ozone layer, resulting in transmission of only small UVB proportion to earth surface. Recently, however, rapid increases of pollutants like CFCs have accelerated depletion of stratospheric ozone layer. Increased UVB irradiation alters affects biomolecule interinity such as DNA, RNA and protein. To understand DNA mutation spectra in response to UVB, in the present study, we used two soybean cultivars, Buseok and Cheongja 3, which were screened as the most UVB tolerant and sensitive genotypes among 140 soybean germplasms, respectively. Whole genomes of Buseok and Cheongja were sequenced at low-coverage depth by illumina Hiseq2000, and we also sequenced 6 hr UVB irradiated genomes of two cultivars. Raw sequence reads were aligned to the soybean reference sequences (cv. Williams 82) by BWA aligner software. To identify DNA mutations induced by UV-B irradiation, multiple comparisons between non-irradiated and irradiated genomes in these two soybean genotypes were conducted using samtools and GenomeAnalyzerTK packages and homebrew python codes. A total, 13,992 and 17,078 single nucleotide polymorphisms (SNPs) were indentified between non-irradiated and irradiated genomes of Buseok and Cheongja 3, respectively. In addition, Buseok and Cheongja 3 have 423 and 465 insertions/deletions induced by UVB, respectively. Approximately 58% of the identified SNPs were C to T or CC to TT transversions, consistent with the previous studies. Chromosomal distributions of the SNPs likely showed differences in UV-B mutation positions depending on the soybean genotype

Mungbean (Vigna radiata) is a fast-growing, warm-season legume crop that is primarily cultivated in developing countries of Asia. We constructed a draft genome sequence of mungbean to facilitate genome research into the subgenus Ceratotropis and to enable a better understanding of the evolution of leguminous species. The draft genome sequence covers 80% of the estimated genome, of which 50.1% consists of repetitive sequences. In total, 22,427 high confidence protein-coding genes were predicted. Based on the de novo assembly of additional wild mungbean species, the divergence of what was eventually domesticated and the sampled wild mungbean species appears to have predated domestication. Moreover, the de novo assembly of a tetraploid Vigna species (Vigna reflexo-pilosa var. glabra) provided genomic evidence of a recent allopolyploid event. To further study speciation, we compared de novo RNA-seq assemblies of 22 accessions of 18 Vigna species and protein sets of Glycine max and Cajanus cajan. The species tree was constructed by a Bayesian Markov chain Monte Carlo method using highly confident orthologs shared by all 24 accessions. The present assembly of V. radiata var. radiata will facilitate genome research and accelerate molecular breeding of the subgenus Ceratotropis.