Draft genome sequence of the pulse crop blackgram [Vigna mungo(L.) Hepper] reveals potential R-genes

Blackgram [Vigna mungo (L.) Hepper] (2n = 2x = 22), an important Asiatic legume crop, is a major source of dietary protein for the predominantly vegetarian population. Here we construct a draft genome sequence of blackgram, for the first time, by employing hybrid genome assembly with Illumina reads and third generation Oxford Nanopore sequencing technology. The final de novo whole genome of blackgram is ~ 475 Mb (82 % of the genome) and has maximum scaffold length of 6.3 Mb with scaffold N50 of1.42 Mb. Genome analysis identified 18655 genes with mean coding sequence length of 970bp. Around 96.7 % of predicted genes were annotated.

Nearly half of the assembled sequence is composed of repetitive elements with retrotransposons as major (47.3% of genome) transposable elements, whereas, DNA transposons made up only 2.29% of the genome. A total of 166014 SSRs, including 65180 compound SSRs, were identified and primer pairs for 34816 SSRs were designed. Out of the 18665 proteins, 678 proteins showed presence of R-gene related domains. KIN class was found in majority of the proteins (372) followed by RLK (79) and N (79).

The genome sequence of blackgram will facilitate identification of agronomically important genes and accelerate the genetic improvement of blackgram.