Chromosome-level reference genome and population genomic analysis provide insight into the evolution and improvement of domesticated mulberry (Morus alba L)

Mulberry (Morus spp.) is the sole plant consumed by the domesticated silkworm. However, the genome of domesticated mulberry has not yet been sequenced, and the ploidy level of this species remains unclear.

Here, we assembled a high-quality, chromosome-level domesticated mulberry (Morus alba L) genome and confirmed that it is diploid with 28 chromosomes (2n=2x=28).

Population genomic analysis based on resequencing of 134 mulberry accessions split domesticated mulberry into three geographical groups, namely, Taihu Basin of southeastern China (Hu mulberry), northern and southwestern China, and Japan, among which Hu mulberry had the lowest nucleotide diversity and demonstrated obvious signatures of selection indicating environmental adaptation.

Our results also supported the idea that multiple domesticated mulberry accessions that were previously classified as different species actually belong to one species.

This study expanded our understanding of the genome evolution of the genus Morus and the population structure of domesticated mulberry and will facilitate mulberry breeding and improvement.