The genome of low-chill Chinese plum ′Sanyueli′ (Prunus salicina Lindl.) provides insights into the regulation of chilling requirement of flower bud

Chinese plum (Prunus salicina Lindl.) is a stone fruit that belongs to the Prunus genus and plays an important role in the global production of plum. In this study, we report the genome sequence of the Chinese plum ′Sanyueli′ (P. salicina Lindl.), which is known to have a low-chill requirement. The assembled genome size was 308.06 Mb, with a contig N50 of 815.7 kb. A total of 30,159 protein-coding genes was predicted from the genome and 56.42% (173.39 Mb) of the genome was annotated as repetitive sequence. Bud dormancy is influenced by chilling requirement in plum and partly controlled by DORMANCY ASSOCIATED MADS-box (DAM) genes. Six tandemly arrayed PsDAM genes were identified in the assembled genome. Sequence analysis of PsDAM6 in ′Sanyueli′ revealed the presence of large insertions in the intron and exon regions. Transcriptome analysis indicated that the expression of PsDAM6 in the dormant flower buds of ′Sanyueli′ was significantly lower than that in the dormant flower buds of the high chill requiring ′Furongli′ plum. In addition, the expression of PsDAM6 was repressed by chilling treatment. The genome sequence of ′Sanyueli′ plum provides a valuable resource for elucidating the molecular mechanisms responsible for the regulation of chilling requirements, and it also useful for the identification of the genes involved in the control of other important agronomic traits and molecular breeding in plum.