Phylogenomic analysis and development of molecular markers for the determination of twelve plum cultivars (Prunus, Rosaceae).

BACKGROUND

Plums are one of the most important economic crops of the Rosaceae family and are produced all over the world. China has many local varieties, but the genomic information is limited for genetic studies. Here, we first sequenced, assembled, and analyzed the plastomes of twelve plum cultivars and developed molecular markers to distinguish them.

RESULTS

The twelve plastomes of plum cultivars have a circular structure of 157,863-157,952 bp containing a large single-copy region (LSC) of 86,109-86,287 bp, a small copy region (SSC) of 18,927-19,031 bp, and two inverted repeats (IR) of 26,353-26,387 bp each. The plastomes of plum cultivars encode 131 genes, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. We detected 50, 54, 54, 53, 53, 50, 54, 54, 54, 49, 50, 54 SSRs in the twelve analyzed varieties, respectively. For repeat sequences, we identified 553 tandem repeats, 204 direct repeats, and 270 palindromic repeats. We also analyzed the expansion/contraction of IR regions. The genes rpl22, rps19, rpl2, ycf1, ndhF, and the trnH span on or near the boundary of IR and single-copy regions. Phylogenetic analysis showed that the twelve cultivars were clustered with the P. salicina and P. domestica. We developed eight markers LZ01 to LZ08 based on whole plastomes and nuclear genes and validated them successfully with six repetitions.

CONCLUSIONS

The results obtained here could fill in the blanks of the plastomes of these twelve plum cultivars and provide a wider perspective based on the basis of the plastomes of Prunus to the molecular identification and phylogenetic construction accurately. The analysis from this study provides an important and valuable resource for studying the genetic basis for agronomic and adaptive differentiation of the Prunus species.