Complete chloroplast genome of Synsepalum dulcificum D.: a magical plant that modifies sour flavors to sweet

Abstract Synsepalum dulcificum D. belongs to the Sapotaceae family, which is an evergreen shrub native to tropical West Africa. It is a kind of magical plant that has the unique characteristic of modifying sour flavors to sweet. In this study, the chloroplast genome of S. dulcificum was sequenced, assembled, and annotated firstly. Chloroplast genome size of S. dulcificum is 158,463 bp, the circular chloroplast genome consists of four regions: a large single-copy region of 88,256 bp, two inverted repeat regions of 25,958 bp, and a small single-copy region of 18,669 bp, with the GC content of 36.87%. A total of 133 genes were annotated in the S. dulcificum chloroplast genome, of which 88 were protein-coding genes (PCGs), 37 were transfer RNA (tRNA) genes, and eight were ribosomal RNA (rRNA) genes. Phylogenetic analysis showed that Pouteria campechiana was most closely related to S. dulcificum. The study provides important genomic data for further utilization and breeding of S. dulcificum.

Synsepalum dulcificum D.; chloroplast genome; phylogenetic relationship Synsepalum dulcificum D. belongs to the Sapotaceae family (Shi et al. 2016), commonly known as miracle berry, miracle fruit, magic fruit, miraculous or asaba (Coronel et al. 2009;Obafemi et al. 2017), which is an evergreen shrub native to tropical West Africa (Wang et al. 2011). It is a kind of magical plant that has the unique characteristic of modifying sour flavors to sweet (Du et al. 2014). It is also a well-known natural source of 'miraculin,' a sweetening glycoprotein (Tchokponhou e et al. 2019). All plant parts of S. dulcificum are of medicinal importance. The berry fruit and leaf contains many nutrients along with many beneficial characteristics (Nkwocha et al. 2014;Njoku et al. 2015). It has the ability to improve insulin sensitivity, and antioxidant and anticancer abilities (Swamy et al. 2014). Thus, it may be used as an adjuvant for treating diabetic patients with insulin resistance (Chen et al. 2006;Obafemi et al. 2017). The seed oil of S. dulcificum is also a rare and exotic fruit oil (Guney and Nawar 1977).
As a valuable plant species, currently, S. dulcificum is utilized in cosmetics and food. Besides, it is also used extensively in the pharmaceutical industry (Achigan- Dako et al. 2015). Surprisingly, there are few studies on the genomics of S. dulcificum, focusing on the nuclear, mitochondrial and chloroplast genome, which severely limits its utilization and breeding. In this study, the chloroplast genome of S. dulcificum was sequenced, assembled, and annotated firstly.
Young leaves of S. dulcificum were collected from the Xishuangbanna Tropical Flowers and Plants Garden (100.789433 E, 22.015939 N) and frozen in liquid nitrogen.
Chloroplast genome size of S. dulcificum is 158,463 bp. Like other plants, the circular chloroplast genome consists of four regions: a large single-copy region of 88,256 bp, two inverted repeat regions of 25,958 bp, and a small single-copy region of 18,669 bp. The composition of the four bases is 49,395 bp of A, 50,640 bp of T, 28,594 bp of G, and 29,834 bp of C, with the GC content of 36.87%. There are 88 proteincoding genes (PCGs), eight ribosomal RNA (rRNA) genes, and 37 transfer RNA (tRNA) genes, with a total number of 133 genes that were annotated in the S. dulcificum chloroplast genome.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Funding
This work was supported by Sci-tech Innovation System Construction for Tropical Crops Grant of Yunnan Province [No. RF2020].

Data availability statement
The data that support the findings of this study are openly available in GenBank at https://www.ncbi.nlm.nih.gov/, reference number MT723946.