Longan
Dimocarpus longan
Gene Expression (SX) Synteny Search (SX) Annotation Extraction
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Dimocarpus longan (longan) is a diploid fruit species (2n = 2x = 30) belonging to the Sapindaceae family, native to China. It is widely cultivated, mainly in China, Thailand, and Vietnam, with additional production in Australia and the United States. Its name means 'dragon's eye' because the shelled fruit, with its shiny black seed visible through the translucent pulp, resembles an eyeball.
- Floral and Fruit Biology: Longan is an evergreen tree that reaches heights of up to 20 meters, with alternate paripinnate leaves composed of 6-9 opposite leaflets. The flowers are unisexual, small, yellow-brown with five petals. Each inflorescence contains between 200 and 1000 functionally female flowers and between 1000 and 4000 functionally male flowers. The flowers usually open at night and pollination takes place in the morning thanks to various insects.
- Varieties and Characteristics: Longan comprises two subspecies: ssp. longan and ssp. malesianus, each with several varieties. There are numerous longan cultivars in South Asia, but only 30 to 40 are commercially grown worldwide, the most common being Dimocarpus longan spp. longan var. longan. They grow well in regions with a two- to three-month period of cool temperatures for floral induction.
- Geographic Production: Longan fruit is economically important in Asia, but its commercial exploitation has only been carried out in Thailand, China, Taiwan and Vietnam. It is also cultivated in Cambodia, Laos, Queensland (Australia), Indonesia, Florida and Hawaii (USA), India, Sri Lanka, and Myanmar.
- Nutritional and Medicinal Importance: Longan pulp is rich in vitamin C, B vitamins, potassium, and antioxidants such as polyphenols. The pericarp, pulp, and seeds are high in phenolic compounds including gallic acid, epicatechin, and ellagic acid, which have anti-inflamatory and antioxidant properties.
- Other Uses: Longan seeds are also used as shampoo due to their high saponin content. The wood is highly resistant to water and moisture, making it an excellent material for shipbuilding, furniture production, and craftsmanship.
Genome assemblies
There are several sequenced genomes available of longan:
- cv. Shi Xia (SX), by the Fujian Agriculture and Forestry University. Available at SapBase .
- cv. Ji Dan Ben (JDB), by Wang et al., 2022. Available at the Genome Warehouse.
- cv. Hong He Zi (HHZ), by Lin et al., 2017. Available at the GigaScience DataBase.
Genome assembly stats
Overall statistics on D. longan genome assemblies for cv. Ji Dan Ben published by Wang et al., 2022 (left), cv. Shi Xia (center), and cv. Hong He Zi published by Lin et al., 2017 (right).
| Ji Dan Ben* | Shi Xiaa | Hong He Zi | |
|---|---|---|---|
| Sequence count | 90 | 34 | 17,367 |
| Total length (Mb) | 454.30 | 483.44 | 495.33 |
| Longest sequence (Mb) | 46.64 | 46.07 | 6.94 | Average length (Mb) | 5.05 | 14.22 | 0.03 |
| Number of Ns (%) | 0.01 | 0.02 | 4.73 |
| GC (%) | 33.93 | 33.74 | 33.78 |
| N50 (Mb) | 29.55 | 31.40 | 0.57 |
| L50 (sequences) | 7 | 7 | 204 |
| BUSCO completenessb (%) | 98.52 | 90.57 | 88.25 |
a Available at SapBase
b BUSCO based on embryophyta_odb12 dataset
Taxonomy
| Kingdom | Plantae |
|---|---|
| Phylum | Streptophyta | Class | Magnoliopsida |
| Order | Sapindales |
| Family | Sapindaceae |
| Genus | Dimocarpus Lour. |
| Species | Dimocarpus longan Lour. |
