Arabidopsis, commonly known as rockcress, is a genus of small annual or perennial flowering plants in the cabbage and mustard family, Brassicaceae (order Brassicales). The genus currently comprises 12 accepted species distributed across temperate and subarctic Eurasia, North America, North Africa, and the mountains of eastern tropical Africa.
The genus holds an exceptional position in science as the home of Arabidopsis thaliana (thale cress), one of the most important model organisms in plant biology. A. thaliana was the first plant to have its entire genome sequenced, a milestone completed in 2001. Its small size, short generation time (about six weeks from seed to seed), prolific seed production, and transparent developmental changes make it ideal for genetic research. The Arabidopsis Information Resource (TAIR) and the Nottingham Arabidopsis Stock Centre (NASC) serve as major repositories for genetic material and molecular biology resources for the global research community.
The genus has also figured in spaceflight history: in 1982, the crew of the Soviet Salyut 7 space station grew Arabidopsis plants, making them the first plants to flower and set seed in space. More recently, seeds of A. thaliana were carried to the Moon aboard China's Chang'e 4 lander in 2019, and as of 2022 the species has been successfully cultivated in lunar regolith.
The current taxonomic circumscription of Arabidopsis is relatively recent, arising from molecular and morphological phylogenetic work by O'Kane and Al-Shehbaz that showed the formerly broad genus was polyphyletic. About 50 species were redistributed into newly erected genera including Beringia, Crucihimalaya, Ianhedgea, Olimarabidopsis, and Pseudoarabidopsis. The genus is closely allied to Boechera. Chromosome numbers within Arabidopsis vary by species: A. thaliana is diploid with n=5, while A. lyrata and A. arenosa have n=8 and can occur as diploids or tetraploids. A. suecica (n=13) is an amphidiploid that originated through hybridization between A. thaliana and diploid A. arenosa.
Distribution
Arabidopsis species are native to temperate and subarctic regions of Eurasia and North America, North Africa, and the mountains of eastern tropical Africa. Individual species have more restricted ranges: A. cebennensis is confined to southeastern France, A. suecica to Fennoscandinavia and the Baltic, and A. lyrata spans northeastern European Russia through Alaska and Canada into the southeastern United States. Arabidopsis thaliana is the most widespread species, native to almost all of Europe through central Asia and now naturalized throughout much of the world.
History
Arabidopsis thaliana came to prominence as a plant model organism in the second half of the 20th century, and in 2000–2001 became the first plant to have its entire genome sequenced. In 1982, Arabidopsis became the first plant to flower and produce seeds in space, when the Soviet Salyut 7 crew grew specimens during a 40-day experiment. Seeds were subsequently flown to the Moon on China's Chang'e 4 lander in 2019, and by 2022 the species had been successfully cultivated in lunar soil samples. The Nottingham Arabidopsis Stock Centre (NASC, est. 1991) and the Arabidopsis Biological Resource Center (ABRC) at Ohio State University are the principal international germplasm repositories.
Taxonomy Notes
The current circumscription of Arabidopsis dates from morphological and molecular phylogenetic studies by O'Kane and Al-Shehbaz, which demonstrated the formerly broad genus was polyphyletic. Around 50 previously included species were transferred into newly created genera (Beringia, Crucihimalaya, Ianhedgea, Olimarabidopsis, Pseudoarabidopsis), while two species from Cardaminopsis and Hylandra and three from Arabis were moved into Arabidopsis. Haploid chromosome numbers across the genus are variable (n=5 in A. thaliana, n=8 in A. lyrata and A. arenosa, n=13 in the amphidiploid A. suecica), reflecting the polyploidization and hybridization events within the group.
