Arabidopsis

Arabidopsis
Thale Cress (Arabidopsis thaliana)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Brassicales
Family:	Brassicaceae
Genus:	Arabidopsis Heynh. in Holl & Heynh.
Species
See text.

Arabidopsis (A-ra-bi-dóp-sis, rockcress) is a genus in the family Brassicaceae. They are small flowering plants related to cabbage and mustard. This genus is of great interest since it contains thale cress (Arabidopsis thaliana), one of the model organisms used for studying plant biology and the first plant to have its entire genome sequenced. Changes in thale cress are easily observed, making it a very useful model.

Status

Currently the genus Arabidopsis has nine species and a further eight subspecies recognised. This delimitation is quite recent, and is based on morphological and molecular phylogenies by O'Kane & Al-Shehbaz (1997, 2003) and others.

Their findings confirm that the species formerly included in Arabidopsis made it polyphyletic. The most recent reclassification moves two species previously placed in Cardaminopsis and Hylandra and three species of Arabis into Arabidopsis, but excludes 50 species that have been moved into the new genera Beringia, Crucihimalaya, Ianhedgea, Olimarabidopsis, and Pseudoarabidopsis.

All of the species in Arabidopsis are indigenous to Europe, while two of the species have broad ranges also extending into North America and Asia.

In the last two decades, Arabidopsis thaliana has gained much interest from the scientific community as a model organism for research on numerous aspects of plant biology. The Arabidopsis Information Resource (TAIR) is a curated online information source for Arabidopsis genetic and molecular biology research, and The Arabidopsis Book is an online compilation of invited chapters on Arabidopsis biology. In Europe, the model organism resource centre for Arabidopsis germplasm, bioinformatics and molecular biology resources (including GeneChips) is the Nottingham Arabidopsis Stock Centre – NASC whilst in North America germplasm services are provided by the Arabidopsis Biological Resource Center, (ABRC) based at the Ohio State University. The ordering system for ABRC was incorporated into The Arabidopsis Information Resource (TAIR) database in June 2001 whilst NASC has always (since 1991) hosted its own ordering system and genome browser.

List of species and subspecies

• Arabidopsis arenosa (L.) Lawalrée,

A. arenosa subsp. arenosa

Distribution: Europe: native in Austria, Belarus, Bosnia Herzegovina, Bulgaria, Croatia, Czech Republic, NE France, Germany, Hungary, N Italy, Latvia, Lithuania, Macedonia, Poland, Romania, Slovakia, Slovenia, Switzerland, Ukraine, and Yugoslavia; naturalized in Belgium, Denmark, Estonia, Finland, Netherlands, Norway, Russia and W Siberia, and Sweden; absent in Albania, Greece, C and S Italy, and Turkey.

A. arenosa subsp. borbasii

Distribution: E Belgium, Czech Republic, NE France, Germany, Hungary, Poland, Romania, Slovakia, Switzerland, Ukraine. Doubtfully occurring in Denmark.

• Arabidopsis cebennensis (D.C.)

Distribution: SE France.

• Arabidopsis croatica (Schott)

Distribution: Bosnia, Croatia.

• Arabidopsis halleri (L.)

A. halleri subsp. halleri

Distribution: Austria, Croatia, Czech Republic, Germany, N and C Italy, Poland, Romania, Slovakia, Slovenia, Switzerland, and S Ukraine. Probably introduced in N France and extinct in Belgium.

A. halleri subsp. ovirensis (Wulfen)

Distribution: Albania, Austria, NE Italy, Romania, Slovakia, Slovenia, SW Ukraine, Yugoslavia.

A. halleri subsp. gemmifera (Matsumura)

Distribution: Russian Far East, northeastern China, Korea, Japan, and Taiwan.

• Arabidopsis lyrata (L.) O'Kane & Al-Shehbaz

A. lyrata subsp. lyrata

Distribution: NE European Russia, Alaska, Canada (Ontario west into British Columbia), and southeastern and central United States (Vermont south into northern Georgia and Mississippi northward into Missouri and Minnesota).

A. lyrata subsp. petraea (Linnaeus) O'Kane & Al-Shehbaz

Distribution: Austria, Czech Republic, England, Germany, Hungary, Iceland, Ireland, N. Italy, Norway, Russia (NW Russia, Siberia and Far East), Scotland, Sweden, Ukraine, boreal North America (Alaska and Yukon). Apparently extinct in Poland.

A. lyrata subsp. kamchatica (Fischer ex D.C.) O'Kane & Al-Shehbaz

Distribution: boreal Alaska, Canada (Yukon, Mackenzie District, British Columbia, northern Saskatchewan), Aleutian Islands, eastern Siberia, the Russian Far East, Korea, northern China, Japan, and Taiwan.

• Arabidopsis neglecta (Schultes)

Distribution: Carpathian Mountains (Poland, Romania, Slovakia, and adjacent Ukraine).

• Arabidopsis pedemontana (Boiss.)

Distribution: northwestern Italy and, presumably extinct, in adjacent SW Switzerland.

• Arabidopsis suecica (Fries) Norrlin, Meddel.

Distribution: Fennoscandinavia and the Baltic region.

• Arabidopsis thaliana (L.) Heynh.

Distribution: native range almost all Europe to central Asia, now naturalized worldwide.

Cytogenetics

Cytogenetic analysis has shown that the haploid chromosome number (n) is variable and can be 5, 8 and 13.

A. thaliana is n=5 and the DNA sequencing of this species was completed in 2001.

A. suecica is n=13 (5+8) and is an amphidiploid species originated through hybridization between A. thaliana and diploid A. arenosa.

A. neglecta is n=8 as are the various subspecies of A. halleri.

Various subspecies of A. lyrata and A. arenosa can be either 2n (diploid) or 4n (tetraploid).

As of 2005, A. cebennensis, A. croatica and A. pedemontana have not been investigated cytologically.

Reclassified species

The following species previously placed in Arabidopsis are not currently considered part of the genus.

• A. bactriana =
• A. brevicaulis = Crucihimalaya himalaica
• A. bursifolia = Beringia bursifolia
• A. campestris = Crucihimalaya wallichii
• A. dentata = Murbeckiella pinnatifida
• A. drassiana =
• A. erysimoides = Erysimum hedgeanum
• A. eseptata = Olimarabidopsis umbrosa
• A. gamosepala = Neotorularia gamosepala
• A. glauca = Thellungiella salsuginea
• A. griffithiana = Olimarabidopsis pumila
• A. himalaica = Crucihimalaya himalaica
• A. huetii = Murbeckiella huetii
• A. kneuckeri = Crucihimalaya kneuckeri
• A. korshinskyi = Olimarabidopsis cabulica
• A. lasiocarpa = Crucihimalaya lasiocarpa
• A. minutiflora = Ianhedgea minutiflora
• A. mollis = Beringia bursifolia
• A. mollissima = Crucihimalaya mollissima
• A. monachorum = Crucihimalaya lasiocarpa
• A. mongolica = Crucihimalaya mongolica
• A. multicaulis = Arabis tibetica
• A. novae-anglicae = Neotorularia humilis
• A. nuda = Drabopsis nuda
• A. ovczinnikovii = Crucihimalaya mollissima
• A. parvula = Thellungiella parvula
• A. pinnatifida = Murbeckiella pinnatifida
• A. pumila = Olimarabidopsis pumila
• A. qiranica = Sisymbriopsis mollipila
• A. richardsonii = Neotorularia humilis
• A. russeliana = Crucihimalaya wallichii
• A. salsuginea = Thellungiella salsuginea
• A. sarbalica = Crucihimalaya wallichii
• A. schimperi = Robeschia schimperi
• A. stenocarpa = Beringia bursifolia
• A. stewartiana = Olimarabidopsis pumila
• A. stricta = Crucihimalaya stricta
• A. taraxacifolia = Crucihimalaya wallichii
• A. tenuisiliqua = Arabis tenuisiliqua
• A. tibetica = Crucihimalaya himalaica
• A. tibetica = Arabis tibetica
• A. toxophylla = Pseudoarabidopsis toxophylla
• A. trichocarpa = Neotorularia humilis
• A. trichopoda = Beringia bursifolia
• A. tschuktschorum = Beringia bursifolia
• A. tuemurnica = Neotorularia humilis
• A. verna = Drabopsis nuda
• A. virgata = Beringia bursifolia
• A. wallichii = Crucihimalaya wallichii
• A. yadungensis =

Sources

• O'Kane Jr, S. L., & Al-Shehbaz, I. A. (1997). A synopsis of Arabidopsis (Brassicaceae): Novon 7: 323–327.
• Al-Shehbaz, I. A., O'Kane, Steve L. (2002). Taxonomy and Phylogeny of Arabidopsis (Brassicaceae). The Arabidopsis Book: 1-22. online version.
• Martin et al. (2002) Evolutionary analysis of Arabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus. online version
• O'Kane Jr, S. L., & Al-Shehbaz, I. A. (2003). Phylogenetic position and generic limits of Arabidopsis (Brassicaceae) based on sequences of nuclear ribosomal DNA: Annals of the Missouri Botanical Garden 90 (4): 603-612