Development of Trifolium occidentale as a Plant Model System for Perennial Clonal Species

Achievements and Challenges in Improving Temperate Perennial Forage Legumes

“…These include Downloaded by [West Virginia University] at 06:45 20 November 2014 T. nigrescens, T. ambiguum and T. uniflorum as the main species exploited for genetic improvement, whilst many other species such as T. pallescens have been used for cytology studies and to explore relationships within the Trifolium genus. T. occidentale has been developed as a model species for genetic and genomic research relating to the white clover complex (Williams et al, 2009). The potential role of interspecific hybridization using these wild relatives in the genetic improvement of white clover has been discussed by Abberton and Marshall (2005) and Ravagnani et al (2012).…”

“…T. occidentale, a diploid (2n = 2x = 16) perennial species, is considered to be a likely ancestral diploid parent of white clover (Ellison et al, 2006), while the other diploid parent has been proposed as T. nigrescens or T. pallescens but has not yet been confirmed (Ravagnani, unpublished data). T. occidentale is also being developed as a model species for genetic and genomic research relating to the white clover complex (Williams et al, 2009).…”

Genetic transformation of western clover (Trifolium occidentale D. E. Coombe.) as a model for functional genomics and transgene introgression in clonal pasture legume species

“…While transformation protocols for white clover are readily available [15-18]; the ability to exploit these resources is limited by a genetic composition resulting in self incompatiblility, cross pollination, allotetraploidy and amphidiploid inheritance with high levels of heterozygosity making the application of genomic technologies problematic at best [19]. Such characteristics are complicating factors for the genetic analysis of transgene inheritance in white clover and are an issue which is common to many crop species.…”

“…repens , therefore, most genes will be highly related. It has both self-fertile and self-incompatible accessions, a relatively short generation time and is able to fix nitrogen in symbiotic association with Rhizobium bacteria [19]. Its natural habitat is along coastal regions of Europe and the British Isles exposed to the Gulf Stream and until its description as a new species was regarded as a variety of white clover [23].…”

“…Its natural habitat is along coastal regions of Europe and the British Isles exposed to the Gulf Stream and until its description as a new species was regarded as a variety of white clover [23]. Tools such as the establishment of EMS mutants [19] and a genome which is currently being sequenced [24] make T . occidentale an ideal candidate as a model species for functional genomics in pasture legumes.…”