transcriptome of holcus lanatus

The wild grass Holcus lanatus L., an outcrossing diploid (2n=14) and closely related to B. distachyon (Aliscioni et al., 2012), has a remarkable balanced polymorphism in arsenate tolerance, screened from a semi-natural, non-arsenic contaminated populations (Meharg et al., 1993), coded by a single gene (Macnair et al., 1992). As arsenate is a phosphate analogue it has been postulated that this polymorphism is maintained due to phosphorus nutrition, not arsenate tolerance per se, particularly as the tolerance gene co-segregates with suppression of High affinity Phosphate Transport (HAPT) (Meharg et al., 1992a; Meharg & Macnair, 1992b), though an explicit ecological link to phosphorus status of soils has yet to be proven (Naylor et al., 1996). The aim of this study is to address soil phosphate responsiveness (+/-) along with the transcriptomic consequences of being of arsenic tolerant (T) or non-tolerant (N) phenotype to ascertain why and how this polymorphism is maintained.