DNA Sequence Characterization of the Malate Transporter Gene-Complex in Rye.

Among the cultivated cereals, the DNA 1C-value of Secale cereale is one of the highest, about 34% greater than the largest haploid genome of wheat (Lukaszewski et al 1982). In addition rye is the most Al-tolerant and represents an important potential source of genes for the improvement of Al-tolerance in wheat. A wheat malate transporter (TaALMT) was cloned and characterized as a constitutively expressed gene associated with aluminum tolerance in wheat (Sasaki et al. 2004). A rye BAC library was screened for the presence of rye malate transporter (ScALMT) gene complexes (Collins et al. 2008). Three rye BAC clones were identified that contained several ScALMT copies, and a transcription factor upstream from the ScALMT region. The BAC sequences clearly showed, at least for the rye genome analyzed, the presence of more than one copy of the ScALMT gene complex. The rye BAC sequence analysis also shed light on evolutionary factors involved in the expansion of the rye genome compared to other cereals.