An analysis of the variation in the waxy gene in Australian native grass species

Global cereal consumption is derived from just eight of the 650 different genera within the Poaceae family, even though this is probably the most diverse flowering plant family. Currently there are over 69 genera of grasses recognised as being native to Australia. These may provide a valuable genetic resource for cereal quality improvement programs in the future. Genetic diversity between representatives of the five sub-families of Australian native grasses was observed at both the nucleotide and amino acid level for the waxy gene. This gene encodes Granule Bound Starch Synthase 1 (GBSS1), a key enzyme of starch synthesis, which displays a high degree of conservation across a wide range of higher plants. Conserved areas of the gene were used for PCR amplification and sequencing of a short fragment of the gene, which was then used as a platform for species specific/gene specific primer design. The BD GenomeWalker™ Universal Kit allowed sequencing of the native cereals’ genomic DNA, both upstream and down of the gene specific primer sites. Sequence analysis of the waxy gene indicated that although Australian native species display some degree of similarity to the ortholog in their respective commercial relatives, significant sequence differences are evident. Further more, the observed single nucleotide polymorphisms and indels translated to variation in the amino acid sequence of the waxy gene in these native species. This data supports the hypothesis that Australian native grasses may provide a new source of genetic diversity for future grain improvement programs.