Reducing an anti-nutritional compound in legumes to increase use of a sustainable biological nitrogen source
A project undertaken in the School of Biological Sciences, Faculty of Sciences, The University of Adelaide, and supervise by Dr. Iain Searle
Common vetch (Vicia sativa) is a leguminous, annual crop plant that provides valuable soil nitrogen to farming systems and is a palatable, cheap, high protein feed source with potential as feed for livestock and humans (1). One significant reason of its limited agricultural use is that anti-nutritional compounds exist in seeds, especially β-cyano-alanine and γ-glutamyl-β-cyano-alanine (GBA), which has high toxicity to monogastric animals, like poultry (especially), pigs, and humans (2-4). Reduction of GBA toxin from 1.6% to 0.55% was successfully achieved over a 20-year-period by using conventional plant breeding methods to generate a line, Lov2 (Tate and Searle, pers comm 2016). However, the GBA level in Lov2 is not sufficiently low enough for human, poultry or pig consumption (5). Hence an alternative approach is required to produce zero GBA vetch.
As vetch is an orphan legume with very limited molecular resources, we are developing various molecular resources in order to develop and implement a strategy to reduce the antinutritional compound GBA and accelerate Vetch improvement in the future. Recently we used a novel RNA-seq phylogenomics (molecular) approach that included vetch, other GBA producing Vicia relatives and non-GBA Vicia producing relatives to identify a candidate casual gene, VsDET1, for GBA accumulation (Nguyen and Searle, unpublished). VsDET1 is predicted to detoxify GBA. In Vicia species that accumulate GBA the VsDET1 gene has a large DNA insertion in the promoter causing it to be non-functional, while in non-GBA accumulating Vicia species the insertion is absent (Nguyen and Searle, unpublished).
In this project, we will test whether the reduction of anti-nutritional compounds in legumes can be harnessed to optimize food production- a valuable protein source. In the future, the mRNA profile of anti-nutritional compound genes with specific functions could be used as a screenable marker to select legume crops with improved nutritional profiles.
In this project, we will;