Crop wild relatives are a valuable source of genetic diversity that may be used to identify and utilise traits to increase plant growth and yield in the face of climate change. Our group are expanding our research into the role of cyanogenesis in plant growth and defence by analysing crop wild relatives of sorghum (CWR). Australia has 17 native sorghum species, including 13 that are endemic, growing predominantly across northern Australia (WA, NT and QLD).
During his PhD, Max Cowan looked at dhurrin levels in all the wild sorghums and it seems that levels are very low in leaf tissue, compared to domesticated sorghum (manuscript in preparation). Max has also investigated the response of a subset of the sorghum CWR in response to drought (Cowan et al. 2020). Max, together with two undergraduate research project students, also mapped the spatial dhurrin distribution during seedling development of two species (submitted).
In collaboration with University of Queensland and the University of Copenhagen (ARC grant) we have sequenced the genomes of six of the sorghum CWR and this data is being analysed to identify potential variations in the genes involved in dhurrin synthesis and turnover. Kalpani Ananda (PhD student based at UQ) assembled and analysed the chloroplast genome of these six species. Using this data and additional publicly available sequences Kalpani determined the phylogenetic relationship within the genus and will confirm this using genomic data (Ananda et al. 2019).
The genome sequence data will also be used to identify variations in domestication genes and identify potential candidate genes conferring tolerance to arid, low nutrient soils in the hope of identifying traits that can be bred into domesticated sorghum. To build on this initial data set all members of the international team are growing all native Australian sorghum species for genomic sequencing.