This plant molecular biology research project is on endogenous pararetrovirus sequences in yam genomes.

Yam is an important food crop that is propagated vegetatively through its tubers. This facilitates the accumulation of viruses which reduce tuber yields, as well as prevent international exchange of improved varieties. Badnaviruses are the most prevalent yam viruses globally, and their gene sequences can be integrated in their host plant species. Such integrated virus sequences are termed ‘endogenous pararetroviruses’ (EPRVs).

EPRVs are of particular concern to yam breeding programmes, as some are ‘activatable’, i.e. able to replicate and initiate virus infections de novo from their sequences integrated in the host genome. This results in plant material containing EPRVs posing a real threat, as virus infections can arise from material that has been certified as ‘virus-free’ based on methods that detect viral particles alone.

EPRVs are widespread in yam germplasm, but fortunately some EPRVs are ‘inert’. Activation of EPRVs is not well understood, but has been shown in banana to be triggered by environmental stresses, as well as epigenetic modifications that occur during hybridization of parental genomes.

The proposed PhD project will study the expression of EPRV sequences and plant signalling genes, following a range of induced stresses (tissue culture, wounding, drought, heat), aiming to establish the link between plant stress signalling and activatable EPRVs.

Supervision of the project will be through the combined expertise in yam virus diagnostics (Dr Seal) and plant stress hormone signalling (Dr Bömer), and will integrate closely with research funded by the Bill and Melinda Gates Foundation on yam virus characterisation.

For further information please contact the supervisor: Dr Susan Seal, email [log in to unmask].