MSV resistance in cereals

Maize streak virus infects most members of the Poaceae and causes major losses of maize crops in Sub-Saharan Africa. Recently we have screened a wide range of cereal varieties for their ability to resist MSV infection and found that a number of wheat, barley and rice cultivars were unable to become infected. The availability of a doubled haploid population between a susceptible (Igri) and a resistant (Triumph) variety of barley has allowed us to map the MSV resistance locus. Molecular hybridisation suggests this gene is different from that identified as providing MSV resistance in maize. Currently we are investigating the basis of the resistance mechanism. Using insect transmission and Southern hybridisation analyses, we have shown that resistance is mediated against all MSV and related virus strains tested to date. We hope that this gene will provide an additional source of resistance against cereal-infecting geminiviruses, thereby providing durable resistance and facilitating sustainable production of cereals worldwide.

This is a collaborative project with Dr David Laurie, Dept. Crop Genetics

Symptoms obtained in barley varieties inoculated with maize streak virus isolates. Barley cvs Triumph (left) and Igri (centre and right) were inoculated, by leafhopper transmission, with the severe variant of the Nigerian strain of MSV (MSV-Ns, right and left) or MSV-Pat (a strain isolated from Digitaria and provided by Dr. E. Rybicki). Stunting and chlorosis (as seen in the leaf samples) were obtained in cv Igri, but Triumph plants never became infected.

Cicadulina mbila, the leafhopper vector of Maize streak virus.

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