1a.Objectives (from AD-416)
Identify genes responsible for Brown Stem Rot (BSR) resistance in resistant genotypes.
1b.Approach (from AD-416)
Conduct experiments to silence candidate BSR resistance genes in a resistant genotype. Silenced plants will be infected with BSR and assayed for resistance or susceptibility.
The Brown Stem Rot (BSR) resistance gene Rbs3 was previously mapped to chromosome 16. By combing marker data with the soybean genome sequence, we identified two classes of receptor like proteins (RLPs), similar to known resistance genes. We developed virus induced gene silencing (VIGS) constructs to try and silence the expression of each RLP gene cluster. Treating BSR resistant plants with the VIGS constructs should silence the resistance genes making them susceptible to BSR. We have completed three experiments testing the function of the RLP genes by VIGS. However, the BSR inoculations did not result in consistent levels of BSR disease. Severity of BSR disease was low and inconsistent, possibly due to variable temperatures in the greenhouse. We plan to repeat the experiment in growth chambers with lower and more consistent temperatures. We are also evaluating different VIGS protocols that could help give us more control over the timing of BSR infection. Progress on this project was monitored through telephone calls, data exchange and written reports.