A Reverse Genetics Platform for Mutation Discovery and Gene Introgression

The horticulture industry is in need of new traits that add value to crops or provide production efficiencies.  Often, the genetic variation is not available within the species so we have turned to creating new variation through mutation in genes known or predicted to control expression of valuable traits.  The Vineland team have developed three ethyl methansulfonate (EMS) populations including petunia, tomato and pepper which are used to identify an allelic series of mutations in candidate genes.  The populations are variable in mutation density but are sufficient to discover novel alleles with commercial value.  For example, the tomato population consists of >5,000 M1 derived lines reaching a mutation density of 1 SNP / 30 bp across the population.  The remainder of the platform consists of Illumina-based DNA sequencing strategies, custom bioinformatics and high resolution DNA melting (HRM) to discover and characterize desired mutations in the EMS populations.  The HRM technology also acts as a reliable genotyping platform for marker-assisted breeding.  The traits under examination include cool temperature growth, low light production, shelf life, drought tolerance, improved flavour and disease resistance through systemic acquired resistance.  Currently we have identified 2 mutants in petunia that exhibit 15% and 60% improvement in water use efficiency.  When mutant alleles are discovered, they are phenotyped and then entered into a breeding program for introgression into advanced lines.