The overall theme of our research is to better characterize the genetic diversity in the wild tomato relatives and to develop new populations and genetic tools that improve access to genetic variation.  Our current research interests are:

Image of incompatible and compatible pollinations


Interspecific reproductive barriers.  We are interested in the molecular genetics of pollen rejection by self- and unilateral interspecific incompatibility, as well as other types of interspecific reproductive barriers that prevent hybridization between related Solanum species.  We showed that loss of a pollen-specific Cullin1 protein in self-compatible tomato species explains why their pollen is rejected on pistils of self-incompatible relatives (the 'SI x SC rule').  This mechanism of pollen rejection requires active S-RNase expression in the pistil. In addition we characterized pollen and pistil factors (FPS2 and ODC2, respectively) that act in an S-RNAse independent manner to bring about pollen rejection. 



Solanum sitiens flowers

Wide hybridization and introgression.  By manipulating or bypassing several reproductive barriers, we hybridized cultivated tomato with two of its most distantly related wild nightshade cousins, S. lycopersicoides and S. sitiens, each of which contain unique abiotic and biotic stress tolerance traits.  We developed introgression line populations that capture ca. 95% of each wild species' genome in the genetic background of S. lycopersicum.  We previously used these genetically-defined, breeder-friendly prebred lines to study the factors that limit recombination in wide crosses.


Fruit of S. sitiens

Pollen and seed traits related to heat stress. We are using the S. sitiens ILs described above to identify QTLs for fruit and seed set under heat stress, and for seed vigor/dormancy.  We are interested in identifying genes underlying these QTLs by using CRISPR-Cas9 to mutate candidate genes.