Professor Jianzhi Zhang was awarded a three-year NSF grant of $510,000 in order to develop the baker’s yeast, Saccharomyces cerevisiae, as a model organism to study hybrid vigor.

According to Zhang’s project summary, one widespread phenomenon in genetics that has a long history of research with limited progress is heterosis, (i.e., hybrid vigor). Hybrid vigor refers to the observation of improved function of any biological quality (e.g., biomass, growth rate, and resistance to pathogens) in a hybrid offspring, compared to decreased fitness in typically inbred parents.

Heterosis is widely applied in crop breeding and has contributed to major improvements in crop yields in the last 50 years. Yet, its genetic basis remains elusive, primarily because of the lack of a powerful model organism.

Specifically, Zhang will establish the basic patterns of heterosis in yeast, map the heterosis loci, test the dominant and overdominant models of heterosis, validate the mapping results, identify the genes and mutations responsible for heterosis, and discern the molecular genetic mechanisms of heterosis. The project is expected to improve understanding of the mechanistic basis of heterosis, which will have profound impacts on and wide applications in multiple fields.

“Heterosis improves the yields of a number of cultivated crops such as rice and corn, but also makes certain pathogens more pathogenic,” Zhang said.