Manipulation of stomatal density to improve CO2 uptake in Strawberry and Blueberry

Numerous studies on the effects of CO2 enrichment in commercial greenhouses have shown that increased crop yields can be obtained through increased photosynthetic carbon assimilation. The uptake of CO2 for assimilation is controlled through small pores on the leaf surface known as stomata. Stomata are composed of a pair of specialized cells (guard cells) with an aperture between them and are located on the majority of the aerial parts of plant but most prevalent on the (lower) leaf epidermis. Alteration in stomatal density (SD), in a number of species - including crops such as rice and barley, has been shown to increase photosynthesis by improving gas diffusion as well as improving water use efficiency. Increasing SD therefore has the potential to significantly enhance strawberry and blueberry yields and improve the consistency of berry quality.
In this proposal, we aim to manipulate SD in Strawberry and Blueberry by altering the expression of epidermal patterning factors (EPFs), involved in stomatal density, through transgenic approaches and genome editing. The over-expressing of one EPF 'stomagen' in Arabidopsis resulted in a more than three-fold increase in SD, an increase in stomatal conductance under ambient CO2 and a 30% increase in photosynthetic rates (Tanaka et al, 2013).
The overall aim of this project is to: 1) produce new transgenic and genome edited strawberry and blueberry lines with altered stomatal density; 2) identify strawberry and blueberry lines with increased photosynthesis, biomass and fruit yield; 3) analyse the impact on the flavour and aroma profiles of selected fruit.