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

大量关于商业温室中CO2富集效应的研究表明，可以通过增加光合作用下的碳同化来提高作物产量。同化二氧化碳的吸收是通过叶片表面的小气孔来控制的。气孔由一对特化的细胞（保卫细胞）组成，它们之间有一个孔，气孔位于植物的大部分地上部分，但最常见的是（下）叶表皮。在包括水稻和大麦等作物在内的许多物种中，气孔密度（SD）的改变已被证明通过改善气体扩散和提高水分利用效率来增加光合作用。因此，增加SD有可能显著提高草莓和蓝莓的产量，并改善浆果品质的一致性。在本研究中，我们的目标是通过转基因和基因组编辑的方法，通过改变参与气孔密度的表皮模式因子（EPFs）的表达来操纵草莓和蓝莓的SD。在拟南芥中过度表达一种EPF“气孔原”导致SD增加3倍以上，环境CO2下气孔导度增加，光合速率增加30% （Tanaka et al, 2013）。该项目的总体目标是：1)产生新的转基因和基因组编辑的草莓和蓝莓品系，改变气孔密度；2)鉴定出光合作用、生物量和产量增加的草莓和蓝莓品系；3)分析对所选水果风味和香气特征的影响。

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.