Abstract/Summary

The production of sweet cherry (Prunus avium L.) has increased constantly in the UK and worldwide, over the last 20 years. Sweet cherry fruit is appealing because of the bright colours, the balance between sweet and sour, the firmness, the juiciness and the good effects on human health, due to mainly the high content of anthocyanins, which are important antioxidants. The interest of growers is not limited just to an increase in production but also to obtain new varieties that can satisfy the market requirements. The study of the molecular and genetic factors involved in the developmental processes of the cherry fruit, can clear the way to the production of genome edited varieties that present specific and desirable traits. The objective of this study was to identify those factors that are responsible for the ovary to fruit transition, to identify potential targets that can be used for the creation of a seedless cherry and to start the setting up protocols for cherry in vitro propagation, regeneration and transformation. The application of gibberellin to unpollinated ovaries resulted in the triggering fruit set, without however being sufficient to complete the entire developmental process. Transcriptomic analysis of those samples, along with the pollinated controls, was used to map out an overview of the changes in gene expression during the first phases of fruit development. The focus was especially on hormones and transcription factors like the MADS-box genes, which are all known to be essential for the complex regulation of this process. Pav_sc0000129.1_g.1480.1.mk (PavARF7), Pav_sc0000464.1_g350.1.mk (PavRGL2), Pav_sc0002327.1_g560.1.mk and Pav_sc0002393.1_g030.1.mk (PavAUX/IAA9) were found to be downregulated in the open pollinated samples at the beginning of fruit development, potentially confirming their role as negative regulators of fruit development in sweet cherry as reported in other species like tomato. In vitro regeneration and propagation from seed tissues, such as embryo axes and cotyledons, resulted successful, while more effort will be needed to achieve the same results starting from somatic tissues like leaves.