Tomato, Solanum lycopersicum, is one of the most cultivated vegetable worldwide with more than two hundred million tonnes of fruit produced in 2018 worldwide. However, between one quarter and half of the production is lost due to uncontrolled conditions during transport and storage. Understanding the biological components and processes that affect the physical properties and structure of tomato fruits during the post-harvest is essential to design new strategies to reduce these losses. The aim of this project is to determine whether the callose metabolism has an indirect or direct positive impact on the shelf-life of the tomato fruit. Callose synthesis is catalysed by a multi-subunit enzyme complex with a catalytic subunit known as Callose Synthases (Cals), whereas callose degradation is mediated by β-1,3- glucanases (BGs).

In this publication, we will present the first objective of the project: “The selection of specific tomato BG genes via an in-silico approach”¹. In this regard, 50 callose degrading enzymes (beta-1,3-glucanases) were identified in-silico using bioinformatic tools. Phylogenetic analysis revealed tomato genes being distributed in three cluster (α, b and γ) with evolutionary relations with previously characterized Arabidopsis thaliana BG enzymes². Expression data revealed different expression patterns across tissues and organs. Interestingly, microarray expression analysis showed two trends in the BG temporal expression in fruit flesh: expression of enzymes in cluster α (which comprises all previously localized plasmodesmata proteins) decreased during the ripening, while enzymes in clusters β and γ (including pathogenesis-induced proteins) increased. To verify correlations between expression and function, two enzymes were selected, one from cluster a, which is repressed during ripening, and one from cluster b, which is induced during ripening. qRT-PCR will be used to confirm the expression of the selected genes. Transient overexpression of the selected genes driven by a 35 S CaMV (Cauliflower Mosaic Virus) promoter in tomato fruit will be performed via infiltration of tomato fruit with Agrobacterium tumefaciens. Preliminary experimental data will be presented.

References:

¹Gaudioso-Pedraza, Rocio, and Yoselin Benitez-Alfonso. ‘A Phylogenetic Approach to Study the Origin and Evolution of Plasmodesmata-Localized Glycosyl Hydrolases Family 17’. Frontiers in Plant Science 5 (23 May 2014). https://doi.org/10.3389/fpls.2014.00212

²Doxey, A.C., Yaish, M.W.F., Moffatt, B.A., Griffith, M., McConkey, B.J. Functional Divergence in the Arabidopsis -1,3- Glucanase Gene Family Inferred by Phylogenetic Reconstruction of Expression States. Molecular Biology and Evolution 24,(2007): 1045–1055. https://doi.org/10.1093/molbev/msm024

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie