Profiling shifts in protein complement in tomato fruit induced by atmospheric ozone-enrichment and/or wound-inoculation with Botrytis cinerea

Abstract

To unravel the mechanism by which low level atmospheric ozone-enrichment (0.05μmolmol-1) increases the shelf-life of tomato fruit (Lycopersicon esculentum Mill.) by suppressing the growth of pathogens (Botrytis cinerea), protein yield and composition were examined during and following exposure to the gas at 13°C/95% RH. Ozone-enrichment caused marked changes in protein yield and composition in control tomato fruit and suppressed shifts in the proteome induced by wounding/fungal attack. Wound/fungal-inoculation with B. cinerea resulted in a 7% increase in protein yield, and the down-regulation of at least 32 proteins. A number of proteins affected under ozone and wound/fungal-inoculation treatments are involved in the control of cellular oxidative status. Proteins that may be enhanced under oxidative stress were induced during ozone exposure (e.g. thioredoxin peroxidase-TPX), but suppressed following transfer to 'clean air' (e.g. ascorbate peroxidase-APX1). Constitutively-expressed proteins tended to increase reversibly under ozone-treatment, however proteins involved in ripening such as an enzyme related to ethylene biosynthesis (1-aminocyclopropane-1-carboxylate oxidase-ACO) were markedly reduced in ozone-treated tomato fruit but increased in wound-inoculated fruit. Levels of proteins involved in carbohydrate metabolism, pentose phosphate pathway, terpenoid and flavonoid biosynthesis differentiated among the treatments. The presented dataset makes a central contribution to a comprehensive analysis of the manner in which tomato fruit react to ozone-enrichment and/or pathogen infection during storage/transit.