Reduced Phosphate Availability Improves Tomato Quality Through Hormonal Modulation in Developing Fruits

Nutrient management is one of the most important agricultural practices to ensure yield and fruit quality. The aim of this study was to examine the effect of N and P availability in the yield and quality of tomato fruits (Solanum lycopersicum var. Meyity), and the hormonal mechanisms underlying these effects. Fruit yield and quality (in terms of sugar accumulation and titratable acidity) at harvest, together with the hormonal profiling of developing fruits were evaluated. While low N caused a reduction of sugars, reduced P availability increased sugars and reduced acidity in fruits. These changes were not accompanied by significant reductions in yield. Enhanced trans-zeatin content at early stages of fruit development and during color break might be associated with an increased sink activity. Furthermore, jasmonic acid, salicylic acid and 1-aminocyclopropane-1-carboxylic acid (the ethylene precursor) concentrations increased at early stages of fruit development, thus suggesting a complex hormonal crosstalk induced by low P availability. In conclusion, a reduction of P availability increased tomato sugar contents, while yield was not negatively impacted. These results have implications to alleviate the depletion of natural P reserves to arrive at a more sustainable horticulture.