The effect of organic nutrient solution on flavor in ripe cherry tomato fruit—Transcriptome and metabolomic analyses

Abstract

Organic nutrient solution is non-polluting and environmentally friendly. Supplying organic nutrient solution instead of chemical fertilizer is helpful in enhancing the aroma and sweetness of ripe tomato fruits. However, the mechanism is still unclear for improving the ripe fruit flavor. We combined transcriptome and metabolomic analyses to answer questions about the synthesis of soluble sugars, organic acids, and aroma volatiles in cherry tomato fruits with changes in metabolites and genes associated with the metabolic pathways. We found that tomatoes supplemented with organic nutrient solutions had the same fruit yield as those supplied with inorganic nutrient solutions; however, the tomatoes supplemented with organic nutrient solutions had increased in phenylalanine and its downstream phenolic volatiles, in addition, methyl salicylate, a unpopular, medicinal-smelling volatiles, was decreased, due to changed expression levels of the key genes (LeAADC, LePAR, SlSAMT); we also observed that organic acid metabolism and the synthesis of fructose and glucose were promoted. The expression level of LOC101254693 (pyruvate dehydrogenase) driving pyruvate metabolism was upregulated. This affects the rate of metabolism of the pyruvate-linked TAC cycle and glycolysis. This study analyzed the positive effects of organic nutrient solutions on the ripe fruit flavor at the molecular level, facilitating further optimization of nutrient solution formulations for soilless tomato cultivation.