Combined Analysis of Transcriptome and Metabolome Reveals the Potential Mechanism of the Enantioselective Effect of Chiral Penthiopyrad on Tomato Fruit Flavor Quality

This study investigated the enantioselective effects of S-, R-, and rac-penthiopyrad (PEN) on the flavor quality of tomato fruit through the levels of sugars, acids, volatiles, and nutrients and explored the potential mechanism by combined analysis of the transcriptome and metabolome. The results revealed that the S-enantiomer increased the content of soluble sugars while decreasing the content of organic acids, thereby increasing the taste of tomato fruit. Furthermore, S-(+)-PEN promoted the accumulation of volatile compounds and nutrients (total phenols, flavonoids, and vitamin C). Transcriptome and metabolome data showed that the S-enantiomer improved fruit flavor and quality by influencing metabolites and genes in glycolysis, starch and sucrose metabolism, the citrate cycle, and amino acid biosynthesis pathways. However, R-(-)-PEN had a negative effect on tomato flavor. The effect of the racemate on fruit flavor quality was between a pair of enantiomers. The comprehensive data of PEN enantiomers will provide theoretical support for the application of PEN in tomatoes. Thus, developing enantiopure S-(+)-PEN products might be more conducive to the flavor and quality of the tomato fruit.