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.