Mechanism of ATS-induced flower thinning in Weihai Gold apple re-vealed by metabolomics analysis
YANG Mengyu
DU Jie
WANG Laiping
WANG Guiping
CHEN Ru
XUE Xiaomin
Abstract：[Objective]The experiment was conducted to explore the secondary differential metabolites of Weihaijin apple after ammonium thiosulfate(ATS)treatment and its mechanism of flower thinning,and to provide scientific basis for efficient and high-quality production and chemical flower thinning.Apple flower and fruit thinning is an important technology to adjust the tree load,control the size of the tree,ensure the high quality and efficient production of apples,and improve the competitiveness on the fruit market.Chemical flower and fruit thinning is a labor-saving and efficient thinning method.By spraying appropriate chemical agents,the side flowers and side fruits in apple clusters are weakened,shriveled,shrunk,and finally fallen off,and only the central flowers and fruits are retained.It is a labor-saving management widely used in developed countries.ATS is a kind of sulfur-based nitrogen fertiliz-er,which can cause damage to style,reduce pollen germination,effectively reduce crop load and im-prove fruit quality after spraying.As a common flower thinning agent,it has achieved good application effect in fruit production.The predecessors have clarified the appropriate spraying concentration and pe-riod of ATS on apples,and its effect on the physiological changes of side fruits has gradually become clear.However,the changes of secondary metabolites in the metabolic pathways of ATS-treated nuts and their removal mechanisms have rarely been reported at home and abroad.Therefore,it is of great significance to study the mechanism of ATS flower thinning from the perspective of metabolomics for the popularization and application of apple chemical flower thinning technology.[Methods]The metab-olites were detected by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS),and the metabolites were qualitatively and quantitatively analyzed by extensive target-ed metabolomics to screen and compare the differential metabolites of siliques after thinning.[Results]A total of 85 differential metabolites were detected,including 34 flavonoids,16 phenolic acids,8 lig-nans and coumarins,6 tannins and 4 lipids,among which flavonoids accounted for the highest propor-tion.KEGG pathway enrichment showed that biosynthesis of secondary metabolism and flavonoid bio-synthesis with different treatments were the most significantly differential metabolic pathways.Two me-tabolites related to sugar metabolism were screened out based on secondary metabolic biosynthesis,which were trans-2-hydroxy-cassia bark acid ester and 6-hydroxy feruloyl-CoA;Nine key metabolites were identified based on the flavonoid biosynthetic metabolic pathway.The metabolites with decreased levels included crocetin,wintersweet glycoside,quercetin-3-O-rutinoside,5,7-dihydroxy-3',4',6-trime-thoxyflavone,isorhamnetin-3,7-O-diglucoside,3',5-dihydroxy-4',6,7-trimethoxyflavone,and apigen-in-6-C-(2"-glucuronidyl)-xyloside.The metabolites with increased levels included alfalfa glycoside-7-O-glucuronide and kaempferol-3-O-(2"-O-acetyl)glucoside.[Conclusion]A total of 1946 metabolites were detected by extensive targeted metabolomics analysis of apple fruits.Based on the screening of fla-vonoid biosynthetic metabolic pathways,11 kinds of flavonols(quercetin-3-O-(4"-O-glucosyl)rhamno-side,quercetin-3-O-apiosyl(1→2)galactoside,isorhamnetin-3,7-O-diglucoside,quercetin-3-O-neohes-peridinoside,kaempferol-7-O-glucuronide,quercetin-3-O-(6"-O-acetyl)glucopyranoside,myricetin-3-O-xyloside,quercetin-3-O-(6"-O-malonyl)glucopyranoside-5-O-glucoside,myricetin-3-O-rhamnopy-ranoside(myricetin),quercetin-3-O-acacia glycosides,quercetin-3-O-rutinoside(rutin)),and 4 kinds of flavonoids(eupatilin;3',5-dihydroxy-4',6,7-trimethoxyflavone,Chimonanthus praecoxin,apigenin-6-C-(2"-glucuronic acid)xylopyranoside,eupatilin)were found to be the key metabolites related to ATS elimination.Through KEGG metabolic pathway enrichment analysis,it was found that the most signifi-cantly enriched differential metabolite pathways were biosynthesis of secondary metabolism and flavo-noid biosynthesis.The results can provide a theoretical basis for the popularization and application of chemical flower and fruit thinning agents and the high-quality development of apple industry.
Keywords：AppleAmmonium thiosulfateChemical flowering thinningSecondary metabolites
Publication Date：2025-06-10
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 1137-1147 )