Comparison of the metabolites profiles between a Graft Chimera ‘Hongrou Huyou’ ( Citrus changshan-huyou + C. unshiu Marc.) and Two Donors
Abstract Background: Chimeras synthesized artificially by grafting are crucial to breeding of perennial woody plants. ‘Hongrou Huyou’ ( Citrus changshan-huyou + C . unshiu Marc.) was a new grafting chimera originated from the junction where a scion Citrus changshan-huyou (“C”) was top-grafted onto a stock Satsuma mandarin ‘Owari’ ( C . unshiu Marc., “O”). The chimera was simplified as OCC because the cell layer constitutions were O for L1 and C for L2 & L3, respectively. In this study, profiles of primary metabolites, volatiles and carotenoids derived from different tissues were investigated between OCC and two donors, aiming to figure out the relationship between layer donor and metabolites. Results: Comparison of the metabolite profiles showed that the amount and composition of metabolites were different between the peels and the juice sacs, as well as between OCC and two donors. Metabolites (such as violaxanthin and β -cryptoxanthin in carotenoids, germacrene D in volatiles, citric acid and sorbose in primary metabolites) specifically present or absent in the certain tissue were identified in three phenotypes. According to the principal component analysis (PCA), the total metabolites of chimeric peel properties were derived from the donor C, whereas those of chimeric juice sac properties came from the donor O. Conclusion: Profiles of primary metabolites, volatiles and carotenoids derived from the peels and the juice sacs were systematically compared between OCC and two donors. The content and composition of metabolites differed in tissues as well as between OCC and two donors. Donor dominant metabolite inheritance was dramatic in the different tissues of OCC and basically consistent with the layer origin that the chimeric peels were derived from C and the chimeric juice sacs came from O. These profiles provide potentially chemical markers for genotype differentiation and citrus breeding assessment, more than that, for donor selection during chimera synthesis artificially.