Metabolite profile comparison of a graft chimera ‘Hongrou Huyou’ (Citrus changshan-huyou + Citrus unshiu) and its two donor plants

Abstract

BackgroundChimeras synthesized artificially by grafting are crucial to the breeding of perennial woody plants. ‘Hongrou Huyou’ (Citrus changshan-huyou + Citrus unshiu) is a new graft chimera originating from the junction where a Citrus changshan-huyou (“C”) scion was top-grafted onto a stock Satsuma mandarin ‘Owari’ (C. unshiu, “O”). The chimera was named OCC because the cell layer constitutions were O for Layer 1(L1) and C for L2 and L3. In this study, profiles of primary metabolites, volatiles and carotenoids derived from different tissues in OCC and the two donors were investigated, with the aim of determining the relationship between the layer donors and metabolites.ResultsThe 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 each of the two donors. The absence or presence of specific metabolites (such as the carotenoids violaxanthin and β-cryptoxanthin, the volatile hydrocarbon germacrene D, and the primary metabolites citric acid and sorbose) in each tissue was identified in the three phenotypes. According to principal component analysis (PCA), overall, the metabolites in the peel of the chimera were derived from donor C, whereas those in the juice sac of the chimera came from donor O.ConclusionThe profiles of primary metabolites, volatiles and carotenoids derived from the peels and juice sacs of OCC and the two donors were systematically compared. The content and composition of metabolites were different between the tissues and between OCC and the each of the two donors. A clear donor dominant pattern of metabolite inheritance was observed in the different tissues of OCC and was basically consistent with the layer origin; the peel of the chimera was derived from C, and the juice sacs of the chimera came from O. These profiles provide potential chemical markers for genotype differentiation, citrus breeding assessment, and donor selection during artificial chimera synthesis.

Citrus aurantium ‘Changshan-huyou’—An ethnopharmacological and phytochemical review

“…Nootkatone (14) is one of the characteristic aroma components in the peel of CACH. Zhang et al (2019) analyzed the volatile components and carotenoids in the peel and juice of CACH. They identified 36 compounds including monoterpenes and sesquiterpenes, such as β-Myrcene (15), γ-elemene, Sabinene (24) and α-terpinene (27),etc., At the same time, they found phytoene of eight carotenoids was detected only in juice.…”

“…In addition to the above components, there are various known complex components in CACH, such as organic acids ( Lu et al, 2018 ) (No. 64–86, Table 1 ), amino acids ( Zheng et al, 2016 ), sugars ( Zhang et al, 2019 ), and inorganic elements (101) ( Xu et al, 2008 ). Some studies have been reported on the content and types of them.…”

“…For example, it was found that CACH contains 16 kinds of amino acids, including eight kinds of essential amino acids, and the content of ASP is the highest ( Zheng et al, 2016 ). Zhang et al (2019) conducted the type identification and content detection of sugars in CACH. These studies provided an extremely important theoretical basis for the industrial development of CACH, and promoted the further development of its medical and food industry.…”

Short Communication: Variations of morphology, anatomy, and metabolite profiles of Citrus reticulata Blanco cv. Tawangmangu grafts produced by shoot tip grafting using several rootstocks

“…In some cases, the characters occurring in composite plants were somewhat different from both the rootstock and scion, which was likely due to a combination or as a result of physiological interactions between scion and the rootstock (Killiny et al 2016;Tietel et al 2020). A study of metabolites comparisons on Citrus grafts conducted by Zhang et al (2019) revealed that the characters of chimeras synthesized artificially by grafting could be dominant in one plant donor, but in other characters, it was closer to other donors. In the case where the metabolite profile of the Tawangmangu autograft was not more similar to Tawangmangu, the most probable cause is that the grafting process might induce a stress response in plants.…”