Anthocyanin accumulation correlates with hormones in the fruit skin of ‘Red Delicious’ and its four generation bud sport mutants

Abstract

BackgroundBud sport mutants of apple (Malus domestica Borkh.) trees with a highly blushed colouring pattern are mainly caused by the accumulation of anthocyanins in the fruit skin. Hormones are important factors modulating anthocyanin accumulation. However, a good understanding of the interplay between hormones and anthocyanin synthesis in apples, especially in mutants at the molecular level, remains elusive. Here, physiological and comparative transcriptome approaches were used to reveal the molecular basis of color pigmentation in the skin of ‘Red Delicious’ (G0) and its mutants, including ‘Starking Red’ (G1), ‘Starkrimson’ (G2), ‘Campbell Redchief’ (G3) and ‘Vallee spur’ (G4).ResultsPigmentation in the skin gradually proliferated from G0 to G4. The anthocyanin content was higher in the mutants than in ‘Red Delicious’. The activation of early phenylpropanoid biosynthesis genes, including ASP3, PAL, 4CL, PER, CHS, CYP98A and F3’H, was more responsible for anthocyanin accumulation in mutants at the color break stage. In addition, IAA and ABA had a positive regulatory effect on the synthesis of anthocyanins, while GA had the reverse effect. The down-regulation of AACT1, HMGS, HMGR, MVK, MVD2, IDI1 and FPPS2 involved in terpenoid biosynthesis influences anthocyanin accumulation by positively regulating transcripts of AUX1 and SAUR that contribute to the synthesis of IAA, GID2 to GA, PP2C and SnRK2 to ABA. Furthermore, MYB and bHLH members, which are highly correlated (r=0.882–0.980) with anthocyanin content, modulated anthocyanin accumulation by regulating the transcription of structural genes, including CHS and F3’H, involved in the flavonoid biosynthesis pathway.ConclusionsThe present comprehensive transcriptome analyses contribute to the understanding of the the relationship between hormones and anthocyanin synthesis as well as the molecular mechanism involved in apple skin pigmentation.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1595-8) contains supplementary material, which is available to authorized users.

UV-B Exposure of Black Carrot (Daucus carota ssp. sativus var. atrorubens) Plants Promotes Growth, Accumulation of Anthocyanin, and Phenolic Compounds

“…As hormones are widespread in the regulation of plant metabolism and morphogenesis, they are also implicated in UV-B stress response and signalling, participating in systemic signalling networks that ultimately affects plant growth and development [14,17]. Likewise, hormones interact in controlling anthocyanin biosynthesis [18,19]. However, the study of phytohormone profiles in carrot has been limited to the flowering process in leaf tissue [20], and the molecular mechanisms underlying differential anthocyanin accumulation in the root in response to above ground stimuli remain unknown.…”

Metabolic Profiling and Gene Expression Analyses of Purple-Leaf Formation in Tea Cultivars (Camellia sinensis var. sinensis and var. assamica)

“…4CL is the upstream gene of anthocyanin/flavonoid biosynthesis that catalyzes p -coumaric acid to form p -coumaroyl CoA. Activation of the 4CL gene is reportedly responsible for anthocyanin/flavonoid accumulation in various plants ( Li et al, 2018b ). ANS and UFGT are key genes in the late stage of anthocyanin biosynthesis.…”

Genetic Architecture Underlying the Metabolites of Chlorogenic Acid Biosynthesis in Populus tomentosa

“…Previous studies have shown that the CGA content in Achillea pachycephala is significantly increased in response to drought stress [ 34 ]. Besides, a previous investigation found that CGA accumulation could enhance the adaptation of apple trees to cold climates [ 35 ]. These studies strongly supported the notion that trees can cope with extremely harsh environments and enhance their adaptability to the environment by accumulating abundant CGA.…”