McMYB10 regulates coloration via activating McF3′H and later structural genes in ever‐red leaf crabapple

Abstract

Summary The ever‐red leaf trait, which is important for breeding ornamental and higher anthocyanin plants, rarely appears in Malus families, but little is known about the regulation of anthocyanin biosynthesis involved in the red leaves. In our study, HPLC analysis showed that the anthocyanin concentration in ever‐red leaves, especially cyanidin, was significantly higher than that in evergreen leaves. The transcript level of McMYB10 was significantly correlated with anthocyanin synthesis between the ‘Royalty’ and evergreen leaf ‘Flame’ cultivars during leaf development. We also found the ever‐red leaf colour cultivar ‘Royalty’ contained the known R6: McMYB10 sequence, but was not in the evergreen leaf colour cultivar ‘Flame’, which have been reported in apple fruit. The distinction in promoter region maybe is the main reason why higher expression level of McMYB10 in red foliage crabapple cultivar. Furthermore, McMYB10 promoted anthocyanin biosynthesis in crabapple leaves and callus at low temperatures and during long‐day treatments. Both heterologous expression in tobacco (Nicotiana tabacum) and Arabidopsis pap1 mutant, and homologous expression in crabapple and apple suggested that McMYB10 could promote anthocyanins synthesis and enhanced anthocyanin accumulation in plants. Interestingly, electrophoretic mobility shift assays, coupled with yeast one‐hybrid analysis, revealed that McMYB10 positively regulates McF3′H via directly binding to AACCTAAC and TATCCAACC motifs in the promoter. To sum up, our results demonstrated that McMYB10 plays an important role in ever‐red leaf coloration, by positively regulating McF3′H in crabapple. Therefore, our work provides new perspectives for ornamental fruit tree breeding.

Purple foliage coloration in tea (Camellia sinensis L.) arises from activation of the R2R3-MYB transcription factor CsAN1

“…This result indicates that a high accumulation of anthocyanin in ‘ZJ’ foliage may be attributed to up-regulation of the R2R3-MYB and/or bHLH genes. The activation of R2R3-MYB TFs leads to the up-regulation of regulators and/or anthocyanin biosynthetic genes that are associated with red pigmentation in many crops, such as apple, peach, pear, purple cauliflower, tomato, plum and crabapple3571013. In this study, we identified two anthocyanin biosynthesis-related R2R3-MYB TFs, but only the CsAN1 homolog of AcMYB110 from Actinidia 26 was strongly upregulated in young foliage of the ‘ZJ’ cultivar, indicating that it is a master anthocyanin regulator in ‘ZJ’ tea plants (Fig.…”

“…The MYB member of this complex often appears to be the major determinant of variation in anthocyanin pigmentation6. Activation of anthocyanin master regulators, including AtMYB75 in Arabidopsis, SlANT1 in tomato, MdMYB10 and MdMYB110a in apple, BoMYB2 in cauliflower, McMYB10 in crabapple, and RsMYB1 in radish, is associated with upregulation of the anthocyanin biosynthetic structural genes and results in anthocyanin accumulation57910111213. In contrast, loss of function or repression of VvMYBA1 in grapevine, MdMYB10 in apple, EgVIR in oil palm, and PcMYB10 in pear leads to color loss in normal anthocyanin-accumulating tissues14151617.…”

An optimized TRV-based virus-induced gene silencing protocol for Malus crabapple

“…To further confirm that the decreased expression of (Tian et al 2015b), were significantly lower in the silenced lines than in the control lines. The expression levels of these genes were consistent with the variation in anthocyanin content and the degree of pigmentation observed in the McMYB10-silenced and control lines (Fig.…”

“…MYB10 transcription factors have been shown to be critical genes in the regulation of anthocyanin biosynthesis in many plants, including pear (Pyrus communis), apple (Malus domestica), strawberry (Fragria 9 ananassa) and nectarine (Prunus persica; Chagné et al 2013;Espley et al 2007;Li et al 2012;Medina-Puche et al 2014;Ravaglia et al 2013). The MdMYB10 gene from apple has been reported to be a key regulatory gene governing anthocyanin accumulation and fruit coloration (Espley et al 2007), and our previous studies showed that McMYB10 regulates anthocyanin accumulation in crabapple, and that over-expression of McMYB10 induces anthocyanin accumulation (Jiang et al 2014a;Tian et al 2015b). Here, we used the McMYB10 gene as a VIGS reporter gene to establish a TRV-based VIGS system in Malus crabapple, and showed that infection of crabapple with TRV with a fragment of McMYB10 incorporated into the RNA2 resulted in a faded red leaf phenotype and green coloration of the upper leaves of tissue cultured plantlets.…”

“…They are also valued for their considerable abiotic stress resistance and for the diverse range of colors of their leaves, flowers and fruits, due to the accumulation of flavonoid compounds (Tian et al 2015b). Since traditional methods for cultivating transgenic Malus crabapple lines are time-consuming and laborious (Dai et al 2013(Dai et al , 2014Kotoda et al 2006;Sharma et al 2013), we reasoned that TRV-VIGS would provide an excellent platform to investigate crabapple gene function.…”