Mitotically heritable epigenetic modifications of CmMYB6 control anthocyanin biosynthesis in chrysanthemum

Abstract

Summary Flower color, which is determined by various chemical pigments, is a vital trait for ornamental plants, in which anthocyanin is a major component. However, the epigenetic regulation of anthocyanin biosynthesis remains poorly understood. During chrysanthemum cultivation, we found a heterochromatic chrysanthemum accession (YP) whose progeny generated by asexual reproduction contained both yellow‐flowered (YP‐Y) and pink‐flowered (YP‐P) plants. In this study, we aimed to elucidate the epigenetic mechanisms of different flower colors in the YP plant progeny. Metabolome and transcriptome analyses revealed that the difference in flower color between YP‐Y and YP‐P was caused by expression variation of the anthocyanin biosynthesis gene CmMYB6. Bisulfite sequencing revealed that methylation at the CmMYB6 promoter, especially in the CHH context, was higher in YP‐Y than YP‐P. After demethylation of the CmMYB6 promoter using the dCas9‐TET1cd system, the flower color returned from yellow to pink. Furthermore, the methylation status of the CmMYB6 promoter was higher in YP‐Y over three consecutive generations, indicating that this methylation status was heritable mitotically. Finally, investigation of other chrysanthemum cultivars showed that the methylation of CmMYB6 decreased gradually with the increase in anthocyanin content. These results lay an epigenetic foundation for the improvement of flower color in horticultural plants.

Genomic and transcriptomic studies on flavonoid biosynthesis in Lagerstroemia indica

“…We used the tobacco transient assay to explore the function of LiTTG1-1. In this experiment, CmMYB6 and SlAN1 were used as positive controls since they upregulate anthocyanin biosynthesis in tobacco [ 39 , 40 ]. As anticipated, CmMYB6 induced anthocyanin biosynthesis alone and in combination with SlAN1 (Fig.…”

“…In brief, the pWM101-LiTTG1-1 plasmid was transformed into agrobacterium GV3101 and infiltrated into 5-week-old leaves. Agrobacterium containing the empty vector pWM101 was used as the negative control and that containing CmMYB6 from chrysanthemum or SlAN1 (bHLH) from tomato as the positive control [ 40 ]. Samples were collected 72 h after infiltration, and quantitative reverse transcript PCR (qRT-PCR) was conducted according to the manufacturer’s instructions.…”

Metabolomics and Transcriptomics Revealed a Comprehensive Understanding of the Biochemical and Genetic Mechanisms Underlying the Color Variations in Chrysanthemums

“…Ray petals of JIN, FEN, and ZSH, whose colors were yellow, pink, and red, respectively, were collected in the S4 stage. Among the three cultivars, JIN and FEN share a similar genetic background [ 31 ] ( Figure 1 ).…”

“…The first component (PC1) separated ZSH and FEN, while the second component (PC2) separated JIN and FEN. This may be due to the fact that JIN and FEN are derived from the same genetic resource [ 31 ].…”

Coloration differences in three Camellia reticulata Lindl. cultivars: ‘Tongzimian’, ‘Shizitou’ and ‘Damanao’

“…Anthocyanins, flavonoids, and carotenoids are crucial pigments that contribute to flower color development and protect against low-temperature stress, ultraviolet light, pests, diseases, and other injuries [ 15 , 16 ]. Pigment biosynthesis pathways are found in most flowering plants, and the genetic mechanisms for coloration were identified, including the related genes for the necessary enzymes and transcriptional factors [ 17 – 19 ], epigenetic modifications [ 20 , 21 ], and RNA interference [ 22 ]. As ornamental plants, the color formation analysis in Camellia species has been the subject of recent studies.…”