Anthocyanin Biosynthesis and a Regulatory Network of Different-Colored Wheat Grains Revealed by Multiomics Analysis

Abstract Background: Anthocyanins, which have important biological functions and have a beneficial effect on human health, notably account for pigmentation in purple-fleshed sweet potato tuberous roots. Individual regulatory factors of anthocyanin biosynthesis have been identified; however, the regulatory network of anthocyanin biosynthesis in purple-fleshed sweet potato is unclear. Results: We functionally determined that IbMYB340 cotransformed with IbbHLH2 in tobacco and strawberry receptacles induced anthocyanin accumulation, and the addition of IbNAC56a or IbNAC56b caused increased pigmentation. Furthermore, we confirmed the interaction of IbMYB340 with IbbHLH2 and IbNAC56a or IbNAC56b via yeast two-hybrid and firefly luciferase complementation assays; these proteins could form a MYB340-bHLH2-NAC56a or MYB340-bHLH2-NAC56b transcriptional complex to regulate anthocyanin biosynthesis by binding to the IbANS promoter rather than the IbUFGT promoter. Furthermore, it was found by a transient expression system in tobacco leaves that IbMYB44 could decrease anthocyanin accumulation. Moreover, the interaction of IbMYB44 with IbMYB340 and IbNAC56a or IbNAC56b was verified. This result suggested that IbMYB44 acts as a repressor of anthocyanin in sweet potato.Conclusions: The repressor IbMYB44 affected anthocyanin biosynthesis by competitively inhibiting the IbMYB340-IbbHLH2-IbNAC56a or IbMYB340-IbbHLH2-IbNAC56b regulatory complex formation. Overall, the present study proposed a novel regulatory network whereby several vital TFs play key roles in regulating anthocyanin biosynthesis, and it provides strong insight into the potential mechanism underlying anthocyanin biosynthesis in sweet potato tuberous roots with purple color.

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Characterization of the regulatory network of BoMYB2 in controlling anthocyanin biosynthesis in purple cauliflower

Planta ◽

10.1007/s00425-012-1665-3 ◽

2012 ◽

Vol 236 (4) ◽

pp. 1153-1164 ◽

Cited By ~ 39

Author(s):

Li-Wei Chiu ◽

Li Li

Keyword(s):

Regulatory Network ◽

Anthocyanin Biosynthesis

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MYB repressors and MBW activation complex collaborate to fine-tune flower coloration in Freesia hybrida

Communications Biology ◽

10.1038/s42003-020-01134-6 ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Yueqing Li ◽

Xiaotong Shan ◽

Ruifang Gao ◽

Taotao Han ◽

Jia Zhang ◽

...

Keyword(s):

Regulatory Network ◽

Anthocyanin Biosynthesis ◽

Freesia Hybrida ◽

C Terminus ◽

Regulatory Loop ◽

Bhlh Proteins ◽

Fine Tune ◽

Suitable System ◽

Activator Complex ◽

Mbw Complex

AbstractFloral anthocyanin has multiple ecological and economic values, its biosynthesis largely depends on the conserved MYB-bHLH-WD40 (MBW) activation complex and MYB repressors hierarchically with the MBW complex. In contrast to eudicots, the MBW regulatory network model has not been addressed in monocots because of the lack of a suitable system, as grass plants exhibit monotonous floral pigmentation patterns. Presently, the MBW regulatory network was investigated in a non-grass monocot plant, Freesia hybrida. FhMYB27 and FhMYBx with different functional manners were confirmed to be anthocyanin related R2R3 and R3 MYB repressors, respectively. Particularly, FhMYBx could obstruct the formation of positive MBW complex by titrating bHLH proteins, whereas FhMYB27 mainly defected the activator complex into suppressor via its repression domains in C-terminus. Furthermore, the hierarchical and feedback regulatory loop was verified, indicating the synergistic and sophisticated regulatory network underlying Freesia anthocyanin biosynthesis was quite similar to that reported in eudicot plants.

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MYB5a/NEGAN activates petal anthocyanin pigmentation and shapes the MBW regulatory network in Mimulus luteus var. variegatus

10.1101/2020.04.09.030536 ◽

2020 ◽

Author(s):

Xingyu Zheng ◽

Kuenzang Om ◽

Kimmy A. Stanton ◽

Daniel Thomas ◽

Philip A. Cheng ◽

...

Keyword(s):

Gene Expression ◽

Regulatory Network ◽

Anthocyanin Biosynthesis ◽

Genomic Region ◽

Anthocyanin Pigmentation ◽

Expression Change ◽

Cascading Effects ◽

Rnai Line ◽

Visual Diversity ◽

Anthocyanin Pathway

AbstractMuch of the visual diversity of angiosperms is due to the frequent evolution of novel pigmentation patterns in flowers. The gene network responsible for anthocyanin pigmentation, in particular, has become a model for investigating how genetic changes give rise to phenotypic innovation. In the monkeyflower genus Mimulus, an evolutionarily recent gain of petal lobe anthocyanin pigmentation in M. luteus var. variegatus was previously mapped to genomic region pla2. Here, we use DNA sequence analysis and spatiotemporal patterns of gene expression to identify MYB5a - homologous to the NEGAN transcriptional activator from M. lewisii - as a likely candidate gene within the pla2 region. Transgenic manipulation of gene expression confirms that MYB5a is both necessary and sufficient for petal lobe anthocyanin pigmentation. The deployment of MYB5a/NEGAN to the petal lobe stands in contrast to its more restricted role as a nectar guide anthocyanin activator in other Mimulus species. Transcriptome sequencing of a MYB5a RNAi line reveals the degree to which other regulators of the anthocyanin pathway - including R3 MYB repressors and bHLH and WD40 co-activators - are responsive to the level of expression of MYB5a. Overall, this work reveals that a genetically simple change, which we hypothesize to be a regulatory mutation in cis to MYB5a, has cascading effects on gene expression, not only on the genes downstream of MYB5a but also on all of its known partners in the anthocyanin regulatory network.Graphical abstract.Solid black arrows indicate the direction (though not magnitude) of gene expression change, following RNAi knockdown of MYB5a/NEGAN in M. l. variegatus. The number of black arrows corresponds to the number of gene copies identified in the transcriptome. Grey symbols denote positive and negative regulatory interactions. RTO is an R3 MYB protein that inhibits anthocyanin biosynthesis by sequestering bHLH proteins away from the MBW complex.

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MYB44 competitively inhibits the formation of the MYB340-bHLH2-NAC56 complex to regulate anthocyanin biosynthesis inpurple-fleshed sweet potato

10.21203/rs.2.23574/v2 ◽

2020 ◽

Author(s):

Zeng-Zheng Wei ◽

Kang-Di Hu ◽

Dong-Lan Zhao ◽

Jun Tang ◽

Zhong-Qin Huang ◽

...

Keyword(s):

Sweet Potato ◽

Regulatory Network ◽

Anthocyanin Biosynthesis ◽

Expression System ◽

Firefly Luciferase ◽

Anthocyanin Accumulation ◽

Tuberous Roots ◽

Regulatory Complex ◽

Transcriptional Complex ◽

Insight Into

Abstract Background: Anthocyanins, which have important biological functions and have a beneficial effect on human health, notably account for pigmentation in purple-fleshed sweet potato tuberous roots. Individual regulatory factors of anthocyanin biosynthesis have been identified; however, the regulatory network of anthocyanin biosynthesis in purple-fleshed sweet potato is unclear. Results: We functionally determined that IbMYB340 cotransformed with IbbHLH2 in tobacco and strawberry receptacles induced anthocyanin accumulation, and the addition of IbNAC56a or IbNAC56b caused increased pigmentation. Furthermore, we confirmed the interaction of IbMYB340 with IbbHLH2 and IbNAC56a or IbNAC56b via yeast two-hybrid and firefly luciferase complementation assays; these proteins could form a MYB340-bHLH2-NAC56a or MYB340-bHLH2-NAC56b transcriptional complex to regulate anthocyanin biosynthesis by binding to the IbANS promoter rather than the IbUFGT promoter. Furthermore, it was found by a transient expression system in tobacco leaves that IbMYB44 could decrease anthocyanin accumulation. Moreover, the interaction of IbMYB44 with IbMYB340 and IbNAC56a or IbNAC56b was verified. This result suggested that IbMYB44 acts as a repressor of anthocyanin in sweet potato.Conclusions: The repressor IbMYB44 affected anthocyanin biosynthesis by competitively inhibiting the IbMYB340-IbbHLH2-IbNAC56a or IbMYB340-IbbHLH2-IbNAC56b regulatory complex formation. Overall, the present study proposed a novel regulatory network whereby several vital TFs play key roles in regulating anthocyanin biosynthesis, and it provides strong insight into the potential mechanism underlying anthocyanin biosynthesis in sweet potato tuberous roots with purple color.

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