From landing lights to mimicry: the molecular regulation of flower colouration and mechanisms for pigmentation patterning

2012 ◽  
Vol 39 (8) ◽  
pp. 619 ◽  
Author(s):  
Kevin M. Davies ◽  
Nick W. Albert ◽  
Kathy E. Schwinn
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Flower Colour ◽  
Signal Pathways ◽  
Plant Signaling ◽  
Pollination Success ◽  
Repeat Proteins ◽  
Regulatory Complex ◽  
Colour Patterns ◽  
And Function ◽  
Plant Pollinator

Flower colour is a key component for plant signaling to pollinators and a staggering variety of colour variations are found in nature. Patterning of flower colour, such as pigment spots or stripes, is common and is important in promoting pollination success. Developmentally programmed pigmentation patterns are of interest with respect to the evolution of specialised plant–pollinator associations and as models for dissecting regulatory signaling in plants. This article reviews the occurrence and function of flower colour patterns, as well as the molecular genetics of anthocyanin pigmentation regulation. The transcription factors controlling anthocyanin biosynthesis have been characterised for many species and an ‘MBW’ regulatory complex of R2R3MYB, bHLH and WD-Repeat proteins is of central importance. In particular, R2R3MYBs are key determinants of pigmentation intensity and patterning in plants. Progress is now being made on how environmental or developmental signal pathways may in turn control the production of the MBW components. Furthermore, additional regulatory proteins that interact with the MBW activation complex are being identified, including a range of proteins that repress complex formation or action, either directly or indirectly. This review discusses some of the recent data on the regulatory factors and presents models of how patterns may be determined.

scholarly journals New insight into the molecular mechanism of colour differentiation among floral segments in orchids

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Bai-Jun Li ◽  
Bao-Qiang Zheng ◽  
Jie-Yu Wang ◽  
Wen-Chieh Tsai ◽  
Hsiang-Chia Lu ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Anthocyanin Biosynthesis ◽  
Flower Colour ◽  
Colour Pattern ◽  
Yellow Colour ◽  
Spatiotemporal Expression ◽  
Pigment Distribution ◽  
Colour Patterns ◽  
R2r3 Myb ◽  
Pigment Accumulation

AbstractAn unbalanced pigment distribution among the sepal and petal segments results in various colour patterns of orchid flowers. Here, we explored this type of mechanism of colour pattern formation in flowers of the Cattleya hybrid ‘KOVA’. Our study showed that pigment accumulation displayed obvious spatiotemporal specificity in the flowers and was likely regulated by three R2R3-MYB transcription factors. Before flowering, RcPAP1 was specifically expressed in the epichile to activate the anthocyanin biosynthesis pathway, which caused substantial cyanin accumulation and resulted in a purple-red colour. After flowering, the expression of RcPAP2 resulted in a low level of cyanin accumulation in the perianths and a pale pink colour, whereas RcPCP1 was expressed only in the hypochile, where it promoted α-carotene and lutein accumulation and resulted in a yellow colour. Additionally, we propose that the spatiotemporal expression of different combinations of AP3- and AGL6-like genes might participate in KOVA flower colour pattern formation.

Repeat proteins challenge the concept of structural domains

2015 ◽  
Vol 43 (5) ◽  
pp. 844-849 ◽  
Author(s):  
Rocío Espada ◽  
R. Gonzalo Parra ◽  
Manfred J. Sippl ◽  
Thierry Mora ◽  
Aleksandra M. Walczak ◽  
...  
Keyword(s):  
Biological Systems ◽  
Modular Structure ◽  
Structural Domains ◽  
Repeat Array ◽  
Repeat Units ◽  
Repeat Proteins ◽  
Folding Dynamics ◽  
And Function

Structural domains are believed to be modules within proteins that can fold and function independently. Some proteins show tandem repetitions of apparent modular structure that do not fold independently, but rather co-operate in stabilizing structural forms that comprise several repeat-units. For many natural repeat-proteins, it has been shown that weak energetic links between repeats lead to the breakdown of co-operativity and the appearance of folding sub-domains within an apparently regular repeat array. The quasi-1D architecture of repeat-proteins is crucial in detailing how the local energetic balances can modulate the folding dynamics of these proteins, which can be related to the physiological behaviour of these ubiquitous biological systems.

scholarly journals Helicase-like functions in phosphate loop containing beta-alpha polypeptides

2021 ◽  
Vol 118 (16) ◽  
pp. e2016131118
Author(s):  
Pratik Vyas ◽  
Olena Trofimyuk ◽  
Liam M. Longo ◽  
Fanindra Kumar Deshmukh ◽  
Michal Sharon ◽  
...  
Keyword(s):  
Phosphoryl Transfer ◽  
Rna Helicases ◽  
Sequence Structure ◽  
Repeat Proteins ◽  
Dynamic Assembly ◽  
Essential Enzyme ◽  
Enzyme Families ◽  
And Function ◽  
Dsdna Binding ◽  
Oligomeric Forms

The P-loop Walker A motif underlies hundreds of essential enzyme families that bind nucleotide triphosphates (NTPs) and mediate phosphoryl transfer (P-loop NTPases), including the earliest DNA/RNA helicases, translocases, and recombinases. What were the primordial precursors of these enzymes? Could these large and complex proteins emerge from simple polypeptides? Previously, we showed that P-loops embedded in simple βα repeat proteins bind NTPs but also, unexpectedly so, ssDNA and RNA. Here, we extend beyond the purely biophysical function of ligand binding to demonstrate rudimentary helicase-like activities. We further constructed simple 40-residue polypeptides comprising just one β-(P-loop)-α element. Despite their simplicity, these P-loop prototypes confer functions such as strand separation and exchange. Foremost, these polypeptides unwind dsDNA, and upon addition of NTPs, or inorganic polyphosphates, release the bound ssDNA strands to allow reformation of dsDNA. Binding kinetics and low-resolution structural analyses indicate that activity is mediated by oligomeric forms spanning from dimers to high-order assemblies. The latter are reminiscent of extant P-loop recombinases such as RecA. Overall, these P-loop prototypes compose a plausible description of the sequence, structure, and function of the earliest P-loop NTPases. They also indicate that multifunctionality and dynamic assembly were key in endowing short polypeptides with elaborate, evolutionarily relevant functions.

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

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.

Two new species of Eupholus Boisduval (Coleoptera, Curculionidae, Entiminae), with observations on coloured cuticular exudates in weevils

Zootaxa ◽  
2010 ◽  
Vol 2338 (1) ◽  
pp. 23
Author(s):  
ALEXANDER RIEDEL
Keyword(s):  
New Species ◽  
Papua New Guinea ◽  
New Guinea ◽  
Colour Pattern ◽  
Yellow Colour ◽  
Male And Female ◽  
Two New Species ◽  
Species Groups ◽  
Colour Patterns ◽  
And Function

Two new species of Eupholus Boisduval from Papua New Guinea are described as new: Eupholus mimicus sp. n. and E. sedlaceki sp. n.. A key to the Eupholus species with yellow colour patterns is provided. E. sedlaceki is closely related to E. euphrosyne Porion but differs in coloration. Male and female terminalia of E. euphrosyne are illustrated for comparison. E. mimicus is superficially very similar to E. euphrosyne, but its yellow colour pattern is composed of scales whereas in the latter it is formed by loose particles. These two species belong to different species groups, and the conspicuous colour patterns have evidently evolved convergently. The occurrence and function of extracuticular pigments among species of Eupholini is discussed.

scholarly journals Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli

Microbiology ◽  
2010 ◽  
Vol 156 (10) ◽  
pp. 2920-2932 ◽  
Author(s):  
Goran Jovanovic ◽  
Christoph Engl ◽  
Antony J. Mayhew ◽  
Patricia C. Burrows ◽  
Martin Buck
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Negative Control ◽  
Stress Conditions ◽  
Bacterial Cells ◽  
Protein Protein Interactions ◽  
Regulatory Complex ◽  
And Function

The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of σ 54-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF–A–C–B–ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been proposed that under stress conditions, the IM-bound sensors PspB and PspC receive and transduce the signal(s) to PspA via protein–protein interactions, resulting in the release of the PspA–PspF inhibitory complex and the consequent induction of psp. In this work we demonstrate that PspB self-associates and interacts with PspC via putative IM regions. We present evidence suggesting that PspC has two topologies and that conserved residue G48 and the putative leucine zipper motif are determinants required for PspA interaction and signal transduction upon stress. We also establish that PspC directly interacts with the effector PspG, and show that PspG self-associates. These results are discussed in the context of formation and function of the Psp regulatory complex.

scholarly journals Physiological effects of climate warming on flowering plants and insect pollinators and potential consequences for their interactions

2013 ◽  
Vol 59 (3) ◽  
pp. 418-426 ◽  
Author(s):  
Victoria L. Scaven ◽  
Nicole E. Rafferty
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Scale Up ◽  
Flowering Plants ◽  
Floral Resources ◽  
Physiological Effects ◽  
Pollination Success ◽  
Insect Pollinators ◽  
Pollinating Insects ◽  
Plant Pollinator

Abstract Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interactions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summarize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also consider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to warming, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating insects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service.

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