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 ◽  
...  

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.

Zootaxa ◽  
2010 ◽  
Vol 2338 (1) ◽  
pp. 23
Author(s):  
ALEXANDER RIEDEL

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.


2012 ◽  
Vol 39 (8) ◽  
pp. 619 ◽  
Author(s):  
Kevin M. Davies ◽  
Nick W. Albert ◽  
Kathy E. Schwinn

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.


This paper presents an attempt to construct a single model that can account for pattern formation in a very broad diversity of Lepidoptera. A pattern database is developed for 330 genera and 2208 species in the family Nymphalidae. It is argued that because of the close taxonomic relation between these species, and that all have patterns that are readily derived from the homology system known as the nymphalid ground-plan, the whole diversity of patterns in the database should emerge from a single model mechanism, and that most of this diversity should emerge from simple quantitative variations of the parameters of that model. A formal list of desiderata and constraints on any model for colour pattern formation is developed and used as the basis for the present modelling effort. Based on the assumptions of simple diffusion and threshold mech­anisms, a pattern of source-sink distributions is deduced that can gen­erate the diversity of patterns in the database. The adequacy of this source-sink ‘toolbox' is tested by computer simulation; it is shown that a two-gradient model with a simple additive relation between the two gradients suffices to generate nearly the entire diversity of patterns observed. The requisite positions of the sources and sinks of the toolbox, in turn, emerge readily from Meinhardt’s lateral inhibition model for reaction diffusion. Thus a two step model, consisting first of a reaction- diffusion system that sets up a source-sink pattern and is followed by simple diffusion of a morphogen from those sources, appears to be able to generate nearly the entire diversity of colour patterns seen in the Nymphalidae.


2020 ◽  
Vol 41 (2) ◽  
pp. 191-200
Author(s):  
Diego Bueno-Villafañe ◽  
Andrea Caballlero-Gini ◽  
Marcela Ferreira ◽  
Flavia Netto ◽  
Danilo Fernández Ríos ◽  
...  

Abstract Ontogenetic colour change (OCC) is defined as the progressive and non-reversible process of changes in colouration of organisms associated with their development. Among the many vertebrate groups, amphibians are particularly impressive for their strikingly wide variety of colours, colour patterns, and signals, whose evolutionary and ecological significance have been poorly studied. Elachistocleis comprises 18 species currently separated into two main groups based on their ventral colour pattern: one immaculate and the other with specks and/or colour patches. Elachistocleis haroi is a small-sized species within the immaculate venter group, distributed in the Yungas and Dry Chaco ecoregions from which little information is known. In a comprehensive sampling of post-metamorphic individuals of E. haroi at different stages of development we identified a significant variation in ventral colour pattern, which could denote a progressive filling of yellow colour according to an ontogenetic pattern. To test this hypothesis, we analysed 39 post-metamorphic individuals of E. haroi at different stages of development with imaging procedures. We found that yellow spots and their intensity are significantly related to snout-vent length, as major expansion of colour on the sides, gular region and male chest, as almost no development on the belly. We briefly discuss our findings in relation to sexual display and predation avoidance. To our knowledge, this is the first analysis of post-metamorphic OCC in ventral colouration in the genus Elachistocleis.


Author(s):  
Danika L. Bannasch ◽  
Christopher B. Kaelin ◽  
Anna Letko ◽  
Robert Loechel ◽  
Petra Hug ◽  
...  

AbstractDistinctive colour patterns in dogs are an integral component of canine diversity. Colour pattern differences are thought to have arisen from mutation and artificial selection during and after domestication from wolves but important gaps remain in understanding how these patterns evolved and are genetically controlled. In other mammals, variation at the ASIP gene controls both the temporal and spatial distribution of yellow and black pigments. Here, we identify independent regulatory modules for ventral and hair cycle ASIP expression, and we characterize their action and evolutionary origin. Structural variants define multiple alleles for each regulatory module and are combined in different ways to explain five distinctive dog colour patterns. Phylogenetic analysis reveals that the haplotype combination for one of these patterns is shared with Arctic white wolves and that its hair cycle-specific module probably originated from an extinct canid that diverged from grey wolves more than 2 million years ago. Natural selection for a lighter coat during the Pleistocene provided the genetic framework for widespread colour variation in dogs and wolves.


2021 ◽  
Vol 41 (8) ◽  
Author(s):  
Jie Zheng ◽  
Hao Wu ◽  
Mingchao Zhao ◽  
Zenan Yang ◽  
Zaihui Zhou ◽  
...  

2021 ◽  
Vol 22 (6) ◽  
pp. 3026
Author(s):  
Xieyu Li ◽  
Fangxin Xiang ◽  
Wei Han ◽  
Bingqing Qie ◽  
Rui Zhai ◽  
...  

The N-terminal of Myc-like basic helix-loop-helix transcription factors (bHLH TFs) contains an interaction domain, namely the MYB-interacting region (MIR), which interacts with the R2R3-MYB proteins to regulate genes involved in the anthocyanin biosynthetic pathway. However, the functions of MIR-domain bHLHs in this pathway are not fully understood. In this study, PbbHLH2 containing the MIR-domain was identified and its function investigated. The overexpression of PbbHLH2 in ”Zaosu” pear peel increased the anthocyanin content and the expression levels of late biosynthetic genes. Bimolecular fluorescence complementation showed that PbbHLH2 interacted with R2R3-MYB TFs PbMYB9, 10, and 10b in onion epidermal cells and confirmed that MIR-domain plays important roles in the interaction between the MIR-domain bHLH and R2R3-MYB TFs. Moreover, PbbHLH2 bound and activated the dihydroflavonol reductase promoter in yeast one-hybrid (Y1H) and dual-luciferase assays. Taken together these results suggested that the MIR domain of PbbHLH2 regulated anthocyanin biosynthesis in pear fruit peel.


2022 ◽  
Vol 293 ◽  
pp. 110674
Author(s):  
Yiguang Wang ◽  
Li-Jie Zhou ◽  
Yuxi Wang ◽  
Zhiqiang Geng ◽  
Baoqing Ding ◽  
...  

Crustaceana ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 799-839 ◽  
Author(s):  
Akihiro Yoshikawa ◽  
Kazuho Ikeo ◽  
Junichi Imoto ◽  
Wachirah Jaingam ◽  
Lily Surayya Eka Putri ◽  
...  

Abstract Species of hermit crabs in the genus Clibanarius Dana, 1852 have adapted to various environments in the intertidal areas, including hard substrates and soft sediments. These species often bear a close morphological resemblance to each other, therefore, the colouration on the pereopods can be one of the reliable characteristics to distinguish the species. However, the evolutionary relationships among species with different colour patterns and relationships between colour patterns and habitat adaptation have not previously been investigated. Therefore, we reconstructed the phylogenetic relationships among 19 species of Clibanarius based on mitochondrial [12S rRNA, 16S rRNA and cytochrome oxidase I] and nuclear [histone H3] DNA markers. The results suggest that the striped and solid colour elements have evolved multiple times independently, with the ancestral colour pattern potentially being scattered, bright colour spots with a bright colour band. Our findings also suggest that evolutionary adaptation from hard substrates to mudflats and soft sediments may have occurred at least twice.


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