Cyclotides in the Violaceae

Göransson, Ulf; Malik, Sohaib Zafar; Ślązak, Błażej

doi:10.1016/bs.abr.2015.09.001

Cited by 10 publications

(12 citation statements)

References 108 publications

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“…Despite reports of cyclotide-like sequences in the Poaceae, none of the described sequences have been shown to exist as cyclic molecules in planta , thus failing the definition of the term cyclotide. The taxonomic distribution of cyclotides is often disjointed in a taxonomic group; for instance the taxonomically sparse occurrence of cyclotides observed in the Rubiaceae (Gruber et al, 2008; Koehbach et al, 2013) contrasts with the ubiquitous occurrence of cyclotides in all species tested far-off the Violaceae family (Burman et al, 2015; Göransson et al, 2015). Within the Fabaceae, C. ternatea is the only family member in which cyclotides have been observed despite examination of diverse Fabaceae, including other species of Clitoria (Gilding et al, 2015).…”

Section: Phytochemical Compositionmentioning

confidence: 99%

“…Cyclotide transcripts of C. ternatea encode for a signal peptide that immediately precedes the N-terminal residue of the cyclotide domain (Poth et al, 2011a; Gilding et al, 2015; Nguyen et al, 2016b). The current model for C. ternatea cyclotide biosynthesis mimics that of other cyclotide producing species and begins with the signal peptide inducing the docking of the ribosome-transcript complex with the rough endoplasmic reticulum (ER) (Conlan and Anderson, 2011; Göransson et al, 2015). Unique to C. ternatea cyclotide precursors is that the signal peptide cleavage alone releases the N-terminus of the cyclotide domain, thus no other N-terminal processing proteases are required.…”

Section: Phytochemical Compositionmentioning

confidence: 99%

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Butterfly Pea (Clitoria ternatea), a Cyclotide-Bearing Plant With Applications in Agriculture and Medicine

et al. 2019

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The perennial leguminous herb Clitoria ternatea (butterfly pea) has attracted significant interest based on its agricultural and medical applications, which range from use as a fodder and nitrogen fixing crop, to applications in food coloring and cosmetics, traditional medicine and as a source of an eco-friendly insecticide. In this article we provide a broad multidisciplinary review that includes descriptions of the physical appearance, distribution, taxonomy, habitat, growth and propagation, phytochemical composition and applications of this plant. Notable amongst its repertoire of chemical components are anthocyanins which give C. ternatea flowers their characteristic blue color, and cyclotides, ultra-stable macrocyclic peptides that are present in all tissues of this plant. The latter are potent insecticidal molecules and are implicated as the bioactive agents in a plant extract used commercially as an insecticide. We include a description of the genetic origin of these peptides, which interestingly involve the co-option of an ancestral albumin gene to produce the cyclotide precursor protein. The biosynthesis step in which the cyclic peptide backbone is formed involves an asparaginyl endopeptidase, of which in C. ternatea is known as butelase-1. This enzyme is highly efficient in peptide ligation and has been the focus of many recent studies on peptide ligation and cyclization for biotechnological applications. The article concludes with some suggestions for future studies on this plant, including the need to explore possible synergies between the various peptidic and non-peptidic phytochemicals.

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Section: Phytochemical Compositionmentioning

confidence: 99%

Section: Phytochemical Compositionmentioning

confidence: 99%

Butterfly Pea (Clitoria ternatea), a Cyclotide-Bearing Plant With Applications in Agriculture and Medicine

et al. 2019

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“…The majority of cyclotides recently discovered are in Violaceae, which is speculated to contain upward of 30,000 unique cyclotides (Zhang et al, 2015). While only a small percentage of species in other cyclotide producing families have tested positive for cyclotide presence, cyclotide expression appears to be ubiquitous in Violaceae, and cyclotides have been identified in all species investigated (Burman et al, 2015; Göransson et al, 2015; Ravipati et al, 2017). While nine Viola transcriptomes have been sequenced to date (Supplementary Table S1), no Viola genome has been assembled (Matasci et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Transcriptomics Identifies Modules of Differentially Expressed Genes and Novel Cyclotides in Viola pubescens

et al. 2019

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Viola is a large genus with worldwide distribution and many traits not currently exemplified in model plants including unique breeding systems and the production of cyclotides. Here we report de novo genome assembly and transcriptomic analyses of the non-model species Viola pubescens using short-read DNA sequencing data and RNA-Seq from eight diverse tissues. First, V. pubescens genome size was estimated through flow cytometry, resulting in an approximate haploid genome of 455 Mbp. Next, the draft V. pubescens genome was sequenced and assembled resulting in 264,035,065 read pairs and 161,038 contigs with an N50 length of 3,455 base pairs (bp). RNA-Seq data were then assembled into tissue-specific transcripts. Together, the DNA and transcript data generated 38,081 ab initio gene models which were functionally annotated based on homology to Arabidopsis thaliana genes and Pfam domains. Gene expression was visualized for each tissue via principal component analysis and hierarchical clustering, and gene co-expression analysis identified 20 modules of tissue-specific transcriptional networks. Some of these modules highlight genetic differences between chasmogamous and cleistogamous flowers and may provide insight into V. pubescens’ mixed breeding system. Orthologous clustering with the proteomes of A. thaliana and Populus trichocarpa revealed 8,531 sequences unique to V. pubescens , including 81 novel cyclotide precursor sequences. Cyclotides are plant peptides characterized by a stable, cyclic cystine knot motif, making them strong candidates for drug scaffolding and protein engineering. Analysis of the RNA-Seq data for these cyclotide transcripts revealed diverse expression patterns both between transcripts and tissues. The diversity of these cyclotides was also highlighted in a maximum likelihood protein cladogram containing V. pubescens cyclotides and published cyclotide sequences from other Violaceae and Rubiaceae species. Collectively, this work provides the most comprehensive sequence resource for Viola , offers valuable transcriptomic insight into V. pubescens , and will facilitate future functional genomics research in Viola and other diverse plant groups.

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“…Cyclotides have been extensively reviewed in the past [62][63][64][65][66][67][68][69][82][83][84][85][86][87][88][89][90][91] and readers are referred to some of these articles and a recent book [92] for a more detailed background on their discovery, biosynthesis and applications. In the current article our focus is on just those plants that grow in Australasia and are thus accessible to researchers in the region.…”

Section: From Animal Venoms To Plant Peptidesmentioning

confidence: 99%

Discovery of Cyclotides from Australasian Plants

Kan

Craik

2020

Aust. J. Chem.

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This article is part of a special issue celebrating the contributions of Professor Paul Alewood to peptide science. We begin by providing a summary of collaborative projects between the Alewood and Craik groups at The University of Queensland and highlighting the impacts of some of these studies. In particular, studies on the discovery, synthesis, structures, and bioactivities of disulfide-rich toxins from animal venoms have led to a greater understanding of the biology of ion channels and to applications of these bioactive peptides in drug design. The second part of the article focuses on plant-derived disulfide-rich cyclic peptides, known as cyclotides, and includes an analysis of the geographical distribution of Australasian plant species that contain cyclotides as well as an analysis of the diversity of cyclotide sequences found in Australasian plants. This should provide a useful resource for researchers to access native cyclotides and explore their chemistry and biology.

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Cyclotides in the Violaceae

Cited by 10 publications

References 108 publications

Butterfly Pea (Clitoria ternatea), a Cyclotide-Bearing Plant With Applications in Agriculture and Medicine

Butterfly Pea (Clitoria ternatea), a Cyclotide-Bearing Plant With Applications in Agriculture and Medicine

Transcriptomics Identifies Modules of Differentially Expressed Genes and Novel Cyclotides in Viola pubescens

Discovery of Cyclotides from Australasian Plants

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