ORCID Profile
0000-0003-1944-7067
Current Organisations
The University of Auckland
,
Apollo therapeutics
,
University of Cambridge
,
The New Zealand Institute for Plant & Food Research Limited
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Publisher: Oxford University Press (OUP)
Date: 02-07-2009
DOI: 10.1093/JXB/ERP218
Publisher: EJournal Publishing
Date: 2013
Publisher: Wiley
Date: 29-11-2010
Publisher: Wiley
Date: 12-01-2009
DOI: 10.1111/J.1469-8137.2008.02737.X
Abstract: DOI: 10.1111/j.1469-8137.2009.02771.x Commentary p 1
Publisher: Springer Science and Business Media LLC
Date: 2007
Publisher: Springer Science and Business Media LLC
Date: 21-03-2010
Abstract: The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called MYBA or MYB1 , while the gene determining fruit flesh and foliage anthocyanin has been termed MYB10 . In order to further understand tissue-specific anthocyanin regulation we have isolated orthologous MYB genes from all the commercially important rosaceous species. We use gene specific primers to show that the three MYB activators of apple anthocyanin ( MYB10/MYB1/MYBA) are likely alleles of each other. MYB transcription factors, with high sequence identity to the apple gene were isolated from across the rosaceous family (e.g. apples, pears, plums, cherries, peaches, raspberries, rose, strawberry). Key identifying amino acid residues were found in both the DNA-binding and C-terminal domains of these MYBs. The expression of these MYB10 genes correlates with fruit and flower anthocyanin levels. Their function was tested in tobacco and strawberry. In tobacco, these MYBs were shown to induce the anthocyanin pathway when co-expressed with bHLHs, while over-expression of strawberry and apple genes in the crop of origin elevates anthocyanins. This family-wide study of rosaceous R2R3 MYBs provides insight into the evolution of this plant trait. It has implications for the development of new coloured fruit and flowers, as well as aiding the understanding of temporal-spatial colour change.
Publisher: Oxford University Press (OUP)
Date: 2009
Abstract: Mutations in the genes encoding for either the biosynthetic or transcriptional regulation of the anthocyanin pathway have been linked to color phenotypes. Generally, this is a loss of function resulting in a reduction or a change in the distribution of anthocyanin. Here, we describe a rearrangement in the upstream regulatory region of the gene encoding an apple (Malus × domestica) anthocyanin-regulating transcription factor, MYB10. We show that this modification is responsible for increasing the level of anthocyanin throughout the plant to produce a striking phenotype that includes red foliage and red fruit flesh. This rearrangement is a series of multiple repeats, forming a minisatellite-like structure that comprises five direct tandem repeats of a 23-bp sequence. This MYB10 rearrangement is present in all the red foliage apple varieties and species tested but in none of the white fleshed varieties. Transient assays demonstrated that the 23-bp sequence motif is a target of the MYB10 protein itself, and the number of repeat units correlates with an increase in transactivation by MYB10 protein. We show that the repeat motif is capable of binding MYB10 protein in electrophoretic mobility shift assays. Taken together, these results indicate that an allelic rearrangement in the promoter of MYB10 has generated an autoregulatory locus, and this autoregulation is sufficient to account for the increase in MYB10 transcript levels and subsequent ectopic accumulation of anthocyanins throughout the plant.
Publisher: Springer Science and Business Media LLC
Date: 26-12-2010
DOI: 10.1038/NG.740
Publisher: Oxford University Press (OUP)
Date: 24-10-2012
Abstract: Anthocyanin accumulation is coordinated in plants by a number of conserved transcription factors. In apple (Malus × domestica), an R2R3 MYB transcription factor has been shown to control fruit flesh and foliage anthocyanin pigmentation (MYB10) and fruit skin color (MYB1). However, the pattern of expression and allelic variation at these loci does not explain all anthocyanin-related apple phenotypes. One such ex le is an open-pollinated seedling of cv Sangrado that has green foliage and develops red flesh in the fruit cortex late in maturity. We used methods that combine plant breeding, molecular biology, and genomics to identify duplicated MYB transcription factors that could control this phenotype. We then demonstrated that the red-flesh cortex phenotype is associated with enhanced expression of MYB110a, a paralog of MYB10. Functional characterization of MYB110a showed that it was able to up-regulate anthocyanin biosynthesis in tobacco (Nicotiana tabacum). The chromosomal location of MYB110a is consistent with a whole-genome duplication event that occurred during the evolution of apple within the Maloideae family. Both MYB10 and MYB110a have conserved function in some cultivars, but they differ in their expression pattern and response to fruit maturity.
Publisher: Wiley
Date: 06-11-2012
DOI: 10.1111/PBI.12017
Abstract: Consumers of whole foods, such as fruits, demand consistent high quality and seek varieties with enhanced health properties, convenience or novel taste. We have raised the polyphenolic content of apple by genetic engineering of the anthocyanin pathway using the apple transcription factor MYB10. These apples have very high concentrations of foliar, flower and fruit anthocyanins, especially in the fruit peel. Independent lines were examined for impacts on tree growth, photosynthesis and fruit characteristics. Fruit were analysed for changes in metabolite and transcript levels. Fruit were also used in taste trials to study the consumer perception of such a novel apple. No negative taste attributes were associated with the elevated anthocyanins. Modification with this one gene provides near isogenic material and allows us to examine the effects on an established cultivar, with a view to enhancing consumer appeal independently of other fruit qualities.
Publisher: Springer Science and Business Media LLC
Date: 25-04-2013
Abstract: Flavonoids such as anthocyanins, flavonols and proanthocyanidins, play a central role in fruit colour, flavour and health attributes. In peach and nectarine ( Prunus persica ) these compounds vary during fruit growth and ripening. Flavonoids are produced by a well studied pathway which is transcriptionally regulated by members of the MYB and bHLH transcription factor families. We have isolated nectarine flavonoid regulating genes and examined their expression patterns, which suggests a critical role in the regulation of flavonoid biosynthesis. In nectarine, expression of the genes encoding enzymes of the flavonoid pathway correlated with the concentration of proanthocyanidins, which strongly increases at mid-development. In contrast, the only gene which showed a similar pattern to anthocyanin concentration was UDP-glucose-flavonoid-3-O-glucosyltransferase ( UFGT) , which was high at the beginning and end of fruit growth, remaining low during the other developmental stages. Expression of flavonol synthase ( FLS1) correlated with flavonol levels, both temporally and in a tissue specific manner. The pattern of UFGT gene expression may be explained by the involvement of different transcription factors, which up-regulate flavonoid biosynthesis ( MYB10 , MYB123 , and bHLH3 ), or repress ( MYB111 and MYB16 ) the transcription of the biosynthetic genes. The expression of a potential proanthocyanidin-regulating transcription factor, MYBPA1 , corresponded with proanthocyanidin levels. Functional assays of these transcription factors were used to test the specificity for flavonoid regulation. MYB10 positively regulates the promoters of UFGT and dihydroflavonol 4-reductase ( DFR ) but not leucoanthocyanidin reductase ( LAR ). In contrast, MYBPA1 trans-activates the promoters of DFR and LAR , but not UFGT . This suggests exclusive roles of anthocyanin regulation by MYB10 and proanthocyanidin regulation by MYBPA1. Further, these transcription factors appeared to be responsive to both developmental and environmental stimuli.
Publisher: Oxford University Press (OUP)
Date: 19-06-2014
DOI: 10.1093/JXB/ERU264
Publisher: Oxford University Press (OUP)
Date: 26-01-2015
DOI: 10.1093/JXB/ERU494
Publisher: Public Library of Science (PLoS)
Date: 11-10-2010
Publisher: Wiley
Date: 19-08-2021
DOI: 10.1111/NPH.17669
Abstract: The regulatory network of R2R3 MYB transcription factors in anthocyanin biosynthesis is not fully understood in blue‐coloured berries containing delphinidin compounds. We used blue berries of bilberry ( Vaccinium myrtillus ) to comprehensively characterise flavonoid‐regulating R2R3 MYBs, which revealed a new type of co‐regulation in anthocyanin biosynthesis between members of MYBA‐, MYBPA1‐ and MYBPA2‐subgroups. VmMYBA1 , VmMYBPA1.1 and VmMYBPA2.2 expression was elevated at berry ripening and by abscisic acid treatment. Additionally, VmMYBA1 and VmMYBPA1.1 expression was strongly downregulated in a white berry mutant. Complementation and transient overexpression assays confirmed VmMYBA1 and VmMYBA2 to induce anthocyanin accumulation. Promoter activation assays showed that VmMYBA1, VmMYBPA1.1 and VmMYBPA2.2 had similar activity towards dihydroflavonol 4‐reductase ( DFR ) and anthocyanidin synthase ( ANS ), but differential regulation activity for UDP‐glucose flavonoid 3‐ O ‐glucosyltransferase ( UFGT ) and flavonoid 3′5′‐hydroxylase ( F3′5′H ) promoters. Silencing of VmMYBPA1.1 in berries led to the downregulation of key anthocyanin and delphinidin biosynthesis genes. Functional analyses of other MYBPA regulators, and a member of novel MYBPA3 subgroup, associated them with proanthocyanidin biosynthesis and F3′5′H expression. The existence of 18 flavonoid‐regulating MYBs indicated gene duplication, which may have enabled functional ersification among MYBA, MYBPA1 and MYBPA2 subgroups. Our results provide new insights into the intricate regulation of the complex anthocyanin profile found in blue‐coloured berries involving regulation of both cyanidin and delphinidin branches.
Publisher: Public Library of Science (PLoS)
Date: 03-04-2014
Publisher: Springer Science and Business Media LLC
Date: 2011
Publisher: American Association for the Advancement of Science (AAAS)
Date: 24-04-2020
Abstract: Bromodomain and extraterminal domain (BET) proteins contribute to the pathogenesis of cancer and immune diseases through their effects on transcriptional regulation. BET proteins contain two nearly identical bromodomains, BD1 and BD2, structural modules that have attracted great interest as targets for drug development. First-generation drugs that inhibited both BD1 and BD2 showed promising therapeutic activity in preclinical models but proved to be less efficacious in clinical trials. Gilan et al. took a different approach and designed drugs that selectively inhibited BD1 or BD2 (see the Perspective by Filippakopoulos and Knapp). They found that BD1 and BD2 inhibitors altered gene expression in different ways and that BD2 inhibitors had greater therapeutic activity than BD1 inhibitors in preclinical models of inflammation and autoimmune disease. Science , this issue p. 387 see also p. 367
Publisher: Wiley
Date: 21-04-2011
DOI: 10.1111/J.1365-3040.2011.02316.X
Abstract: The biosynthesis of anthocyanin in many plants is affected by environmental conditions. In apple (Malus × domestica Borkh.), concentrations of fruit anthocyanins are lower under hot climatic conditions. We examined the anthocyanin accumulation in the peel of maturing 'Mondial Gala' and 'Royal Gala' apples, grown in both temperate and hot climates, and using artificial heating of on-tree fruit. Heat caused a dramatic reduction of both peel anthocyanin concentration and transcripts of the genes of the anthocyanin biosynthetic pathway. Heating fruit rapidly reduced expression of the R2R3 MYB transcription factor (MYB10) responsible for coordinative regulation for red skin colour, as well as expression of other genes in the transcriptional activation complex. A single night of low temperatures is sufficient to elicit a large increase in transcription of MYB10 and consequently the biosynthetic pathway. Candidate genes that can repress anthocyanin biosynthesis did not appear to be responsible for reductions in anthocyanin content. We propose that temperature-induced regulation of anthocyanin biosynthesis is primarily caused by altered transcript levels of the activating anthocyanin regulatory complex.
Publisher: Springer Science and Business Media LLC
Date: 2008
Publisher: Oxford University Press (OUP)
Date: 08-2012
DOI: 10.1093/JXB/ERS193
Publisher: Wiley
Date: 08-01-2007
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: New Zealand
No related grants have been discovered for Andrew C Allan.