Publications by authors named "Masumi Yamagishi"

16 Publications

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High promoter sequence variation in subgroup 6 members of R2R3-MYB genes is involved in different floral anthocyanin color patterns in Lilium spp.

Authors:
Masumi Yamagishi

Mol Genet Genomics 2021 Jul 30;296(4):1005-1015. Epub 2021 May 30.

Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo, 060-8589, Japan.

The spatially and temporally distinct expression of R2R3-MYB positive regulators is among the major mechanisms that create various anthocyanin color patterns in many flowers. However, we do not know how these positive regulators have gained different expression profiles. In the Asiatic hybrid lily 'Lollypop' (derived from the crosses of species belonging to Sinomartagon/Daurolirion section), MYB12 and MYB19S regulate the pigmentation at whole tepals and raised tepal spots, respectively. In the Oriental hybrid lily 'Sorbonne' (derived from the crosses of species belonging to the Archelirion section), MYB12 regulates both whole tepal and raised spot pigmentation. The genes have similar amino acid sequences with similar protein functions but exhibit different expression profiles in lily flowers. As promoters are among the most significant factors affecting gene expression profiles, their promoter sequences were determined in this study. The three genes had very different promoter sequences, and putative cis-regulatory elements were not conserved in numbers or order. To further confirm the promoter functions, tobacco plants were transformed with native promoter-driven MYB12 or MYB19S genes of 'Lollypop.' Expression levels of MYB12 were higher in corolla tubes than in lobes, while those of MYB19S were higher in corolla lobes than in tubes. Thus, the diverse promoter functions were likely to be the leading causes of their different expression profiles and generation of unique color patterns. Finally, the history of R2R3-MYB gene establishment during lily evolution was estimated using sequence data.
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http://dx.doi.org/10.1007/s00438-021-01799-6DOI Listing
July 2021

Expression of , the Flowering Inducer of Asiatic Hybrid Lily, in the Bulb Scales.

Front Plant Sci 2020 9;11:570915. Epub 2020 Nov 9.

Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.

Asiatic hybrid lily leaves emerge from their bulbs in spring, after cold exposure in winter, and the plant then blooms in early summer. We identified four ()-like genes, , , , and , from an Asiatic hybrid lily. Floral bud differentiation initiated within bulbs before the emergence of leaves. genes were mainly expressed in bulb scales, and hardly in leaves, in which the genes of many plants are expressed in response to environmental signals. was expressed in bulb scales after vernalization and was correlated to flower bud initiation in two cultivars with different flowering behaviors. was upregulated in bulb scales after cold exposure and three alternative splicing variants with a nonsense codon were simultaneously expressed. was upregulated in bulb scales after flower initiation, whereas was expressed constantly in all organs. overexpression complemented the late-flowering phenotype of , whereas that of did so partly. and overexpression could not complement. Yeast two-hybrid and analyses showed that the LhFT1 protein interacted with the LhFD protein. LhFT6 and LhFT8 proteins also interacted with LhFD, as observed in AlphaScreen assay. Based on these results, we revealed that acts as a floral activator during floral bud initiation in Asiatic hybrid lilies. However, the biological functions of , , and remain unclear.
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http://dx.doi.org/10.3389/fpls.2020.570915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693649PMC
November 2020

The MicroRNA828/MYB12 Module Mediates Bicolor Pattern Development in Asiatic Hybrid Lily ( spp.) Flowers.

Front Plant Sci 2020 30;11:590791. Epub 2020 Oct 30.

Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.

Some Asiatic hybrid lily cultivars develop bicolor tepals, which consist of anthocyanin-pigmented upper halves and un-pigmented lower halves. , a subgroup 6 member of R2R3-MYB that positively regulates anthocyanin biosynthesis, is downregulated in the lower halves. However, is usually expressed over entire tepal regions in numerous lily cultivars. Why of bicolor cultivars exhibits variable expression spatially in a single tepal remains unclear. Since the lily mRNA harbored a binding site for microRNA828 (miR828), the involvement of miR828 in variable spatial accumulation of transcripts was evaluated. We analyzed the cleavage of mRNA, mature miR828 accumulation, and transcript-derived siRNA generation (microRNA-seq). In the bicolor tepals, mature miR828 was more highly accumulated in the lower halves than in the upper halves, and miR828-directed cleavage of transcripts was observed predominantly in the lower halves. Moreover, the cleavage triggered the production of secondary siRNA from transcripts, and the siRNAs were accumulated predominantly in the lower halves. Consequently, miR828 suppressed transcript accumulation in the white region, and the miR828/MYB12 module participated in the development of bicolor patterns in lily flowers. The results present the first example of a microRNA mediating flower color patterns. Finally, we discuss the potential of miR828 creating flower color variations through suppressing the activity of subgroup 6 R2R3-MYB positive regulators in other species.
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http://dx.doi.org/10.3389/fpls.2020.590791DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661471PMC
October 2020

Virus-Induced Gene Silencing in Lilies Using Cucumber Mosaic Virus Vectors.

Methods Mol Biol 2020 ;2172:1-13

Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan.

Virus-induced gene silencing (VIGS) systems are effective for rapid analysis of gene functions in plants that require a long period of growth such as Lilium. We successfully developed a VIGS system using the cucumber mosaic virus (HL strain, CMV-HL) vector to induce RNA silencing of the L. leichtlinii phytoene desaturase gene (LlPDS), where at 30 days postinoculation (dpi), photo-bleaching was observed in the upper leaves of L. leichtlinii, and at 57 dpi, white regions appeared on flower tepals that accumulate orange carotenoids. This vector spreads in bulbs, and it could induce silencing on emerged shoots in the following year. The CMV-HL vector can be easily constructed by insertion of a 30-60 nt fragment into the cloning site of the RNA3 genome. In this chapter, we describe how to use the CMV-HL vector system in the context of Lilium plants.
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http://dx.doi.org/10.1007/978-1-0716-0751-0_1DOI Listing
March 2021

Isolation and identification of MYB transcription factors (MYB19Long and MYB19Short) involved in raised spot anthocyanin pigmentation in lilies (Lilium spp.).

Authors:
Masumi Yamagishi

J Plant Physiol 2020 Jul 16;250:153164. Epub 2020 May 16.

Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo, 060-8589, Japan. Electronic address:

Although anthocyanin color patterns on flowers are among the most attractive characteristics, the genetic mechanisms through which color patterns are developed are not well understood, especially for color patterns associated with altered petal structure. Lilium species and cultivars often develop raised spots, where the interior surfaces of tepals increase to develop bumps with accompanying anthocyanin accumulation. The aim of this study was to identify transcription factors regulating pigmentation of the bumps. We identified two R2R3-MYB genes, MYB19Long and MYB19Short, in Lilium leichtlinii, L. lancifolium, and Asiatic hybrid lily cultivars. Their amino acid sequences were similar; however, part of the C-terminal region was triplicated in MYB19Long. Spatial and temporal expression profiles in lilies were strongly associated with anthocyanin biosynthesis gene expression in the bumps, and some defects were found in these genes in L. lancifolium 'Pure Gold' that developed colorless bumps. Thus, both MYB19Long and MYB19Short were likely to be involved in the bump pigmentation. MYB19Long had a stronger ability to stimulate target gene expression than MYB19Short, and expression levels of MYB19Long were greater than those of MYB19Short in lily tepals; thus, the ability to biosynthesize anthocyanin pigments was greater for MYB19Long than for MYB19Short. Among the F population, MYB19Short expression was found only in the tepals of F plants that developed bumps, although all of the F plants possessed the MYB19Short gene, indicating that MYB19 expression followed bump development. These findings helped to elucidate the genetic mechanisms underlying raised spot development.
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http://dx.doi.org/10.1016/j.jplph.2020.153164DOI Listing
July 2020

Repression of anthocyanin biosynthesis by R3-MYB transcription factors in lily (Lilium spp.).

Plant Cell Rep 2019 May 5;38(5):609-622. Epub 2019 Feb 5.

Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo, 060-8589, Japan.

Key Message: Lily R3-MYB transcription factors are involved in negative regulation to limit anthocyanin accumulation in lily flowers and leaves and create notable color patterns on ectopically expressed petunia flowers. In eudicots, both positive and negative regulators act to precisely regulate the level of anthocyanin accumulation. The R3-MYB transcription factor is among the main factors repressing anthocyanin biosynthesis. Although, in monocots, the positive regulators have been well characterized, the negative regulators have not been examined. Two R3-MYBs, LhR3MYB1 and LhR3MYB2, which were identified in lily transcriptomes, were characterized in this study to understand the regulatory mechanisms of anthocyanin biosynthesis. LhR3MYB1 and LhR3MYB2 had a C2 suppressor motif downstream of a single MYB repeat; the similar amino acid motif appears only in AtMYBL2 among the eudicot R3-MYB proteins. Stable and transient overexpression of LhR3MYB1 and LhR3MYB2 in tobacco plants showed suppression of anthocyanin biosynthesis by both; however, suppression by LhR3MYB2 was stronger than that by LhR3MYB1. In the lily plant, the LhR3MYB2 transcript was detected in leaves with light stimulus-induced anthocyanin accumulation and in pink tepals. Although LhR3MYB1 was expressed in some, but not all tepals, its expression was not linked to anthocyanin accumulation. In addition, LhR3MYB1 expression levels in the leaves remained unchanged by the light stimulus, and LhR3MYB1 transcripts predominantly accumulated in the ovaries, which did not accumulate anthocyanins. Thus, although LhR3MYB1 and LhR3MYB2 have an ability to repress anthocyanin accumulation, LhR3MYB2 is more strongly involved in the negative regulation to limit the accumulation than that by LhR3MYB1. In addition, the overexpression of LhR3MYB2 generated notable color patterns in petunia flowers; thus, the usefulness of the LhR3MYB genes for creating unique color patterns by genetic engineering is discussed.
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http://dx.doi.org/10.1007/s00299-019-02391-4DOI Listing
May 2019

Floral pigmentation pattern in Oriental hybrid lily (Lilium spp.) cultivar 'Dizzy' is caused by transcriptional regulation of anthocyanin biosynthesis genes.

J Plant Physiol 2018 Sep 24;228:85-91. Epub 2018 May 24.

School of Agriculture, Meiji University, Higashimita, Tama-ku, Kawasaki 214-8571, Japan.

Flower color patterns are the result of spatially and temporally restricted pigment deposition, and clarifying the mechanisms responsible for restricted pigment deposition is a topic of broad interest for both theoretical and practical reasons. The Oriental hybrid lily cultivar 'Dizzy' develops red stripes along the tepal midribs; in order to clarify the genetic basis of these stripes, we isolated most of the genes related to anthocyanin accumulation from 'Dizzy' tepals and compared their expression levels between the red stripe region and the white marginal region of the tepals. RNA-seq revealed a complete set of genes necessary for anthocyanin biosynthesis and transport, including anthocyanidin 3-O-glucosyltransferase and glutathione S-transferase. Most of these genes were expressed at higher rates in the red stripe region than in the white region, suggesting that transcriptional regulation of these genes is primarily responsible for the spatially restricted anthocyanin deposition in 'Dizzy' tepals. Subgroup 6 R2R3-MYB is a major factor regulating anthocyanin biosynthesis: RNA-seq clarified three subgroup 6 R2R3-MYB genes expressed in 'Dizzy' tepals, of which MYB12 was predominantly expressed. Expression of MYB12 was six-fold higher in the red-pigmented region than in the white region. Thus, MYB12 is more likely to be involved in the regulation of the restricted anthocyanin deposition in 'Dizzy', even though MYB12 is expressed in the entire tepal region of many Oriental hybrid lily cultivars. Diversity of the expression profiles of MYB12 among lily cultivars and species is also discussed.
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http://dx.doi.org/10.1016/j.jplph.2018.05.008DOI Listing
September 2018

RNA-seq-based evaluation of bicolor tepal pigmentation in Asiatic hybrid lilies (Lilium spp.).

BMC Genomics 2016 08 11;17(1):611. Epub 2016 Aug 11.

Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo, 060-8589, Japan.

Background: Color patterns in angiosperm flowers are produced by spatially and temporally restricted deposition of pigments. Identifying the mechanisms responsible for restricted pigment deposition is a topic of broad interest. Some dicots species develop bicolor petals, which are often caused by the post-transcriptional gene silencing (PTGS) of chalcone synthase (CHS) genes. An Asiatic hybrid lily (Lilium spp.) cultivar Lollypop develops bicolor tepals with pigmented tips and white bases. Here, we analyzed the global transcription of pigmented and non-pigmented tepal parts from Lollypop, to determine the main transcriptomic differences.

Results: De novo assembly of RNA-seq data yielded 49,239 contigs (39,426 unigenes), which included a variety of novel transcripts, such as those involved in flavonoid-glycosylation and sequestration and in regulation of anthocyanin biosynthesis. Additionally, 1258 of the unigenes exhibited significantly differential expression between the tepal parts (false discovery rates <0.05). The pigmented tepal parts accumulated more anthocyanins, and unigenes annotated as anthocyanin biosynthesis genes (e.g., CHS, dihydroflavonol 4-reductase, and anthocyanidin synthase) were expressed 7-30-fold higher than those in non-pigmented parts. These results indicate that the transcriptional regulation of biosynthesis genes is more likely involved in the development of bicolor lily tepals rather than the PTGS of CHS genes. In addition, the expression level of a unigene homologous to LhMYB12, which often regulates full-tepal anthocyanin pigmentation in lilies, was >2-fold higher in the pigmented parts. Thus, LhMYB12 should be involved in the transcriptional regulation of the biosynthesis genes in bicolor tepals. Other factors that potentially suppress or enhance the expression of anthocyanin biosynthesis genes, including a WD40 gene, were identified, and their involvement in bicolor development is discussed.

Conclusions: Our results indicate that the bicolor trait of Lollypop tepals is caused by the transcriptional regulation of anthocyanin biosynthesis genes and that the transcription profile of LhMYB12 provides a clue for elucidating the mechanisms of the trait. The tepal transcriptome constructed in this study will accelerate investigations of the genetic controls of anthocyanin color patterns, including the bicolor patterns, of Lilium spp.
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http://dx.doi.org/10.1186/s12864-016-2995-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982199PMC
August 2016

Virus-induced gene silencing (VIGS) in using the vector.

Plant Biotechnol (Tokyo) 2016 26;33(5):373-381. Epub 2016 Nov 26.

Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.

Lilies () are among the most important floriculture crops, and to accelerate research regarding lily genetics, the development of reverse-genetics tools is necessary. However, -mediated transformation in is time-consuming, since the plants require several years to progress from acclimation to flowering. Thus, virus-induced gene silencing (VIGS) is an attractive method for assaying gene function. In the present study, we modified a lily-derived strain of (CMV-HL) as a VIGS vector and evaluated its effectiveness for inducing gene silencing in by introducing () gene fragments into an intercistronic region between the 3a and 3b genes of the CMV-HL RNA3 genome. At 30 days after inoculation (dpi) with -containing CMV-HL, photo-bleaching was observed in the upper leaves of , and at 57 dpi, we observed that the natural orange color in flower tepals had faded. Reduced expression and the detection of small interfering RNA indicated that the color changes were the result of gene silencing. In addition, the leaves also exhibited a mild photo-bleaching phenotype in the following year. Therefore, our results indicate that CMV-HL spreads systemically in the leaves and flowers of during the first year of infection, as well as in new shoots during the following year, and that the vector system can be successfully applied to induce short-term endogenous gene silencing in lilies.
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http://dx.doi.org/10.5511/plantbiotechnology.16.1018aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587034PMC
November 2016

The novel allele of the LhMYB12 gene is involved in splatter-type spot formation on the flower tepals of Asiatic hybrid lilies (Lilium spp.).

New Phytol 2014 Feb 1;201(3):1009-1020. Epub 2013 Nov 1.

Research Faculty of Agriculture, Hokkaido University, N9W9 Kita-ku, Sapporo, 060-8589, Japan.

Many angiosperm families develop spatially regulated anthocyanin spots on their flowers. The Asiatic hybrid lily (Lilium spp.) cv 'Latvia' develops splatter-type spots on its tepals. The splatters arise simply from the deposition of anthocyanin pigments in the tepal epidermis. To determine how splatter development was regulated, we analysed the transcription of anthocyanin biosynthesis genes, and isolated and characterized an R2R3-MYB gene specific to splatter pigmentation. All anthocyanin biosynthesis genes were expressed in splatter-containing regions of tepals, but not in other regions, indicating that splatter pigmentation is caused by the transcriptional regulation of biosynthesis genes. Previously characterized LhMYB12 regulators were not involved in splatter pigmentation, but, instead, a new allele of the LhMYB12 gene, LhMYB12-Lat, isolated in this study, contributed to splatter development. In 'Latvia' and other lily plants expressing splatters, LhMYB12-Lat was preferentially transcribed in the splatter-containing region of tepals. Progeny segregation analysis showed that LhMYB12-Lat genotype and splatter phenotype were co-segregated among the F1 population, indicating that LhMYB12-Lat determines the presence or absence of splatters. LhMYB12-Lat contributes to splatter development, but not to full-tepal pigmentation and raised spot pigmentation. As a result of its unique sequences and different transcription profiles, this new allele of LhMYB12 should be a novel R2R3-MYB specifically associating with splatter spot development.
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http://dx.doi.org/10.1111/nph.12572DOI Listing
February 2014

Pigment accumulation and transcription of LhMYB12 and anthocyanin biosynthesis genes during flower development in the Asiatic hybrid lily (Lilium spp.).

Plant Sci 2012 Sep 9;193-194:136-147. Epub 2012 Jun 9.

Research Faculty of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan. Electronic address:

Anthocyanin biosynthesis is often regulated by MYB transcription factors that are classified into AN2 and C1 subgroups. The AN2 subgroup regulates the late genes in the anthocyanin biosynthesis pathway of eudicots, whereas the C1 subgroup controls both early and late genes in monocots. Anthocyanin is a major pigment in Asiatic hybrid lilies (Lilium spp.), with LhMYB12 being the first AN2 subgroup in monocots. In this study, the accumulation of pigments and gene transcripts during flower bud development was evaluated to determine the genes regulated by LhMYB12. LhMYB12 and anthocyanin biosynthesis genes showed the same transcription profiles, with LhMYB12 directly activating the promoters of chalcone synthase and dihydroflavonol 4-reductase. This indicates that LhMYB12 regulates both early and late genes, despite belonging to the AN2 subgroup. The cultivar Landini accumulated anthocyanin and flavonol. The contents of these pigments increased during the late stages of flower bud development; this might result from the coordinated expression of early and late genes. During the early stages of flower bud development, the tepals contained no flavonoids but accumulated cinnamic acid derivatives. These results indicate that the profiles of pigment accumulation and gene transcription in lily tepals are unique among angiosperm flowers.
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http://dx.doi.org/10.1016/j.plantsci.2012.05.013DOI Listing
September 2012

Reduced transcription of a LEAFY-like gene in Alstroemeria sp. cultivar Green Coral that cannot develop floral meristems.

Plant Sci 2012 Apr 3;185-186:298-308. Epub 2012 Jan 3.

Graduate School of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan.

Alstroemeria sp. cv. Green Coral has numerous bracts instead of flowers, and its cyme structures are repeated eternally. Observations of the development and morphology of inflorescence in cv. Green Coral revealed that transition from inflorescence to floral meristem was restricted. We isolated and characterized floral meristem identity genes LEAFY-like (AlsLFY) and SQUAMOSA-like (AlsSQa and AlsSQb) genes from Alstroemeria ligtu. In situ hybridization results indicated that AlsSQa and AlsSQb were expressed in the dome-shaped floral meristems and all floral organ primordia in A. ligtu. Transcripts of AlsLFY accumulated early in the dome-shaped floral meristems; the signals were restricted later to the outer region of the floral meristem. These results indicate that AlsLFY, AlsSQa, and AlsSQb function as floral meristem identity genes. Expression profiles of AlsLFY, AlsSQa, AlsSQb, and other MADS-box genes were compared between A. ligtu and cv. Green Coral. AlsLFY, AlsDEFa, and AlsAGL6 transcripts were not detected at the shoot apices of cv. Green Coral but were detected in A. ligtu. The early induction and accumulation of AlsLFY transcripts in the inflorescence meristem of A. ligtu prior to development of the floral meristem suggest that downregulation of AlsLFY is likely to restrict the inflorescence-to-floral meristem transition in cv. Green Coral.
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http://dx.doi.org/10.1016/j.plantsci.2011.12.017DOI Listing
April 2012

Segregation distortion in F(2) and doubled haploid populations of temperate japonica rice.

J Genet 2010 Aug;89(2):237-41

Research Institute of Agricultural Resources, Ishikawa Agricultural College, Ishikawa, Japan.

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http://dx.doi.org/10.1007/s12041-010-0032-zDOI Listing
August 2010

Two R2R3-MYB genes, homologs of Petunia AN2, regulate anthocyanin biosyntheses in flower Tepals, tepal spots and leaves of asiatic hybrid lily.

Plant Cell Physiol 2010 Mar 28;51(3):463-74. Epub 2010 Jan 28.

Research Faculty of Agriculture, Hokkaido University, Kita-ku, Sapporo, 060-8589 Japan.

Anthocyanins are secondary metabolites that contribute to colors of flowers, fruits and leaves. Asiatic hybrid lily (Lilium spp.) accumulates cyanidin anthocyanins in flower tepals, tepal spots and leaves of juvenile shoots. To clarify their mechanisms of regulation of anthocyanin pigmentation, two full-length cDNAs of R2R3-MYB (LhMYB6 and LhMYB12) were isolated from the anthocyanin-accumulating tepals of cultivar 'Montreux'. Analysis of the deduced amino acid sequences indicated they have homology with petunia AN2, homologous sequences of which had not been isolated in species of monocots. Yeast two-hybrid analysis showed that LhMYB6 and LhMYB12 interacted with the Lilium hybrid basic helix-loop-helix 2 (LhbHLH2) protein. Transient expression analysis indicated that co-expression of LhMYB6 and LhbHLH2 or LhMYB12 and LhbHLH2, introduced by a microprojectile, activated the transcription of anthocyanin biosynthesis genes in lily bulbscales. Spatial and temporal transcription of LhMYB6 and LhMYB12 was analyzed. The expression of LhMYB12 corresponded well with anthocyanin pigmentation in tepals, filaments and styles, and that of LhMYB6 correlated with anthocyanin spots in tepals and light-induced pigmentation in leaves. These results indicate that LhMYB6 and LhMYB12 positively regulate anthocyanin biosynthesis and determine organ- and tissue-specific accumulation of anthocyanin.
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http://dx.doi.org/10.1093/pcp/pcq011DOI Listing
March 2010

Sugar signalling mediates cluster root formation and phosphorus starvation-induced gene expression in white lupin.

J Exp Bot 2008 17;59(10):2749-56. Epub 2008 May 17.

Graduate School of Agriculture, Hokkaido University, N9W9, Kita-ku, Sapporo 060-8589, Japan.

Cluster root (CR) formation contributes much to the adaptation to phosphorus (P) deficiency. CR formation by white lupin (Lupinus albus L.) is affected by the P-limiting level in shoots, but not in roots. Thus, shoot-derived signals have been expected to transmit the message of P-deficiency to stimulate CR formation. In this study, it is shown that sugars are required for a response to P starvation including CR formation and the expression of P starvation-induced genes. White lupin plants were grown in vitro on P-sufficient or P-deficient media supplemented with sucrose for 4 weeks. Sucrose supply stimulated CR formation in plants on both P-sufficient and P-deficient media, but no CR appeared on the P-sufficient medium without sucrose. Glucose and fructose also stimulated CR formation on the P-sufficient medium. On the medium with sucrose, a high concentration of inorganic phosphate in leaves did not suppress CR formation. Because sorbitol or organic acid in the media did not stimulate CR formation, the sucrose effect was not due to increased osmotic pressure or enriched energy source, that is, sucrose acted as a signal. Gene transcription induced by P starvation, LaPT1 and LaPEPC3, was magnified by the combination of P limitation and sucrose feeding, and that of LaSAP was stimulated by sucrose supply independently of P supply. These results suggest that at least two sugar-signalling mediating systems control P starvation responses in white lupin roots. One system regulates CR formation and LaSAP expression, which acts even when P is sufficient if roots receive sugar as a signal. The other system controls LaPT1 and LaPEPC3 expression, which acts when P is insufficient.
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http://dx.doi.org/10.1093/jxb/ern130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2486467PMC
August 2008

Ty1-copia group retrotransposons in persimmon (Diospyros kaki Thunb.).

Genes Genet Syst 2002 Apr;77(2):131-6

Faculty of Life and Environmental Sciences, Shimane University, Japan.

We cloned and characterized Ty1-copia group retrotransposons in persimmon (Diospyros kaki Thunb.). Genomic DNA or methyl jasmonate (MJA)-treated cDNA were used as templates to amplify the reverse transcriptase region of Ty1-copia group retrotransposons. About 280 bp fragments were amplified and cloned, and 97 clones were sequenced. Forty-nine clones included frameshift or the stop codon, or both. Among 48 clones containing complete reading frames, 42 clones had unique nucleotide sequences. Alignment and phylogenetic analysis of putative amino acid sequences in the 42 clones indicated that these clones (named Tdk; retroTransposon in Diospyros kaki) fell into seven subgroups and six ungrouped sequences, indicating high sequence heterogeneity in Tdk clones. Phylogenetic analysis comparing unrelated plant species shows that some Tdk clones are more closely related to Ty1-copia group retrotransposons in the orders Solanales and Sapindales rather than to other Tdk clones. Southern blot analysis using Tdk2B, Tdk4c, Tdk6Ac, Tdk12K and Tdk13G clones as probes showed that persimmon and its related species, D. lotus, D. lotus var. glabba, D. oleifera, D. rhombifolia and D. virginiana, contained multiple Tdk-like sequences, indicating that homologous elements exist in other Diospyros species.
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http://dx.doi.org/10.1266/ggs.77.131DOI Listing
April 2002
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