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Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian

BACKGROUND: Generally, double-flowered varieties are more attractive than single-flowered varieties in ornamental plants. Japanese gentian is one of the most popular floricultural plants in Japan, and it is desirable to breed elite double-flowered cultivars. In this study, we attempted to characteri...

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Autores principales: Nakatsuka, Takashi, Saito, Misa, Yamada, Eri, Fujita, Kohei, Yamagishi, Noriko, Yoshikawa, Nobuyuki, Nishihara, Masahiro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4504037/
https://www.ncbi.nlm.nih.gov/pubmed/26183329
http://dx.doi.org/10.1186/s12870-015-0569-3
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author Nakatsuka, Takashi
Saito, Misa
Yamada, Eri
Fujita, Kohei
Yamagishi, Noriko
Yoshikawa, Nobuyuki
Nishihara, Masahiro
author_facet Nakatsuka, Takashi
Saito, Misa
Yamada, Eri
Fujita, Kohei
Yamagishi, Noriko
Yoshikawa, Nobuyuki
Nishihara, Masahiro
author_sort Nakatsuka, Takashi
collection PubMed
description BACKGROUND: Generally, double-flowered varieties are more attractive than single-flowered varieties in ornamental plants. Japanese gentian is one of the most popular floricultural plants in Japan, and it is desirable to breed elite double-flowered cultivars. In this study, we attempted to characterize a doubled-flower mutant of Japanese gentian. To identify the gene that causes the double-flowered phenotype in Japanese gentian, we isolated and characterized MADS-box genes. RESULTS: Fourteen MADS-box genes were isolated, and two of them were C-class MADS-box genes (GsAG1 and GsAG2). Both GsAG1 and GsAG2 were categorized into the PLE/SHP subgroup, rather than the AG/FAR subgroup. In expression analyses, GsAG1 transcripts were detected in the second to fourth floral whorls, while GsAG2 transcripts were detected in only the inner two whorls. Transgenic Arabidopsis expressing GsAG1 lacked petals and formed carpeloid organs instead of sepals. Compared with a single-flowered gentian cultivar, a double-flowered gentian mutant showed decreased expression of GsAG1 but unchanged expression of GsAG2. An analysis of the genomic structure of GsAG1 revealed that the gene had nine exons and eight introns, and that a 5,150-bp additional sequence was inserted into the sixth intron of GsAG1 in the double-flowered mutant. This insert had typical features of a Ty3/gypsy-type LTR-retrotransposon, and was designated as Tgs1. Virus-induced gene silencing of GsAG1 by the Apple latent spherical virus vector resulted in the conversion of the stamen to petaloid organs in early flowering transgenic gentian plants expressing an Arabidopsis FT gene. CONCLUSIONS: These results revealed that GsAG1 plays a key role as a C-functional gene in stamen organ identity. The identification of the gene responsible for the double-flowered phenotype will be useful in further research on the floral morphogenesis of Japanese gentian. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-015-0569-3) contains supplementary material, which is available to authorized users.
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spelling pubmed-45040372015-07-17 Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian Nakatsuka, Takashi Saito, Misa Yamada, Eri Fujita, Kohei Yamagishi, Noriko Yoshikawa, Nobuyuki Nishihara, Masahiro BMC Plant Biol Research Article BACKGROUND: Generally, double-flowered varieties are more attractive than single-flowered varieties in ornamental plants. Japanese gentian is one of the most popular floricultural plants in Japan, and it is desirable to breed elite double-flowered cultivars. In this study, we attempted to characterize a doubled-flower mutant of Japanese gentian. To identify the gene that causes the double-flowered phenotype in Japanese gentian, we isolated and characterized MADS-box genes. RESULTS: Fourteen MADS-box genes were isolated, and two of them were C-class MADS-box genes (GsAG1 and GsAG2). Both GsAG1 and GsAG2 were categorized into the PLE/SHP subgroup, rather than the AG/FAR subgroup. In expression analyses, GsAG1 transcripts were detected in the second to fourth floral whorls, while GsAG2 transcripts were detected in only the inner two whorls. Transgenic Arabidopsis expressing GsAG1 lacked petals and formed carpeloid organs instead of sepals. Compared with a single-flowered gentian cultivar, a double-flowered gentian mutant showed decreased expression of GsAG1 but unchanged expression of GsAG2. An analysis of the genomic structure of GsAG1 revealed that the gene had nine exons and eight introns, and that a 5,150-bp additional sequence was inserted into the sixth intron of GsAG1 in the double-flowered mutant. This insert had typical features of a Ty3/gypsy-type LTR-retrotransposon, and was designated as Tgs1. Virus-induced gene silencing of GsAG1 by the Apple latent spherical virus vector resulted in the conversion of the stamen to petaloid organs in early flowering transgenic gentian plants expressing an Arabidopsis FT gene. CONCLUSIONS: These results revealed that GsAG1 plays a key role as a C-functional gene in stamen organ identity. The identification of the gene responsible for the double-flowered phenotype will be useful in further research on the floral morphogenesis of Japanese gentian. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-015-0569-3) contains supplementary material, which is available to authorized users. BioMed Central 2015-07-17 /pmc/articles/PMC4504037/ /pubmed/26183329 http://dx.doi.org/10.1186/s12870-015-0569-3 Text en © Nakatsuka et al. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Nakatsuka, Takashi
Saito, Misa
Yamada, Eri
Fujita, Kohei
Yamagishi, Noriko
Yoshikawa, Nobuyuki
Nishihara, Masahiro
Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian
title Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian
title_full Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian
title_fullStr Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian
title_full_unstemmed Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian
title_short Isolation and characterization of the C-class MADS-box gene involved in the formation of double flowers in Japanese gentian
title_sort isolation and characterization of the c-class mads-box gene involved in the formation of double flowers in japanese gentian
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4504037/
https://www.ncbi.nlm.nih.gov/pubmed/26183329
http://dx.doi.org/10.1186/s12870-015-0569-3
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