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Miyagi, Japan

Arabidopsis thaliana is a quantitative long-day plant with the timing of the floral transition being regulated by both endogenous signals and multiple environmental factors. fwa is a late-flowering mutant, and this phenotype is due to ectopic FWA expression caused by hypomethylation at the FWA locus. The floral transition results in the activation of the floral development process, the key regulators being the floral meristem identity genes, AP1 (APETALA1) and LFY (LEAFY). In this study, we describe inflorescence abnormalities in plants overexpressing the Arabidopsis lyrata FT (AlFT) and A. thaliana FWA (AtFWA) genes simultaneously. The inflorescence abnormality phenotype was present in only a proportion of plants. All plants overexpressing both AlFT and AtFWA flowered earlier than fwa, suggesting that the inflorescence abnormality and earlier flowering time are caused independently. The inflorescence abnormality phenotype was similar to that of the double mutant of ap1 and lfy, and AP1 and LFY genes were down-regulated in the abnormal inflorescences. From these results, we suggest that not only does ectopic AtFWA expression inhibit AtFT/AlFT function to delay flowering but that overexpression of AtFWA and AlFT together inhibits AP1 and LFY function to produce abnormal inflorescences. © 2011 Elsevier Ireland Ltd. Source

Kawamura K.,Niigata University | Kawanabe T.,Kobe University | Shimizu M.,Niigata University | Nagano A.J.,Ryukoku University | And 9 more authors.
Plant Gene | Year: 2016

Chinese cabbage (Brassica rapa L. var. pekinensis) is an important vegetable in Asia. Most Japanese commercial cultivars of Chinese cabbage use an F1 hybrid seed production system because of the high yielding cultivars produced. An efficient method for predicting hybrid performance in the parental generations is desired, and genetic distance between parental lines might be a good indicator of the level of hybrid vigor in a cross. Information concerning the genetic relationships among parental candidate inbred lines is useful for variety protection. The number of DNA markers available that can be used to assess the purity of inbred lines is limited in B. rapa. The aim of this study is to use DNA markers to assess the genetic distance between inbred lines to examine early developmental and yield heterosis so as to develop methods for selecting the best parental lines for the production of hybrids. We screened highly polymorphic SSR and CAPS markers to assess the genetic uniformity of inbred lines and characterize their genetic relationship. We examined the early size and yield heterosis in 32 F1 hybrids of Chinese cabbage. There was a moderate correlation in mid-parent heterosis between leaf size at 21 days after sowing and harvested biomass but not in best-parent heterosis. In contrast there was no correlation between genetic distance and mid-parent or best-parent heterosis, indicating that genetic distance does not predict the heterosis phenotype. © 2015 The Authors. Source

Kawanabe T.,Watanabe seed Co. | Fujimoto R.,CSIRO | Fujimoto R.,Niigata University | Sasaki T.,Gregor Mendel Institute of Molecular Plant Biology | And 2 more authors.
Gene | Year: 2012

Difference in the level of expression of genes is one of the factors contributing to plant phenotype. As well as being under genetic control, gene expression is regulated by epigenetic processes such as DNA methylation and histone modifications. We compared genome-wide gene expression between . Arabidopsis thaliana and the related species . Arabidopsis lyrata subsp. . lyrata and . Arabidopsis halleri subsp. . gemmifera to understand which genes might contribute to species differences. Genes categorized into response to stress tended to show differential expression between species, suggesting that divergence of expression in these genes contributes to adaptation to environmental conditions following the divergence of species. Regions methylated in . A. lyrata were identified from Methylated-DNA immunoprecipitation, and this DNA methylation profile together with transcriptome data revealed that gene body methylation was not associated with differential gene expression between . A. thaliana and . A. lyrata. The DNA methylation status of four putative imprinted genes of . A. lyrata was examined and found to be conserved in vegetative tissues between . A. thaliana and . A. lyrata in . FIS2, . HDG3, and . HDG9, but not in . HDG8. © 2012 Elsevier B.V. Source

Fujimoto R.,Niigata University | Sasaki T.,Gregor Mendel Institute of Molecular Plant Biology | Ishikawa R.,Kobe University | Ishikawa R.,John Innes Center | And 3 more authors.
International Journal of Molecular Sciences | Year: 2012

Natural variation is defined as the phenotypic variation caused by spontaneous mutations. In general, mutations are associated with changes of nucleotide sequence, and many mutations in genes that can cause changes in plant development have been identified. Epigenetic change, which does not involve alteration to the nucleotide sequence, can also cause changes in gene activity by changing the structure of chromatin through DNA methylation or histone modifications. Now there is evidence based on induced or spontaneous mutants that epigenetic changes can cause altering plant phenotypes. Epigenetic changes have occurred frequently in plants, and some are heritable or metastable causing variation in epigenetic status within or between species. Therefore, heritable epigenetic variation as well as genetic variation has the potential to drive natural variation. © 2012 by the authors; licensee MDPI, Basel, Switzerland. Source

Fujimoto R.,CSIRO | Fujimoto R.,National Institute of Genetics | Taylor J.M.,CSIRO | Sasaki T.,National Institute of Genetics | And 2 more authors.
Plant Molecular Biology | Year: 2011

The merging of two different genomes occurs during the formation of amphidiploids, and the merged regulatory networks have the potential to generate a new gene expression pattern. We examined the genome-wide gene expression of two newly synthesized amphidiploids between Arabidopsis thaliana and the related species Arabidopsis lyrata subsp. lyrata and Arabidopsis halleri subsp. gemmifera. 1,137 (4. 7%) and 1,316 (5. 4%) of probesets showed differential gene expression in A. thaliana-A. halleri and A. thaliana-A. lyrata hybrids respectively, compared to the mid parent value and of these, 489 were in common. Genes that differed in expression between the parental lines tended to have an expression level in both hybrids differing from the mid parent value. In contrast to protein coding genes, there is little differential expression of transposons. Genes in the categories of chloroplast-targeted and response to stress were overrepresented in the non-additively expressed genes in both amphidiploids. As these genes have the potential to contribute directly to the plant phenotype, we suggest that rapid changes of gene expression in amphidiploids might be important for producing greater biomass. © 2011 Springer Science+Business Media B.V. Source

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