• Title, Summary, Keyword: gene expression in flowering

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Overriding Photoperiod Sensitivity of Flowering Time by Constitutive Expression of a MADS Box Gene

  • N, Gynheung-A
    • Proceedings of the Botanical Society of Korea Conference
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    • pp.4-9
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    • 1996
  • The majority of plants sense environmental signals, such as day length or temperature, to select their transition timing from vegetative growth t flowering. Here, we report the identification of a regulatory gene, OsMADS1, that controls the photoperiod sensitivity of flowering time. Constitutive expression of OsMADS1 in a long-day flowering plant, Nicotiana sylvestris, resulted in flowering in both short-day long-day conditions. Similarly, ectopic expression of the gene in a short-day flowering plant, N. tabacum cv. Maryland Mammoth, also induced flowering regardless of the day length. The transition time was dependent on the level of the OsMADS1 transcript in transgenic plants. These suggest that OsMADS1 is a key regulatory factor that determines the transition from shoot apex to floral meristem and that it can be used for controlling flowering time in a variety of plant species.

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Expression of Flowering-Related Genes in Two Inbred Lines of Chinese Cabbage

  • Jang Hyun-Seung;Lim Yong-Pyo;Hur Yoon-Kang
    • Journal of Plant Biotechnology
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    • v.5 no.4
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    • pp.209-214
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    • 2003
  • Expression of 43 flowering-related genes was examined in two inbred lines of Chinese cabbage, Chiifu and Kenshin, under different photoperiod, vernalization and flower development stages. The floral genes cloned by RT-PCR with degenerated primers showed high homology with Arabidopsis counterparts. Genes in two inbred lines, TOC, CRY1, CO, RGAL and GAl, were highly expressed under all tested conditions. However, expression of three genes was regulated by particular experimental conditions. The expression of LHY gene was predominant in Chiifu under the short-day conditions, whereas the expression of RGAL gene was influenced by vernalization in both inbred lines. Besides, the expression of NAP gene was induced by vernalization only in Chiifu. Most of the flower identity-related genes were expressed during flower development. The transcript level for several genes was not detected in this experiment.

Arabidopsis AMY1 expressions and early flowering mutant phenotype

  • Jie, Wang;Dashi, Yu;XinHong, Guo;Xuanming, Liu
    • BMB Reports
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    • v.42 no.2
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    • pp.101-105
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    • 2009
  • The homozygous T-DNA mutant of the AMY1 gene in Arabidopsis was identified and importantly, shown to cause an early flowering phenotype. We found that the disruption of AMY1 enhanced expression of CO and FT. The expression analyses of genes related to starch metabolism revealed that expression of the AGPase small subunit APS1 in the wild type was higher than in the amy1 mutant. However, there were no significant differences in expression levels of the AGPase large subunit genes ApL1, AMY2, or AMY3 between wild type and the amy1 mutant. Expression profiling showed that AMY1 was highly expressed in leaves, stems, and flowers, and expressed less in leafstalks and roots. Furthermore, the level of AMY1 mRNA was highly elevated with age and in senescing leaves. RT-PCR analyses showed that the expression of AMY1 was induced by heat shock, GA, and ABA, while salt stress had no apparent effect on its expression.

OsAREB1, an ABRE-binding protein responding to ABA and glucose, has multiple functions in Arabidopsis

  • Jin, Xiao-Fen;Xiong, Ai-Sheng;Peng, Ri-He;Liu, Jin-Ge;Gao, Feng;Chen, Jian-Min;Yao, Quan-Hong
    • BMB Reports
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    • v.43 no.1
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    • pp.34-39
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    • 2010
  • Expression patterns of OsAREB1 revealed that expression of OsAREB1 gene can be induced by ABA, PEG and heat. Yeast one-hybrid assay demonstrated it can bind to ABA-responsive element (ABRE), which was found in most stress-induced genes. Transgenic Arabidopsis over-expressing OsAREB1 had different responses to ABA and glucose compared to wild-type plants, which suggest OsAREB1 might have a crucial role in these two signaling pathways. Further analysis indicate that OsAREB1 have multiple functions in Arabidopsis. First, OsAREB1 transgenic plants had higher resistance to drought and heat, and OsAREB1 up-regulated the ABA/stress related gene such as RD29A and RD29B. Second, it delayed plant flowering time by down-regulating the expression of flowering-related genes, such as FT, SOC1, LFY and AP1. Due to the dates, OsAREB1 may function as a positive regulator in drought/heat stresses response, but a negative regulator in flowering time in Arabidopsis.

Functional analysis of a homologue of the FLORICAULA/LEAFY gene in litchi (Litchi chinensis Sonn.) revealing its significance in early flowering process

  • Ding, Feng;Zhang, Shuwei;Chen, Houbin;Peng, Hongxiang;Lu, Jiang;He, Xinhua;Pan, Jiechun
    • Genes and Genomics
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    • v.40 no.12
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    • pp.1259-1267
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    • 2018
  • Litchi (Litchi chinensis Sonn.) is an important subtropical fruit crop with high commercial value due to its high nutritional values and favorable tastes. However, irregular bearing attributed to unstable flowering is a major ongoing problem for litchi producers. Previous studies indicate that low-temperature is a key factor in litchi floral induction. In order to reveal the genetic and molecular mechanisms underlying the reproductive process in litchi, we had analyzed the transcriptome of buds before and after low-temperature induction using RNA-seq technology. A key flower bud differentiation associated gene, a homologue of FLORICAULA/LEAFY, was identified and named LcLFY (GenBank Accession No. KF008435). The cDNA sequence of LcLFY encodes a putative protein of 388 amino acids. To gain insight into the role of LcLFY, the temporal expression level of this gene was measured by real-time RT-PCR. LcLFY was highly expressed in flower buds and its expression correlated with the floral developmental stage. Heterologous expression of LcLFY in transgenic tobacco plants induced precocious flowering. Meantime, we investigated the sub-cellular localization of LcLFY. The LcLFY-Green fluorescent protein (GFP) fusion protein was found in the nucleus. The results suggest that LcLFY plays a pivotal role as a transcription factor in controlling the transition to flowering and in the development of floral organs in litchi.

Loss of Function in GIGANTEA Gene is Involved in Brassinosteroid Signaling

  • Hwang, Indeok;Park, Jaeyoung;Lee, Beomgi;Cheong, Hyeonsook
    • Journal of the Chosun Natural Science
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    • v.4 no.2
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    • pp.113-120
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    • 2011
  • Brassinosteroids (BRs) are plant steroid hormones that play essential roles in growth and development. Mutations in BR-signaling pathways cause defective in growth and development like dwarfism, male sterility, abnormal vascular development and photomorphogenesis. Transition from vegetative to reproductive growth is a critical phase change in the development of a flowering plant. In a screen of activation-tagged Arabidopsis, we identified a mutant named abz126 that displayed longer hypocotyls when grown in the dark on MS media containing brassinazole (Brz), an inhibitor of BRs biosynthesis. We have cloned the mutant locus using adapter ligation PCR walking and identified that a single T-DNA had been integrated into the ninth exon of the GIGANTEA (GI) gene, involved in controling flowering time. This insertion resulted in loss-of-function of the GI gene and caused the following phenotypes: long petioles, tall plant height, many rosette leaves and late flowering. RT-PCR assays on abz126 mutant showed that the T-DNA insertion in GIGANTEA led to the loss of mRNA expression of the GI gene. In the hormone dose response assay, abz126 mutant showed: 1) an insensitivity to paclobutrazole (PAC), 2) an altered response with 6-benzylaminopurine (BAP) and 3) insensitive to Brassinolide (BL). Based on these results, we propose that the late flowering and tall phenotypes displayed by the abz126 mutant are caused by a loss-of-function of the GI gene associated with brassinosteroid hormone signaling.

Overexpression of RICE FLOWERING LOCUS T 1 (RFT1) Induces Extremely Early Flowering in Rice

  • Pasriga, Richa;Yoon, Jinmi;Cho, Lae-Hyeon;An, Gynheung
    • Molecules and Cells
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    • v.42 no.5
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    • pp.406-417
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    • 2019
  • RICE FLOWERING LOCUS T 1 (RFT1) is a major florigen that functions to induce reproductive development in the shoot apical meristem (SAM). To further our study of RFT1, we overexpressed the gene and examined the expression patterns of major regulatory genes during floral transition and inflorescence development. Overexpression induced extremely early flowering in the transgenics, and a majority of those calli directly formed spikelets with a few spikelets, thus bypassing normal vegetative development. FRUITFULL (FUL)-clade genes OsMADS14, OsMADS15, and OsMADS18 were highly induced in the RFT1-expressing meristems. OsMADS34 was also induced in the meristems. This indicated that RFT1 promotes the expression of major regulatory genes that are important for inflorescence development. RFT1 overexpression also induced SEPALLATA (SEP)-clade genes OsMADS1, OsMADS5, and OsMADS7 in the greening calli before floral transition occurred. This suggested their possible roles at the early reproductive stages. We found it interesting that expression of OsFD1 as well as OsFD2 and OsFD3 was strongly increased in the RFT1-expressing calli and spikelets. At a low frequency, those calli produced plants with a few leaves that generated a panicle with a small number of spikelets. In the transgenic leaves, the FUL-clade genes and OsMADS34 were induced, but SEP-clade gene expression was not increased. This indicated that OsMADS14, OsMADS15, OsMADS18, and OsMADS34 act immediately downstream of RFT1.

The Effect of Fluctuations in Photoperiod and Ambient Temperature on the Timing of Flowering: Time to Move on Natural Environmental Conditions

  • Song, Young Hun
    • Molecules and Cells
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    • v.39 no.10
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    • pp.715-721
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    • 2016
  • Plants have become physiologically adapted to a seasonally shifting environment by evolving many sensory mechanisms. Seasonal flowering is a good example of adaptation to local environmental demands and is crucial for maximizing reproductive fitness. Photoperiod and temperature are major environmental stimuli that control flowering through expression of a floral inducer, FLOWERING LOCUS T (FT) protein. Recent discoveries made using the model plant Arabidopsis thaliana have shown that the functions of photoreceptors are essential for the timing of FT gene induction, via modulation of the transcriptional activator CONSTANS (CO) at transcriptional and post-translational levels in response to seasonal variations. The activation of FT transcription by the fine-tuned CO protein enables plants to switch from vegetative growth to flowering under inductive environmental conditions. The present review briefly summarizes our current understanding of the molecular mechanisms by which the information of environmental stimuli is sensed and transduced to trigger FT induction in leaves.

Expression of Proteinase Inhibitor II gene in Transgenic Flowering Cabbage, Brassica oleracea var. acephala DC. (형질전환된 꽃양배추에서 Proteinase Inhibitor II 유전자의 발현)

  • 김창길;정재동
    • Korean Journal of Plant Tissue Culture
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    • v.25 no.2
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    • pp.95-98
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    • 1998
  • Hypocotyl explants of flowering cabbage were cocultured with Agrobacterium tumefaciens LBA4404;;pGA875 harboring proteinase inhibitor II(PI-II) cDNA and then regenerated into plants. Sucessful transcripts of PI-II gene were detected by RNA dot blot analysis. Bioassay was conducted on transgenic flowering cabbage. It was confirmed that insecticidal activities of transformants were much higer than that of control plants. In progeny test of hansformants, 27.4% of T$_1$ seeds was resistant on MS medium containing 20 mg/L kanamycin.

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Transfer and Expression of a Tomato Inhibitor II and $\beta$-Glucuronidae Fusion Gene in Flowering Cabbage, Brassica oleracea var. acephala DC. (꽃양배추로의 프로타제 저해제 II와 $\beta$-Glucuronidase 융합 유전자의 도입 및 발현)

  • 김창길;정재동;안진흥;김경민
    • Korean Journal of Plant Tissue Culture
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    • v.25 no.1
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    • pp.37-43
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    • 1998
  • The highest transformation frequency was observed when cotyledonary and hypocotyl explants of flowering cabbage (Brassica oleracea var. acephala DC) 'Eunbae' were cultured on shoot induction medium without kanamycin for 1 day, then cocultured with Agrobacterium tumefaciens LBA4404;;pGA1036 harboring tomato inhibitor II promoter and $\beta$-glucuronidae (GUS) fusion gene for 3 days. These explants were transferred to MS medium containing 20 mg/L kanamycin, 500 mg/L carbenicillin, and 1 mg/L BA. The explants were subsequently subcultured every 2 weeks. Incorporation of the GUS gene into flowering cabbage was confirmed by PCR analysis of DNA. Southern blot analysis showed that ECL-labeled GUS gene was hybridized to the expected amplified genomic DNA fragment of about 366 bp from transgenic flowering cabbage. Histochemical analysis based on the enzymatic activity of the GUS protein indicated that PI-II promoter activity was sysmatically associated with vascular tissue in wonded as well as in non-wounded leaves, petioles and stems, but not in roots. Partial wounding with razor blade showed not systemic induction but partial induction.

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