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Dang X, Zhang Y, Li Y, Chen S, Liu E, Fang B, Liu Q, She D, Dong Z, Fan Z, Li D, Wang H, Zhu S, Hu X, Li Y, Jiang J, Hong D. SYL3-k increases style length and yield of F 1 seeds via enhancement of endogenous GA 4 content in Oryza sativa L. pistils. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:321-336. [PMID: 34657161 PMCID: PMC8741667 DOI: 10.1007/s00122-021-03968-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
SYL3-k allele increases the outcrossing rate of male sterile line and the yield of hybrid F1 seeds via enhancement of endogenous GA4 content in Oryza sativa L. pistils. The change in style length might be an adaptation of rice cultivation from south to north in the northern hemisphere. The style length (SYL) in rice is one of the major factors influencing the stigma exertion, which affects the outcross rate of male sterile line and the yield of hybrid F1 seeds. However, the biological mechanisms underlying SYL elongation remain elusive. Here, we report a map-based cloning and characterisation of the allele qSYL3-k. The qSYL3-k allele encodes a MADS-box family transcription factor, and it is expressed in various rice organs. The qSYL3-k allele increases SYL via the elongation of cell length in the style, which is associated with a higher GA4 content in the pistil. The expression level of OsGA3ox2 in pistils with qSYL3-k alleles is significantly higher than that in pistils with qSYL3-n allele on the same genome background of Nipponbare. The yield of F1 seeds harvested from plants with 7001SSYL3-k alleles was 16% higher than that from plants with 7001SSYL3-n allele. The sequence data at the qSYL3 locus in 136 accessions showed that alleles containing the haplotypes qSYL3AA, qSYL3AG, and qSYL3GA increased SYL, whereas those containing the haplotype qSYL3GG decreased it. The frequency of the haplotype qSYL3GG increases gradually from the south to north in the northern hemisphere. These findings will facilitate improvement in SYL and yield of F1 seeds henceforward.
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Affiliation(s)
- Xiaojing Dang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
- Institute of Rice Research, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Yuanqing Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yulong Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Siqi Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Erbao Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bingjie Fang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qiangming Liu
- Special Crop Research Institute, Chongqing Academy of Agricultural Sciences, Chongqing, 402160, China
| | - Dong She
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhiyao Dong
- Department of Student Affairs, Jilin Normal University, Siping, 136000, Jilin, China
| | - Zhilan Fan
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Dalu Li
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hui Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shangshang Zhu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiaoxiao Hu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yanhui Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianhua Jiang
- Institute of Rice Research, Anhui Academy of Agricultural Sciences, Hefei, 230031, China.
| | - Delin Hong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China.
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2
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Chen H, Yu H, Jiang W, Li H, Wu T, Chu J, Xin P, Li Z, Wang R, Zhou T, Huang K, Lu L, Bian M, Du X. Overexpression of ovate family protein 22 confers multiple morphological changes and represses gibberellin and brassinosteroid signalings in transgenic rice. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 304:110734. [PMID: 33568286 DOI: 10.1016/j.plantsci.2020.110734] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/21/2020] [Accepted: 10/18/2020] [Indexed: 05/27/2023]
Abstract
OVATE family proteins (OFPs) are plant-specific transcription factors that regulate plant growth and development. OFPs interact with 3-aa loop extension (TALE) homeodomain proteins and brassinosteroid (BR) signaling components to modulate gibberellic acid (GA) biosynthesis and BR responses. Bioactive GAs are essential in regulating plant organogenesis and organ growth by promoting cell differentiation and elongation. DELLA proteins act as the central repressors of GA-regulated processes and are targeted to be degraded by the 26S proteasome in the presence of GA. We discovered that the rice OFP22 negatively regulates GA and BR signal transduction. OsOFP22 expression was rapidly up-regulated by exogenous GA and BR application, detected predominantly in the calli and spikelets. Overexpression of OsOFP22 conferred multiple morphological phenotypes, including reduced plant height, dark green leaves, and shortened and widened leaves, floral organs and grains. The GA-induced elongation of the second leaf sheath in the seedlings, and α-amylase activity in the endosperms were attenuated in transgenic lines overexpressing OsOFP22, while GA-biosynthesis gene transcripts and bioactive GA3 and GA4 contents were increased in the transgenic plants. OsOFP22 promotes the protein accumulation of SLR1, the single DELLA in rice protein. Furthermore, Overexpression of OsOFP22 suppresses BR response and the expression of BR-related genes. OsOFP22 is thus involved in the repression of GA and BR signal transduction and integrates GA with BR to regulate plant growth and development.
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Affiliation(s)
- Haoyuan Chen
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Hui Yu
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China; Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
| | - Wenzhu Jiang
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Hongyu Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Tao Wu
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Jinfang Chu
- National Centre for Plant Gene Research (Beijing), Innovation Academy for Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Peiyong Xin
- National Centre for Plant Gene Research (Beijing), Innovation Academy for Seed Design, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhao Li
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Rui Wang
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Tie Zhou
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Kai Huang
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Lin Lu
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China
| | - Mingdi Bian
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China.
| | - Xinglin Du
- Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun 130062, China.
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3
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Hugalde IP, Agüero CB, Barrios-Masias FH, Romero N, Viet Nguyen A, Riaz S, Piccoli P, McElrone AJ, Walker MA, Vila HF. Modeling vegetative vigour in grapevine: unraveling underlying mechanisms. Heliyon 2020; 6:e05708. [PMID: 33385078 PMCID: PMC7770548 DOI: 10.1016/j.heliyon.2020.e05708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/30/2020] [Accepted: 11/09/2020] [Indexed: 11/17/2022] Open
Abstract
Mechanistic modeling constitutes a powerful tool to unravel complex biological phenomena. This study describes the construction of a mechanistic, dynamic model for grapevine plant growth and canopy biomass (vigor). To parametrize and validate the model, the progeny from a cross of Ramsey (Vitis champinii) × Riparia Gloire (V. riparia) was evaluated. Plants with different vigor were grown in a greenhouse during the summer of 2014 and 2015. One set of plants was grafted with Cabernet Sauvignon. Shoot growth rate (b), leaf area (LA), dry biomass, whole plant and root specific hydraulic conductance (kH and Lpr), stomatal conductance (gs), and water potential (Ψ) were measured. Partitioning indices and specific leaf area (SLA) were calculated. The model includes an empirical fit of a purported seasonal pattern of bioactive GAs based on published seasonal evolutionary levels and reference values. The model provided a good fit of the experimental data, with R = 0.85. Simulation of single trait variations defined the individual effect of each variable on vigor determination. The model predicts, with acceptable accuracy, the vigor of a young plant through the measurement of Lpr and SLA. The model also permits further understanding of the functional traits that govern vigor, and, ultimately, could be considered useful for growers, breeders and those studying climate change.
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Affiliation(s)
- Inés P. Hugalde
- Estación Experimental Agropecuaria Mendoza, INTA, San Martín 3853, M. Drummond, 5507, Mendoza, Argentina
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
- Corresponding author.
| | - Cecilia B. Agüero
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
| | - Felipe H. Barrios-Masias
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
- Dept. Agriculture, Veterinary and Rangeland Sciences, University of Nevada, Reno, Reno, NV 89557, USA
| | - Nina Romero
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
| | - Andy Viet Nguyen
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
| | - Summaira Riaz
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
| | - Patricia Piccoli
- Instituto de Biología Agrícola de Mendoza, UNCuyo – CONICET, Argentina
| | - Andrew J. McElrone
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
- USDA-ARS, Davis, CA, 95616, USA
| | - M. Andrew Walker
- Dept. Viticulture and Enology, UC Davis, One Shields Ave, Davis, CA 95616, USA
| | - Hernán F. Vila
- Estación Experimental Agropecuaria Mendoza, INTA, San Martín 3853, M. Drummond, 5507, Mendoza, Argentina
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Itoh H, Ueguchi-Tanaka M, Sentoku N, Kitano H, Matsuoka M, Kobayashi M. Cloning and functional analysis of two gibberellin 3 beta -hydroxylase genes that are differently expressed during the growth of rice. Proc Natl Acad Sci U S A 2001; 98:8909-14. [PMID: 11438692 PMCID: PMC37534 DOI: 10.1073/pnas.141239398] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have cloned two gibberellin (GA) 3 beta-hydroxylase genes, OsGA3ox1 and OsGA3ox2, from rice by screening a genomic library with a DNA fragment obtained by PCR using degenerate primers. We have used full-scan GC-MS and Kovats retention indices to show function for the two encoded recombinant fusion proteins. Both proteins show 3 beta-hydroxylase activity for the steps GA(20) to GA(1), GA(5) to GA(3), GA(44) to GA(38), and GA(9) to GA(4). In addition, indirect evidence suggests that the OsGA3ox1 protein also has 2,3-desaturase activity, which catalyzes the steps GA(9) to 2,3-dehydro-GA(9) and GA(20) to GA(5) (2,3-dehydro GA(20)), and 2 beta-hydroxylase activity, which catalyzes the steps GA(1) to GA(8) and GA(4) to GA(34). Molecular and linkage analysis maps the OsGA3ox1 gene to the distal end of the short arm of chromosome 5; the OsGA3ox2 gene maps to the distal end of the short arm of chromosome 1 that corresponds to the D18 locus. The association of the OsGA3ox2 gene with the d18 locus is confirmed by sequence and complementation analysis of three d18 alleles. Complementation of the d18-AD allele with the OxGA3ox2 gene results in transgenic plants with a normal phenotype. Although both genes show transient expression, the highest level for OsGA3ox1 is from unopened flower. The highest level for OsGA3ox2 is from elongating leaves.
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Affiliation(s)
- H Itoh
- Bioscience Center, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
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5
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Cassán FD, Lucangeli CD, Bottini R, Piccoli PN. Azospirillum spp. metabolize [17,17-2H2]gibberellin A20 to [17,17-2H2]gibberellin A1 in vivo in dy rice mutant seedlings. PLANT & CELL PHYSIOLOGY 2001; 42:763-7. [PMID: 11479384 DOI: 10.1093/pcp/pce099] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Azospirillum spp. are endophytic bacteria with beneficial effects on cereals--effects partially attributed to gibberellin production by the microorganisms. Azospirillum lipoferum and Azospirillum brasilense inoculated to rice dy mutant reversed dwarfism in seedlings incubated with [17,17-2H2]GA20 with formation of [17,17-2H2]GA1, showing the in vivo capacity to perform the 3beta-hydroxylation. When prohexadione-Ca, an inhibitor of late steps in gibberellin biosynthesis, was added to the culture medium, no complementation was observed and no [17,17-2H2]GA1 was produced. The latter suggests that the bacterial operating enzyme may be a 2-oxoglutarate-dependent dioxygenase, similar to those of plants.
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Affiliation(s)
- F D Cassán
- Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Universidad Nacional de Río Cuarto, Campus Universitario, 5800 Río Cuarto, Argentina
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6
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Cassán F, Bottini R, Schneider G, Piccoli P. Azospirillum brasilense and Azospirillum lipoferum hydrolyze conjugates of GA20 and metabolize the resultant aglycones to GA1 in seedlings of rice dwarf mutants. PLANT PHYSIOLOGY 2001; 125:2053-8. [PMID: 11299384 PMCID: PMC88860 DOI: 10.1104/pp.125.4.2053] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2000] [Revised: 10/18/2000] [Accepted: 01/03/2001] [Indexed: 05/23/2023]
Abstract
Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3beta-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant.
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Affiliation(s)
- F Cassán
- Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Universidad Nacional de Río Cuarto, Campus Universitario, 5800 Río Cuarto, Argentina
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7
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Sakamoto T, Kobayashi M, Itoh H, Tagiri A, Kayano T, Tanaka H, Iwahori S, Matsuoka M. Expression of a gibberellin 2-oxidase gene around the shoot apex is related to phase transition in rice. PLANT PHYSIOLOGY 2001; 125:1508-16. [PMID: 11244129 PMCID: PMC65628 DOI: 10.1104/pp.125.3.1508] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2000] [Accepted: 12/20/2000] [Indexed: 05/18/2023]
Abstract
A major catabolic pathway for gibberellin (GA) is initiated by 2beta-hydroxylation, a reaction catalyzed by GA 2-oxidase. We have isolated and characterized a cDNA, designated Oryza sativa GA 2-oxidase 1 (OsGA2ox1) from rice (Oryza sativa L. cv Nipponbare) that encodes a GA 2-oxidase. The encoded protein, produced by heterologous expression in Escherichia coli, converted GA(1), GA(4), GA(9), GA(20), and GA(44) to the corresponding 2beta-hydroxylated products GA(8), GA(34), GA(51), GA(29), and GA(98), respectively. Ectopic expression of the OsGA2ox1 cDNA in transgenic rice inhibited stem elongation and the development of reproductive organs. These transgenic plants were deficient in endogenous GA(1). These results indicate that OsGA2ox1 encodes a GA 2-oxidase, which is functional not only in vitro but also in vivo. OsGA2ox1 was expressed in shoot apex and roots but not in leaves and stems. In situ hybridization analysis revealed that OsGA2ox1 mRNA was localized in a ring at the basal region of leaf primordia and young leaves. This ring-shaped expression around the shoot apex was drastically decreased after the phase transition from vegetative to reproductive growth. It was absent in the floral meristem, but it was still present in the lateral meristem that remained in the vegetative phase. These observations suggest that OsGA2ox1 controls the level of bioactive GAs in the shoot apical meristem; therefore, reduction in its expression may contribute to the early development of the inflorescence meristem.
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Affiliation(s)
- T Sakamoto
- Institute of Agriculture and Forestry, University of Tsukuba, Tsukuba 305-8572, Japan
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8
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Kobayashi M, MacMillan J, Phinney B, Gaskin P, Spray CR, Hedden P. Gibberellin biosynthesis: metabolic evidence for three steps in the early 13-hydroxylation pathway of rice. PHYTOCHEMISTRY 2000; 55:317-321. [PMID: 11117879 DOI: 10.1016/s0031-9422(00)00265-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
[14C4]GA53, [14C4]GA44, and [2H2/14C4]GA19 were injected separately into seedlings of rice (Oryza sativa) using a dwarf mutant (d35) that has low levels of endogenous gibberellins (GAs). After 8 h incubation, the shoots were extracted and the labeled metabolites were identified by full-scan gas chromatography mass spectrometry (GC-MS) and Kovats retention indices (KRIs). Our results document the metabolic sequence, GA53-->GA44-->GA19-->GA20 and the presence of endogenous GA53, GA44, GA19, GA20 and GA1. Previous metabolic studies have shown the presence of the step, GA20-->GA1 in rice. Taken together, the data establish in vegetative shoots of rice the presence of the early 13-hydroxylation pathway, a pathway that originates from GA12 and leads to bioactive GA1.
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Affiliation(s)
- M Kobayashi
- Plant Molecular Biology Laboratory, Tsukuba Life Science Center, The Institute of Chemical and Physical Research, Tsukuba-Ibaraki, Japan
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9
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Hedden P. Regulation of gibberellin biosynthesis. BIOCHEMISTRY AND MOLECULAR BIOLOGY OF PLANT HORMONES 1999. [DOI: 10.1016/s0167-7306(08)60487-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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10
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Williams J, Phillips AL, Gaskin P, Hedden P. Function and substrate specificity of the gibberellin 3beta-hydroxylase encoded by the Arabidopsis GA4 gene. PLANT PHYSIOLOGY 1998; 117:559-63. [PMID: 9625708 PMCID: PMC34975 DOI: 10.1104/pp.117.2.559] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/1997] [Accepted: 03/11/1998] [Indexed: 05/18/2023]
Abstract
cDNA corresponding to the GA4 gene of Arabidopsis thaliana L. (Heynh. ) was expressed in Escherichia coli, from which cell lysates converted [14C]gibberellin (GA)9 and [14C]GA20 to radiolabeled GA4 and GA1, respectively, thereby confirming that GA4 encodes a GA 3beta-hydroxylase. GA9 was the preferred substrate, with a Michaelis value of 1 microm compared with 15 microm for GA20. Hydroxylation of these GAs was regiospecific, with no indication of 2beta-hydroxylation or 2,3-desaturation. The capacity of the recombinant enzyme to hydroxylate a range of other GA substrates was investigated. In general, the preferred substrates contained a polar bridge between C-4 and C-10, and 13-deoxy GAs were preferred to their 13-hydroxylated analogs. Therefore, no activity was detected using GA12-aldehyde, GA12, GA19, GA25, GA53, or GA44 as the open lactone (20-hydroxy-GA53), whereas GA15, GA24, and GA44 were hydroxylated to GA37, GA36, and GA38, respectively. The open lactone of GA15 (20-hydroxy-GA12) was hydroxylated but less efficiently than GA15. In contrast to the free acid, GA25 19,20-anhydride was 3beta-hydroxylated to give GA13. 2,3-Didehydro-GA9 and GA5 were converted by recombinant GA4 to the corresponding epoxides 2, 3-oxido-GA9 and GA6.
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Affiliation(s)
- J Williams
- IACR-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS41 9AF, United Kingdom
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11
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Abstract
The recent impressive progress in research on gibberellin (GA) biosynthesis has resulted primarily from cloning of genes encoding biosynthetic enzymes and studies with GA-deficient and GA-insensitive mutants. Highlights include the cloning of ent-copalyl diphosphate synthase and ent-kaurene synthase (formally ent-kaurene synthases A and B) and the demonstration that the former is targeted to the plastid; the finding that the Dwarf-3 gene of maize encodes a cytochrome P450, although of unknown function; and the cloning of GA 20-oxidase and 3beta-hydroxylase genes. The availability of cDNA and genomic clones for these enzymes is enabling the mechanisms by which GA concentrations are regulated by environmental and endogenous factors to be studied at the molecular level. For example, it has been shown that transcript levels for GA 20-oxidase and 3beta-hydroxylase are subject to feedback regulation by GA action and, in the case of the GA 20-oxidase, are regulated by light. Also discussed is other new information, particularly from mutants, that has added to our understanding of the biosynthetic pathway, the enzymes, and their regulation and tissue localization.
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Affiliation(s)
- Peter Hedden
- IACR-Long Ashton Research Station, Department of Agricultural Science, University of Bristol, Bristol, BS18 9AF, United Kingdom, Frontier Research Program, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-01, Japan
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12
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Affiliation(s)
- P M Dewick
- Department of Pharmaceutical Sciences, University of Nottingham, UK
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13
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14
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Spray CR, Kobayashi M, Suzuki Y, Phinney BO, Gaskin P, MacMillan J. The dwarf-1 (dt) Mutant of Zea mays blocks three steps in the gibberellin-biosynthetic pathway. Proc Natl Acad Sci U S A 1996; 93:10515-8. [PMID: 11607708 PMCID: PMC38417 DOI: 10.1073/pnas.93.19.10515] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In plants, gibberellin (GA)-responding mutants have been used as tools to identify the genes that control specific steps in the GA-biosynthetic pathway. They have also been used to determine which native GAs are active per se, i.e., further metabolism is not necessary for bioactivity. We present metabolic evidence that the D1 gene of maize (Zea mays L.) controls the three biosynthetic steps: GA20 to GA1, Ga20 to GA5, and GA5 to GA3. We also present evidence that three gibberellins, GA1, GA5, and GA3, have per se activity in stimulating shoot elongation in maize. The metabolic evidence comes from the injection of [17-13C,3H]GA20 and [17-13C,3H]GA5 into seedlings of d1 and controls (normal and d5), followed by isolation and identification of the 13C-labeled metabolites by full-scan GC-MS and Kovats retention index. For the controls, GA20 was metabolized to GA1,GA3, and GA5; GA5 was metabolized to GA3. For the d1 mutant, GA20 was not metabolized to GA1, GA3, or to GA5, and GA5 was not metabolized to GA3. The bioassay evidence is based on dosage response curves using d1 seedlings for assay. GA1, GA3, and GA5 had similar bioactivities, and they were 10-times more active than GA20.
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Affiliation(s)
- C R Spray
- Department of Biology, University of California, Los Angeles, CA 90095-1606, USA
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15
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Spray CR, Kobayashi M, Suzuki Y, Phinney BO, Gaskin P, MacMillan J. The dwarf-1 (dt) Mutant of Zea mays blocks three steps in the gibberellin-biosynthetic pathway. Proc Natl Acad Sci U S A 1996. [PMID: 11607708 DOI: 10.2307/40418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
In plants, gibberellin (GA)-responding mutants have been used as tools to identify the genes that control specific steps in the GA-biosynthetic pathway. They have also been used to determine which native GAs are active per se, i.e., further metabolism is not necessary for bioactivity. We present metabolic evidence that the D1 gene of maize (Zea mays L.) controls the three biosynthetic steps: GA20 to GA1, Ga20 to GA5, and GA5 to GA3. We also present evidence that three gibberellins, GA1, GA5, and GA3, have per se activity in stimulating shoot elongation in maize. The metabolic evidence comes from the injection of [17-13C,3H]GA20 and [17-13C,3H]GA5 into seedlings of d1 and controls (normal and d5), followed by isolation and identification of the 13C-labeled metabolites by full-scan GC-MS and Kovats retention index. For the controls, GA20 was metabolized to GA1,GA3, and GA5; GA5 was metabolized to GA3. For the d1 mutant, GA20 was not metabolized to GA1, GA3, or to GA5, and GA5 was not metabolized to GA3. The bioassay evidence is based on dosage response curves using d1 seedlings for assay. GA1, GA3, and GA5 had similar bioactivities, and they were 10-times more active than GA20.
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Affiliation(s)
- C R Spray
- Department of Biology, University of California, Los Angeles, CA 90095-1606, USA
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