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Yang Z, Wu X, Zhu Y, Qu Y, Zhou C, Yuan M, Zhan Y, Li Y, Teng W, Zhao X, Han Y. Joint GWAS and WGCNA Identify Genes Regulating the Isoflavone Content in Soybean Seeds. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:18573-18584. [PMID: 39105709 DOI: 10.1021/acs.jafc.4c03012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Isoflavone is a secondary metabolite of the soybean phenylpropyl biosynthesis pathway with physiological activity and is beneficial to human health. In this study, the isoflavone content of 205 soybean germplasm resources from 3 locations in 2020 showed wide phenotypic variation. A joint genome-wide association study (GWAS) and weighted gene coexpression network analysis (WGCNA) identified 33 single-nucleotide polymorphisms and 11 key genes associated with soybean isoflavone content. Gene ontology enrichment analysis, gene coexpression, and haplotype analysis revealed natural variations in the Glyma.12G109800 (GmOMT7) gene and promoter region, with Hap1 being the elite haplotype. Transient overexpression and knockout of GmOMT7 increased and decreased the isoflavone content, respectively, in hairy roots. The combination of GWAS and WGCNA effectively revealed the genetic basis of soybean isoflavone and identified potential genes affecting isoflavone synthesis and accumulation in soybean, providing a valuable basis for the functional study of soybean isoflavone.
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Affiliation(s)
- Zhenhong Yang
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Xu Wu
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Yina Zhu
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Yuewen Qu
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Changjun Zhou
- Daqing Branch, Heilongjiang Academy of Agricultural Science, Daqing 163711, China
| | - Ming Yuan
- Qiqihar Branch, Heilongjiang Academy of Agricultural Science, Qiqihar 161006, China
| | - Yuhang Zhan
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Yongguang Li
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Weili Teng
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Xue Zhao
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
| | - Yingpeng Han
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin 150030, China
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Wang L, Li C, Luo K. Biosynthesis and metabolic engineering of isoflavonoids in model plants and crops: a review. FRONTIERS IN PLANT SCIENCE 2024; 15:1384091. [PMID: 38984160 PMCID: PMC11231381 DOI: 10.3389/fpls.2024.1384091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 06/10/2024] [Indexed: 07/11/2024]
Abstract
Isoflavonoids, the major secondary metabolites within the flavonoid biosynthetic pathway, play important roles in plant defense and exhibit free radical scavenging properties in mammals. Recent advancements in understanding the synthesis, transport, and regulation of isoflavonoids have identified their biosynthetic pathways as promising targets for metabolic engineering, offering potential benefits such as enhanced plant resistance, improved biomass, and restoration of soil fertility. This review provides an overview of recent breakthroughs in isoflavonoid biosynthesis, encompassing key enzymes in the biosynthetic pathway, transporters influencing their subcellular localization, molecular mechanisms regulating the metabolic pathway (including transcriptional and post-transcriptional regulation, as well as epigenetic modifications). Metabolic engineering strategies aimed at boosting isoflavonoid content in both leguminous and non-leguminous plants. Additionally, we discuss emerging technologies and resources for precise isoflavonoid regulation. This comprehensive review primarily focuses on model plants and crops, offering insights for more effective and sustainable metabolic engineering approaches to enhance nutritional quality and stress tolerance.
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Affiliation(s)
- Lijun Wang
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
| | - Chaofeng Li
- Maize Research Institute, Southwest University, Chongqing, China
- Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing, China
| | - Keming Luo
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
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Azam M, Zhang S, Li J, Ahsan M, Agyenim-Boateng KG, Qi J, Feng Y, Liu Y, Li B, Qiu L, Sun J. Identification of hub genes regulating isoflavone accumulation in soybean seeds via GWAS and WGCNA approaches. FRONTIERS IN PLANT SCIENCE 2023; 14:1120498. [PMID: 36866374 PMCID: PMC9971994 DOI: 10.3389/fpls.2023.1120498] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
INTRODUCTION Isoflavones are the secondary metabolites synthesized by the phenylpropanoid biosynthesis pathway in soybean that benefits human and plant health. METHODS In this study, we have profiled seed isoflavone content by HPLC in 1551 soybean accessions grown in Beijing and Hainan for two consecutive years (2017 and 2018) and in Anhui for one year (2017). RESULTS A broad range of phenotypic variations was observed for individual and total isoflavone (TIF) content. The TIF content ranged from 677.25 to 5823.29 µg g-1 in the soybean natural population. Using a genome-wide association study (GWAS) based on 6,149,599 single nucleotide polymorphisms (SNPs), we identified 11,704 SNPs significantly associated with isoflavone contents; 75% of them were located within previously reported QTL regions for isoflavone. Two significant regions on chromosomes 5 and 11 were associated with TIF and malonylglycitin across more than 3 environments. Furthermore, the WGCNA identified eight key modules: black, blue, brown, green, magenta, pink, purple, and turquoise. Of the eight co-expressed modules, brown (r = 0.68***), magenta (r = 0.64***), and green (r = 0.51**) showed a significant positive association with TIF, as well as with individual isoflavone contents. By combining the gene significance, functional annotation, and enrichment analysis information, four hub genes Glyma.11G108100, Glyma.11G107100, Glyma.11G106900, and Glyma.11G109100 encoding, basic-leucine zipper (bZIP) transcription factor, MYB4 transcription factor, early responsive to dehydration, and PLATZ transcription factor respectively were identified in brown and green modules. The allelic variation in Glyma.11G108100 significantly influenced individual and TIF accumulation. DISCUSSION The present study demonstrated that the GWAS approach, combined with WGCNA, could efficiently identify isoflavone candidate genes in the natural soybean population.
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Affiliation(s)
- Muhammad Azam
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shengrui Zhang
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jing Li
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Muhammad Ahsan
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kwadwo Gyapong Agyenim-Boateng
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Qi
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yue Feng
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yitian Liu
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bin Li
- Ministry of Agriculture and Rural Affairs (MARA) Key Laboratory of Soybean Biology (Beijing), Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lijuan Qiu
- The National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI)/Key Laboratory of Germplasm and Biotechnology Ministry of Agriculture and Rural Affairs (MARA), Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junming Sun
- The National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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Current perspectives on the beneficial effects of soybean isoflavones and their metabolites on plants. Food Sci Biotechnol 2022; 31:515-526. [PMID: 35529690 PMCID: PMC9033921 DOI: 10.1007/s10068-022-01070-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 03/04/2022] [Accepted: 03/21/2022] [Indexed: 11/04/2022] Open
Abstract
Soybeans have traditionally been a staple part of the human diet being highly rich in protein and lipid content. In an addition to the high nutritional components, soybeans have several functional components, like isoflavones, saponins, lecithin, and oligosaccharides. Soybeans emerge as a healthy functional food option. Isoflavones are most notable functional component of soybeans, exhibiting antioxidant activity while preventing plant-related diseases (e.g., antimicrobial and antiherbivore activities) and having positive effects on the life quality of plants. Isoflavones are thus sometimes referred to as phytochemicals. The latest research trends evince substantial interest in the biological efficacy of isoflavones in the human body as well as in plants and their related mechanisms. However, there is little information on the relationship between isoflavones and plants than beneficial human effects. This review discusses what is known about the physiological communication (transport and secretion) between isoflavones and plants, especially in soybeans.
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Wu Y, Wen J, Xia Y, Zhang L, Du H. Evolution and functional diversification of R2R3-MYB transcription factors in plants. HORTICULTURE RESEARCH 2022; 9:uhac058. [PMID: 35591925 PMCID: PMC9113232 DOI: 10.1093/hr/uhac058] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 02/24/2022] [Indexed: 05/31/2023]
Abstract
R2R3-MYB genes (R2R3-MYBs) form one of the largest transcription factor gene families in the plant kingdom, with substantial structural and functional diversity. However, the evolutionary processes leading to this amazing functional diversity have not yet been clearly established. Recently developed genomic and classical molecular technologies have provided detailed insights into the evolutionary relationships and functions of plant R2R3-MYBs. Here, we review recent genome-level and functional analyses of plant R2R3-MYBs, with an emphasis on their evolution and functional diversification. In land plants, this gene family underwent a large expansion by whole genome duplications and small-scale duplications. Along with this population explosion, a series of functionally conserved or lineage-specific subfamilies/groups arose with roles in three major plant-specific biological processes: development and cell differentiation, specialized metabolism, and biotic and abiotic stresses. The rapid expansion and functional diversification of plant R2R3-MYBs are highly consistent with the increasing complexity of angiosperms. In particular, recently derived R2R3-MYBs with three highly homologous intron patterns (a, b, and c) are disproportionately related to specialized metabolism and have become the predominant subfamilies in land plant genomes. The evolution of plant R2R3-MYBs is an active area of research, and further studies are expected to improve our understanding of the evolution and functional diversification of this gene family.
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Affiliation(s)
- Yun Wu
- Department of Landscape Architecture, School of Civil Engineering and Architecture, Zhejiang Sci-Tech University, Hangzhou, 310018, China
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Jing Wen
- College of Agronomy and Biotechnology, Southwest University, Chongqing, 400716, China
| | - Yiping Xia
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Liangsheng Zhang
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Hai Du
- College of Agronomy and Biotechnology, Southwest University, Chongqing, 400716, China
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Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans. Antioxidants (Basel) 2021; 10:antiox10071064. [PMID: 34209224 PMCID: PMC8301030 DOI: 10.3390/antiox10071064] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/13/2022] Open
Abstract
Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.
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Dinkins RD, Hancock J, Coe BL, May JB, Goodman JP, Bass WT, Liu J, Fan Y, Zheng Q, Zhu H. Isoflavone levels, nodulation and gene expression profiles of a CRISPR/Cas9 deletion mutant in the isoflavone synthase gene of red clover. PLANT CELL REPORTS 2021; 40:517-528. [PMID: 33389047 DOI: 10.1007/s00299-020-02647-4] [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: 09/23/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
Isoflavones are not involved in rhizobial signaling in red clover, but likely play a role in defense in the rhizosphere. Red clover (Trifolium pratense) is a high-quality forage legume, well suited for grazing and hay production in the temperate regions of the world. Like many legumes, red clover produces a number of phenylpropanoid compounds including anthocyanidins, flavan-3-ols, flavanols, flavanones, flavones, and isoflavones. The study of isoflavone biosynthesis and accumulation in legumes has come into the forefront of biomedical and agricultural research due to potential for medicinal, antimicrobial, and environmental implications. CRISPR/Cas9 was used to knock out the function of a key enzyme in the biosynthesis of isoflavones, isoflavone synthase (IFS1). A hemizygous plant carrying a 9-bp deletion in the IFS1 gene was recovered and was intercrossed to obtain homozygous mutant plants. Levels of the isoflavones formononetin, biochanin A and genistein were significantly reduced in the mutant plants. Wild-type and mutant plants were inoculated with rhizobia to test the effect of the mutation on nodulation, but no significant differences were observed, suggesting that these isoflavones do not play important roles in nodulation. Gene expression profiling revealed an increase in expression of the upstream genes producing the precursors for IFS1, namely, phenylalanine ammonium lyase and chalcone synthase, but there were no significant differences in IFS1 gene expression or in the downstream genes in the production of specific isoflavones. Higher expression in genes involved in ethylene response was observed in the mutant plants. This response is normally associated with biotic stress, suggesting that the plants may have been responding to cues in the surrounding rhizosphere due to lower levels of isoflavones.
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Affiliation(s)
- Randy D Dinkins
- USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY, USA.
| | - Julie Hancock
- College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, USA
| | - Brenda L Coe
- USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY, USA
| | - John B May
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Jack P Goodman
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - William T Bass
- USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY, USA
| | - Jinge Liu
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Yinglun Fan
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
- College of Agriculture, Liaocheng University, Liaocheng, China
| | - Qiaolin Zheng
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
- Department of Plant Pathology, University of Florida, IFAS, Fort Pierce, FL, USA
| | - Hongyan Zhu
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
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Sohn SI, Pandian S, Oh YJ, Kang HJ, Cho WS, Cho YS. Metabolic Engineering of Isoflavones: An Updated Overview. FRONTIERS IN PLANT SCIENCE 2021; 12:670103. [PMID: 34163508 PMCID: PMC8216759 DOI: 10.3389/fpls.2021.670103] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 04/21/2021] [Indexed: 05/04/2023]
Abstract
Isoflavones are ecophysiologically active secondary metabolites derived from the phenylpropanoid pathway. They were mostly found in leguminous plants, especially in the pea family. Isoflavones play a key role in plant-environment interactions and act as phytoalexins also having an array of health benefits to the humans. According to epidemiological studies, a high intake of isoflavones-rich diets linked to a lower risk of hormone-related cancers, osteoporosis, menopausal symptoms, and cardiovascular diseases. These characteristics lead to the significant advancement in the studies on genetic and metabolic engineering of isoflavones in plants. As a result, a number of structural and regulatory genes involved in isoflavone biosynthesis in plants have been identified and characterized. Subsequently, they were engineered in various crop plants for the increased production of isoflavones. Furthermore, with the advent of high-throughput technologies, the regulation of isoflavone biosynthesis gains attention to increase or decrease the level of isoflavones in the crop plants. In the review, we begin with the role of isoflavones in plants, environment, and its benefits in human health. Besides, the main theme is to discuss the updated research progress in metabolic engineering of isoflavones in other plants species and regulation of production of isoflavones in soybeans.
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Affiliation(s)
- Soo In Sohn
- Biosafety Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju, South Korea
- *Correspondence: Soo-In Sohn,
| | - Subramani Pandian
- Biosafety Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju, South Korea
| | - Young Ju Oh
- Institute for Future Environmental Ecology Co., Ltd., Jeonju, South Korea
| | - Hyeon Jung Kang
- Biosafety Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju, South Korea
| | - Woo Suk Cho
- Biosafety Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju, South Korea
| | - Youn Sung Cho
- Biosafety Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Jeonju, South Korea
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Matsuda H, Nakayasu M, Aoki Y, Yamazaki S, Nagano AJ, Yazaki K, Sugiyama A. Diurnal metabolic regulation of isoflavones and soyasaponins in soybean roots. PLANT DIRECT 2020; 4:e00286. [PMID: 33241173 PMCID: PMC7673354 DOI: 10.1002/pld3.286] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/23/2020] [Accepted: 10/14/2020] [Indexed: 05/05/2023]
Abstract
Isoflavones and soyasaponins are major specialized metabolites accumulated in soybean roots and secreted into the rhizosphere. Unlike the biosynthetic pathway, the transporters involved in metabolite secretion remain unknown. The developmental regulation of isoflavone and soyasaponin secretions has been recently reported, but the diurnal regulation of their biosynthesis and secretion still needs to be further studied. To address these challenges, we conducted transcriptome and metabolite analysis using hydroponically grown soybean plants at 6-hr intervals for 48 hr in a 12-hr-light/12-hr-dark condition. Isoflavone and soyasaponin biosynthetic genes showed opposite patterns in the root tissues; that is, the former genes are highly expressed in the daytime, while the latter ones are strongly induced at nighttime. GmMYB176 encoding a transcription factor of isoflavone biosynthesis was upregulated from ZT0 (6:00 a.m.) to ZT6 (12:00 a.m.), followed by the induction of isoflavone biosynthetic genes at ZT6. The isoflavone aglycone content in the roots accordingly increased from ZT6 to ZT18 (0:00 a.m.). The isoflavone aglycone content in root exudates was kept consistent throughout the day, whereas that of glucosides increased at ZT6, which reflected the decreased expression of the gene encoding beta-glucosidase involved in the hydrolysis of apoplast-localized isoflavone conjugates. Co-expression analysis revealed that those isoflavone and soyasaponin biosynthetic genes formed separate clusters, which exhibited a correlation to ABC and MATE transporter genes. In summary, the results in this study indicated the diurnal regulation of isoflavone biosynthesis in soybean roots and the putative transporter genes responsible for isoflavone and soyasaponin transport.
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Affiliation(s)
- Hinako Matsuda
- Research Institute for Sustainable HumanosphereKyoto UniversityGokasho, UjiJapan
| | - Masaru Nakayasu
- Research Institute for Sustainable HumanosphereKyoto UniversityGokasho, UjiJapan
| | - Yuichi Aoki
- Tohoku Medical Megabank OrganizationTohoku UniversitySendaiJapan
| | | | | | - Kazufumi Yazaki
- Research Institute for Sustainable HumanosphereKyoto UniversityGokasho, UjiJapan
| | - Akifumi Sugiyama
- Research Institute for Sustainable HumanosphereKyoto UniversityGokasho, UjiJapan
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