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Ding Z, Yao K, Yao Y, Pan X, Luo L, Li L, Wang C, Liao W. Characterization of the GGP gene family in potato (Solanum tuberosum L.) and Pepper (Capsicum annuum L.) and its expression analysis under hormonal and abiotic stresses. Sci Rep 2024; 14:15329. [PMID: 38961199 PMCID: PMC11222470 DOI: 10.1038/s41598-024-66337-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 07/01/2024] [Indexed: 07/05/2024] Open
Abstract
GDP-L-galactose phosphorylase (GGP) is a key rate-limiting enzyme in plant ascorbic acid synthesis, which plays an important role in plant growth and development as well as stress response. However, the presence of GGP and its function in potato and pepper are not known. In this study, we first identified two GGP genes in each potato and pepper genomes using a genome-wide search approach. We then analyzed their physicochemical properties, conserved domains, protein structures and phylogenetic relationships. Phylogenetic tree analysis revealed that members of the potato and pepper GGP gene families are related to eggplant (Solanum melongena L.), Arabidopsis (Arabidopsis thaliana L.), tobacco (Nicotiana tabacum L.) and tomato (Solanum lycopersicum L.), with tomato being the most closely related. The promoter sequences mainly contain homeopathic elements such as light-responsive, hormone-responsive and stress-responsive, with light-responsive elements being the most abundant. By analyzing the structure of the genes, it was found that there is no transmembrane structure or signal peptide in the GGP gene family of potatoes and peppers, and that all of its members are hydrophilic proteins. The expression profiles of different tissues show that StGGP1 has the highest expression levels in leaves, StGGP2 has the highest expression levels in stamens, and CaGGPs have the highest expression levels in the early stages of fruit development (Dev1). It was found that StGGPs and CaGGPs genes showed different response to phytohormones and abiotic stresses. Abscisic acid (ABA) treatment induced the most significant change in the expression of StGGPs, while the expression of CaGGPs showed the most pronounced change under methyl jasmonate (MeJA) treatment. StGGPs responded mainly to dark treatment, whereas CaGGPs responded mainly to NaCl stress. These results provide an important basis for a detailed study about the functions of GGP homologous genes in potato and pepper in response to abiotic stresses.
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Affiliation(s)
- Zhiqi Ding
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Kangding Yao
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Yandong Yao
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Xuejuan Pan
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Lizhen Luo
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Long Li
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Chunlei Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China
| | - Weibiao Liao
- College of Horticulture, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China.
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Yang T, Amanullah S, Li S, Gao P, Bai J, Li C, Ma J, Luan F, Wang X. Deciphering the Genomic Characterization of the GGP Gene Family and Expression Verification of CmGGP1 Modulating Ascorbic Acid Biosynthesis in Melon Plants. Antioxidants (Basel) 2024; 13:397. [PMID: 38671845 PMCID: PMC11047344 DOI: 10.3390/antiox13040397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/19/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
Ascorbic acid (AsA), also known as vitamin C, is a well-known antioxidant found in living entities that plays an essential role in growth and development, as well as in defensive mechanisms. GDP-L-galactose phosphorylase (GGP) is a candidate gene regulating AsA biosynthesis at the translational and transcriptional levels in plants. In the current study, we conducted genome-wide bioinformatic analysis and pinpointed a single AsA synthesis rate-limiting enzyme gene in melon (CmGGP1). The protein prediction analysis depicted that the CmGGP1 protein does not have a signaling peptide or transmembrane structure and mainly functions in the chloroplast or nucleus. The constructed phylogenetic tree analysis in multispecies showed that the CmGGP1 protein has a highly conserved motif in cucurbit crops. The structural variation analysis of the CmGGP1 gene in different domesticated melon germplasms showed a single non-synonymous type-base mutation and indicated that this gene was selected by domestication during evolution. Wild-type (WT) and landrace (LDR) germplasms of melon depicted close relationships to each other, and improved-type (IMP) varieties showed modern domestication selection. The endogenous quantification of AsA content in both the young and old leaves of nine melon varieties exhibited the major differentiations for AsA synthesis and metabolism. The real-time quantitative polymerase chain reaction (qRT-PCR) analysis of gene co-expression showed that AsA biosynthesis in leaves was greater than AsA metabolic consumption, and four putative interactive genes (MELO3C025552.2, MELO3C007440.2, MELO3C023324.2, and MELO3C018576.2) associated with the CmGGP1 gene were revealed. Meanwhile, the CmGGP1 gene expression pattern was noticed to be up-regulated to varying degrees in different acclimated melons. We believe that the obtained results would provide useful insights for an in-depth genetic understanding of the AsA biosynthesis mechanism, aimed at the development of improving crop plants for melon.
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Affiliation(s)
- Tiantian Yang
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Sikandar Amanullah
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Shenglong Li
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Peng Gao
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Junyu Bai
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Chang Li
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Jie Ma
- Bayannur Institute of Agriculture and Animal Husbandry Science, Inner Mongolia Autonomous Region, Bayannur 015000, China;
| | - Feishi Luan
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
| | - Xuezheng Wang
- College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China; (T.Y.); (S.L.); (P.G.); (J.B.); (C.L.); (F.L.)
- Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China
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Chaturvedi S, Thakur N, Khan S, Sardar MK, Jangra A, Tiwari S. Overexpression of banana GDP-L-galactose phosphorylase (GGP) modulates the biosynthesis of ascorbic acid in Arabidopsis thaliana. Int J Biol Macromol 2023; 237:124124. [PMID: 36966859 DOI: 10.1016/j.ijbiomac.2023.124124] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023]
Abstract
l-Ascorbic acid (AsA) is a potent antioxidant and essential micronutrient for the growth and development of plants and animals. AsA is predominantly synthesized by the Smirnoff-Wheeler (SW) pathway in plants where the GDP-L-galactose phosphorylase (GGP) gene encodes the rate-limiting step. In the present study, AsA was estimated in twelve banana cultivars, where Nendran carried the highest (17.2 mg/100 g) amount of AsA in ripe fruit pulp. Five GGP genes were identified from the banana genome database, and they were located at chromosome 6 (4 MaGGPs) and chromosome 10 (1 MaGGP). Based on in-silico analysis, three potential MaGGP genes were isolated from the cultivar Nendran and subsequently overexpressed in Arabidopsis thaliana. Significant enhancement in AsA (1.52 to 2.20 fold) level was noted in the leaves of all three MaGGPs overexpressing lines as compared to non-transformed control plants. Among all, MaGGP2 emerged as a potential candidate for AsA biofortification in plants. Further, the complementation assay of Arabidopsis thaliana vtc-5-1 and vtc-5-2 mutants with MaGGP genes overcome the AsA deficiency that showed improved plant growth as compared to non-transformed control plants. This study lends strong affirmation towards development of AsA biofortified plants, particularly the staples that sustain the personages in developing countries.
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Yan Y, Liu Y, Lu M, Lu C, Ludlow RA, Yang M, Huang W, Liu Z, An H. Gene expression profiling in Rosa roxburghii fruit and overexpressing RrGGP2 in tobacco and tomato indicates the key control point of AsA biosynthesis. FRONTIERS IN PLANT SCIENCE 2023; 13:1096493. [PMID: 36704162 PMCID: PMC9871823 DOI: 10.3389/fpls.2022.1096493] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 12/12/2022] [Indexed: 06/18/2023]
Abstract
Rosa roxburghii Tratt. is an important commercial horticultural crop endemic to China, which is recognized for its extremely high content of L-ascorbic acid (AsA). To understand the mechanisms underlying AsA overproduction in fruit of R. roxburghii, content levels, accumulation rate, and the expression of genes putatively in the biosynthesis of AsA during fruit development have been characterized. The content of AsA increased with fruit weight during development, and AsA accumulation rate was found to be highest between 60 and 90 days after anthesis (DAA), with approximately 60% of the total amount being accumulated during this period. In vitro incubating analysis of 70DAA fruit flesh tissues confirmed that AsA was synthesized mainly via the L-galactose pathway although L-Gulono-1, 4-lactone was also an effective precursor elevating AsA biosynthesis. Furthermore, in transcript level, AsA content was significantly associated with GDP-L-galactose phosphorylase (RrGGP2) gene expression. Virus-induced RrGGP2 silencing reduced the AsA content in R. roxburghii fruit by 28.9%. Overexpressing RrGGP2 increased AsA content by 8-12-fold in tobacco leaves and 2.33-3.11-fold in tomato fruit, respectively, and it showed enhanced resistance to oxidative stress caused by paraquat in transformed tobacco. These results further justified the importance of RrGGP2 as a major control step to AsA biosynthesis in R. roxburghii fruit.
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Affiliation(s)
- Yali Yan
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | - Yiyi Liu
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | - Min Lu
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | - Chen Lu
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | | | - Man Yang
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | - Wei Huang
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | - Zeyang Liu
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
| | - HuaMing An
- Engineering Research Center of National Forestry and Grassland Administration for Rosa roxburghii, Agricultural College, Guizhou University, Guiyang, China
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Chaturvedi S, Khan S, Bhunia RK, Kaur K, Tiwari S. Metabolic engineering in food crops to enhance ascorbic acid production: crop biofortification perspectives for human health. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2022; 28:871-884. [PMID: 35464783 PMCID: PMC9016690 DOI: 10.1007/s12298-022-01172-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 03/18/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Ascorbic acid (AsA) also known as vitamin C is considered as an essential micronutrient in the diet of humans. The human body is unable to synthesize AsA, thus solely dependent on exogenous sources to accomplish the nutritional requirement. AsA plays a crucial role in different physiological aspects of human health like bone formation, iron absorption, maintenance and development of connective tissues, conversion of cholesterol to bile acid and production of serotonin. It carries antioxidant properties and is involved in curing various clinical disorders such as scurvy, viral infection, neurodegenerative diseases, cardiovascular diseases, anemia, and diabetes. It also plays a significant role in COVID-19 prevention and recovery by improving the oxygen index and enhancing the production of natural killer cells and T-lymphocytes. In plants, AsA plays important role in floral induction, seed germination, senescence, ROS regulation and photosynthesis. AsA is an essential counterpart of the antioxidant system and helps to defend the plants against abiotic and biotic stresses. Surprisingly, the deficiencies of AsA are spreading in both developed and developing countries. The amount of AsA in the major food crops such as wheat, rice, maize, and other raw natural plant foods is inadequate to fulfill its dietary requirements. Hence, the biofortification of AsA in staple crops would be feasible and cost-effective means of delivering AsA to populations that may have limited access to diverse diets and other interventions. In this review, we endeavor to provide information on the role of AsA in plants and human health, and also perused various biotechnological and agronomical approaches for elevating AsA content in food crops.
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Affiliation(s)
- Siddhant Chaturvedi
- Plant Tissue Culture and Genetic Engineering Lab, National Agri-
Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali, Punjab, 140306 India
- Department of Biotechnology, Panjab University, Chandigarh, 160014 India
| | - Shahirina Khan
- Plant Tissue Culture and Genetic Engineering Lab, National Agri-
Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali, Punjab, 140306 India
- Department of Botany, Central University of Punjab, Bathinda, Punjab, 151001 India
| | - Rupam Kumar Bhunia
- Plant Tissue Culture and Genetic Engineering Lab, National Agri-
Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali, Punjab, 140306 India
| | - Karambir Kaur
- Plant Tissue Culture and Genetic Engineering Lab, National Agri-
Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali, Punjab, 140306 India
| | - Siddharth Tiwari
- Plant Tissue Culture and Genetic Engineering Lab, National Agri-
Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali, Punjab, 140306 India
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Xiao C, Guo H, Tang J, Li J, Yao X, Hu H. Expression Pattern and Functional Analyses of Arabidopsis Guard Cell-Enriched GDSL Lipases. FRONTIERS IN PLANT SCIENCE 2021; 12:748543. [PMID: 34621289 PMCID: PMC8490726 DOI: 10.3389/fpls.2021.748543] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/18/2021] [Indexed: 05/27/2023]
Abstract
There are more than 100 GDSL lipases in Arabidopsis, but only a few members have been functionally investigated. Moreover, no reports have ever given a comprehensive analysis of GDSLs in stomatal biology. Here, we systematically investigated the expression patterns of 19 putative Guard-cell-enriched GDSL Lipases (GGLs) at various developmental stages and in response to hormone and abiotic stress treatments. Gene expression analyses showed that these GGLs had diverse expression patterns. Fifteen GGLs were highly expressed in guard cells, with seven preferentially in guard cells. Most GGLs were localized in endoplasmic reticulum, and some were also localized in lipid droplets and nucleus. Some closely homologous GGLs exhibited similar expression patterns at various tissues and in response to hormone and abiotic stresses, or similar subcellular localization, suggesting the correlation of expression pattern and biological function, and the functional redundancy of GGLs in plant development and environmental adaptations. Further phenotypic identification of ggl mutants revealed that GGL7, GGL14, GGL22, and GGL26 played unique and redundant roles in stomatal dynamics, stomatal density and morphology, and plant water relation. The present study provides unique resources for functional insights into these GGLs to control stomatal dynamics and development, plant growth, and adaptation to the environment.
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Affiliation(s)
- Chuanlei Xiao
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Huimin Guo
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jing Tang
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiaying Li
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xuan Yao
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Honghong Hu
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Anisimova OK, Shchennikova AV, Kochieva EZ, Filyushin MA. Identification and Variability of the GDP-L-Galactose Phosphosphorylase Gene ApGGP1 in Leek Cultivars. RUSS J GENET+ 2021. [DOI: 10.1134/s1022795421030030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Broad RC, Bonneau JP, Hellens RP, Johnson AA. Manipulation of Ascorbate Biosynthetic, Recycling, and Regulatory Pathways for Improved Abiotic Stress Tolerance in Plants. Int J Mol Sci 2020; 21:E1790. [PMID: 32150968 PMCID: PMC7084844 DOI: 10.3390/ijms21051790] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 02/03/2023] Open
Abstract
Abiotic stresses, such as drought, salinity, and extreme temperatures, are major limiting factors in global crop productivity and are predicted to be exacerbated by climate change. The overproduction of reactive oxygen species (ROS) is a common consequence of many abiotic stresses. Ascorbate, also known as vitamin C, is the most abundant water-soluble antioxidant in plant cells and can combat oxidative stress directly as a ROS scavenger, or through the ascorbate-glutathione cycle-a major antioxidant system in plant cells. Engineering crops with enhanced ascorbate concentrations therefore has the potential to promote broad abiotic stress tolerance. Three distinct strategies have been utilized to increase ascorbate concentrations in plants: (i) increased biosynthesis, (ii) enhanced recycling, or (iii) modulating regulatory factors. Here, we review the genetic pathways underlying ascorbate biosynthesis, recycling, and regulation in plants, including a summary of all metabolic engineering strategies utilized to date to increase ascorbate concentrations in model and crop species. We then highlight transgene-free strategies utilizing genome editing tools to increase ascorbate concentrations in crops, such as editing the highly conserved upstream open reading frame that controls translation of the GDP-L-galactose phosphorylase gene.
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Affiliation(s)
- Ronan C. Broad
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Julien P. Bonneau
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Roger P. Hellens
- Centre for Tropical Crops and Biocommodities, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4001, Australia
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Broad RC, Bonneau JP, Beasley JT, Roden S, Sadowski P, Jewell N, Brien C, Berger B, Tako E, Glahn RP, Hellens RP, Johnson AAT. Effect of Rice GDP-L-Galactose Phosphorylase Constitutive Overexpression on Ascorbate Concentration, Stress Tolerance, and Iron Bioavailability in Rice. FRONTIERS IN PLANT SCIENCE 2020; 11:595439. [PMID: 33343598 PMCID: PMC7744345 DOI: 10.3389/fpls.2020.595439] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/16/2020] [Indexed: 05/12/2023]
Abstract
Ascorbate (vitamin C) is an essential multifunctional molecule for both plants and mammals. In plants, ascorbate is the most abundant water-soluble antioxidant that supports stress tolerance. In humans, ascorbate is an essential micronutrient and promotes iron (Fe) absorption in the gut. Engineering crops with increased ascorbate levels have the potential to improve both crop stress tolerance and human health. Here, rice (Oryza sativa L.) plants were engineered to constitutively overexpress the rice GDP-L-galactose phosphorylase coding sequence (35S-OsGGP), which encodes the rate-limiting enzymatic step of the L-galactose pathway. Ascorbate concentrations were negligible in both null segregant (NS) and 35S-OsGGP brown rice (BR, unpolished grain), but significantly increased in 35S-OsGGP germinated brown rice (GBR) relative to NS. Foliar ascorbate concentrations were significantly increased in 35S-OsGGP plants in the vegetative growth phase relative to NS, but significantly reduced at the reproductive growth phase and were associated with reduced OsGGP transcript levels. The 35S-OsGGP plants did not display altered salt tolerance at the vegetative growth phase despite having elevated ascorbate concentrations. Ascorbate concentrations were positively correlated with ferritin concentrations in Caco-2 cells - an accurate predictor of Fe bioavailability in human digestion - exposed to in vitro digests of NS and 35S-OsGGP BR and GBR samples.
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Affiliation(s)
- Ronan C. Broad
- School of Biosciences, The University of Melbourne, Melbourne, VIC, Australia
- *Correspondence: Ronan C. Broad,
| | - Julien P. Bonneau
- School of Biosciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Jesse T. Beasley
- School of Biosciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Sally Roden
- Centre for Agriculture and the Bioeconomy, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Pawel Sadowski
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Nathaniel Jewell
- Australian Plant Phenomics Facility and School for Agriculture, Food and Wine, The University of Adelaide, Adelaide, SA, Australia
| | - Chris Brien
- Australian Plant Phenomics Facility and School for Agriculture, Food and Wine, The University of Adelaide, Adelaide, SA, Australia
| | - Bettina Berger
- Australian Plant Phenomics Facility and School for Agriculture, Food and Wine, The University of Adelaide, Adelaide, SA, Australia
| | - Elad Tako
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | - Raymond P. Glahn
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Ithaca, NY, United States
| | - Roger P. Hellens
- Centre for Agriculture and the Bioeconomy, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
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