Progress 10/01/01 to 09/30/06
Outputs
Carotenoids and tocopherols are powerful antioxidants arising from related chemical pathways. Recent evidence has suggested strong health benefits for both groups of compounds. Most sources of tocopherols are high in oils. In an attempt to create a food source high in both carotenoids and tocopherols, populations have been developed for increased levels of these compounds in carrot (Daucus carota). Three populations have been developed from open-pollinated varieties through differing selection schemes to better understand inheritance and interaction of these compounds, an Alpha-only population, selection based on alpha tocopherol levels, an Index population, selection based on an index for increased levels of alpha-tocopherol and alpha- and beta-carotene, and Random, an unselected drift population. Two cycles of recurrent half-sib family selection have been completed. Selection for alpha-tocopherol in the Alpha-only population was effective, with a gain of 0.30 ppm
per-cycle for a population average of 0.72 ppm after two cycles. The Index population showed seen changes in all three compounds, with an increase in alpha-tocopherol of 0.21 ppm per-cycle to a population average of 0.55 ppm and increases per-cycle for alpha- and beta-carotene of 83.83 ppm and 135.56 ppm, respectively. The Random population showed a slight increase alpha-tocopherol and decreases in the carotenoids. A separate population selected for alpha-tocopherol showed an increase after one cycle from an average of nearly 0 ppm to an average of 0.06 ppm, with the highest half-sib family showing 1.56 ppm. Various colored carrot varieties showed a significant (p<0.05) correlation of alpha-tocopherol with beta-carotene (r=0.42) in orange roots. Early cycle gains that indicate selection for increased tocopherols is feasible in carrot.
Impacts
If we can show that alpha tocopherol is present in carrot and that there is genetic variability for this compound, we can potentially increase the nutritional profile of carrot by enhancing its Vitamin E value, along with its already well established high levels of pro Vitamin A. This work has the potential to better understand the nutritional value of this important vegetable and enhance its nutritional profile for the health of consumers.
Publications
- Goldman, I.L. 2003. Recognition of fruits and vegetables as healthful: vitamins, minerals, fiber, and phytonutrients. HortTechnology. 13:1-6.
- Goldman, I.L. 2003. Why medicine needs agriculture. In Foods for Health. A. Eagelsham, C. Carlson, and R.W. Hardy, eds. 14th Proceedings of the National Agricultural Biotechnology Council. Ithaca, NY. P. 113-121.
- Goldman, I.L. 2003. Medicine, Agriculture, and Functional Foods. In Melhoramento Genomico. Borem, A., Giudice, M., and T. e Sediyama, eds. Universidade Federal De Vicosa, Brazil. P. 211-224.
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Progress 01/01/04 to 12/31/04
Outputs
Carotenoids and tocopherols are powerful antioxidants synthesized in plants from a common precursor. They may offer significant health benefits to humans. Seed oils have been shown to possess high levels of tocopherols, but little is known about their levels in the edible portions of most vegetable crops. Carotenoids and tocopherols are health-functional phytochemicals that occur in a wide range of fruit and vegetable crops. These two classes of compounds are synthesized from a common precursor, geranyl-geranyl pyrophosphate, and are typically analyzed separately via HPLC techniques. Because carotenoids and tocopherols are present in many edible horticultural crops, it would be advantageous to measure them simultaneously in plant tissues. Herein we report a one-pass reverse-phase HPLC method for extraction and analysis of carotenoids and tocopherols in carrot that can be extended to other high-moisture plant organs. Elution times ranged from 5 minutes for alpha
tocopherol to 24 minutes for beta carotene. This method improves the efficiency of analyzing these compounds by up to 50%, and should increase the efficiency of assessing carotenoid and tocopherol profiles in horticultural crops. A two-year field experiment was conducted at two locations to assess levels of major carotenoids and tocopherols in carrot root and leaf tissue. Levels of compounds in root tissue reported on a dry weight basis were: alpha tocopherol, 0.04 to 0.18 ppm; lycopene, 0.00 to 52.94 ppm; alpha carotene, 10.63 to 1504.76 ppm; and beta carotene, 26.69 to 1673.76 ppm. Higher levels of all carotenoids were measured in phloem tissue than xylem. Leaf tissue levels of tocopherols measured on a dry weight basis ranged from 0.02 to 0.85 ppm, while levels of carotenoids ranged from 12.81 to 411.66 ppm. In xylem tissue, alpha tocopherol was significantly positively correlated with alpha carotene (r = 0.65) and with beta carotene (r = 0.52). This positive correlation indicates
it may be possible to select for both increased alpha tocopherol and carotenoids in carrot. The reduced pigment mutation (rp) of carrot exhibited a 96% reduction in levels of alpha and beta carotene and a 25-43% reduction in alpha tocopherol when compared to a near-isogenic line. In plants homozygous for rp, a substantial increase was observed in phytoene, a precursor to carotenoids, suggesting the location of the rp lesion in the carotenoid synthesis pathway.
Impacts
If we can show that alpha tocopherol is present in carrot and that there is genetic variability for this compound, we can potentially increase the nutritional profile of carrot by enhancing its Vitamin E value, along with its already well established high levels of pro Vitamin A. This work has the potential to better understand the nutritional value of this important vegetable and enhance its nutritional profile for the health of consumers.
Publications
- Koch, T., and I.L. Goldman. 2004. A one-pass semi-quantitative method for extraction and anallysis of carotenoids and tocopherols in carrot. HortScience. 39:1260-1261.
- Koch, T., and I.L. Goldman. 2004. Relationship of carotenoids and tocopherols in a sample of carrot root-color accessions and carrot germplasm carrying RP and rp alleles. Journal of Agricultural and Food Chemistry, In press.
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Progress 01/01/03 to 12/31/03
Outputs
Carotenoids and tocopherols are health-functional phytochemicals that occur in a wide range of fruit and vegetable crops. These two classes of compounds are synthesized from a common precursor, geranyl-geranyl pyrophosphate, and are typically analyzed separately via HPLC techniques. Because carotenoids and tocopherols are present in many edible horticultural crops, it would be advantageous to measure them simultaneously in plant tissues. Herein we report a one-pass reverse-phase HPLC method for extraction and analysis of carotenoids and tocopherols in carrot that can be extended to other high-moisture plant organs. Elution times ranged from 5 minutes for alpha-tocopherol to 24 minutes for beta-carotene. This method improves the efficiency of analyzing these compounds by up to 50%, and should increase the efficiency of assessing carotenoid and tocopherol profiles in horticultural crops. Carotenoids and tocopherols are synthesized in plants from a common precursor which
may benefit the human diet. Seed oils have been shown to possess high levels of tocopherols, but little is known about their levels in the edible portions of most vegetable crops. A two-year field experiment was conducted at two locations to assess levels of major carotenoids and tocopherols in carrot (Daucus carota) root and leaf tissue. Levels of compounds in root tissue reported on a dry weight basis were: alpha tocopherol, 0.04 to 0.18 ppm; lycopene, 0.00 to 52.94 ppm; beta-carotene, 10.63 to 1504.76 ppm; and alpha-carotene, 26.69 to 1673.76 ppm. Higher levels of all carotenoids were measured in phloem tissue than xylem. Leaf tissue levels of tocopherols measured on a dry weight basis ranged from 0.02 to 0.85 ppm, while levels of carotenoids ranged from 12.81 to 411.66 ppm. In xylem tissue, alpha-tocopherol was significantly (P <= 0.001) positively correlated with beta-carotene (r = 0.65) and with alpha-carotene (r = 0.52). This positive correlation indicates it may be possible to
select for both increased alpha-tocopherol and carotenoids in carrot. The reduced pigment (rp) mutation of carrot exhibited a 96% reduction in levels of alpha- and beta-carotene and a 25-43% reduction in alpha-tocopherol when compared to a near-isogenic line. In plants homozygous for rp, a substantial increase was observed in phytoene, a precursor to carotenoids, suggesting the location of the rp lesion in the carotenoid synthesis pathway.
Impacts
If we can show that alpha tocopherol is present in carrot and that there is genetic variability for this compound, we can potentially increase the nutritional profile of carrot by enhancing its Vitamin E value, along with its already well established high levels of pro Vitamin A. This work has the potential to better understand the nutritional value of this important vegetable and enhance its nutritional profile for the health of consumers.
Publications
- Koch, T.C., and I.L. Goldman. 2003. A one-pass semi-quantitative method for extraction and analysis of carotenoids and tocopherols in carrot and examination of the reduced pigment mutation. HortScience 38:804.
- Koch, T.C., I.L. Goldman. 2004. A one-pass semi-quantitative method for extraction and analysis of both carotenoids and tocopherols in carrot (Daucus carota). HortScience. In press.
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Progress 01/01/02 to 12/31/02
Outputs
Spiraling interest in functional foods has been fueled by an emerging market for novel agricultural products such as nutritionally-enhanced crops. Carrot contributes ca. 14-30% of the Vitamin A in the U.S. diet due to its high concentration of carotenoids. The carotenoids may also contribute to human health via their powerful antioxidant activity, and a growing body of research suggests the potential for high levels of health functionality from dietary carotenoid-rich fruits and vegetables. We recently reported the discovery of a gene, rp, that inhibits carotenoid biosynthesis by 92% compared to wild type plants, resulting in a white-yellow root. Although carrot has never been described as a source of the provitamin E tocopherols, we have recently demonstrated elevated a-tocopherol biosynthesis in rprp genotypes compared to wild type plants. Carotenoids and tocopherols are synthesized from pathways linked through a common precursor, gernanylgeranyl pyrophosphate. If
the rp lesion is not responsible for collateral increases in tocopherols, opportunities may exist to enhance the nutritional profile of carrot for both vitamins A and E. If carotenoid biosynthetic mutants can increase tocopherol concentrations, development of enhanced tocopherol levels in carrot may be possible. The primary goal of this research is to ask and answer questions concerning the relationship between biosynthesis of carotenoids and tocopherols in carrot through study of the rp gene. We have investigated the relationship of these compounds via classical genetic studies with the rp gene, making use of liquid chromatographic techniques to assess carotenoid and tocopherol profiles. Through the work of graduate student Thomas Koch, we have accomplished two major goals in 2002. Our first accomplishment was development of a single-pass chromatographic technique for measurement of both compounds simultaneously. Our second accomplishment was completing a two-year field analysis of
the relationship among these compounds. A positive correlation between alpha tocopherol and both alpha and beta carotene in carrot root tissue was demonstrated. Carrot plants carrying rprp were not among those with the highest alpha tocopherol levels; however. when examined on a per-caroteneoid basis, their levels of alpha tocopherol were indeed elevated. Significant levels of phytoene were measured in roots of rprp plants, suggesting a blockage at this particular step in the carotenoid biosynthesis pathway could explain the rprp phenotype. With a correlation between alpha tocopherol and the carotenoids, breeding for elevated levels of both compounds may be feasible. Further work will examine the accumulation of phytoene, the inheritance of alpha tocopherol, and the possiblity of selecting higher provitamin A and E simultaneously in carrot.
Impacts
A positive correlation between alpha tocopherol and both alpha and beta carotene in carrot root tissue was demonstrated. Given this correlation, breeding for elevated levels of both compounds may be feasible. Therefore, it may be possible to develop carrot plants that deliver both provitamin A and provitamin E to the human diet, thereby enriching the nutritional status of this vegetable.
Publications
- Goldman, I.L., and D.N. Breitbach. 2002. Reduced pigment gene of carrot and its use. US patent 6,437,222 B1.
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Progress 01/01/01 to 12/31/01
Outputs
Spiraling interest in functional foods has been fueled by an emerging market for novel agricultural products such as nutritionally-enhanced crops. Carrot contributes ca. 14-30% of the Vitamin A in the U.S. diet due to its high concentration of carotenoids. The carotenoids may also contribute to human health via their powerful antioxidant activity, and a growing body of research suggests the potential for high levels of health functionality from dietary carotenoid-rich fruits and vegetables. We recently reported the discovery of a gene, rp, that inhibits carotenoid biosynthesis by 92% compared to wild type plants, resulting in a white-yellow root. Although carrot has never been described as a source of the provitamin E tocopherols, we have recently demonstrated elevated a-tocopherol biosynthesis in rprp genotypes compared to wild type plants. Carotenoids and tocopherols are synthesized from pathways linked through a common precursor, gernanylgeranyl pyrophosphate. If
the rp lesion is not responsible for collateral increases in tocopherols, opportunities may exist to enhance the nutritional profile of carrot for both vitamins A and E. If carotenoid biosynthetic mutants can increase tocopherol concentrations, development of enhanced tocopherol levels in carrot may be possible. The primary goal of this research is to ask and answer questions concerning the relationship between biosynthesis of carotenoids and tocopherols in carrot through study of the rp gene. We propose to investigate the relationship of these compounds via classical genetic studies with the rp gene, making use of liquid chromatographic techniques to assess carotenoid and tocopherol profiles. Results should lead to an improved understanding of the biosynthetic tradeoff between carotenoids and tocopherols, determine if the rp gene is likely responsible for enhanced tocopherol production, and identify the potential for a nutritionally-enhanced carrot for Vitamins A and E.
Impacts
The finding that a carrot mutant, deficient in carotenoids compared to standard carrot, produces vitamin E was a first step toward understanding the relationship between carotenoid and tocopherol biosynthesis in carrot. We hope with this work to investigate this relationship further and develop a mechanism for breeding high tocopherol carrots, that can deliver both vitamin E and carotenoids.
Publications
- Poon, W.Y.L. and I.L. Goldmman. 200x. Comparative carotenoid accumulation and retention in carrot inbred lines near-isogenic for reduced pigment (rp). Journal of the American Society for Horticultural Science. In press.
- Goldman, I.L. 2001. Making use of the health benefits of carrot in marketing initiatives. United Kingdom Carrot Conference, England, November, 2001. Abstract.
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