Abstract Selenium (Se) and iodine (I) are essential micronutrients for humans and animals, and de... more Abstract Selenium (Se) and iodine (I) are essential micronutrients for humans and animals, and deficient and marginal intakes are widespread. Staple cereals with superior ability to take up these elements from the soil and load them into grain have the potential to improve the Se and I status of whole populations. In this study, diverse cereal germplasm from surveys and field trials conducted in Australia, Mexico, Nigeria and the USA, was evaluated for genotypic variation in grain density of Se and I. Much of the variation in grain Se ...
The 11th International Wheat Genetics Symposium proceedings Edited by Rudi Appels Russell Eastwood Evans Lagudah Peter Langridge Michael Mackay Lynne, 2008
Drought stress is a pervasive feature of wheat production in many of the world's major cerea... more Drought stress is a pervasive feature of wheat production in many of the world's major cereal-growing regions. To improve the productivity in these areas the importance of traits associated with tolerance to drought needs to be quantified. Yield is a complex trait and many physiological, morphological and developmental characteristics have been suggested as being important to yield in water limited environments. However, yield can be considered in terms of a few fundamental processes: the ability of the crop to use the available ...
Chloride (Cl) is an essential micronutrient for plant growth, but can be toxic at high concentrat... more Chloride (Cl) is an essential micronutrient for plant growth, but can be toxic at high concentrations resulting in reduced2 growth and yield. Although saline soils are generally dominated by both sodium (Na) and Cl+ 2 ions, compared to Na+ toxicity, very little is known about physiological and genetic control mechanisms of tolerance to Cl toxicity. In hydroponics2 and field studies, a bread wheat mapping population was tested to examine the relationships between physiological traits [Na, potassium (K) and Cl concentration] involved in salinity tolerance (ST) and seedling growth or grain yield, and to+ + 2 elucidate the genetic control mechanism of plant Cl accumulation using a quantitative trait loci (QTL) analysis approach.2 + 2 accordance with phenotypic responses, QTL controlling Cl accumulation differed entirely between hydroponics and field2 locations, and few were detected in two or more environments, demonstrating substantial QTL-by-environment interactions. The presence of s...
Zinc deficiency limits yield of cereals on vast areas in the world, and developing genotypes with... more Zinc deficiency limits yield of cereals on vast areas in the world, and developing genotypes with the ability to grow and yield on zinc deficient soils is considered a long-term sustainable approach. A good understanding of this ability will facilitate breeding for this ...
More than half the world’s population is at moderate to high risk of zinc (Zn) deficiency, and bi... more More than half the world’s population is at moderate to high risk of zinc (Zn) deficiency, and biofortification has become an important strategy to alleviate the problem. Grain loading is likely to be a major bottleneck in cereal biofortification. However, very little is known about the transporters involved in this process. We have used barley as a model system to study the transporter genes which are potentially important in grain Zn loading. Here we report effect of over-expressing a barley ZIP gene in barley on grain Zn content. Our results showed that when the transgenic plants were grown at low Zn supply, grain Zn concentrations of transgenic lines were not different from those of the null lines, but with a low dose of Zn supplement during anthesis grain Zn content in transgenic lines increased by 50%. When plants were grown at a high Zn supply, grain Zn concentration of the transgenic lines was doubled relative to the null lines and wildtype. The enhanced concentration of Zn ...
Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley ... more Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley (Hordeum vulgare) genotypes, but the underlying mechanisms for the variation remain elusive. High- and low-affinity phosphate (Pi) PHT1 transporters play an indispensable role in P acquisition and remobilization. However, little is known about genetic variation in PHT1 gene expression and association with P acquisition efficiency (PAE) and P utilization efficiency (PUE). Here, we present quantitative analyses of transcript levels of high- and low-affinity PHT1 Pi transporters in four barley genotypes differing in PAE. The results showed that there was no clear pattern in the expression of four paralogs of the high-affinity Pi transporter HvPHT1;1 among the four barley genotypes, but the expression of a low-affinity Pi transporter, HvPHT1;6, and its close homolog HvHPT1;3 was correlated with the genotypes differing in PUE. Interestingly, the expression of HvPHT1;6 and HvPHT1;3 was correla...
Journal of Trace Elements in Medicine and Biology, 2005
More than 2 billion people consume diets that are less diverse than 30 years ago, leading to defi... more More than 2 billion people consume diets that are less diverse than 30 years ago, leading to deficiencies in micronutrients, especially iron (Fe), zinc (Zn), selenium (Se), iodine (I), and also vitamin A. A strategy that exploits genetic variability to breed staple crops with enhanced ability to fortify themselves with micronutrients (genetic biofortification) offers a sustainable, cost-effective alternative to conventional supplementation and fortification programs. This is more likely to reach those most in need, has the added advantages of requiring no change in current consumer behaviour to be effective, and is transportable to a range of countries. Research by our group, along with studies elsewhere, has demonstrated conclusively that substantial genotypic variation exists in nutrient (e.g. Fe, Zn) and nutrient promotor (e.g. inulin) concentrations in wheat and other staple foods. A rapid screening technique has been developed for lutein content of wheat and triticale, and also for pro-vitamin A carotenoids in bread wheat. This will allow cost-effective screening of a wider range of genotypes that may reveal greater genotypic variation in these traits. Moreover, deeper understanding of genetic control mechanisms and development of molecular markers will facilitate breeding programs. We suggest that a combined strategy utilising plant breeding for higher micronutrient density; maximising the effects of nutritional promoters (e.g. inulin, vitamin C) by promoting favourable dietary combinations, as well as by plant breeding; and agronomic biofortification (e.g. adding iodide or iodate as fertiliser; applying selenate to cereal crops by spraying or adding to fertiliser) is likely to be the most effective way to improve the nutrition of populations. Furthermore, the importance of detecting and exploiting beneficial interactions is illustrated by our discovery that in Fe-deficient chickens, circulating Fe concentrations can be restored to normal levels by lutein supplementation. Further bioavailability/bioefficacy trials with animals and humans are needed, using varying dietary concentrations of Fe, Zn, carotenoids, inulin, Se and I to elucidate other important interactions in order to optimise delivery in biofortification programs.
Journal of Trace Elements in Medicine and Biology, 2005
Selenium (Se) is an essential micronutrient for humans and animals, but is deficient in at least ... more Selenium (Se) is an essential micronutrient for humans and animals, but is deficient in at least a billion people worldwide. Wheat (Triticum aestivum L.) is a major dietary source of Se. The largest survey to date of Se status of Australians found a mean plasma Se concentration of 103 microg/l in 288 Adelaide residents, just above the nutritional adequacy level. In the total sample analysed (six surveys from 1977 to 2002; n = 834), plasma Se was higher in males and increased with age. This study showed that many South Australians consume inadequate Se to maximise selenoenzyme expression and cancer protection, and indicated that levels had declined around 20% from the 1970s. No significant genotypic variability for grain Se concentration was observed in modern wheat cultivars, but the diploid wheat Aegilops tauschii L. and rye (Secale cereale L.) were higher. Grain Se concentrations ranged 5-720 microg/kg and it was apparent that this variation was determined mostly by available soil Se level. Field trials, along with glasshouse and growth chamber studies, were used to investigate agronomic biofortification of wheat. Se applied as sodium selenate at rates of 4-120 g Se/ha increased grain Se concentration progressively up to 133-fold when sprayed on soil at seeding and up to 20-fold when applied as a foliar spray after flowering. A threshold of toxicity of around 325 mg Se/kg in leaves of young wheat plants was observed, a level that would not normally be reached with Se fertilisation. On the other hand sulphur (S) applied at the low rate of 30 kg/ha at seeding reduced grain Se concentration by 16%. Agronomic biofortification could be used by food companies as a cost-effective method to produce high-Se wheat products that contain most Se in the desirable selenomethionine form. Further studies are needed to assess the functionality of high-Se wheat, for example short-term clinical trials that measure changes in genome stability, lipid peroxidation and immunocompetence. Increasing the Se content of wheat is a food systems strategy that could increase the Se intake of whole populations.
A growth room study was conducted to compare responses to zinc of two barley (Hordeum vulgare L. ... more A growth room study was conducted to compare responses to zinc of two barley (Hordeum vulgare L. cw. Tarm and Hami-diye) genotypes differing in zinc (Zn) efficiency and to deter-mine a critical deficiency concentration of Zn in tissue. Two genotypes of barley, Tarm (Zn efficient) and ...
Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley ... more Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley (Hordeum vulgare) genotypes, but the underlying mechanisms for the variation remain elusive. High-and low-affinity phosphate (Pi) PHT1 transporters play an indispensable role in P acquisition and remobilization. However, little is known about genetic variation in PHT1 gene expression and association with P acquisition efficiency (PAE) and P utilization efficiency (PUE). Here, we present quantitative analyses of ...
Abstract Selenium (Se) and iodine (I) are essential micronutrients for humans and animals, and de... more Abstract Selenium (Se) and iodine (I) are essential micronutrients for humans and animals, and deficient and marginal intakes are widespread. Staple cereals with superior ability to take up these elements from the soil and load them into grain have the potential to improve the Se and I status of whole populations. In this study, diverse cereal germplasm from surveys and field trials conducted in Australia, Mexico, Nigeria and the USA, was evaluated for genotypic variation in grain density of Se and I. Much of the variation in grain Se ...
The 11th International Wheat Genetics Symposium proceedings Edited by Rudi Appels Russell Eastwood Evans Lagudah Peter Langridge Michael Mackay Lynne, 2008
Drought stress is a pervasive feature of wheat production in many of the world's major cerea... more Drought stress is a pervasive feature of wheat production in many of the world's major cereal-growing regions. To improve the productivity in these areas the importance of traits associated with tolerance to drought needs to be quantified. Yield is a complex trait and many physiological, morphological and developmental characteristics have been suggested as being important to yield in water limited environments. However, yield can be considered in terms of a few fundamental processes: the ability of the crop to use the available ...
Chloride (Cl) is an essential micronutrient for plant growth, but can be toxic at high concentrat... more Chloride (Cl) is an essential micronutrient for plant growth, but can be toxic at high concentrations resulting in reduced2 growth and yield. Although saline soils are generally dominated by both sodium (Na) and Cl+ 2 ions, compared to Na+ toxicity, very little is known about physiological and genetic control mechanisms of tolerance to Cl toxicity. In hydroponics2 and field studies, a bread wheat mapping population was tested to examine the relationships between physiological traits [Na, potassium (K) and Cl concentration] involved in salinity tolerance (ST) and seedling growth or grain yield, and to+ + 2 elucidate the genetic control mechanism of plant Cl accumulation using a quantitative trait loci (QTL) analysis approach.2 + 2 accordance with phenotypic responses, QTL controlling Cl accumulation differed entirely between hydroponics and field2 locations, and few were detected in two or more environments, demonstrating substantial QTL-by-environment interactions. The presence of s...
Zinc deficiency limits yield of cereals on vast areas in the world, and developing genotypes with... more Zinc deficiency limits yield of cereals on vast areas in the world, and developing genotypes with the ability to grow and yield on zinc deficient soils is considered a long-term sustainable approach. A good understanding of this ability will facilitate breeding for this ...
More than half the world’s population is at moderate to high risk of zinc (Zn) deficiency, and bi... more More than half the world’s population is at moderate to high risk of zinc (Zn) deficiency, and biofortification has become an important strategy to alleviate the problem. Grain loading is likely to be a major bottleneck in cereal biofortification. However, very little is known about the transporters involved in this process. We have used barley as a model system to study the transporter genes which are potentially important in grain Zn loading. Here we report effect of over-expressing a barley ZIP gene in barley on grain Zn content. Our results showed that when the transgenic plants were grown at low Zn supply, grain Zn concentrations of transgenic lines were not different from those of the null lines, but with a low dose of Zn supplement during anthesis grain Zn content in transgenic lines increased by 50%. When plants were grown at a high Zn supply, grain Zn concentration of the transgenic lines was doubled relative to the null lines and wildtype. The enhanced concentration of Zn ...
Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley ... more Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley (Hordeum vulgare) genotypes, but the underlying mechanisms for the variation remain elusive. High- and low-affinity phosphate (Pi) PHT1 transporters play an indispensable role in P acquisition and remobilization. However, little is known about genetic variation in PHT1 gene expression and association with P acquisition efficiency (PAE) and P utilization efficiency (PUE). Here, we present quantitative analyses of transcript levels of high- and low-affinity PHT1 Pi transporters in four barley genotypes differing in PAE. The results showed that there was no clear pattern in the expression of four paralogs of the high-affinity Pi transporter HvPHT1;1 among the four barley genotypes, but the expression of a low-affinity Pi transporter, HvPHT1;6, and its close homolog HvHPT1;3 was correlated with the genotypes differing in PUE. Interestingly, the expression of HvPHT1;6 and HvPHT1;3 was correla...
Journal of Trace Elements in Medicine and Biology, 2005
More than 2 billion people consume diets that are less diverse than 30 years ago, leading to defi... more More than 2 billion people consume diets that are less diverse than 30 years ago, leading to deficiencies in micronutrients, especially iron (Fe), zinc (Zn), selenium (Se), iodine (I), and also vitamin A. A strategy that exploits genetic variability to breed staple crops with enhanced ability to fortify themselves with micronutrients (genetic biofortification) offers a sustainable, cost-effective alternative to conventional supplementation and fortification programs. This is more likely to reach those most in need, has the added advantages of requiring no change in current consumer behaviour to be effective, and is transportable to a range of countries. Research by our group, along with studies elsewhere, has demonstrated conclusively that substantial genotypic variation exists in nutrient (e.g. Fe, Zn) and nutrient promotor (e.g. inulin) concentrations in wheat and other staple foods. A rapid screening technique has been developed for lutein content of wheat and triticale, and also for pro-vitamin A carotenoids in bread wheat. This will allow cost-effective screening of a wider range of genotypes that may reveal greater genotypic variation in these traits. Moreover, deeper understanding of genetic control mechanisms and development of molecular markers will facilitate breeding programs. We suggest that a combined strategy utilising plant breeding for higher micronutrient density; maximising the effects of nutritional promoters (e.g. inulin, vitamin C) by promoting favourable dietary combinations, as well as by plant breeding; and agronomic biofortification (e.g. adding iodide or iodate as fertiliser; applying selenate to cereal crops by spraying or adding to fertiliser) is likely to be the most effective way to improve the nutrition of populations. Furthermore, the importance of detecting and exploiting beneficial interactions is illustrated by our discovery that in Fe-deficient chickens, circulating Fe concentrations can be restored to normal levels by lutein supplementation. Further bioavailability/bioefficacy trials with animals and humans are needed, using varying dietary concentrations of Fe, Zn, carotenoids, inulin, Se and I to elucidate other important interactions in order to optimise delivery in biofortification programs.
Journal of Trace Elements in Medicine and Biology, 2005
Selenium (Se) is an essential micronutrient for humans and animals, but is deficient in at least ... more Selenium (Se) is an essential micronutrient for humans and animals, but is deficient in at least a billion people worldwide. Wheat (Triticum aestivum L.) is a major dietary source of Se. The largest survey to date of Se status of Australians found a mean plasma Se concentration of 103 microg/l in 288 Adelaide residents, just above the nutritional adequacy level. In the total sample analysed (six surveys from 1977 to 2002; n = 834), plasma Se was higher in males and increased with age. This study showed that many South Australians consume inadequate Se to maximise selenoenzyme expression and cancer protection, and indicated that levels had declined around 20% from the 1970s. No significant genotypic variability for grain Se concentration was observed in modern wheat cultivars, but the diploid wheat Aegilops tauschii L. and rye (Secale cereale L.) were higher. Grain Se concentrations ranged 5-720 microg/kg and it was apparent that this variation was determined mostly by available soil Se level. Field trials, along with glasshouse and growth chamber studies, were used to investigate agronomic biofortification of wheat. Se applied as sodium selenate at rates of 4-120 g Se/ha increased grain Se concentration progressively up to 133-fold when sprayed on soil at seeding and up to 20-fold when applied as a foliar spray after flowering. A threshold of toxicity of around 325 mg Se/kg in leaves of young wheat plants was observed, a level that would not normally be reached with Se fertilisation. On the other hand sulphur (S) applied at the low rate of 30 kg/ha at seeding reduced grain Se concentration by 16%. Agronomic biofortification could be used by food companies as a cost-effective method to produce high-Se wheat products that contain most Se in the desirable selenomethionine form. Further studies are needed to assess the functionality of high-Se wheat, for example short-term clinical trials that measure changes in genome stability, lipid peroxidation and immunocompetence. Increasing the Se content of wheat is a food systems strategy that could increase the Se intake of whole populations.
A growth room study was conducted to compare responses to zinc of two barley (Hordeum vulgare L. ... more A growth room study was conducted to compare responses to zinc of two barley (Hordeum vulgare L. cw. Tarm and Hami-diye) genotypes differing in zinc (Zn) efficiency and to deter-mine a critical deficiency concentration of Zn in tissue. Two genotypes of barley, Tarm (Zn efficient) and ...
Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley ... more Genetic variation in phosphorus (P) efficiency exists among wheat (Triticum aestivum) and barley (Hordeum vulgare) genotypes, but the underlying mechanisms for the variation remain elusive. High-and low-affinity phosphate (Pi) PHT1 transporters play an indispensable role in P acquisition and remobilization. However, little is known about genetic variation in PHT1 gene expression and association with P acquisition efficiency (PAE) and P utilization efficiency (PUE). Here, we present quantitative analyses of ...
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