Selenium concentrations in UK wheat and biofortification strategies
1
2006 Plos Genetics 2(12): e210.). By varying the concentrations of multiple nutrients in the soil, we have observed several unexpected alterations in the ionome, including significant differences in the accumulation of macro- and micronutrients in response to changing soil iron levels. In a complementary reverse genetic approach we have also characterized over 1000 unique sequenced T-DNA insertional alleles for genes that affect the shoot ionome. To maximize the value of this ionomics approach, we have developed a publicly searchable online database containing ionomic information on over 60,000 plants (www. purdue.edu/dp/ionomics; Baxter et al., 2007 Plant Physiol 143(2) in press), and the database is being updated regularly. doi:10.1016/j.cbpa.2007.01.570 P4.9 Selenium concentrations in UK wheat and biofortification strategies F. Zhao, S. McGrath, C. Gray, J. Lopez-Bellido, (Rothamsted) μμSelenium is essential for humans and animals but has no known function in plants. Dietary intake of selenium is low in a large number of people worldwide. In some European countries, dietary Se intakes have decreased significantly in recent decades. For example, average Se intake of UK adults has decreased by more than 40% from the mid 1970s to 1995. The main reason for this trend is the decreased importation of bread- making wheat from North America, which generally contains much more Se than European wheat. Our survey of 452 grain samples of bread-making wheat produced in the UK shows a range of 6–858 μg Se/kg dry weight with a mean and median of 32 and 22 μg Se/kg, respectively. Furthermore, 91% of the samples contained <50 μg Se/kg, which is considered to be insufficient for the requirements of humans and animals. The main reason for the generally low Se status in UK wheat is a low Se supply from soil. Other soil factors such as pH, organic matter content and the availability of sulphate also have a major influence on selenium uptake by plants. Because cereals are an important source of Se to humans, Se biofortification of wheat would have a desirable effect on increasing human Se intake. Results from a field trial show that grain Se concentration was increased by 3–27 fold by additions of 10–20 g Se/ha as sodium selenate at the stem extension stage. Other strategies of Se biofortification, such as genetic improvement to enhance Se accumulation potential, should also be explored. doi:10.1016/j.cbpa.2007.01.571 P4.10 Genetic aspects of mineral biofortification P. White, (SCRI); M. Broadley, (University of Nottingham) Humans require at least 22 mineral elements. These can all be supplied by an appropriate diet. Nevertheless, over 60% of the world's 6 billion people are Fe deficient, over 30% are Zn deficient, 30% are I deficient and about 15% are Se deficient (White and Broadley, TiPS 10: 586–593, 2005). Deficiencies of Ca, Mg and Cu are also common. Mineral malnutrition can be addressed through supplementation, food fortification or dietary diversification, but these interventions have had limited success. ‘Biofortification’ is a complimentary strategy that aims to increase bioavailable concentrations of essential elements in edible portions of crop plants by applying mineral fertilizers and/ or growing crops that accumulate minerals more effectively. Since fertilisers impose a financial and environmental burden, and many infertile soils contain sufficient minerals to support mineral-dense crops if they became phytoavailable, there is considerable interest in breeding for mineral-dense crops that produce high yields on infertile soils. This presentation will first describe the contrasting mineralogies of angiosperm orders and quantify the phylogenetic impacts on species' mineral composi- tion. These data support the hypothesis that a change from bean- rich to cereal-rich diets can increase the incidence of Ca, Zn and Fe deficiencies in rural populations. It will then consider variation in mineral composition within plant orders and species. The survey supports the hypothesis that sufficient genetic variation exists in most crop species to breed mineral-dense crops for infertile soils. Such studies provide the platform to identify genes that underpin agriculturally-useful mineralogical traits and develop molecular markers to assist plant breeding. doi:10.1016/j.cbpa.2007.01.572 P4.11 Natural genetic variation in the mineral nutrient composition of Brassica oleracea M. Broadley, M. Meacham, (University of Nottingham); H. Bowen, J. Hammond, R. Hayden, A. Mead, G. Teakle, (University of Warwick); G. King, (Rothamsted Research); P. White, (Scottish Crop Research Institute) Plants require at least 14 mineral elements to complete their life cycles, which are acquired primarily from the soil. The mineral composition of plant tissues varies widely due to environmental factors, such as soil mineral availability, and due to plant developmental and genetic factors. Substantial natural genetic variation in the mineral composition of plant tissues occurs between populations and varieties of the same species. This within-species variation is being used in genetic biofortification programmes, i.e. to breed staple crops with higher mineral contents in their edible portions to alleviate human dietary mineral deficiencies. A significant proportion of the variation in the leaf composition of some minerals (e.g. Ca, K, Mg, Si, Zn) has also been attributed to phylogenetic effects occurring above the species level, for example, at the family level and above. Here, we conducted a thorough, species-wide, genetic dissection of mineral composition using Brassica oleracea L. (Brassicaceae) as a S246 Abstracts / Comparative Biochemistry and Physiology, Part A 146 (2007) S243–S253
Selenium concentrations in UK wheat and biofortification strategies
main reason for the generally low Se status in UK wheat is a
lowSe supply from soil. Other soil factors such as pH, organic
variation in mineral composition within plant orders and
species.
d Phmatter content and the availability of sulphate also have a
majorinfluence on selenium uptake by plants. Because cereals are
animportant source of Se to humans, Se biofortification of
wheatwould have a desirable effect on increasing human Se
intake.Results from a field trial show that grain Se concentration
wasincreased by 327 fold by additions of 1020 g Se/ha as
sodiumselenate at the stem extension stage. Other strategies of
Sebiofortification, such as genetic improvement to enhance
Seaccumulation potential, should also be explored.
doi:10.1016/j.cbpa.2007.01.571
P4.102006 Plos Genetics 2(12): e210.). By varying the
concentrationsof multiple nutrients in the soil, we have observed
severalunexpected alterations in the ionome, including
significantdifferences in the accumulation of macro- and
micronutrients inresponse to changing soil iron levels. In a
complementary reversegenetic approach we have also characterized
over 1000 uniquesequenced T-DNA insertional alleles for genes that
affect theshoot ionome. To maximize the value of this ionomics
approach,we have developed a publicly searchable online
databasecontaining ionomic information on over 60,000 plants
(www.purdue.edu/dp/ionomics; Baxter et al., 2007 Plant Physiol
143(2)in press), and the database is being updated regularly.
doi:10.1016/j.cbpa.2007.01.570
P4.9Selenium concentrations in UK wheat and
biofortificationstrategies
F. Zhao, S. McGrath, C. Gray, J. Lopez-Bellido, (Rothamsted)
Selenium is essential for humans and animals but has noknown
function in plants. Dietary intake of selenium is low in alarge
number of people worldwide. In some European countries,dietary Se
intakes have decreased significantly in recentdecades. For example,
average Se intake of UK adults hasdecreased by more than 40% from
the mid 1970s to 1995. Themain reason for this trend is the
decreased importation of bread-making wheat from North America,
which generally containsmuch more Se than European wheat. Our
survey of 452 grainsamples of bread-making wheat produced in the UK
shows arange of 6858 g Se/kg dry weight with a mean and median of32
and 22 g Se/kg, respectively. Furthermore, 91% of thesamples
contained
