Biofortification of Edible Crops with Zinc

Transcription

1 Biofortification of Edible Crops with Zinc Philip J. White Plant Nutritional Genomics Martin R. Broadley University of Nottingham 5 th June 2012 COST FA0905, ETH Zurich

2 Mineral Malnutrition The Hidden Hunger If we had an extra $75 billion to put to good use, which problems would we solve first? INVESTMENT 1 Bundled Micronutrient Interventions, to fight hunger and improve education 2 Expanding the Subsidy for Malaria Combination Treatment 3 Expanded Childhood Immunization Coverage 4 Deworming of Schoolchildren, to improve educational and health outcomes 5 Expanding Tuberculosis Treatment 6 R&D to Increase Yield Enhancements, to decrease hunger, fight biodiversity destruction, and lessen the effects of climate change 7 Investing in Effective Early Warning Systems to protect against natural disaster 8 Strengthening Surgical Capacity 9 Hepatitis B Immunization 10 Using Low-Cost Drugs in the case of Acute Heart Attacks in poorer nations

3 Mineral Malnutrition The Hidden Hunger The greatest concern lies with deficiencies in Vitamin A, iron, iodine and zinc. Of the 7 billion people in the world, 60-80% are Fe deficient 30% are I deficient >30% are Zn deficient Of the agricultural soils in the world, 25-30% are alkaline with low Fe, Zn, Cu and Mn availability White & Broadley (2005) Trends in Plant Science 10, White & Broadley (2009) New Phytologist 182, 49-84

4 Increasing Mineral Concentrations In Edible Crops If mineral elements are absent from the soil they must be applied to crops as soil or foliar fertilisers If mineral elements are present in the soil, either agronomic or genetic strategies can be developed to increase their acquisition, or mineral elements can be added as soil or foliar fertilisers White & Broadley (2005) Trends in Plant Science 10, White & Broadley (2009) New Phytologist 182, 49-84

5 Increasing Zinc Concentrations In Edible Crops Through Agronomy the application of zinc fertilisers Biofortification of cereals brassicas & potatoes Through Genetics select or breed varieties that accumulate zinc Screening potato genotypes Screening brassica genotypes White & Broadley (2005) Trends in Plant Science 10, White & Broadley (2009) New Phytologist 182, 49-84

6 Mineral Concentrations of Edible Portions Physiological Constraints Movement of mineral elements to edible tissues White & Broadley (2005) Trends in Plant Science 10, White & Broadley (2009) New Phytologist 182, White & Broadley (2011) Frontiers in Plant Science 2:80

7 Mineral Concentrations of Edible Portions Physiological Constraints Genotypic Variation USDA Food Composition HarvestPlus Target White & Broadley (2011) Frontiers in Plant Science 2:80

8 Brassica oleracea a model crop brassica Borecole - kale Kohlrabi Cauliflower and Broccoli Cabbages Brussels sprout

9 Screening Brassica oleracea ( ) 10 standard genotypes at many P-fertilisation rates screened in glasshouse and field 74 commercial genotypes at two P-fertilisation rates in the glasshouse and field 90 informative genotypes AGDH genetic mapping population at two P-fertilisation rates in the glasshouse and field Core collection 376 genotypes at two P-fertilisation rates in the glasshouse

10 Genetic Variation in Zinc Concentrations In Shoots of Brassica oleracea h=0.7% h=12.4% h=18.5% h=13.4% Broadley et al. (2010) J. Hort. Sci. Biotech. 85,

11 Genetic Loci Impacting Zinc Concentrations In Shoots of Brassica oleracea Experiment Chromosome LOD Additive Effect (A12DHa allele) GE2 (Zn both P) 2 (82.2 cm) (69.2 cm) GE2 (Zn high P) 5 (54.7 cm) FE2 (Zn all P) 1 (91.2 cm) (21.1 cm) (38.5 cm) FE2 (298 kg ha -1 P) 1 (89.2 cm) (21.1 cm) (43.4 cm) (52.4 cm) FE2 (1125 kg ha -1 P) 7 (58.4 cm) Broadley et al. (2010) J. Hort. Sci. Biotech. 85,

12 Effects of Phosphorus Fertilisation on Shoot Zinc Concentrations of B. oleracea DFS, Glasshouse (GE1) Broadley et al. (2010) J. Hort. Sci. Biotech. 85,

13 Increasing Zinc Concentrations in Shoots of B. oleracea with Zn-fertilisers DFS, Glasshouse (GE4) Broadley et al. (2010) J. Hort. Sci. Biotech. 85,

14 Phytotoxicity Limits Zinc Biofortification of Shoots brassica lettuce spinach legumes Critical Shoot Zinc (mg / kg) cereals solanum MacNicol & Beckett (1985) Plant & Soil 85, White & Broadley (2011) Frontiers in Plant Science 2:80

15 Zinc in the UK Diet Percentage of Population % females < LRNI 4% males < LRNI female male LRNI female LRNI Male vegetables 6% potatoes 5% fruit & nuts 2% Zn Intake (dietary sources, mg d -1 ) Henderson et al. (2003) The National Diet & Nutrition Survey: Adults Aged 19 to 64 Years. London, HMSO.

16 Agronomic Biofortification of Potato Tubers with Zinc Scottish Government Programme 7 ( )

17 Agronomic Biofortification of Potato Tubers with Zinc White et al. (2012) J. Hort. Sci. Biotech. 87,

18 Biofortification of Rice Grain with Zinc Grain Zinc (mg kg -1 DM) Handao297 K150 Solution Zinc (µm) Jiang, Struik, van Keulen, Zhao, Jin, Stomph (2008) Ann. Appl. Biol. 153,

19 Relationship Between Tuber Zinc and Nitrogen Concentrations Tuber Zn concentration (mg kg -1 DM) y = 6.8x R 2 = y = 6.7x R 2 = 0.66 y = 6.3x R 2 = 0.62 y = 6.0x R 2 = Tuber N concentration (% DM) White et al. (2012) J. Hort. Sci. Biotech. 87,

20 Agronomic Biofortification of Cereal Grain with Zinc Zinc biofortification of durum wheat through soil and foliar applications of nitrogen-fertilisers Kutman et al. (2010) Cereal Chemistry 87, 1-9

21 Strategies for the Biofortification of Potato Tubers with Zinc zinc transport in the phloem is the process limiting Zn biofortification of potato tubers zinc is transported as Zn-nicotianamide Cereals overexpressing nicotianamine synthase (NAS) often have greater grain Zn concentrations Option A foliar N fertilisation Option B biosynthesis of nicotianamide Scottish Government Programme 7 ( )

22 Overexpression of OsNAS Genes Increases Zinc Concentrations in Unpolished Rice Johnson, Kyriacou, Callahan, Carruthers, Stangoulis, Lombi, Tester (2011) PLoS ONE 6(9): e24476

23 Overexpression of OsNAS Genes Increases Zinc Concentrations in Unpolished Rice Johnson et al. (2011) PLoS ONE 6(9): e24476

24 Biofortification of Rice Grain with Zinc Grain Zinc (mg kg -1 DM) Handao297 K150 Solution Zinc (µm) Jiang et al. (2008) Ann. Appl. Biol. 153,

25 The Genetics of Biofortification Potatoes, Brassicas & Cereals Potatoes Commonwealth Potato Collection Neotuberosum Collection Commercial Core Collection Mapping Populations Brassicas (B. oleracea) WHRI Core Collection Mapping Populations Cereals (barley) Commercial Collection Mapping Populations Bowman Mutant Collection Induced Mutant Collections

26 Phureja Potatoes Diploid Popular in parts of the Andes Selected at SCRI for UK conditions Excellent flavour Reduced cooking time Commercial Varieties: Mayan Gold & Inca Sun (2001), Inca Dawn (2003), Mayan Queen, Mayan Star & Mayan Twilight (2008)

27 Tuber Zinc Concentrations in S. tuberosum groups Phureja & Tuberosum 16 Tuber Zinc (mg g -1 DM) H P T Solanum tuberosum Group Subramanian (2012) PhD Thesis. University of Nottingham

28 Zinc in Tubers of Tuberosum Potato Varieties (effects of increased yield) Tuber Zinc (mg kg -1 DM) Tuber Yield (kg / plot) White et al. (2009) HortScience 44, 6-11 Subramanian et al., data from four field trials of 23 genotypes

29 Mg (40% var) Maturity (53% var) S (27% var) Genetic Loci Impacting Tuber Mineral Concentrations Yield (7% var) Mn (20% var) Zn (13% var) K (22% var) Tetraploid mapping population (12601 ab1 x Stirling ) - Bradshaw et al. (2008) Theor Appl Genetics 116, Software ( QTLs impacting tuber mineral concentrations Cu (10% var) Ca (10% var) - LG V of Stirling (QTLs for minerals, yield and maturity) - QTLs for several mineral elements Stirling LG V contains QTL for both maturity and several mineral elements

30 Zinc in Tubers of Tetraploid Potato Varieties (effects of maturity) 16 Tuber Zinc (mg kg -1 DM) Maturity Score Subramanian et al., unpublished. (mean data from field trials in 2007 and 2008)

31 Potatoes (crop longevity increases tuber yield) Tuber dry matter (g m -2 ) Wilja Cara Intercepted radiation (MJ m -2 ) Harris (1992) The Potato Crop. Chapman & Hall, London

32 Genetic Loci Impacting Tuber Zinc Concentrations LG XIa Stirling LG B (XII) ab1 LG II LG III LG VI LG XIc AtOPT3 LeNRAMP1 Zn-2007 LeNRAMP3, HMA, YSL LeIRT1 & LeIRT2 Zn-2007 Zn-2007 Zn Zn-2007 Zn-2009 Zn-2008 Zn-2009 Zn-2007 Zn-2009 Zn-2008 YSL YSL Zn-2007 Zn-2008 Subramanian et al., unpublished.

33 Combining Agronomy and Genetics To Increase Zinc Concentrations in Potatoes Tuber Zn (μg g -1 DM) Scottish Government Programme 7 ( ) UK Food Tables Vales Everest VE-ZC-D2X4 VE-ZC-D2X4+U VE-ZS-D2X4 VE-ZS-D2X4+U 12601ab1 126-ZC-D2X4 126-ZC-D2X4+U 126-ZS-D2X4 126-ZS-D2X4+U Golden Millenium GM-ZC-D2X4 GM-ZC-D2X4+U GM-ZS-D2X4 GM-ZS-D2X4+U Saxon SX-ZC-D2X4 SX-ZC-D2X4+U SX-ZS-D2X4 SX-ZS-D2X4+U

34 Combining Agronomy and Genetics To Increase Zinc Concentrations in Potatoes Zinc (μg g -1 DM) Saxon (30-45 mm) Flesh Skin Flesh Skin Flesh Skin control D2X4 D2X4+U Scottish Government Programme 7 ( )

35 Combining Agronomy and Genetics To Increase Zinc Concentrations in Potatoes peeled potatoes = 10 mg kg -1 DM peeled biofortified Saxon potatoes = 50 mg kg -1 DM increase UK dietary Zn intake 20% Percentage of Population % to 2.2% males < LRNI Zn Intake (dietary sources, mg d -1 ) Scottish Government Programme 7 ( ) conventional biofortified LRNI Male

36 Summary Many people s diets lack sufficient zinc Zinc concentrations in edible crops can be increased by agronomic or genetic strategies Leaves generally have greater Zn concentrations than seeds or tubers Leaf Zn concentration limited by phytotoxicity Seed and tuber Zn concentrations limited by phloem mobility Seed and tuber Zn concentrations correlate with N concentrations Significant natural genetic variation in Zn concentrations of brassicas but huge environmental effects (e.g. P or Zn supply) Zn concentration of potato tubers is associated with maturity class Minor QTL perhaps linked to genes for transport proteins Biofortification of Edible Crops with Zinc

37 Acknowledgements Zinc in Brassica Martin Broadley, John Hammond, Joe Ó Lochlainn (Nottingham); Helen Bowen (WHRI); Graham King (Southern Cross); Ismail Cakmak (Sabanci); Selim Eker, Halil Erdem (Cukurova). Zinc in Potato Nithya Subramanian, Gavin Ramsay, John Bradshaw, Finlay Dale, Glenn Bryan, Ralph Wilson, Jackie Thompson, Gladys Wright (JHI); Christine Hackett (BioSS); Martin Broadley, John Hammond (Nottingham).

38 Summary Many people s diets lack sufficient zinc Zinc concentrations in edible crops can be increased by agronomic or genetic strategies Leaves generally have greater Zn concentrations than seeds or tubers Leaf Zn concentration limited by phytotoxicity Seed and tuber Zn concentrations limited by phloem mobility Seed and tuber Zn concentrations correlate with N concentrations Significant natural genetic variation in Zn concentrations of brassicas but huge environmental effects (e.g. P or Zn supply) Zn concentration of potato tubers is associated with maturity class Minor QTL perhaps linked to genes for transport proteins Biofortification of Edible Crops with Zinc