Biofortification of rice


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A description of the history, variation in methods/ approaches for biofortifying rice, benefits and challenges faced with biofortified rice and consequences for future generations..

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Biofortification of rice

  1. 1. BIOFORTIFICATION OF RICE FOOD BIOTECHNOLOGY PRESENTATION BY EUGENE MADZOKERE 4.1 Biotech Undergrad Student Chinhoyi University of Technology (Zim)
  2. 2. PRESENTATION OUTLINE  INTRODUCTION: -What is Biofortification? -Reason for Rice Biofortification -Micronutrients Biofortified into Rice -Methods used to Biofortify Rice -Where Biofortification is done?   TYPES OF RICE BIOFORTIFICATION IN DETAIL: CONCLUSION: Advantages & Disadvantages?  REFERENCES:
  3. 3. INTRODUCTION: Biofortification: “The development of nutrient dense staple crops using the best traditional breeding practices and modern biotechnology”.  It makes foods more nutritious as plants are growing rather than having nutrients added to plant foods during processing. 
  4. 4. Reason for Rice Biofortification     Rice is a staple food crop for more than one billion poor people The Rice endosperm (starchy & most edible part of rice seed) is deficient in many nutrients including vitamins, proteins, micronutrients, EAAs, etc. The Aleurone layer of dehusked rice grains is nutrient rich but is lost during milling and polishing Unprocessed rice becomes rancid i.e. smelly or unpleasant in taste
  7. 7. Micronutrients Biofortified into Rice:  Vitamin A (Retinol) – Golden Rice  Iron  Zinc  Vitamin B9 (Folic acid/ Folate)  Glycinin
  8. 8. Methods used for Rice Biofortification:  Agrobacterium mediated gene transfer  Particle gene gun method
  9. 9. Where is Biofortification done? India  China  USA  Phillipines  Vietnam  Bangladesh  Japan 
  10. 10. Vitamin A Rice Biofortification:        Done by Prof. Ingo Potreykus & Dr. Peter Beyer Because the rice endosperm lacks vitamin A and; Vitamin A deficiency causes night blindness; impaired vision, epithelial tissue integrity, immune response; hematopoiesis & skeletal growth mostly in young children aged 1-5 years old Biofortification involved introduction of three genes in rice grain via Agrobacterium tumefaciens: 1. phytoene synthase (psy) – daffodil (Narcissus pseudonarcissus) 2. lycopene B - cyclase (crt) – daffodil (Narcissus pseudonarcissus) 3. phytoene desaturase – bacterium (Erwinia uredovora)
  11. 11. Vitamin A Rice Biofortification: Successful production of Golden rice 1 (GR1) and Golden rice 2 (GR2)  GR1- yield of 1.6µg provitamin A/g in endosperm  GR2- higher yield of 31µg/g provitamin A in endosperm by replacement of psy gene from daffodil with a psy gene from maize  72µg of GR2 could provide the recommended daily vitamin A allowance for 1-3 year olds, because they consume 100200g of rice per meal. 
  12. 12. Vitamin A Biofortification: Engineering The Carotenoid Biosynthetic Pathway Phytoene synthase GGPP (C20) Phytoene (C40) Phytoene desaturase (PDS) CRT 1 C-Carotene Zeta carotene desaturase (ZDS) Lycopene Lycopene β- cyclase B-carotene Vitamin A
  13. 13. Iron (Fe) Biofortification of Rice: Iron (Fe) is a redox - active constituent of the catalytic site of heme and non-heme iron proteins  Metabolic functions of Fe include: 1. Serving as an element in blood production 2. Serving as a component of enzymes involved in synthesis of collagen & some neurotransmitters 3. Providing a transport medium for electrons within the cells in the form of cytochromes 4. Being a structural component of haemoglobin 
  14. 14. Iron Biofortification of Rice: Consequences of Fe deficiency include: 1. Blood loss leading up to Sickle Cell Anaemia 2. Causes Gastro-intestinal blood loss in men & post-menopausal women Normal RBC Sickled RBC 
  15. 15. Iron Biofortification of Rice:  In the Fe-Rice Biofortification process; 1. Three genes were introduced into a) b) c) the Japonica rice variety: Ferritin – enhances iron storage in grains & was expressed under an endosperm specific promoter. Nicotianamine synthase – was expressed under a constitutive promoter & produces nicotinamine which chelates iron temporarily facilitating its transport in plants Phytase – degrades phytate
  16. 16. Zinc Biofortification of Rice: Zn is an important micronutrient: 1. Critical in tissue growth, wound healing, connective tissue growth & maintenance, immune system function, prostaglandin production, bone mineralization, proper thyroid function, blood clotting, cognitive functions, fetal growth & sperm production 2. It plays an important role in the health of skin, bones, hair, nails, muscles, nerves & brain function.  3. Is required for metabolic activity of enzymes (as a cofactor) involved in repair & replacement of body cells. 4. Its essential for cell division & synthesis of DNA & proteins
  17. 17. Zinc Biofortification of Rice: Zn deficiency leads to: 1.Impairment of physical growth, immune system & learning ability 2.Fetal brain cell disease & affects mental development in pregnant mothers 3.Hindered normal growth and development in children 4.Increased risk of infections, DNA damage & cancer 
  18. 18. Zinc Biofortification of Rice:  In the Zn-Rice Biofortification process; • Three (3) genes of the OSNAS family • • • • were introduced into Japonica rice cultivar Nipponbarp These three genes encode production of nicotianamine (NA) - a chelator of transition metals that facilitates uptake & transport of metal cations including, Zn2+ Specific over-expression of OSNAS resulted in significant increase in NA concentration and Zn OSNAS 2 activation had 20 fold more NA & 2.7 fold Zn in polished rice grains OSNAS 3 activation was reported to reverse signs of Fe-deficiency when fed to anaemic mice
  19. 19. Folate Biofortification of Rice:    Folates (vitamin B9) are tripartite molecules containing the pterin moiety, PABA, & one or several Glutamate residues It plays a major role in the methylation & in DNA biosynthesis Biofortification is achieved by overexpressing 2 Arabidopsis thaliana genes of the pterin and para-aminobenzoate branch of the biosynthetic pathway from a single locus
  20. 20. Folate Biofortification of Rice: Folate biosynthesis requires the plastid chromate pathway intermediate (PABA) & Pterin precursor from GTP  Rice engineered using targeted expression of GTPCHI & ADCS to increase folic acid biosynthesis in seeds  Transformed plants with ADCS had 49 fold increase in levels of PABA 
  21. 21. Folate Biofortification of Rice: Folate dietary deficiency results in : 1. Neural tube defects e.g. Spina bifida 2. Cardio vascular diseases 3. Different forms of dementia 4. Megaloblastic anaemia 
  22. 22. Glycinin Biofortification of Rice: Glycinin is a lysine rich globulin protein found in soybean seeds  Lysine is an essential amino acid (EAA)  Rice seed endosperm is deficient in lysine  Glycinin accounts for more than 20% seed dry weight & is a reserve for carbon & nitrogen used in seed germination  Five Glycinin genes: Gy1; Gy2; Gy3; Gy4; & Gy5 
  23. 23. Glycinin Biofortification of Rice: Four molecular approaches that are commonly used: 1. modifying the higher protein sequence of a major crop protein to contain higher content of desired EAA 2. Producing a synthetic protein rich in target EAA 3. Expressing a heterologous protein with high content of desired EAA 4. Manipulating the expression of a homologous protein for desired EAA 5. By increasing the pool of a specific free EAA through metabolic engineering 
  24. 24. Glycinin Biofortification of Rice:     Approach 4 was used Biofortification involved insertion of 4 contiguous methionine residues into the 11S variable regions of the soybean Glycinin gene corresponding to the C-terminal regions of the acidic & basic polypeptides Modified Met-rich soybean Glycinin gene under control of GluB-1 promoter was transformed using Agrobacterium tumefaciens and expressed in rice, 5% total glycinin protein was obtained
  25. 25. Glycinin Biofortification of Rice: Mainly introduced because it is a seed storage protein which is lacking in the rice grain  Lysine facilitates normal growth & development; lowering of serum cholesterol; LDL cholesterol – hence lowered risk of heart disease  Effects of lysine deficiency include: 1. Hair loss or Poor growth 2. Excessive fatigue & mood changes 3. Loss of Appetite 4. Anemia  Supplements or food sources should provide 12mg/kg body weight of lysine/day 
  26. 26. CONCLUSION: Advantages of Rice Biofortification Advantages of biofortification of rice include: Increase in nutritional value .i.e. bioavailable Vitamin A & B6; Fe; Protein (glycinine) & Zn 2. Increase in yield e.g. Rice biofortified with Glycine betaine for enhanced abiotic stress tolerance 3. Reduced adult & child micronutrient caused mortality 4. Reduced dietary deficiency diseases e.g. Blindness in children, diarrhoea, anemia 5. Healthier populations with strong and quick immune responses to infections.  1.
  27. 27. CONCLUSION: Disadvantages of Rice Biofortification  1. 2. 3. 4. 5. Disadvantages of biofortification of rice include: High production costs .i.e. equipment, technology, patenting, etc; Potential negative interaction of biofortified rice on other plants/ non-GM rice crops causing loss of wild-type rice varieties Low substantial equivalence- i.e. inability to provide high micronutrient and protein content compared to supplements Poor rural populations have limited access & resources to purchase biofortified rice Genetic engineering methods used may compromise immunity in humans .i.e. introduce increased risk of allergenicity
  28. 28. REFERENCES:   Sun, S.S.M., Liu, Q.Q. (2004). Trangenic approaches to improve the nutrional quality of plant proteins. In Vitro Cell Development. Biology Plants. 40: pp. 155-162 Katsube, T., Kurisaka, N., Ogawa, M., Maruyama, N., Ohtsuka, R., Utsumi, S., and Takaiwa, F. (1999). Accumulation of soybean glycinin and its assembly with glutelins in rice. Plant Physiology. 120: pp. 1063-1073