Biofortifying Vegetable Crops with
Selenium
Hassan El-Ramady1,3, Neama Abdalla2,3,
Éva Domokos Szabolcsy3 and Miklós fári3
(1) Soil and Water Dept., Agriculture Fac., Kafrelsheikh Uni., Egypt,
(2) Plant Biotechnology Dept., National Research Center, Giza, Egypt,
(3) Plant Biotechnology Dept., Debrecen Uni., Debrecen, Hungary
Outlines
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Characterization of Selenium
Selenium in food-chain and human health
Selenium in agroecosystems
Selenium biofortification
Further research
Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
1- Selenium characterization
Selenium is a contradictory nutrient
called the essential poison or
double-edged sword element or
two-faced element (like the moon)
Name origin: Se from Greek word Selēnē (the moon)
Discovery: by J. Berzelius (1817)
Essentiality:
for humans and animals (Schwarz & Foltz 1957)
for some lower plants, algae (Lindstrom 1983)
NOT yet for higher plants (Terry et al. 2000)
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Selenium in the Periodic Table
Selenium is chemically related to Group 16/VIA
(chalcogen group), which includes Oxygen (O),
Sulfur (S), Tellurium (Te), and Polonium (Po)
Therefore, it is classified as a half metal or
metalloid
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Biofortifying vegetable crops with
Selenium (ACS, Long Beach, CA,
USA)
Selenium: the new/old essential poison
Se is essential component of glutathione peroxidase (Combs 2005) and
an essential constituent of some 25 selenoenzymes (Zeng et al. 2013)
Se highly toxic Se carcinogenic
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Se essential
Se anticarcinogenic
Source: L.N. Vernie (1984)
Selenium deficiency and toxication in human
• Deficiency:
- Muscle weakness and pain
– Fragile red blood cells
- Kashin-beck disease: disorder of
the bones and joints:
osteoarthropahty
- Keshan disease (cardiomyopathy)
• Toxication:
–
–
–
–
–
Hair and nail fall (loss)
Liver and kidneys damage
Necrosis of heart and liver
Blood clotting
Nausea and vomiting
RDA (Recommended dietary allowance) of
Selenium (adjusted to body weight)
Men70 μg
Women55 μg
The range between Se deficiency (< 40 μg d-1) and toxicity
(> 400 μg d-1) is very narrow (Plant et al. 2005)
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
2- Food-chain selenium and human health
How selenium gets into the food chain
Selenium enters the food chain through:
- Plants or food crops
- Intake through drinking water, trivial (Reilly 2006)
The amount of Selenium in foods depends on:
- Se concentration in soil
- Bioavailability of Selenium to plants
This bioavailability dependent on:
- Soil pH, and redox conditions, microbial activity,
- Soil organic matter content, soil moisture
- Competing ionic species such as sulfate,
- Soil texture,
- Pedoclimatic variables (temperature, rain) (Rayman 2008)
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Table 1: Typical Se contents (μg/g) of major classes of
foods from several countries (adapted from Combs 2005)
Food
England
Germany
Cereal products 0.03-0.66
0.02-0.53
0.03-0.88 0.005-0.12
China
Se-def. area
0.005-0.02
Vegetables
0.001-0.1
0.01-0.09
0.04-0.10 0.001-0.02
0.002-0.02
Fruits
0.002-0.01 0.005-0.01 0.002-0.04 0.002-0.03
0.001-0.003
Red meats
0.05-0.27
0.05-0.14
0.13-0.28
0.01-0.07
0.01-0.03
Poultry
0.04-0.15
0.05-0.15
0.05-0.15
0.05-0.10
0.02-0.06
Fish
0.19-1.9
0.10-0.61
0.24-0.53
0.18-0.98
0.03-0.20
Milk products
0.01-0.24
0.01-0.08
0.01-0.10
0.01-0.09
0.002-0.01
Eggs
0.06-0.20
0.05-0.20
0.05-0.20
0.10-0.20
0.02-0.06
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USA
Finland
Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Table 2: Thresholds values for Se in food and forage
Source: Kabata-Pendias and Mukherjee (2007)
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
3- Selenium in agroecosystems
Selenium forms and sources
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Table 3: Abundance of selenium in different environments comparing
with some micronutrients and beneficial mineral elements
Element
Earth
crust
Igneous
rock, acid
B
Cl
10
145
10 – 30 120-130
300 – 850 500-800
Co
Cu
10-12
26
Mn
950
Mo
Ni
Se
Zn
Sedimentary rocks
Argi.
Sandstone Calcareous
30 – 35
50-270
1-15
5 – 30
14-20
40 – 60
0.3-10
5 – 30
350-1200
400-850
100-500
1.2
1–2
20
5 – 20
0.05 0.01–0.05
52-80 40 – 100
2 – 2.5
40 – 90
0.3–0.6
80–120
0.2 – 0.8
5 – 20
0.01–0.08
15 – 30
Soils,
Water
mg kg-1 (µg l-1)†
Air ‡
(ng m-3)
20 – 30
50-350
15 – 35 10–100
–
300
501–7
2700
0.1-3.0
8.0
0.15
0.05
2 – 10
20
0.27- 150-1600
3.5
200-1000
500.2-130 2.8-4.5
2000
0.2 – 0.4
1.8
0.1
< 0.2
5 – 20
19 – 22
0.8
0.9
0.03–0.10
0.44
0.07
0.2
10 – 25
63
3.5-10 18 – 41
Abbreviations: Argi., Argillaceous; † Water of river; ‡ Greenland
Source: compiled from Kabata-Pendias and Mukherjee (2007) and Kabata-Pendias (2011)
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Table 4: Soil factors affecting the mobility of selenium and impact of
soil pH–Eh system on the formation of soluble Se species
Soil factors
Selenium form
Mobility
Soil acidity (pH)
High (alkaline)
Selenates (Se6+)
High
Medium (neutral)
Selenites (Se4+)
Moderate
Low (acid)
Selenides (Se2–)
Low
Redox potential (Eh)
High (high oxidation, > 400 mv)
Selenates (SeO42-)
High
Moderate (200 – 400 mv)
Selenites (SeO32–)
Medium
Low (low oxidation, < 200 mv)
Selenides (HSe-)
Low
Hydroxides (Fe, Mn)
High content
Absorbed all forms of Se
Low
Low content
Slight absorption
High
Organic Matter
Undecayed
Absorbed
Low
Decayed (e.g., peat)
Complexed
High
Enhanced biomethylation
Volatilized
High
Clays
High content
Absorbed all Se forms
Low
Low content
Not fixed or soluble all Se forms
High
Interaction with
S, P and N
Antagonistic effects
Rather low
Source: Kabata-Pendias and Mukherjee (2007) and Kabata-Pendias (2011)
Biogeochemistry of Selenium
The phytoavailability
of different Se
species in soils
decreases in the
following order:
selenate >
selenomethionine >
selenocysteine >
selenite > elemental
selenium > selenide
(Kabata-Pendias and
Mukherjee 2007).
Biogeochemical cycles of
Se under field conditions
Source:
El-Ramady et al. (2014)
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Table 5: Selected properties of Se comparing with sulfur
and copper as an elements (El-Ramady et al. 2014)
Properties or items
(unit)
Copper (Cu)
Sulfur (S)
Selenium (Se)
Principal forms for plant
uptake
Cupric cation (Cu2+)
Sulfate anion
(SO4-2)
Selenate (SeO42− ) or
selenite (SeO32−)
Essentiality for animals and
plants
Essential for both
Essential for both
Essential for animals
Beneficial for plants
Sufficient level in plant leaf
(DW, dry weight)
6 mg kg-1 DM
0.10 – 0.50 (%)
0.1 – 2.0 (mg kg-1)
Toxic level in plant leaf
(DW, dry weight)
15 – 30 mg kg-1
0.5 – 0.7 (%)
5.0 – 30 (mg kg-1)
Active (Cu2+)
Active (SO4-2)
Ca, Mg, P, and N
As, Fe, Pb, Mo,
and Se
Moderately
mobile
Mass flow (SO4-2)
Passive (SeO32−) and active
for (SeO42−) and SeMe
Hg, Mn, Zn, Cu, and Cd
Principal forms for plant
uptake
Major antagonistic elements
Mobility in plant
Immobile
Mobility in Soil
Mass flow
Moderately mobile
Very mobile in soil by mass
flow (SeO4-2)
SeMe, selenomethionine
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Se roles in
higher plants
Physiological
functions or roles of
Se in higher plants.
Compiled from:
Tamaoki et al. (2008),
Pilon-Smits and Quinn
(2010),
Hasanuzzaman et al.
(2010) and
Hajiboland (2012)
Source:
El-Ramady et al. (2014)
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4. Selenium Biofortification
Biofortification is considered to be a costeffective way to alleviate micronutrient
malnutrition in the rural populations in
developing countries
Greek word (bios) life
Latin word (fortificare) make strong
Biofortification strategies:
• Agronomic (fertilization)
• Conventional plant breeding
• Genetic engineering
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
Biofortification nutrients:
Iron (Fe), zinc (Zn), iodine (I), selenium (Se)
copper (Cu) calcium (Ca), magnesium (Mg)
Biofortification stable crops:
Rice, wheat, cassava, beans, sweet potato,
pearl millet, maize, Jerusalem artichoke,
pineapple
17
Methods to
produce
Biofortified
crops
1- Micro-farms
2- Plastic trays
3- In vitro
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The micro-farm model structure
Micro-farm
uses:
1-Biofortified
crops
2-Sprouts
production
3-Acclimatization
of in vitro
plants
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Biofortifying vegetable crops with
Selenium (ACS, Long Beach, CA,
USA)
2 mg Se/l
20
5 mg Se/l
10 mg Se/l
21
100 mg nano-Se/l
Se-biofortified pineapple
(Ananas comosus L.)
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Se-biofortified Jerusalem artichoke
(Helianthus tuberosus L.)
In vivo
propagation of
Jerusalem
artichoke
using:
1- Tubers
2- Transplants
3- Stem nods
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(2) Plastic trays using perlite
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Total selenium content (mg/kg)
120
100
Makói bronz
Makói lila
80
60
40
20
0
0
2
5
10
Selenate treatment (mg/l)
Fig 1: Total selenium content of Makói bronz and Makói
lila spring onions depending on selenate treatments
Source: Domokos-Szabolcsy et al. (2011)
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Biofortifying vegetable crops with Selenium
(ACS, Long Beach, CA, USA)
Selenium concentration of Makói
bronz (µg/kg)
2500
2000
control
2 mg/l
5 mg/l
10 mg/l
1500
1000
500
0
organic form
selenite
selenate
Selenate treatment (mg/l)
Relative concentrations of selenium species in green onion
(Makói bronz variety) depending on selenate treatments
Source: Domokos-Szabolcsy et al. (2011)
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Biofortifying vegetable crops with Selenium
(ACS, Long Beach, CA, USA)
(3) In vitro method
Pepper and radish
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Fig. 4: Total Se content of shoots of seedlings on
medium which contained selenate
Source: Domokos-Szabolcsy (2011)
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Biofortifying vegetable crops with Selenium
(ACS, Long Beach, CA, USA)
5-Further research
Relationship between Se and other nutrients
I. Selenium and Sulfur
White et al. (2004)
White et al. (2007)
Pilon-Smits and Quinn (2010)
Collins et al. (2012)
Hawrylak-Nowak (2013)
II. Selenium and Zinc
Germ et al. (2013) Impact of double Zn and Se biofortification of
wheat plants on the element concentrations in the grain. Plant Soil
Environ, Vol. 59 (7): 316–321
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Biofortifying vegetable crops with Selenium (ACS, Long Beach, CA, USA)
III. Selenium and Copper
Hu et al. (2013) Ecotoxicological effects of copper and
selenium combined pollution on soil enzyme activities in planted
and unplanted soils. Environ Toxicol Chem. 32(5): 1109-16.
What more!!!
Field-to-Fork Perspective:
Soil nutrition/biofortification as a root of human health
Selenium and its implications to human health under
global climate changes
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Biofortifying vegetable crops with Selenium
(ACS, Long Beach, CA, USA)
List of some publications
Book chapters:
El-Ramady H, Alshaal T, Shehata S, Domokos-Szabolcsy É, Elhawat N, Prokisch
J, Fári M, Marton L (2014) Plant Nutrition from liquid medium to Micro-farms. In: H.
Ozier-Lafontaine and M. Lesieur-Jannoyer (eds.), Sustainable Agriculture Reviews 14:
Agroecology and Global Change, Sustainable Agriculture Reviews 14, DOI
10.1007/978-3-319-06016-3_12, Springer International Publishing Switzerland
El-Ramady H, Domokos-Szabolcsy É, Shalaby TA, Prokisch J, Fári M (2015)
Selenium in agriculture: water, air, soil, plants, food, animals and nanoselenium. In E.
Lichtfouse (ed.), Environmental Chemistry for a Sustainable World Vol. 5 (CO2
sequestration, biofuels and depollution), DOI 10.1007/978-3-319-11906-9_5, Springer
Berlin
El-Ramady H, Alshaal T, Domokos-Szabolcsy É, Shalaby T, Bayoumi Y, Elhawat
N, Sztrik A, Prokisch J, Fári M (2015) Selenium and its role in higher plants. In E.
Lichtfouse (ed.), Environmental Chemistry for a Sustainable World Vol. 6, Springer
Science + Business Media B.V. (in press)
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Papers in international peer-reviewed journals (Impacted)
El-Ramady H, Domokos-Szabolcsy É, Abdalla N, Alshaal T, Shalaby T, Sztrik A,
Prokisch J, Fári M (2014) Selenium and nano-selenium in agroecosystems.
Environmental Chemistry Letters, DOI 10.1007/s10311-014-0476-0 (IF: 1.906)
El-Ramady H, Abdalla N, Alshaal T, Domokos-Szabolcsy É, Elhawat N, Prokisch
J, Sztrik A, Fári M, El-Marsafawy S, Shams M (2014) Selenium in soils under
climate change, implications to human health. Environmental Chemistry Letters, DOI
10.1007/s10311-014-0480-4 (IF: 1.906)
Papers in international peer-reviewed journals (Non-Impacted)
Domokos-Szabolcsy É, H El-Ramady, A Sztrik, O Zsíros, G Garab, L Márton and
M Fári (2014). Higher plants as a biological tool alleviating selenium demand and
pollution. The 14th International Conference Scientific Days 27-28 March 2014
Gyöngyös, Hungary.
El-Ramady H, N Abdalla, M Fári, É. Domokos-Szabolcsy (2014). Selenium
enriched vegetables as biofortification alternative for alleviating micronutrient
malnutrition. International Journal of Horticulture Sciences, 20 (1-2): 75 – 81.
El-Ramady H, N Abdalla, T Alshaal, N Elhawat, É Domokos-Szabolcsy, J
Prokisch, A Sztrik, M Fári (2014) Nano-selenium: from in vitro to micro farm
experiments. International Journal of Environmental Quality (in press)
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Acknowledgments
Authors acknowledge the Hungarian
Ministry of Education and Culture
(Hungarian Scholarship Board, HSB and
the Balassi Institute) for funding and
supporting this
work.
34
Biofortifying vegetable crops with Selenium
(ACS, Long Beach, CA, USA)
Thank you for your attention