Thursday Lecture

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Thursday Lecture Legumes
Reading Textbook, Chapter 6
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Optional Assignment - Due Tuesday March 1 Where
do baby carrots come from? - How are they
produced? is there such a thing as a pregnant
mama-carrot?!
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Quiz
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• Quiz
• What is a legume?
• List two crop plants that are members of the
  legume family

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Fabaceae
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Fabaceae Leguminosae Legume family (also called
bean family or pea family)
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Fabaceae Leguminosae Legume family (also called
bean family or pea family) legere Latin for
too gather
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Fabaceae Leguminosae Legume family (also called
bean family or pea family) legere Latin for
too gather 19,000 species 3d largest
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Fabaceae Leguminosae Legume family (also called
bean family or pea family) legere Latin for
too gather 19,000 species 3d largest 41 crop
species most of any family
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Fabaceae Leguminosae Legume family (also called
bean family or pea family) legere Latin for
too gather 19,000 species 3d largest 41 crop
species most of any family Cereal Legume ?
complete protein
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Legume Papilionoid flower
See Fig. 6.1, 6.2, page 138
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Legume Papilionoid flower
See Fig. 6.1, 6.2, page 138
Banner petal
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Legume Papilionoid flower
See Fig. 6.1, 6.2, page 138
Banner petal
wing
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Legume Papilionoid flower
See Fig. 6.1, 6.2, page 138
Banner petal
wing
keel
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Legume Papilionoid flower
See Fig. 6.1, 6.2, page 138
Banner petal
wing
keel
Stamens 9 1
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Papilionoid legumes
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Papilionoid legumes
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Other Legumes
See Fig. 6.1, page 137
Acacia - Mimosoideae
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Other Legumes
See Fig. 6.1, page 137
Acacia - Mimosoideae
Senna - Caesalpinoideae
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Nitrogen Fixation
Paradox atmosphere is 80 nitrogen (N) yet N is
a limiting factor for plant growth in almost all
ecosystems
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Nitrogen Fixation
Paradox atmosphere is 80 nitrogen (N) yet N is
a limiting factor for plant growth in almost all
ecosystems Resolution atmospheric nitrogen is
in a form (N2) that is not available for chemical
reactions in biological organisms
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Nitrogen Fixation
Paradox atmosphere is 80 nitrogen (N) yet N is
a limiting factor for plant growth in almost all
ecosystems Resolution atmospheric nitrogen is
in a form (N2) that is not available for chemical
reactions in biological organisms How does
nitrogen become available to living organisms?
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Nitrogen Fixation

• Paradox atmosphere is 80 nitrogen (N) yet N is
  a limiting factor for plant growth in almost all
  ecosystems
• Resolution atmospheric nitrogen is in a form
  (N2) that is not available for chemical reactions
  in biological organisms
• How does nitrogen become available to living
  organisms?
• reaction is called fixation

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Nitrogen Fixation

• Paradox atmosphere is 80 nitrogen (N) yet N is
  a limiting factor for plant growth in almost all
  ecosystems
• Resolution atmospheric nitrogen is in a form
  (N2) that is not available for chemical reactions
  in biological organisms
• How does nitrogen become available to living
  organisms?
• reaction is called fixation
• can occur with input of energy (lightning
  strike)

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Nitrogen Fixation

• Paradox atmosphere is 80 nitrogen (N) yet N is
  a limiting factor for plant growth in almost all
  ecosystems
• Resolution atmospheric nitrogen is in a form
  (N2) that is not available for chemical reactions
  in biological organisms
• How does nitrogen become available to living
  organisms?
• reaction is called fixation
• can occur with input of energy (lightning
  strike)
• some microorganisms can carry out this reaction

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Nitrogen Fixation

• Paradox atmosphere is 80 nitrogen (N) yet N is
  a limiting factor for plant growth in almost all
  ecosystems
• Resolution atmospheric nitrogen is in a form
  (N2) that is not available for chemical reactions
  in biological organisms
• How does nitrogen become available to living
  organisms?
• reaction is called fixation
• can occur with input of energy (lightning
  strike)
• some microorganisms can carry out this reaction
• mutualism between bacteria (Rhizobium etc.) and
  members of Fabaceae

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N2 Fixing Nodules
Nitrogen-fixing Root Nodules
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N2 Fixing Nodules
Nitrogen-fixing Root Nodules
Bacteria in cells
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Can we transfer N-fixation to other crops?
See Box 6.1, page 141
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Can we transfer N-fixation to other crops?

• See Box 6.1, page 141
• Morphological changes development of nodule

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Can we transfer N-fixation to other crops?

• See Box 6.1, page 141
• Morphological changes development of nodule
• - critically important because need to exclude O2

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Can we transfer N-fixation to other crops?

• See Box 6.1, page 141
• Morphological changes development of nodule
• - critically important because need to exclude
  O2
• Host/symbiont recognition

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Can we transfer N-fixation to other crops?

• See Box 6.1, page 141
• Morphological changes development of nodule
• - critically important because need to exclude
  O2
• Host/symbiont recognition
• Chemical reactions to carry out N2 fixation

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Can we transfer N-fixation to other crops?

• See Box 6.1, page 141
• Morphological changes development of nodule
• - critically important because need to exclude
  O2
• Host/symbiont recognition
• Chemical reactions to carry out N2 fixation
• ? Multiple genes, multiple chromosome locations,
  not trivial

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Nitrogen Cycle
See Fig. 6.4, page 140
1. nitrogen fixation
2. ammonification
3. nitrification
atmospheric fixation
4. denitrification
ammonification
nitrogen fixing bacteria
nitrification
denitrifying bacteria
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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)

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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)
• - poisons (alkaloids, cyanogens)

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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)
• - poisons (alkaloids, cyanogens)
• Amino acid content of proteins complements
  grains

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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)
• - poisons (alkaloids, cyanogens)
• Amino acid content of proteins complements
  grains
• High fiber levels

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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)
• - poisons (alkaloids, cyanogens)
• Amino acid content of proteins complements
  grains
• High fiber levels
• Isoflavones appear to lower cholesterol levels

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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)
• - poisons (alkaloids, cyanogens)
• Amino acid content of proteins complements
  grains
• High fiber levels
• Isoflavones appear to lower cholesterol levels
• Phytoestrogens ? may help relieve menopause
  symptoms

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Nutritional Aspects of Legumes
See Box 6.2, page 142

• Legumes produce many N-containing compounds
• - nutritious foods (proteins, vitamins)
• - poisons (alkaloids, cyanogens)
• Amino acid content of proteins complements
  grains
• High fiber levels
• Isoflavones appear to lower cholesterol levels
• Phytoestrogens ? may help relieve menopause
  symptoms
• Oligosaccharides (beans, beans, the musical fruit
  - see Box 6.3, page 150)

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A Poisonous Legume
Abrus precatorius Precatory Bean
Abrin toxin, one of most toxic substances
known 1 crushed seed can be fatal if ingested
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Legumes Changes Under Domestication

1. Annual habit, selfing breeding system

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Legumes Changes Under Domestication

1. Annual habit, selfing breeding system
2. Less seed scattering

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Legumes Changes Under Domestication

1. Annual habit, selfing breeding system
2. Less seed scattering
3. Greater seed size

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Legumes Changes Under Domestication

1. Annual habit, selfing breeding system
2. Less seed scattering
3. Greater seed size
4. Synchronous fruiting

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Legumes Changes Under Domestication

• Annual habit, selfing breeding system
• Less seed scattering
• Greater seed size
• Synchronous fruiting
• Loss of dormancy

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Legumes Changes Under Domestication

• Annual habit, selfing breeding system
• Less seed scattering
• Greater seed size
• Synchronous fruiting
• Loss of dormancy
• - question which came first, domestication or
  loss of dormancy?

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Legumes Changes Under Domestication

• Annual habit, selfing breeding system
• Less seed scattering
• Greater seed size
• Synchronous fruiting
• Loss of dormancy
• - question which came first, domestication or
  loss of dormancy?
• Recent studies no common set of domesticated
  genes

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Major Legume Food Crops - Pulses
Pulses dried legume seeds used for food
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Major Legume Food Crops - Pulses
Pulses dried legume seeds used for food
Near East lentils, peas, chick-peas, broad
beans Far East soybean, pigeon pea Africa
cowpeas Mexico common bean, lima bean South
America common bean, lima bean, peanut
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Major Legume Food Crops - Pulses
Pulses dried legume seeds used for food
Near East lentils, peas, chick-peas, broad
beans Far East soybean, pigeon pea Africa
cowpeas Mexico common bean, lima bean South
America common bean, lima bean, peanut
Commonality Legumes food of the poor
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Near Eastern Pulses 1. Lentils
Lens culinaris genus name refers to shape of
seeds
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Near Eastern Pulses 1. Lentils
Lens culinaris genus name refers to shape of
seeds
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Near Eastern Pulses 2. Peas
Pisum sativum used as food since ancient times
(8-9,000 yrs ago) and domesticated by about 5,800
yrs ago.
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Peas porridge or green
Pease porridge hot Pease porridge cold Pease
porridge in the pot Nine days old
1600s first use as fresh green vegetable
(Holland) Specialized peas snow peas, sugar
snap peas bred so that pods are edible in
entirely, have high sugar levels
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Near Eastern Pulses 3. Broad Beans
Vicia faba from Mediterranean region,
cultivated 8800 yrs ago. Favism type of anemia,
aggravated in susceptible individual by Vicia
alkaloids
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Near Eastern Pulses 4. Chick-Peas
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cow-without-bones - soybean
Glycine max domesticated in China gt3000 yrs
ago.
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The Cinderella Crop
U.S. introduced as crop in 1765
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The Cinderella Crop
U.S. introduced as crop in 1765 1920s used
for fruit rather than just forage
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The Cinderella Crop
U.S. introduced as crop in 1765 1920s used
for fruit rather than just forage Soybeans
contain a trypsin inhibitor, destroyed by heating
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Soybean Products
Oriental Foodstuffs Miso, Tofu, Tempeh, Soy
Milk, Soy Sauce Soybean Oil widely used Soy
proteins used in many products Soy lecithin
widely used in chocolate products Non-food uses
inks, plastics, cleaners
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Other Old World Pulses
Pigeon peas, Cajanus cajan from
India Black-eyed peas (Cowpeas), Vigna
unguiculata from Africa, in U.S. considered to
be southern regional specialty
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Soybean Products
Oriental Foodstuffs Miso, Tofu, Tempeh, Soy
Milk, Soy Sauce Soybean Oil widely used Soy
proteins used in many products Soy lecithin
widely used in chocolate products Non-food uses
inks, plastics, cleaners
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Roundup - Glyphosate
Herbicide chemical structure
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Roundup - Glyphosate
Herbicide chemical structure
Mode of action blocks synthesis of certain
amino acids (aromatic amino acids produced by the
shikimic acid pathway)
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Roundup - Glyphosate
Herbicide chemical structure
Mode of action blocks synthesis of certain
amino acids (aromatic amino acids produced by the
shikimic acid pathway)
? Toxic to most plants, but not to animals
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Roundup - Glyphosate
Herbicide chemical structure
Mode of action blocks synthesis of certain
amino acids (aromatic amino acids produced by the
shikimic acid pathway)

• Toxic to most plants, but not to animals
• Note can still be toxic to animals, not just
  the active chemical but other components of the
  formulation

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Roundup - Glyphosate
Herbicide chemical structure
Mode of action blocks synthesis of certain
amino acids (aromatic amino acids produced by the
shikimic acid pathway)

• Toxic to most plants, but not to animals
• Note can still be toxic to animals, not just
  the active chemical but other components of the
  formulation
• Monsanto Chemical Company major moneymaker
  while under patent protection

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Monsanto - post-Roundup
Next stage ? produce genetically modified crops
that are resistant to glyphosate
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Monsanto - post-Roundup
Next stage ? produce genetically modified crops
that are resistant to glyphosate Source of
resistance (1) microorganisms, have enzyme that
is resistant to glyphosate
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Monsanto - post-Roundup

• Next stage ? produce genetically modified crops
  that are resistant to glyphosate
• Source of resistance
• microorganisms, have enzyme that is resistant to
  glyphosate
• Microorganisms or plants, find enzymes that alter
  glyphosate structure to make it harmless

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Monsanto - post-Roundup

• Next stage ? produce genetically modified crops
  that are resistant to glyphosate
• Source of resistance
• microorganisms, have enzyme that is resistant to
  glyphosate
• Microorganisms or plants, find enzymes that alter
  glyphosate structure to make it harmless
• Using (1) Monsanto has created crops that are
  resistant to glyphosate Roundup Ready

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Monsanto - post-Roundup

• Next stage ? produce genetically modified crops
  that are resistant to glyphosate
• Source of resistance
• microorganisms, have enzyme that is resistant to
  glyphosate
• Microorganisms or plants, find enzymes that alter
  glyphosate structure to make it harmless
• Using (1) Monsanto has created crops that are
  resistant to glyphosate Roundup Ready
• First Major Target Soybeans, very successful

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Monsanto - post-Roundup

• Next stage ? produce genetically modified crops
  that are resistant to glyphosate
• Source of resistance
• microorganisms, have enzyme that is resistant to
  glyphosate
• Microorganisms or plants, find enzymes that alter
  glyphosate structure to make it harmless
• Using (1) Monsanto has created crops that are
  resistant to glyphosate Roundup Ready
• First Major Target Soybeans, very successful
• Can spray crop after germination, kill weeds but
  crop little affected

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Roundup Ready Wheat

• The Latest Battlefield in the Biotech Wars
• Roundup Ready Crops corn, soybeans, cotton
• None of these have major use in human consumption
• Roundup Ready Wheat produced and marketed by
  Monsanto
• major use of wheat human food
• major export crop (? Japan, Europe)
• Worry if any farmers grown GM Wheat, some
  importers (Japan) will ban all wheat from U.S. ?
  all farmers will lose this market

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New World Beans 1. Lima Beans
Phaeolus lunata Mexico to Peru, independently
domesticated in the two areas. Mostly used dry.
Wild plants and some cultivars contain cyanogenic
glycosides release toxic cyanide (cooking
destroys compounds)
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New World Beans 2. Common Beans
Phaseolus vulgaris source of many types Another
independent domesticate in Mexico and South
America
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Beans, Beans, Beans
Selection for the variations in the seed in color
and size have produced a bewildering number of
variants, several of which have widespread use in
our country.
Kidney bean
Black bean
Pinto bean
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Another New World Legume - Peanut
Arachis hypogaea peanut, ground nut, goober
central South America
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The Underground Crop
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Forage Legumes Sitting in the Clover
Alfalfa Medicago sativa - king of forage crops
associated with horse husbandry Clovers
Trifolium Lespedeza Sweet Clovers - Melilotus
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Thursday Lecture Leaf, Stem and Root Crops
Reading Textbook, Chapter 7