Transcript Document

Lecture 16 &17
Modification of plant nutrient
content
The Golden Rice Story
• Vitamin A deficiency is a major health problem
• Causes blindness
• Influences severity of diarrhea, measles
• >100 million children suffer from the problem
• For many countries, the infrastructure doesn’t exist
to deliver vitamin pills
• Improved vitamin A content in widely consumed crops
an attractive alternative
-Carotene Pathway Problem in Plants
IPP
Geranylgeranyl diphosphate
Phytoene synthase
Phytoene
Problem:
Rice lacks
these enzymes
Phytoene desaturase
ξ-carotene desaturase
Lycopene
Lycopene-beta-cyclase
Normal
Vitamin A
“Deficient”
Rice
 -carotene
(vitamin A precursor)
The Golden Rice Solution
-Carotene Pathway Genes Added
IPP
Geranylgeranyl diphosphate
Daffodil gene
Phytoene synthase
Phytoene
Vitamin A
Pathway
is complete
and functional
Phytoene desaturase
Single bacterial gene;
performs both functions
ξ-carotene desaturase
Lycopene
Daffodil gene
Golden
Rice
Lycopene-beta-cyclase
 -carotene
(vitamin A precursor)