Carotenoid Pathway in Capsicum Annuum
Laura Rodriguez-Uribe
Department of Plant and Environmental Sciences,
New Mexico State University, Las Cruces, NM USA
Carotenoids
•Most abundant natural pigments, more than 700 carotenoids have been
identified in photosynthetic organisms such as plants, algae, and bacteria
Carrot
β-carotene
Corn
Lutein/Zeaxanthin
Tomato
Lycopene
Pepper
Capsanthin/Capsorubin
Algae
Bacteria
β-carotene
Deinoxanthin
Carotenoid biosynthetic pathway in
Capsicum
Peppers possess the
most evolved
carotenoid pathway
Carotenoid biosynthesis and accumulation
Fruit wall
Carotenoid composition changes during
fruit ripening
Chromoplasts
Biological Antioxidants, Vitamin A precursor
Carotenoids quench free radicals, prevent protein oxidation and DNA damage
Sources of Free Radicals:
Cigarette smoke
Environmental pollutants
Radiation
Effects:
Cancers
Atherosclerosis
Damaged DNA
Ultraviolet light
Heart disease
Pesticides
Rheumatoid arthritis
Industry
New Mexico red pepper
Pigments (natural dyes)
Cosmetics
Carotenoid Quantities
Carotenoids in Orange Peppers
Carotenoid profile in ripe orange peppers
Thin layer chromatography with the carotenoid
composition at different ripening stages
G GO O G GO O G GO O Cs Cr V
Green
Green/Orange
Orange
Valencia
Fogo
NuMex Standards
Sunset
Objectives
• Investigate the β-carotene content of orange fruited capsicum
varieties to correlate the relationship between fruit color and
β-carotene content
Carotenoid biosynthetic genes in orange colored
peppers
• Carotenoid pathway genes phytoene synthase (Psy),
lycopene-β cyclase (Lcyb), β-carotenoid hydrolase (CrtZ-2),
and casanthin-capsorubin synthase (Ccs), from six orange
fruited peppers were cloned and sequenced.
• Mutations in the Lcyb of the six orange peppers,
and a new version of the Ccs gene from Fogo pepper genes.
Multiple alignment of the capsanthincapsorubin synthase protein
Multiple alignment with the Ccs amino acid sequences from
Yolo wonder, Valencia, and Fogo.
Expression of carotenoid biosynthetic genes
during ripening in orange peppers
G GO O G GO O G GO O
Psy
Green
Lcyb
CrtZ-2
Ccs
EtBr
Green/Orange
Valencia
Orange
Fogo
NM Sunset
Approaches to test the functionality of the CCS
mutant
• Biotechnological:
Expression of the wild type and mutant Capsanthin-Capsorubin
synthases as recombinant proteins in an heterologous system
such as Escerichia. Coli (E.coli) and assay its activity.
• Biochemical:
Purification and characterization of the Capsanthin-Capsorubin
from Valencia and Fogo peppers chromoplasts
Expression of Capsanthin capsorubin synthase in
E. coli as a recombinant protein
kD 1 2 3 4 5 6 7
75
50
37
25
Ccs
Purification of CCS from pepper fruit wall
chromoplasts
Chromoplast
Fruit wall
Percoll density
gradient
Isolation and Purification
of CCS protein
Conclusions
Carotenoid composition differs among peppers
The six orange peppers in this study have a new version of the
Lcyb gene
A novel version of the Ccs gene was found in the Fogo cultivar
Differences in gene expression in the carotenoid pathway might
determine the carotenoid composition in mature peppers .
Overall Significance
NMSU Research
Metabolomics / Breeding
New Mexico
Breeders
Nutrient + Pigment Rich Peppers
↑ β-Carotene
↑ Capsanthin/Capsorubin
↑ Quality in New Mexico
World Nutrition
Improvement of other
agronomically important crops
Thank You!
Dr. Mary A. O’Connell
Dr. Richard D. Richins
Lab members
Dr. Paul Bosland
Chile Pepper Institute
Supported in part by
NM Agricultural Experiment Station and
NIH grant R25 GM61222
Carotenoid Chemistry
 Two kinds of carotenoids
» Non Pro-Vitamin A
lycopene
» Pro-Vitamin A
-carotene