apunts bt vegetal, Apuntes de Biotecnología Vegetal

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Breeding plants for β-carotene carotene

(pro-carotene vitamin A) enrichment

Image sources: Petaholmes based on WHO data; Vitamin A deficiency is a leading cause of blindness

Synthesis, storage and breakdown

all affect β-carotene carotene content

Vitamin A To increase beta-carotene carotene levels in plants, you need more synthesis, more storage or less catabolism

GGPP

phytoene lycopene β-carotenecarotene Synthesis Storage Catabolism or conversion to other forms Chromoplasts – organelles that store carotenoids Photo credit: University of Wisconsin

There is no

inherently right

or wrong way to

enhance plant

nutritional

quality

β-carotene carotene makes the rice look golden Vitamin A Photo credit: Golden rice humanitarian board β-carotenecarotene The β-carotene carotene enriched foods shown here have been produced using GM and non-carotene GM approaches

Arròs daurat Arròs daurat Endosperma d’arròs sintetitza geranil geranil difosfat però no fitoè Es va posar el gen de la fitoè sintasa de narcís sota control del promotor específic d’endosperma d’arròs i aquesta construcció es va introduir a l’arròs Es podia sintetitzar fitoè a partir de geranil geranil difosfat en arròs Grusak M.A (2005) Nature Biotechnology No obstant el gra no era taronja Què passava?

Carotenoid desaturasa bacteriana

Quan es posa aquest operó en E.coli s’obtenen carotenoids Gatsby resources (Peter Beyer)

PSY: Fitoè sintasa tpCrtI: transit peptide + carotè desaturasa Β-carotene LCY: licopè β ciclasa Gt1p: promotor glutelina 35Sp: promotor 35S Gatsby resources aph IV: higromicina fosfotransferasa (Peter Beyer)

Gatsby resources (Peter Beyer)

Gatsby resources (Peter Beyer)

Gatsby resources (Peter Beyer)

Averigueu quins promotors, terminadors i gens es fan servir en cada cas Paine et al 2005