Download Transgénesis Vegetal. Aplicaciones a la mejora agrícola.

Transgénesis Vegetal.
Aplicaciones a la mejora agrícola.
1ª generación de productos vegetales
transgénicos
• Modificaciones genéticas dirigidas a
incrementar la productividad agraria
• Dirigidos fundamentalmente al productor
• Mercado tradicional de variedades vegetales
• Resistencias a plagas, patógenos, herbicidas,...
Herbicide tolerance
Glifosato (N-(phosphonomethyl) glycine)
Acción del glifosato
El glifosato inhibe a la enzima EPSPS (5enolpiruvilshikimato-3-fosfato sintetasa),
que cataliza la reacción de S3P (shikimato3-fosfato y el fosfoenol-piruvato para
formar el ESP (5-enolpiruvil-shikimato-3fosfato ).
Corismato , precursor esencial
en plantas de los aa aromáticos
Glyphosate-tolerant transgenic
plants
Some micro-organisms have a version of (EPSPS) that is resistant to
glyphosate inhibition.
The version used in genetically modified crops was isolated from
Agrobacterium strain CP4 (CP4 EPSPS) that was resistant to
glyphosate.
The CP4 EPSPS gene was engineered for plant expression by fusing
the 5' end of the gene to a chloroplast transit peptide derived from
the petunia EPSPS. This transit peptide was used because it had
shown previously an ability to deliver bacterial EPSPS to the
chloroplasts of other plants .
The chloroplasts of higher plants synthesize amino acids
phenylalanine, tyrosine and tryptophan.
Insect resistance
Las toxinas Cry de Bacillus thuringiensis
Las toxinas Cry de Bacillus thuringiensis
• Bt produces insecticidal proteins (d-endotoxins) during
sporulation as parasporal crystals. These crystals are
predominantly comprised of one or more proteins, called Cry and
Cyt toxins These toxins are highly specific to their target insect,
are innocuous to humans, vertebrates and plants, and are
completely
biodegradable.
.
• Different Bt strains show activity towards lepidopteran, dipteran
or coleopteran insects. Bt strains active against Hymenoptera,
Homoptera, Orthoptera and Mallophaga insect orders and to
other non-insect organisms like nematodes, mites and protozoa
have been isolated. More than 200 different cry genes have been
isolated. This constitutes an important arsenal for the control of a
wide variety of insect pests.
Taladro del maíz (European corn borer, Sesamia nonagrioides)
Bt corn effect
Pathogen-derived resistance
RESISTENCIA TRANSGÉNICA A TMV
RESISTENCIA TRANSGÉNICA A PRSV
RESISTENCIA TRANSGÉNICA A PRSV
Healthy Puna papaya fields in 1992.
RESISTENCIA TRANSGÉNICA A PRSV
Severely PRSV-infected papaya fields in 1994 that were abandoned.
RESISTENCIA TRANSGÉNICA A PRSV
Kapoho field trial started in 1995, showing a solid block of PRSV-resistant
Rainbow growing well while the surrounding susceptible non-transgenic Sunrise
is severely infected with PRSV. Picture taken 19 months after start of the field trial.
RESISTENCIA TRANSGÉNICA A PRSV
Comparative infection of transgenic and nontransgenic papaya in the 1995 field trial
in Kapoho .
RESISTENCIA TRANSGÉNICA A PRSV
PRSV infected papaya that were cut down in the foreground and healthy transgenic
Rainbow papaya in the background. Resistance of Rainbow held up even under strong
inoculum pressure of PRSV. Picture taken in 1999.
RESISTENCIA TRANSGÉNICA A PRSV
Green healthy transgenic Rainbow papaya growing among PRSV-infected trees in
an abandoned papaya field. Picture taken in 1999.
RESISTENCIA TRANSGÉNICA A PRSV
By 1999 healthy fields of transgenic papaya were commonly seen as opposed to
the period of 1994-1998 where it was very difficult to find healthy papaya fields
in Puna. Picture taken in 1999.
RESISTENCIA TRANSGÉNICA A PRSV
PRSV is still in Puna, and more infections are occurring among the non-transgenic Kapoho.
This site shows the dramatic difference between a block of nontransgenic papaya
(foreground) adjacent to a block of transgenic Rainbow (background). Nontransgenic trees
that became infected were cut down as seen in foreground. Plants were established at the
same time. Picture taken in 2004.