Claude Fauquet, Ph.D., Biochemistry,
University of Strasbourg
The mission of the International
Laboratory for Tropical Agricultural
Biotechnology (ILTAB) is threefold:
to advance the application
Roger Beachy, Ph.D.,
of molecular biology and
Botany and Plant Pathology,
biotechnology for tropical crop
Michigan State University
improvement; to promote research
Research in my laboratory focuses
capacity building in developing
on elucidating molecular and
countries; and to help coordinate
cellular mechanisms that regulate
global biotechnology research
how plants respond to infection
on cassava. Research and product
by viruses and developing
development in the Fauquet laboratory
mechanisms to limit diseases in
includes: (1) Understanding how
transgenic plants. Studies address
geminiviruses infect their hosts.
how to determine the method
Geminiviruses and their satellite
by which viruses construct ‘virus
DNAs cause very destructive
factories’ and how infection moves
diseases that can result in
from cell to cell. Virus replication
devastating losses in food crops
factories/complexes established
all over the world; the most serious
by tobacco mosaic tobamovirus
diseases occur in tropical regions.
are bound to internal membranes
Their genomes are composed of
that appear to anchor large rope-
circular single stranded DNA and
like structures where replication
are subjected to gene silencing.
occurs: virus assembly occurs on
We have studied in detail the
the periphery of the complexes.
suppressors of gene silencing that
Current studies include
are encoded by geminiviruses
characterizing the structures (via
and the response of the infected
EM tomography and biochemical
plants. (2) Improving cassava
approaches) and developing
through biotechnology: ILTAB has
greater knowledge of how the
established a highly efficient set of
complexes move from cell to cell
technologies to develop genetically
during disease development.
enhanced cassava varieties and
Our studies with rice tungro
produce high quality transgenic
bacilliform pararetrovirus include
plants. This work has resulted in
Cross sectional images of stems of
characterizing host transcription
cultivars that express a variety of
Arabidopsis thaliana stained to show
factors that regulate virus
genes to induce virus resistance
lignin deposition (red). replication, and determining
and to enhance the nutritional
Left: parental plant; Right: stem
the role of these factors on plant
quality of cassava. Cassava
of genetically enhanced plant with growth and development. We
plants have been developed with
reduced lignin following activation have established collaborations
resistance to geminiviruses and
of a target gene via a chemical gene
in Africa, So. and S.E. Asia to
cassava ipomovirus,and cassava
switch to control its expression.
develop plants that are resistant
roots with very high contents of
to virus diseases, including sweet
vitamin A and proteins have been
potato, peanut and rice.
produced.
Updates from our Scientists 11
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