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MITOCHONDRIAL MOLECULAR GENETICS IN RELATION TO CROP IMPROVEMENT

Objective

THE STRUCTURE AND FUNCTION OF THE GENETIC SYSTEMS OF PLANT MITOCHONDRIA (MT) IS ONLY BEGINNING TO BE ELUCIDATED, BUT THE TECHNOLOGIES OF MOLECULAR BIOLOGY AND OF SOMATIC CELL GENETICS ARE NOW ALLOWING RAPID ADVANCES TO BE MADE. FROM THIS WILL COME THE ABILITY TO MANIPULATE THESE GENETIC SYSTEMS FOR CROP PLANT IMPROVEMENT. THE FIRST BENEFITS WILL BE SEEN IN THE ABILITY TO INDUCE AND MANIPULATE CYTOPLASMIC MALE STERILITY (CMS) WHICH IS OF CRITICAL IMPORTANCE IN THE PRODUCTION OF HYBRID FORMS OF MANY IMPORTANT AGRICULTURAL AND HORTICULTURAL CROPS WITHIN THE EEC. IN THE LONGER TERM WILL COME A MORE DETAILED UNDERSTANDING AND ULTIMATELY IMPROVEMENT OF THE METABOLIC PROCESSES WHICH UNDERLIE CELL ENERGETICS AND IN WHICH THE MITOCHONDRIA PLAY A CRITICAL ROLE.
The mitochondrial genome of higher plants cooperates with the nuclear information to drive the mitochondrial functions, which are determinant for the plant energy and metabolism. Cytoplasmic male sterility (CMS) is a mitochondrially encoded dysfunction, which is routinely used by plant breeders to produce economically important F1 seeds (cereals, vegetables).

For a better understanding of the real information encoded by the mitochondrial genome research focussed on:
basic knowledge, such as molecular organisation, expression, recombination and replication mechanisms in fertile plants;
the comparison of fertile and cms lines of economically important plants;
the development of cytoplasmic selectable markers;
the design of new strategies to modify the mitochondrial content of a higher plant;
combined classical molecular biology techniques supplemented with somatic cell fusion, somaclonal variations and mechanical microinjection.

The research gave the following results:
identification of plasmid and native deoxyribonucleic acid (DNA) molecules;
characterization of sequences involved in replication (ORI, D) and recombination;
molecular characterization of CMS plants at the DNA level and protein level;
development of cytoplasmic selectable markers.

Mechanical microinjection of total organelles and mitochondria into protoplasts was used to construct new plants. A nuclear gene alters the maternal inheritance of organelles. In vitro culture of immature embryos induced reorganizations of the mitochondrial genome through nuclear genes and led to regenerated plants with permanently altered genome. This reorganization is related to regeneration capacity. The recently demonstrated ribonucleic acid (RNA) editing mechanism was confirmed at the protein level.
THE RESEARCH WILL BE CARRIED OUT AS PART OF AN INTEGRATED EFFORT BETWEEN 5 LABORATORIES (UCL LOUVAIN, BELGIQUE,INRA DIJON,FRANCE,JOHN INNES INSTITUTE NORWICH,UNITED KINGDOM,FREE UNIVERSITY AMSTERDAM,NEDERLAND,UNIVERSITE DE PARIS,ORSAY,FRANCE).

THIS JOINT EFFORT INVOLVES THE FOUR ESSENTIAL STEPS :

- STUDY OF THE STRUCTURE AND EXPRESSION OF THE MITOCHONDRIAL GENOME IN DIFFERENT PLANT SPECIES
- TRANSFER OF MITOCHONDRIA
- TRANSFORMATION
- CHARACTERIZATION OF PLASMIDS AND RNA CONTAINING PARTICLES.

THE CONTRACTANT WILL PARTICIPATE IN STEPS A,B,C AND D OF THE JOINT EFFORT.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITE CATHOLIQUE DE LOUVAIN
Address
Faculte Des Sciences Agronomiques Labo D'etude De L'heredite Cytoplasmique Place Croix Du Sud 1
1348 Louvain-la-neuve
Belgium

Participants (4)

Institut National de la Recherche Agronomique (INRA)
France
Address

Dijon
JOHN INNES CENTRE
United Kingdom
Address
Norwich Research Park, Colney
Norwich
UNIVERSITE DE PARIS-SUD XI
France
Address
Rue Georges Clemenceau 15
91405 Orsay
University of Amsterdam
Netherlands
Address

Amsterdam