Gregoire Bianchetti

Thesis started november 1st, 2017 - Defended november 16^th, 2021
Funding: INRA, Dpt BAP / Région Bretagne
Direction: Nathalie Nesi, Julia Buitink (IRHS Angers)

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Abstract :

Seed quality acquisition is an environmental modulated process that is finely controlled by the expression of many interconnected molecular and metabolic actors. Current climate projections predict that crops will be exposed to an increase of multiple and combined environmental constraints, leading to complex and generally non-deductible impacts. A better knowledge of these impacts on seed development, still poorly studied, appears thus as a relevant lever to enhance environmental resilience of agricultural productions. This thesis work is part of this scientific theme and sought to answer the following question: what are the impacts of a combination of biotic and abiotic stress on the yield elaboration and seed quality acquisition of rapeseed? To answer this question two rapeseed genotypes were grown in a large experimental device and subjected to a combination of stresses that are major for this crop, the water deficit and clubroot, caused by the pathogen Plasmodiophora brassicae. Signature impacts of water deficit on plants and mature seed quality have been identified using physiological and metabolic data as well as germination kinetics. Subsequently, RNAseq, metabolic and physiological data, were used for the characterization of the rapeseed transcriptional developmental program and the identification of stresses specific modulations on developing seed gene transcriptions and quality acquisition. The correlations between these modulations and their agronomic perspectives are discussed.

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