Thesis Gontran ARNAULT (2021 - 2024)

Study of the transmission of the seed microbiota and its impact on the phenotype of young plants

Despite the central role of seeds in producing food and maintaining plant biodiversity, studies on their microbiota remain in a minority. Because of this, knowledge is still limited regarding the role of this microbiota during the early stages of plant life, particularly during germination and emergence. Seeds have a diversified microbiota but the causal relationships between the composition of the seed microbiota and the phenotype of the young plant have not yet been established.

Obtaining a clearer understanding of the dynamics and influence of this microbiota during crop establishment would be particularly valuable because the seed industry is preparing itself for a major revolution regarding the treatment of seeds combined with a reduction in synthetic pesticide use.  In this context, this PhD project proposes to use synthetic ecology approaches in a controlled manner to study the dynamics of a microbiota with a known composition (synthetic community) and its impact on the host phenotype. In particular, the first part of this project will focus on studying transmission of the microbiota from seed to plantlet, in order to determine which fraction actually constitutes the “primary inoculum” of the plant. The second part will evaluate the effects of this microbiota on different plant traits using high-throughput phenotyping by digital imaging, and on characterising the metabolome of the plantlet. Finally, we shall try to identify the strains/consortia and microbial functions involved in modifying the phenotype of the plantlet by means of targeted reconstructions of synthetic communities and comparative genomics.

Contact - Coordination :

  • Gontran ARNAULT (Doctoral Candidate)
  • Marie SIMONIN (Doctoral Adviser, IRHS, Département SPE)
  • Matthieu BARRET (Doctoral Adviser, IRHS, Département SPE)

Funding :

  • 50% INRAE
  • 50% Région Pays-de-la-Loire