Thesis defense: Chandrodhay Saccaram
Wednesday, December 4th 2024, 2 pm, INRAE, Versailles
Characterisation of germinating common bean (Phaseolus vulgaris L.) seed exudates for the identification of bioactive molecules stimulating and protecting seeds and seedlings
Seeds play a fundamental role in the reproduction and dispersal of higher plants. Seeds used for cultivation are crucial to agricultural performance, with their physiological and sanitary quality being key elements. The vigour of a seed lot is characterised by rapid and uniform germination, robust early seedling development, and the capacity to adapt to biotic and abiotic environmental stresses.
During germination sensu stricto, from water uptake to radicle emergence, seeds release exudates into their immediate microenvironment, known as the spermosphere. These exudates, which consist of complex mixtures of organic and inorganic compounds, are poorly documented in the literature, and the influence of their composition on the biotic environment of seeds remains largely unknown.
Our study aimed to gain a deeper understanding of the composition and functional properties of seed exudates during germination. We selected common bean (Phaseolus vulgaris L.) as a model, due to its susceptibility to seedling damping-off. Eight bean genotypes, produced in two contrasting regions of France, were examined.
Our objectives were to characterise the chemical and microbiological diversity of the spermosphere based on genotype and production environment, to identify the relationships between these two components, and to search for antimicrobial peptides within the studied biological material.
To achieve these objectives, we employed an integrative multi-omics data approach, analysing the diversity of metabolites, peptides, and microorganisms within the spermosphere. This method allowed us to identify correlations between molecules and microorganisms present in this complex environment.
The results of our study led to the identification of potential candidate molecules for the development of bio-inspired seed protection strategies. These findings contribute to a better understanding of the complex interactions within the spermosphere and open promising avenues for improving seed quality and crop productivity. Our innovative approach could thus lead to practical applications in seed treatment, building on the natural mechanisms observed within the spermosphere of common bean.
Seeds play a fundamental role in the reproduction and dispersal of higher plants. Seeds used for cultivation are crucial to agricultural performance, with their physiological and sanitary quality being key elements. The vigour of a seed lot is characterised by rapid and uniform germination, robust early seedling development, and the capacity to adapt to biotic and abiotic environmental stresses.
During germination sensu stricto, from water uptake to radicle emergence, seeds release exudates into their immediate microenvironment, known as the spermosphere. These exudates, which consist of complex mixtures of organic and inorganic compounds, are poorly documented in the literature, and the influence of their composition on the biotic environment of seeds remains largely unknown.
Our study aimed to gain a deeper understanding of the composition and functional properties of seed exudates during germination. We selected common bean (Phaseolus vulgaris L.) as a model, due to its susceptibility to seedling damping-off. Eight bean genotypes, produced in two contrasting regions of France, were examined.
Our objectives were to characterise the chemical and microbiological diversity of the spermosphere based on genotype and production environment, to identify the relationships between these two components, and to search for antimicrobial peptides within the studied biological material.
To achieve these objectives, we employed an integrative multi-omics data approach, analysing the diversity of metabolites, peptides, and microorganisms within the spermosphere. This method allowed us to identify correlations between molecules and microorganisms present in this complex environment.
The results of our study led to the identification of potential candidate molecules for the development of bio-inspired seed protection strategies. These findings contribute to a better understanding of the complex interactions within the spermosphere and open promising avenues for improving seed quality and crop productivity. Our innovative approach could thus lead to practical applications in seed treatment, building on the natural mechanisms observed within the spermosphere of common bean.
Director : Loïc Rajjou - INRAE, IJPB, Versailles, PHYGERM team
Members of the jury
> Eric Gontier (Rapporteur) - Université de Picardie Jules Verne, BioEcoAgro, Amiens
> Vanessa Vernoud (Rapportrice) - INRAE, Agroécologie, Dijon
> Sandrine Dhondt-Cordelier (Examinatrice) - Université de Reims Champagne Ardenne, Vignes et Vins de Champagne, Reims
> Alia Dellagi (Examinatrice) - AgroParisTech, INRAE, IJPB, Versailles
To attend, contact Loïc Rajjou
Research developed at the Institute Jean-Pierre Bourgin for Plant Sciences.
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