Plant Storage Polysaccharides Team

Starch is a plant storage polysaccharide, composed of α(1→4) glucans branched into α(1→6), synthesized to store carbon and energy from photosynthetic processes. It accumulates in the chloroplast of photosynthetic cells (transient starch) or in the amyloplast of storage organ cells (storage starch).

Starch accounts for more than 30% of the caloric intake of the human diet (and up to 70% in some specific regions), and this polysaccharide is also extracted in large quantities (11 million tons of starch extracted in Europe in 2016) for food (60%) or non-food purposes (40%). In Europe, only 26% of extracted starch is used in its native form. The rest is either degraded into simpler sugars (glucose, maltodextrin, etc.) or chemically modified for specific uses. Extraction yields, digestibility and efficiency of physicochemical transformations are parameters that are influenced by the characteristics of the polysaccharide: granule size and shape, amylopectin chain length, amylose/amylopectin ratio, etc. Understanding the mechanisms of starch synthesis and degradation is therefore essential to improve extraction and processing yields. This knowledge represents an essential stake in a context of world population growth and climate change.

Since its creation in 2002, the Plant Glycobiology team has dedicated its research to the study of starch metabolism in plants by developing a functional genomics approach using Arabidopsis thaliana as a model. In 2015, two CR1 CNRS researchers decided to join the team: Coralie Bompard brought her skills in structural biology which were used to characterize several proteins involved in starch metabolism; David Dauvillée is using Chlamydomonas reinhardtii to elucidate the mechanisms of synthesis and degradation of transient or storage starch in this green microalga.