UPR 5301

The architecture of starch blocklets follows phyllotaxic rules

Nous venons de publier dans je journal Nature-Scientic Reports, les résultats de notre collaboration avec l'Université Polytechnique de Marche (Italie) et l'ESRF - European Synchrotron Radiation Facility à Grenoble (France), portant sur l’application des règles de la phyllotaxie au grain d’amidon qui débouche sur un nouveau modèle de son architecture et de la structure de l’amylopectine. Cliquez sur le site pour plus d'informations.

« The starch granule is Nature’s way to store energy in green plants over long periods. Irrespective of their origins, starches display distinct structural features that are the fingerprints of levels of organization over six orders of magnitude. We hypothesized that Nature retains hierarchical material structures at all levels and that some general rules control the morphogenesis of these structures. We considered the occurrence of a «phyllotaxis» like features that would develop at scales ranging from nano to micrometres, and developed a novel geometric model capable of building complex structures from simple components. We applied it, according to the Fibonacci Golden Angle, to form several Golden Spirals, and derived theoretical models to simulate scattering patterns. A GSE, constructed with elements made up of parallel stranded double-helices, displayed shapes, sizes and high compactness reminiscent of the most intriguing structural element: the ‘blocklet’. From the convergence between the experimental findings and the theoretical construction, we suggest that the «phyllotactic» model represents an amylopectin macromolecule, with a high molecular weight. Our results offer a new vision to some previous models of starch. They complete a consistent description of the levels of organization over four orders of magnitude of the starch granule. »

L’article est disponible ici: https://www.nature.com/articles/s41598-020-72218-w