posted on 2024-01-04, 02:13authored byOskar Siemianowski, Sintu Rongpipi, Joshua T. Del Mundo, Guillaume Freychet, Mikhail Zhernenkov, Enrique D. Gomez, Esther W. Gomez, Charles T. Anderson
Plant cell walls
are abundant sources of materials and
energy.
Nevertheless, cell wall nanostructure, specifically how pectins interact
with cellulose and hemicelluloses to construct a robust and flexible
biomaterial, is poorly understood. X-ray scattering measurements are
minimally invasive and can reveal ultrastructural, compositional,
and physical properties of materials. Resonant X-ray scattering takes
advantage of compositional differences by tuning the energy of the
incident X-ray to absorption edges of specific elements in a material.
Using Tender Resonant X-ray Scattering (TReXS) at the calcium K-edge
to study hypocotyls of the model plant, Arabidopsis thaliana, we detected distinctive Ca features that we hypothesize correspond
to previously unreported Ca-Homogalacturonan (Ca-HG) nanostructures.
When Ca-HG structures were perturbed by chemical and enzymatic treatments,
cellulose microfibrils were also rearranged. Moreover, Ca-HG nanostructure
was altered in mutants with abnormal cellulose, pectin, or hemicellulose
content. Our results indicate direct structural interlinks between
components of the plant cell wall at the nanoscale and reveal mechanisms
that underpin both the structural integrity of these components and
the molecular architecture of the plant cell wall.