Lineage, development, and cell type, shape xylan architecture and wall properties in monocots
Theodora Tryfona (UK)1; Xiaolan Yu (UK)1; Tamiris Kobayasi (Brazil)2; Parveen K. Deralia (UK)1; Frédéric Mentink-Vigier (United States)3 4; Xiao Peng (United States)5; Tuo Wang (United States)5; Fransisco Vilaplana (Sweden)6 7; Paul Dupree (UK)1;
1 - School of Biological Sciences, Department of Biochemistry, University of Cambridge, Cambridge, England, UK; 2 - Universidade Federal do ABC, Santo Andre, Sao Paulo, Brazil; 3 - National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA; 4 - Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA; 5 - Department of Chemistry, Michigan State University, East Lansing, MI 48824; 6 - Wallenberg Wood Science Centre, KTH Royal Institute of Technology, Stockholm, Sweden; 7 - Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, Stockholm, Sweden;
Keywords: commelinid-monocots; grass-xylan divesrification; cell-wall evolution;
Abstract Topics: Theme 3: Hemicelluloses: Structure and Function
Type of Presentation: Oral Communication

Abstract text: Xylan is the main hemicellulose in grass cell walls and plays an important role in wall structure and function. Grass xylan is not a single uniform polymer but is made of several structural domains with different substitution patterns. These differences are likely to influence how xylan interacts with cellulose and lignin in the wall. Here, we examined the distribution and cell-type specificity of these xylan domains across monocot plants and grass tissues.
Comparative analysis of representative monocot species showed that grass-type diversification of xylan is largely confined to commelinid monocots. Within grasses, xylan structure varied strongly between tissues and developmental stages. Different xylan populations were linked to tissues rich in primary or secondary cell walls. Early developmental stages contained highly substituted xylans that were not prominent in mature tissues.
In addition, fibre and parenchyma cells from bamboo, showed differences in xylan domain abundance, which were associated with changes in wall porosity and biomass recalcitrance. Solid-state NMR analysis indicated that these compositional differences are also linked to differences in xylan organisation within the wall.
Together, our results show that xylan structure in grasses is shaped by evolution, development, and cell identity, suggesting that different xylan architectures support specific cell wall functions.