3. Evolution of the plant cell wall

Most likely AGPs are present in cell walls of all seed land plants, which is supported by our own investigations on several species from different families. These AGPs have common features but differ in fine structure with regard to protein and arabinogalactan moiety. In the wood of gymnosperms, often big amounts of arabinogalactans without protein part are present; sometimes accompanied by AGPs. Up to now there is limited knowledge on occurence and structure of AGPs in spore plants (ferns, lycopods, mosses, algae); and therefore the question of development of AGPs during plant cell wall evolution is still unsolved. In 2017 we proved special structural features of AGPs from ferns, lycopods and mosses, which do not occur in AGPs from angiosperms. Especially of interest is the appearance of the unusual monosaccharide 3-O-methylrhamnose (acofriose) as part of AGPs from mosses and ferns and big amounts of terminal pyranosidic arabinose in AGP from Lycopodium. At the moment we extend these investigations on groups of algae phylogenetically close to land plants (Zygnematophyceae, Charophyceae) to clarify structure modifications of AGPs in the course of evolution. Additionally, we start to investigate also cell walls of marine angiosperms (e.g. Zostera, Enhalus) and their relatives in fresh water (e.g. Lemna), to clarify adaptations of angiosperm cell walls with regard to life in salt- or freshwater. These results might also help to draw conclusions on different functions of AGPs in the different plant groups.

 

GLC neutral sugars

GLC of neutral monosaccharides (alditol aceatates) from Sphagnum AGP

 

Selected publications

Happ K, Classen B: Arabinogalactan-proteins from the liverwort Marchantia polymorpha L., a member of a basal land plant lineage, are structurally different to those of angiosperms. Plants (2019) 8 (11): 460.

Classen B, Baumann A, Utermoehlen J: Arabinogalactan-proteins in spore-producing land plants. Carbohydr Pol (2019) 210: 215-224.

Bartels D, Classen B: Structural investigations on arabinogalactan-proteins from a lycophyte and different monilophytes (ferns) in the evolutionary context. Carbohydr Pol (2017) 172: 342-351.

Bartels D, Baumann A, Maeder M, Geske T, Heise EM, v Schwartzenberg K, Classen B: Evolution of plant cell wall: Arabinogalactan-proteins from three moss genera show structural differences compared to seed plants. Carbohydr Pol (2017) 163: 227–235.