Editing Cell wall (section)

==Evolution==
{{Expand section|date=October 2013}}
Cell walls evolved independently in many groups.

The [[photosynthesis|photosynthetic]] [[eukaryote]]s (so-called plant and algae) is one group with cellulose cell walls, where the cell wall is closely related to the evolution of [[multicellularity]], terrestrialization and vascularization. The [[Cellulose synthase (UDP-forming)|CesA cellulose synthase]] evolved in ''[[Cyanobacteria]]'' and was part of [[Archaeplastida]] since [[Symbiogenesis|endosymbiosis]]; [[secondary endosymbiosis]] events transferred it (with the [[arabinogalactan]] proteins) further into [[brown algae]] and [[oomycetes]]. Plants later evolved various genes from CesA, including the Csl (cellulose synthase-like) family of proteins and additional Ces proteins. Combined with the various glycosyltransferases (GT), they enable more complex chemical structures to be built.<ref name=popper>{{cite journal | vauthors = Popper ZA, Michel G, Hervé C, Domozych DS, Willats WG, Tuohy MG, Kloareg B, Stengel DB | s2cid = 11961888 | display-authors = 6 | title = Evolution and diversity of plant cell walls: from algae to flowering plants | journal = Annual Review of Plant Biology | volume = 62 | pages = 567–90 | date = 2011 | issue = 1 | pmid = 21351878 | doi = 10.1146/annurev-arplant-042110-103809 | bibcode = 2011AnRPB..62..567P | hdl = 10379/6762 | hdl-access = free }}</ref><!-- try 10.3389/fpls.2012.00152 -->

Fungi use a [[Chitin-glucan complex|chitin-glucan-protein]] cell wall.<ref name="Webster_2007" /> They share the 1,3-β-glucan synthesis pathway with plants, using homologous GT48 family [[1,3-Beta-glucan synthase]]s to perform the task, suggesting that such an enzyme is very ancient within the eukaryotes. Their glycoproteins are rich in [[mannose]]. The cell wall might have evolved to deter viral infections. Proteins embedded in cell walls are variable, contained in [[tandem repeat]]s subject to [[homologous recombination]].<ref>{{cite journal | vauthors = Xie X, Lipke PN | title = On the evolution of fungal and yeast cell walls | journal = Yeast | volume = 27 | issue = 8 | pages = 479–88 | date = August 2010 | pmid = 20641026 | pmc = 3074402 | doi = 10.1002/yea.1787 }}</ref> An alternative scenario is that fungi started with a [[chitin]]-based cell wall and later acquired the GT-48 enzymes for the 1,3-β-glucans via [[horizontal gene transfer]]. The pathway leading to 1,6-β-glucan synthesis is not sufficiently known in either case.<ref>{{cite journal | vauthors = Ruiz-Herrera J, Ortiz-Castellanos L | title = Analysis of the phylogenetic relationships and evolution of the cell walls from yeasts and fungi | journal = FEMS Yeast Research | volume = 10 | issue = 3 | pages = 225–43 | date = May 2010 | pmid = 19891730 | doi = 10.1111/j.1567-1364.2009.00589.x | doi-access = free }}</ref>