Editing Cell wall (section)

===Water molds===
The group [[Oomycete]]s, also known as water molds, are [[saprotroph]]ic [[Plant pathology|plant pathogens]] like fungi. Until recently they were widely believed to be fungi, but [[organelle|structural]] and [[molecular biology|molecular]] evidence<ref name="Sengbusch_2003">{{cite web | last = Sengbusch | first = Peter V. | name-list-style = vanc | date = 2003-07-31 | url = http://www.biologie.uni-hamburg.de/b-online/e33/33.htm | title = Interactions between Plants and Fungi: the Evolution of their Parasitic and Symbiotic Relations | archive-url = https://web.archive.org/web/20061208024328/http://www.biologie.uni-hamburg.de/b-online/e33/33.htm | archive-date = December 8, 2006 | work = Biology Online | access-date = 2007-10-29 }}</ref> has led to their reclassification as [[heterokont]]s, related to [[autotroph]]ic [[brown algae]] and [[diatom]]s. Unlike fungi, oomycetes typically possess cell walls of cellulose and [[glucan]]s rather than chitin, although some genera (such as ''[[Achlya]]'' and ''[[Saprolegnia]]'') do have chitin in their walls.<ref name="Alexopoulos 1996">{{cite book | vauthors = Alexopoulos CJ, Mims W, Blackwell M | date = 1996 | title = Introductory Mycology | chapter = 4 | location = New York | publisher = John Wiley & Sons | pages = 687–688 | isbn = 978-0-471-52229-4 }}</ref> The fraction of cellulose in the walls is no more than 4 to 20%, far less than the fraction of glucans.<ref name="Alexopoulos 1996" /> Oomycete cell walls also contain the [[amino acid]] [[hydroxyproline]], which is not found in fungal cell walls.