Editing Hypha

{{About|fungal structures|the identically pronounced slang term and hip-hop subculture|hyphy}}
{{Short description|Long, filamentous structure in fungi and Actinobacteria}}
[[File:Penicillium.jpg|thumb|Hyphae of ''[[Penicillium]]'']]
[[File:HYPHAE.png|thumb|Fungal hyphae cells: (1) Hyphal wall. (2) [[Septum (cell biology)|Septum]]. (3) [[Mitochondrion]]. (4) Vacuole. (5) [[Ergosterol]] crystal. (6) [[Ribosome]]. (7) [[Cell nucleus|Nucleus]]. (8) [[Endoplasmic reticulum]]. (9) Lipid body. (10) [[Plasma membrane]]. (11) [[Spitzenkörper]]. (12) [[Golgi apparatus]]]]
[[File:Hypha on rice.jpg|thumb|Hyphae growing on [[tomato sauce]] (the pale oblong objects to the side are rice grains)]] 
[[File:Aspergillus niger 01.jpg|thumb|''[[Aspergillus niger]]'']]
[[File:Conidium.png|thumb|[[conidium|Conidia]] on conidiophores]]

A '''hypha''' ({{etymology|grc|''{{wikt-lang|grc|ὑφή}}'' ({{grc-transl|ὑφή}})|web}}; {{plural abbr|'''hyphae'''}}) is a long, branching, filamentous structure of a [[fungus]], [[oomycete]], or [[actinobacterium]].<ref name=Brock>{{cite book | editor = Madigan M | editor2 = Martinko J | title = Brock Biology of Microorganisms | edition = 11th | publisher = Prentice Hall | year = 2005 | isbn = 0-13-144329-1 }}</ref> In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a [[mycelium]].

==Structure==
A hypha consists of one or more [[cell (biology)|cell]]s surrounded by a tubular [[cell wall]].  In most fungi, hyphae are divided into cells by internal cross-walls called "septa" (singular [[septum]]). Septa are usually perforated by pores large enough for [[ribosome]]s, [[Mitochondrion|mitochondria]], and sometimes [[cell nucleus|nuclei]] to flow between cells. The major structural polymer in fungal cell walls is typically [[chitin]], in contrast to plants and [[oomycete]]s that have [[cellulose|cellulosic]] cell walls.  Some fungi have aseptate hyphae, meaning their hyphae are not partitioned by septa.

Hyphae have an average diameter of 4–6 [[μm]].<ref name="Maheshwari">{{cite book | last=Maheshwari | first=R. | title=Fungi: Experimental Methods In Biology | edition=Second | publisher=CRC Press | series=Mycology | year=2016 | isbn=978-1-4398-3904-1 | page=3}}</ref>

==Growth==
Hyphae grow at their tips. During tip growth, cell walls are extended by the external assembly and [[polymerization]] of cell wall components, and the internal production of new cell membrane.<ref name="Gooday1995">{{Cite journal | last1 = Gooday | first1 = G. W. | title = The dynamics of hyphal growth | doi = 10.1016/S0953-7562(09)80634-5 | journal = Mycological Research | volume = 99 | issue = 4 | pages = 385–389 | year = 1995 }}</ref> The [[Spitzenkörper]] is an intracellular organelle associated with tip growth. It is composed of an aggregation of membrane-bound vesicles containing cell wall components. The Spitzenkörper is part of the [[endomembrane system]] of fungi, holding and releasing [[vesicle (biology)|vesicle]]s it receives from the [[Golgi apparatus]].  These vesicles travel to the cell membrane via the [[cytoskeleton]] and release their contents (including various cysteine-rich proteins including [[cerato-platanin]]s and [[hydrophobin]]s)<ref>{{cite journal |last1=Baccelli |first1=Ivan |last2=Comparini |first2=Cecilia |last3=Bettini |first3=Priscilla P. |last4=Martellini |first4=Federica |last5=Ruocco |first5=Michelina |last6=Pazzagli |first6=Luigia |last7=Bernardi |first7=Rodolfo |last8=Scala |first8=Aniello |title=The expression of the ''cerato-platanin'' gene is related to hyphal growth and chlamydospores formation in ''Ceratocystis platani'' |journal=FEMS Microbiology Letters |date=1 February 2012 |volume=327 |issue=2 |pages=155–163 |doi=10.1111/j.1574-6968.2011.02475.x |pmid=22136757 |doi-access=free |hdl=2158/645742 |hdl-access=free }}</ref><ref>{{cite journal |last1=Wösten |first1=Han A.B. |last2=van Wetter |first2=Marie-Anne |last3=Lugones |first3=Luis G. |last4=van der Mei |first4=Henny C. |last5=Busscher |first5=Henk J. |last6=Wessels |first6=Joseph G.H. |title=How a fungus escapes the water to grow into the air |journal=Current Biology |date=28 January 1999 |volume=9 |issue=2 |pages=85–88 |doi=10.1016/S0960-9822(99)80019-0 |pmid=10021365|s2cid=15134716 |doi-access=free |bibcode=1999CBio....9...85W }}</ref> outside the cell by the process of [[exocytosis]], where they can then be transported to where they are needed. Vesicle membranes contribute to growth of the cell membrane while their contents form new cell wall. The Spitzenkörper moves along the [[Apical (anatomy)#Elongated organisms with distinctive ends|apex]] of the hyphal strand and generates apical growth and branching; the apical growth rate of the hyphal strand parallels and is regulated by the movement of the Spitzenkörper.<ref>{{cite journal | last1 = Steinberg | first1 = G | year = 2007 | title = Hyphal growth: a tale of motors, lipids, and the Spitzenkörper | journal = Eukaryotic Cell | volume = 6 | issue = 3| pages = 351–360 | doi = 10.1128/ec.00381-06 | pmid = 17259546 | pmc = 1828937 }}</ref>

As a hypha extends, [[septum|septa]] may be formed behind the growing tip to partition each hypha into individual cells. Hyphae can branch through the bifurcation of a growing tip, or by the emergence of a new tip from an established hypha.

== Behaviour ==
The direction of hyphal growth can be controlled by environmental stimuli, such as the application of an electric field.  Hyphae can also sense reproductive units from some distance, and grow towards them.  Hyphae can weave through a permeable surface to penetrate it.<ref name="Gooday1995" />

==Modifications==
Hyphae may be modified in many different ways to serve specific functions. Some [[parasitism|parasitic]] fungi form [[haustorium|haustoria]] that function in absorption within the host cells. The [[Arbuscular mycorrhiza|arbuscules]] of [[Mutualism (biology)|mutualistic]] [[mycorrhiza]]l fungi serve a similar function in nutrient exchange, so are important in assisting nutrient and water absorption by plants. [[Ectomycorrhizal extramatrical mycelium]] greatly increases the soil area available for exploitation by plant hosts by funneling water and nutrients to [[ectomycorrhizas]], complex fungal organs on the tips of plant roots.  Hyphae are found enveloping the [[gonidia]] in [[lichen]]s, making up a large part of their structure. In nematode-trapping fungi, hyphae may be modified into trapping structures such as constricting rings and adhesive nets. [[Mycelial cord]]s can be formed to transfer nutrients over larger distances. Bulk fungal tissues, cords, and membranes, such as those of mushrooms and [[lichen]]s, are mainly composed of [[felted]] and often [[Anastomosis|anastomosed]] hyphae.<ref>Moore, David. Robson, Geoffrey D. Trinci, Anthony P. J. 21st Century Guidebook to Fungi. Publisher: Cambridge University Press 2011 {{ISBN|978-0521186957}}</ref>

== Types ==

=== Classification based on cell division ===
*'''Septate''' (with septa)
**''[[Aspergillus]]''<ref name="urlMycology Online -- Aspergillosis">{{cite web|url=http://www.mycology.adelaide.edu.au/Mycoses/Opportunistic/Aspergillosis/|title=Mycology Online – Aspergillosis|access-date=2008-12-10|url-status=dead|archive-url=https://web.archive.org/web/20081207081944/http://www.mycology.adelaide.edu.au/Mycoses/Opportunistic/Aspergillosis/|archive-date=2008-12-07}}</ref> and many other species have septate hyphae.
*'''Aseptate''' ('''non-septate''') or [[coenocyte|coenocytic]] (without septa)
**Non-septate hyphae are associated with ''[[Mucor]]'',<ref name="urlInfection">{{cite web|last=Klatt|first=Edward C.|website=WebPath|publisher=University of Utah School of Medicine|url= http://library.med.utah.edu/WebPath/INFEHTML/INFEC022.html |title=Mucormycosis |access-date=10 December 2008}}</ref> some [[zygomycota|zygomycetes]], and other fungi.
*'''Pseudohyphae''' are distinguished from true hyphae by their method of growth, relative frailty and lack of [[cytoplasm]]ic connection between the cells.
** Yeasts form pseudohyphae.<ref name="urlYeasts">{{cite book |last1=Reiss |first1=Errol |last2=DiSalvo |first2=Art |editor1-last=Hunt |editor1-first=Richard |title=Microbiology and Immunology On-line |date=31 May 2018 |publisher=University of South Carolina |url=https://www.microbiologybook.org/mycology/2018mycology-3.htm |access-date=20 November 2020 |chapter=Yeasts}}</ref> They are the result of a sort of incomplete [[budding]] where the cells elongate but remain attached after division. Some yeasts can also form true septate hyphae.<ref name="SudberyGowBerman2004">{{Cite journal | last1 = Sudbery | first1 = Peter | last2 = Gow | first2 = Neil | last3 = Berman | first3 = Judith | title = The distinct morphogenic states of ''Candida albicans'' | doi =  10.1016/j.tim.2004.05.008 | journal = Trends in Microbiology | volume = 12 | issue = 7 | pages = 317–324 | year = 2004 | pmid =  15223059}}</ref>

=== Classification based on cell wall and overall form ===
Characteristics of hyphae can be important in fungal classification. In [[Basidiomycota|basidiomycete]] taxonomy, hyphae that comprise the [[sporocarp (fungi)|fruiting body]] can be identified as generative, skeletal, or binding hyphae.<ref name=IMA>{{cite web|title=Hyphal System |publisher=Illinois Mycological Association |url=http://www.mushroomthejournal.com/greatlakesdata/Terms/trimi142.html |access-date=2007-02-11 |archive-url=https://web.archive.org/web/20061014024902/http://www.mushroomthejournal.com/greatlakesdata/Terms/trimi142.html |archive-date=2006-10-14 |url-status=dead }}</ref>
*'''Generative''' hyphae are relatively undifferentiated and can develop reproductive structures.  They are typically thin-walled, occasionally developing slightly thickened walls, usually have frequent septa, and may or may not have [[clamp connection]]s. They may be embedded in mucilage or gelatinized materials.
*'''Skeletal''' hyphae are of two basic types.  The classical form is thick-walled and very long in comparison to the frequently septate generative hyphae, which are unbranched or rarely branched, with little cell content.  They have few septa and lack clamp connections. Fusiform skeletal hyphae are the second form of skeletal hyphae. Unlike typical skeletal hyphae these are swollen centrally and often exceedingly broad, hence giving the hypha a [[wikt:fusiform|fusiform]] shape.
*'''Binding''' hyphae are thick-walled and frequent branched. Often they resemble deer antlers or defoliated trees because of the many tapering branches.

Based on the generative, skeletal and binding hyphal types, in 1932 [[E. J. H. Corner]] applied the terms monomitic, dimitic, and trimitic to hyphal systems, in order to improve the classification of [[polypore]]s.<ref name=Corner_1932>{{cite journal | author = Corner EJH | title = A Fomes with two systems of hyphae | journal = Trans. Br. Mycol. Soc.| year = 1932 | volume = 17 | issue = 1–2 | pages = 51–81 | doi = 10.1016/S0007-1536(32)80026-4}}</ref><ref name=Cunningham_1954>{{cite journal | author = Cunningham GH | title = Taxonomic Problems of some Hymenomycetes | journal = Transactions and Proceedings of the Royal Society of New Zealand | year = 1954–55 | volume = 82 | pages = 893–6 | url=http://paperspast.natlib.govt.nz/periodicals/TPRSNZ1954-82.2.11.12 }}</ref>
*Every fungus must contain generative hyphae.  A fungus which only contains this type, as do fleshy mushrooms such as [[agaric]]s, is referred to as '''monomitic'''.
*If a fungus contains the obligate generative hyphae (as mentioned in the last point, "every fungus must contain generative hyphae") and just one of the other two types (either skeletal or binding hyphae), it is called '''dimitic'''.  In fact dimitic fungi almost always contain generative and skeletal hyphae; there is one exceptional genus, ''[[Laetiporus]]'' that includes only generative and binding hyphae.
*Skeletal and binding hyphae give leathery and woody fungi such as [[polypore]]s their tough consistency.  If a fungus contains all three types (example: ''[[Trametes versicolor|Trametes]]''), it is called '''trimitic'''.
Fungi that form [[wikt:fusiform|fusiform]] skeletal hyphae bound by generative hyphae are said to have '''sarcodimitic''' hyphal systems.  A few fungi form fusiform skeletal hyphae, generative hyphae, and binding hyphae, and these are said to have '''sarcotrimitic''' hyphal systems.  These terms were introduced as a later refinement by E. J. H. Corner in 1966.<ref name=Corner_1966>{{cite journal |author = Corner EJH | title = Monograph of cantharelloid fungi| journal = Ann. Bot. Mem.| year = 1966 | volume = 2 | pages = 1–255}}</ref>

=== Classification based on refractive appearance ===
Hyphae are described as "gloeoplerous" ("gloeohyphae") if their high refractive index gives them an oily or granular appearance under the microscope.  These cells may be yellowish or clear ([[hyaline]]).  They can sometimes selectively be coloured by sulphovanillin or other reagents.  The specialized cells termed [[cystidia]] can also be gloeoplerous.<ref>See glossary of Meinhard Moser, translated by Simon Plant: ''Keys to Agarics and Boleti'' (Roger Phillips 1983)  {{ISBN|0-9508486-0-3}}.</ref><ref>See section "Microscopic features ..." of [http://www.clarku.edu/faculty/dhibbett/workshops%20and%20outreach/2006%20workshop%20documents/collecting%20and%20id.pdf 2006 Summer Workshop in Fungal Biology for High School Teachers] {{webarchive|url=https://web.archive.org/web/20080625202455/http://www.clarku.edu/faculty/dhibbett/workshops%20and%20outreach/2006%20workshop%20documents/collecting%20and%20id.pdf |date=2008-06-25 }}, Hibbett lab, Biology Department, Clark University, "Guidelines for collecting and identifying macrofungi (basidiomycetes)".</ref>

=== Classification based on growth location ===
Hyphae might be categorized as 'vegetative' or 'aerial.' Aerial hyphae of fungi produce asexual reproductive spores.<ref name="Dr Kaiser Baltimore">{{cite web| title = II: FUNGI| url = http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit4/fungi/mold.html| access-date = 2020-03-10| date = 2014-06-01| author = Kaiser, Gary E.| archive-date = 2019-12-25| archive-url = https://web.archive.org/web/20191225214828/http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit4/fungi/mold.html| url-status = dead}}</ref>

==See also==

*{{annotated link|Ascocarp}} 
*{{annotated link|Hartig net}} 
*{{annotated link|Mycorrhizal network}}

==References==
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== External links ==
{{wiktionary|hypha}}
{{Commons category|Hyphae}}
* Close-up [http://botit.botany.wisc.edu/images/130/Protista_I/Oomycota_Saprolegnia/Coenocytic_hyphae_MC.html light micrograph] of coenocytic hyphae
* [https://web.archive.org/web/20070224232014/http://www.microbiologybytes.com/introduction/myc1.html MicrobiologyBytes: Introduction to Mycology]
* [https://web.archive.org/web/20070505094104/http://129.215.156.68/Movies/hypha.htm Hyphal growth and branching] movies by P.C. Hickey and N. Read, University of Edinburgh
* [https://web.archive.org/web/20120323140450/http://www.fungionline.org.uk/glossary.html Fungi Online] Fungi Online: An Introduction to the Biology of Fungi

{{Fungus structure}}

[[Category:Fungal morphology and anatomy]]