The Spitzenkörper (
German for 'pointed body', SPK) is a structure found in fungal
hyphae that is the organizing center for hyphal growth and
morphogenesis. It consists of many small
vesicles and is present in growing hyphal tips, during spore
germination, and where branch formation occurs. Its position in the hyphal tip correlates with the direction of hyphal growth. The Spitzenkörper is a part of the
endomembrane system in fungi.[1]
The vesicles are organized around a central area that contains a dense meshwork of
microfilaments.
Polysomes are often found closely to the posterior boundary of the Spitzenkörper core within the Ascomycota,
microtubules extend into and often through the Spitzenkörper and within the Ascomycota
Woronin bodies are found in the apical region near the Spitzenkörper.[2]
The
cytoplasm of the extreme apex is occupied almost exclusively by secretory vesicles. In the higher fungi (
Ascomycota and
Basidiomycota), secretory and endocytic vesicles are arranged into a dense, spherical aggregation called the Spitzenkörper or ‘apical body’.[1] The Spitzenkörper may be seen in growing hyphae even with a light microscope. Hyphae of the
Oomycota and some lower Eumycota (notably the
Zygomycota) do not contain a recognizable Spitzenkörper, and the vesicles are instead distributed more loosely often in a crescent-shaped arrangement beneath the apical
plasma membrane.[3]
This structure is most commonly found in
Dikarya and was at first thought to only occur among them.[4][5][6][7][8] Vargas et al 1993 however were the first to find a Spitzenkörper in another clade, specifically the
Allomyces (
Blastocladiomycota),[5][9][6][4][7][8] then subsequently Basidiobolus ranarum – which has been placed in several different phyla – was also found to have an SPK.[4] As of 2020[update] these and the
Blastocladiella (also in Blastocladiomycota) are the only known taxa to bear this structure.[8]
^
abPowell, Martha J.; Letcher, Peter M. (2014). "Chytridiomycota, Monoblepharidomycota, and Neocallimastigomycota". In Esser, K.; (Editor); McLaughlin, David J.; (Volume editor); Spatafora, Joseph W.; (Volume editor) (eds.). Systematics and Evolution. Vol. 7A (2 ed.).
Berlin:
Springer. pp. 141–175.
ISBN978-3-642-55318-9.
OCLC889948520. {{
cite book}}: |editor2= has generic name (
help)ISBN978-3-642-55317-2.