Question about sectoring

Mark Spear MCSpear at
Sun Dec 22 03:39:19 EST 1996

Most broadly, sectoring is any change in the morphology of a fungal 
culture.  It is most classically exemplified by a wedge shaped area 
of aberrent growth seen on a petri dish.  In three dimensional 
cultures like sawdust blocks, spawn bags, flasks, or compost beds it 
can be a sphereical or hemisphereical area differing in aspect from 
the surrounding mycelium.

The most common type of sector in the basidiomycetes is thick fluffy 
to leathery growth.  The most severe cases look like mushroom tissue 
forming down in the substrate without any obvious organogenisis.

Sectoring is commercially undesirable and in extreme cases can be 
evidence of instability or degeneration of the cell line.  Most 
experienced workers deliberately use techniques, media, and 
conditions that tend to minimize sector formation.  It is one of the 
areas of art in culture maintenance.

Sectoring can also represents a source of genetic variation without 
having to go thru meiosis.  

There has been some recent work done by Paul Horgen at Erindale you 
might want to look up.

    ---- Mark

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