Manipulations with Filamentous Fungi

"David Brayford ", IMI D.BRAYFORD at CABI.org
Tue Oct 18 06:23:43 EST 1994


1. Silica gel is fine for, say, 5 years if you keep it refrigerated.  Liquid 
nitrogen or lyophilisation are better, but obviously more expensive.  It is 
not recommended to keep them growing on agar since they are likely to 
mutate.

2.  I don't know a synthetic medium for crossing this fungus.  However, a 
good ploy is to mimic the natural conditions by pairing isolates on bits of 
autoclaved barley straw (say 2-3 cm lengths) placed on plain agar.  Allow 
the isolates to grow for 2 weeks to allow colonisation of the straw, then 
transfer to cool conditions (10 C) for 2-3 weeks, then transfer to 20-25 C 
in alternating dark and daylight.  The fungus usually forms its sexual state 
in spring after a cold winter snap - so the cool incubation period may help 
promote perithecial formation - it certainly does in other fungi.

Dave Brayford
International Mycological Institute
d.brayford at cabi.org

 ----------
From: BIOSCI-REQUEST
To: mycology
Subject: Manipulations with Filamentous Fungi
Date: 15 October 1994 8:41


I'm kind of new to these beasts, and am looking for some input into the
following questions.  The fungus I'm working with is a pathogen of barley
called Pyrenophora teres.

1)      We currently store long-term cultures of the fungus on silica
gel.  Is this a standard long term storage media?  Can spores be stored
in glycerol at -80 degrees C.  Can they be stored as stabs in agar (like
many bacterial isolates)?

2)      Conidia of P. teres can be collected from mycelia grown in
culture.  Ascospores, however, result from the mating of two opposite
mating types of the fungus on barley plants (but not in culture).  Has
anyone seen mention of mutations in the fungus, or culture conditions,
that may induce productive mating of such a fungus in culture, rather
than on its normal host plant?

3)      Any papers out there on the "bulk segregation analysis" of traits
in haploid fungi using PCR?   Did Michelmore's group do it with the
fungus, or just with the plant traits?

Thanks in advance!

John Weiland            jweiland at badlands.nodak.edu




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