| dc.description.abstract | Long-term preservation of experimental fungi without genetic, morphological, and pathogenic changes is of
paramount importance in mycological and plant pathological investigations. Several cryogenic and non-cryo-
genic methods are available for the preservation of fungi, but the methods can be cumbersome, hazardous,
expensive, and often not suitable for long-term storage of non-spore-forming (sterile) fungi. A method of pre-
servation of spore-forming fungi in commercially available porous beads (Micrbank™) under cryogenic condition
was successfully tested for three non-spore-forming basidiomycetes genera: Rhizoctonia solani (teleomorph:
Thanatephorus cucumeris) (n = 19), Ceratobasidium species (n = 1), and Waitea circinata (n = 3), and a non-spore
forming ascomycetes, Sclerotinia sclerotiorum (n = 1). For comparison, spore-forming ascomycetous fungi,
Alternaria alternata (n = 1), Bauveria basiana (n = 2), Botrytis cinerea (n = 1), Fusarium oxysporum f.sp. gladiolii
(n = 1), Trichoderma spp. (n = 3), and Thielaviopsis basicola (n = 2) were also cryopreserved in Microbank
beads. Viable fungal isolates of all test species were retrieved after five years of storage at −80 °C, which was
longer than the viabilities of the corresponding isolates cryopreserved in agar plugs or colonized wheat seeds.
Fungi revived from the Microbank beads maintained identical morphology and cultural characteristics of the
parent isolates. Randomly selected Rhizoctonia isolates revived from the Microbank beads maintained respective
pathological properties of the parent isolates; also, no mutation was detected in the internal transcribed spacer
(ITS) ribosomal DNA when compared with respective cultures maintained at ambient temperature. This finding
demonstrated the utility of cryopreservation in Microbank beads as a convenient alternative to conventional
long-term preservation of a wide group of fungal cultures for plant pathological investigations and serves as the
first report of using porous beads under cryogenic conditions for long-term storage of sterile fungi. | |
