title: Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity.
abstract: OBJECTIVE
  The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties.
  
  
  RESULTS
  Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5.8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 + or - 0.2 degrees C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae (Ma-an) and Metarhizium from the flavoviride complex (Mf) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum (Ma-ac) isolates demonstrated high heat tolerance (c. 70-100% RG). Conidial suspensions also were plated on PDAY and incubated at 5 degrees C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG).
  
  
  CONCLUSIONS
  Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties.
  
  
  CONCLUSIONS
  Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes.
authors: Department of Biology, Utah State University, Logan, UT, USA.
authors: E K K
authors: EK
authors: Fernandes
authors: C A
authors: CA
authors: Keyser
authors: J P
authors: JP
authors: Chong
authors: D E N
authors: DE
authors: Rangel
authors: M P
authors: MP
authors: Miller
authors: D W
authors: DW
authors: Roberts
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis / Q000379:methods; D003080:Cold Temperature; D004271:DNA, Fungal / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D006358:Hot Temperature; D052981:Metarhizium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D017422:Sequence Analysis, DNA / Q000379:methods; D013045:Species Specificity
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal