Submitted to: International Coloquim on Invertebrate Pathology and Microbial Control
Publication Type: Abstract only
Publication Acceptance Date: 4/30/2002
Publication Date: 8/15/2002
Citation: DELALIBERA, I., HAJEK, A.E., CHERRY, A., BRIGGS, B., HOUTONDJI, F., HANNA, R., HUMBER, R.A. MOLECULAR VARIATION AMONG ISOLATES OF THE MITE PATHOGENIC FUNGI NEOZYGITES TANAJOAE AND N. FLORIDANA: DEVELOPMENT OF RAPD, AFLP AND SCAR MARKERS. INTERNATIONAL COLOQUIM ON INVERTEBRATE PATHOLOGY AND MICROBIAL CONTROL. 2002. Interpretive Summary:
Technical Abstract: NEOZYGITES TANAJOAE is a key natural enemy of cassava green mite in Brazil that was experimentally released in cassava fields in Benin (W. Africa) in 1988/1999. N. FLORIDANA closely resembles N. TANAJOAE but is a widespread pathogen of tetranychid mites in temperate and tropical regions. Genetic variability in 6 strains of N. TANAJOAE from Brazil, 1 from Benin isolates of N. FLORIDANA from US & Colombia was tested with 3 PCR techniques. Sequencing information from the small subunit (SSU) rDNA showed consistent variability between N. TANAJOAE & N. FLORIDANA with no Intraspecific variation observed in this conserved DNA region. We could not compare ITS regions of rDNA (which are variable in many fungi) since none of the common fungus-specific primers tested amplified NEOZYGITES DNA. The PCR-based methods, random amplified polymorphisms (RAPD) & amplified fragment length polymorphisms (AFLP) were used to assess inter- & intraspecific variation. Similarity coefficients for pairwise combinations of RAPD amplification patterns were 84-100% among N. TANAJOAE isolates & 90% between the N. FLORIDANA isolates. However, similarity between both fungal species was 14-22%. No correlation was found in clustering of RAPD polymorphisms of N. TANAJOAE isolates & geographical origin. RAPD results were consistent with AFLP comparisons among N. TANAJOAE from Brazil and Benin with N. FLORIDANA from the U.S. The difference between these 2 species was first based on host specificity & physiological patterns & is supported by genetic variation demonstrated here. Polymorphic RAPD markers have been sequence characterized (SCAR) for use as isolate-specific DNA probes. These fragments may help to identify Brazilian strains of N. TANAJOAE introduced to W. Africa & to monitor their impact on CGM populations there.