Submitted to: Society for Invertebrate Pathology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 1998
Publication Date: N/A
Technical Abstract: A DNA-mediated transformation system was developed for the entomopathogenic fungus Paecilomyces fumosoroseus based on resistance to the herbicide glufosinate ammonium. The resistance is provided by the bar gene from Streptomyces hygroscopicus under the control of the Aspergillus nidulans trp C promoter and terminator sequences. Frequencies of up to 110 transformants /ug of linearized plasmid DNA were obtained. The transformants were stable for drug-resistance for five generations under selective and non-selective conditions. Southern analyses revealed that the transforming DNA integrated into the P. fumosoroseus genome in single and multiple copies. Single-copy integration events were generated with higher efficiency by Restriction Enzyme-Mediated Integration (REMI), although rates of transformation were not enhanced as reported for other fungi. Two REMI mutants showed reduced virulence for the Russian wheat aphid. These and other strains showed altered pigmentation, vegetative growth and sporulation. Other isolates have been co-transformed with a gene expressing green fluorescent protein. These transformants have been used in studies of the infection process. Studies are underway to use this transformation- based manipulation of P. fumosoroseus to facilitate insertional mutagenesis and the functional analysis of various genes.