Submitted to: Mycological Society of America
Publication Type: Abstract Only
Publication Acceptance Date: 8/7/1997
Publication Date: N/A
Technical Abstract: Penicillium bilaiae is a phosphate solubilizing fungus available commercially as seed inoculant under the trademark name of Provide. P. bilaiae increases crop yields by improving availability of phosphate to plants, however, very little is known about the colonization of roots by P. bilaiae under natural soil conditions. The objectives of this study were to i) determine by sequencing of the internal transcribed spacers (ITS) and 5.8S genes of Penicillium species which are phylogenetically closely related to P. bilaiae, ii) develop a species specific PCR assay for P. bilaiae, iii) develop a species specific hybridization assay to validate the PCR results, and iv) verify if this PCR hybridization assay can be used to detect P. bilaiae in the rhizosphere or in soil. Phylogenetic analysis using the ITS region gave better resolution generally supporting the results from the large ribosomal subunit obtained by the third author. PCR primers were designed to amplify DNA from the beginning of the ITS region to 600 b.p. into the large ribosomal subunit. Three P. bilaiae specific oligonucleotide probes were nested within the ITS I region and tested by hybridization against a wide range of species using PCR products amplified with universal primers. Large scale assays were done without gel electrophoresis using the specific PCR primers combined with a dot-blot hybridization with the nested oligonucleotide probes. The assay was used on a range of crop species and soil to detect P. bilaiae in the environment.