Zimmerman, Erin , Hijri, Mohamed , St-Arnaud, Marc .
Genetic diversity and selection pressure in the AMF protein-coding gene, PLS.
The arbuscular mycorrhizal fungi (AMF) are a group of asexual, root-inhabiting, symbiotic fungi which have been found to be multigenomic. It is believed that the large amount of sequence diversity found in these organisms arose through the buildup of mutations in individual nuclei, in the absence of a genetic bottleneck. While several studies have been done characterizing ribosomal gene variation, the extent of this diversity is not known in AMF protein-coding genes. The objective of this study is to quantify genetic variation in the two-copy gene PLS (POL1-like sequence), found in the AMF species Glomus etunicatum Becker & Gerdemann. Polymorphisms will also be analysed to determine the type and strength of selection pressure and whether mutations found in the DNA are also present in transcripts. PLS was amplified from a composite gDNA sample extracted from a group of spores and was then cloned using E. coli cells. In total, 185 clones were sequenced. Of these, 101 contained distinct PLS variants. When plotted as a Monte-Carlo simulation, no plateau is reached. Further sequencing will be done in order to determine a plateau value for the total theoretical number of haplotypes. After sequencing, the most dissimilar sequences will be chosen as genetic markers. These markers will be compared using denaturing gradient gel electrophoresis (DGGE) to the PLS allele content of groups of sister spores of G. etunicatum, allowing a first look at the amount of genetic variation present among clonally produced spores of AMF. This research will be an important step towards understanding the behaviour of populations of nuclei in multigenomic organisms.
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1 - Institut de recherche en biologie végétale, Université de Montréal and Jardin botanique de Montréal, 4101 rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 2:30 PM