Isolation and characterisation of a Bam HI element in psam3 a gene of Pisum sativum L. induced during early stages of arbuscular mycorrhiza development

An Alu-like element was identified in the 5'-UTR of psam 3, a Pisum sativum L. gene which shows enhanced expression during early events of AM formatio n. Two sets of primers specific for the 5' UTR of the gene psam 3 and for t he Alu-like element, respectively, were designed to study psam 3 gene organ isation by targeted Alu PCR carried out on pea genomic DNA. PCR products fr ee of Alu-like sequences were produced. A 1.0 kb DNA fragment showing up to 65% similarity to a Bam HI repeated sequence of Vicia faba was isolated in both wild-type and mycorrhiza-resistant pea. Southern blot analysis reveal ed the presence of other Bam HI related sequences in pea. The possibility t hat Bam HI repeated sequences might constitute complex repeating units toge ther with an Alu-like element in the P. sativum genome is discussed.