Abstract

Slow growing actinobacteria of the genus Frankia are best known for their nitrogen-fixing mutualism with dicotyledonous host plants called actinorhizal plants. Twenty nine (29) strains obtained from diverse host plants and geographic area, have been studied based on amplified ribosomal DNA restriction analysis (ARDRA) and repetitive element polymorphism-polymerase chain reaction (rep-PCR) DNA fingerprinting using BOX A1R primer. The collection has been classified into 28 ARDRA haplotypes clustered into three genogroups. The first genogroup 1 contains Frankia strains infecting Elaeagnus, genogroup 2 includes strains infecting Casuarina, while Frankia strains infective on Alnus, Comptonia and Myrica were grouped in genogroup 3. The results of BOX-PCR fingerprinting, supported the observation that BOX-PCR seems to be able to discriminate Frankia at strain level but are not useful for assigning strain to their respective genogroups or host infection groups.

Key words: Frankia, ARDRA, BOX-PCR, host infection groups.