Use of DNA/DNA hybridization techniques to authenticate the production of new Azolla‐Anabaena symbiotic associations

The establishment of Azolla‐Anabaena ‘recombination’ symbioses by grafting the Anabaena ‐containing indusium (cap) from the donor megasporocarp onto a decapitated megasporocarp from an Anabaena ‐free recipient has been recently reported. We have generated strain‐ and species‐specific DNA probes for unequivocally establishing the identity of Anabaena azollae strains isolated from Azolla‐Anabaena symbioses (whether new, i.e. heterosymbioses or natural i.e. homosymbioses). Eight out of nine heterosymbioses tested proved to contain the expected heterosymbiont while one recombined association was shown to contain both its own homosymbiont and a heterosymbiotic Anabaena strain. In addition, a species‐specific plant probe was isolated from the total DNA of Azolla microphylla roots and used to establish the identity of a host plant used for recombination experiments.