High cyanobacterial diversity in coralloid roots of cycads revealed by PCR fingerprinting.

The genetic diversity of symbiotic cyanobacteria in coralloid roots of cycads was examined using PCR fingerprinting with primers derived from repetitive sequences. The highest genetic resolution was achieved using the primer corresponding to the short tandemly repeated repetitive sequences. The cyanobacteria were collected from the coralloid roots of a large number of indigenous cycad plants and used directly in the PCR. It could be demonstrated that numerous cyanobacteria were present in a single coralloid root. Even within a single cluster in the coralloid root, diversity could be observed between the apical, middle and basal regions.