Genetic relation between three morphological states of N2-fixing Cyanobacteria by using PCR technique

Abstract

Three nitrogen fixing Cyanobacteria purified isolates were selected which express the three
morphological states, first Oscillatoria chlorina as an example of filamentous non Heterocysts
Cyanobacteria and second Microcystis rubusta as an example of Unicellular Cyanobactera and
third Anabaena spiroides as an example of filamentous Cyanobacteria containing a Hetrocysis,
these isolate were cultured on ASM-1 free nitrogen medium using light tension of lux (2500) and
temperature of 25°C. Total DNA were isolated and found that its concentration varied between
(1.3 to 1.8) the concentration was fixed in order to obtain that each 100 l contains 50 ng/l.
Primers for RAPD-PCR were used to detect the genetic variation between the three genera of
Cyanobacteria understudy and in order to diagnose the genetic relationship and to detect the
genetic dimension between these isolates in order to use these results to found the genetic
fingerprint. Eleven primers were used in RAPD-PCR reaction and 10 of them were positive. The
OPC-05 gave the high number of bands (20 bands) while OPA-18 and OPJ-13 gave the lowest (9
bands).The genetic dimension between the three isolates were compatible with the morphological,
microscopical and physiological results obtained as we found that Microcyctis rubusta and
Anabaena spiroides were closely related and Oscillatoria chlorine was far genetically.