title: Morphological and genetic diversity of symbiotic cyanobacteria from cycads.
abstract: The morphological and genetic diversity of cyanobacteria associated with cycads was examined using PCR amplification techniques and 16S rRNA gene sequence analysis. Eighteen symbiotic cyanobacteria were isolated from different cycad species. One of the symbiotic isolates was a species of Calothrix, a genus not previously reported to form symbioses with Cycadaceae family, and the remainder were Nostoc spp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the repetitive sequences. Based on fingerprint patterns and phenograms, it was revealed that cyanobacterial symbionts exhibit important genetic diversity among host plants, both within and between cycad populations. A phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that most of the symbiotic cyanobacterial isolates fell into well-separated clades.
authors.affiliation: Department of Microbiology, School of Life Sciences, Bharathidasan University, Tiruchirappalli Tamilnadu, India.
authors.forename: Nooruddin
authors.initials: N
authors.lastname: Thajuddin
authors.forename: Gangatharan
authors.initials: G
authors.lastname: Muralitharan
authors.forename: Mariappan
authors.initials: M
authors.lastname: Sundaramoorthy
authors.forename: Rengasamy
authors.initials: R
authors.lastname: Ramamoorthy
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Ramachandran
authors.forename: Mohamed Abdulkadar
authors.initials: MA
authors.lastname: Akbarsha
authors.forename: Muthukumaran
authors.initials: M
authors.lastname: Gunasekaran
mesh_terms: D016000:Cluster Analysis; D000458:Cyanobacteria / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D032462:Cycadopsida / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S