Taxonomic And Molecular Phylogenetic Studies Of Nostoc (Cyanobacteria)

Nostoc is a genus of non-branching filamentous nitrogen-fixing cyanobacteria, which is widely distributed in both terrestrial and aquatic ecosystems in the global seven continents. Some kinds of nostoc are useful with very high economic value and application value, therefore, which got great concern attention.In this study,31 strains of Nostoc were obtained from various regions of, including Shanxi Province, Jilin Province, Hubei Province, Hunan Province, Gansu Province, Jiangsu Province, Zhejiang Province, Yunnan Province, Inner Mongolia autonomous region, Xinjiang uygur autonomous region, Ningxia hui autonomous region in china, Hiroshima University in Japan and the Philippines. Using morphological observation such as the shape of trichomes, the characters and dimensions of vegetative cells, sheath, heterocysts and akinetes and so on, the main results were summarized as follows:(1) Morphology of 10 strains of Nostoc from Xinjiang uygur autonomous region is different。(2) Morphology of Nostoc sphaeroids,Nostoc flagelliforme and Nostoc commune is different in the filed, but it is difficult to distinguish if we cultured it on the solid medium in the lab, which is present the same glial globular,and Nostoc flagelliforme grew in the liquid media,which is filamentous.(3) Morphology of Nostoc from Jilin Province and Nostoc sphaeroids is same in the filed, but the vegetative cells of Nostoc sp.is bigger than Nostoc sphaeroids, and the sheath is thicker than it.(4) Nostoc from Dongqian lake Zhejiang Province is olive green, brittle, and thiner sheath.With the development of molecular biology and molecular systematic, it is important to taxonomic and molecular phylogenetic studies of nostoc by using the method of molecular biology.16 gene or sequences (16s rRNA,rbcL,hetR,nifH,kaiBC,tufA,gyrB,sodF,tRNALeu (UAA),ntcA,rpoB,rpoCl,ITS,cpcBA-IGS,glnA,psbA) and the combined sequences of 13 gene sequences have been analyzed, the main results were summarized as follows:(1) 10 strains of Nostoc from Xinjiang uygur autonomous have close relationship, but the strains XA013 and other nine strains algae have far paternity.(2) sodF and ntcA is good molecular tools to distinguish Nostoc sphaeroids,Nostoc flagelliforme and Nostoc commune.(3) Nostoc sphaeroids,Nostoc flagelliforme and Nostoc commune are three separate species of Nostoc.(4) Nostoc commune from Nanjing Normal University and Nostoc commune from Hiroshima University in Japan have close relationship.(5) Symbiosis of nostoc in Cycads have far relationship with other nostoc in this study.(6) Nostoc,Nodularia and Anabaena cluster in three different clades. So, Nostoc,Nodularia and Anabaena are three separate genera.In this study, we have good results in the taxonomic and the molecular phylogenetic studies of nostoc by using both the traditional taxonomic and the molecular biology method.