The Relationships Of Rhizobia Based On nifD Gene Similarity For Potency Analysis As Biofertilizer

Biological fertilizer is an inoculant contained active living organisms, with function infacilitating the availability of nutrients in the soil for plants. Rhizobia are one type of microbesthat used as biological fertilizer, which is able to fixed nitrogen in association with thepresence of nitrogenase enzyme. This enzymes consists of dinitrogenase components encoded byone gene nifD. NifD genes are often used as a marker of a microorganism that can be fixednitrogen. This research aims were to study the kinship between Rhizobia and its potential as abiological fertilizer based on the similaritas nifDgene using bioinformatics from molecular genebank DDBJ (DNA Data Bank of Japan). BioEdit software used for alignment, calculation of theindex similaritas, and construction of phylogenetic trees based on complex algorithms ofphylogeny Neighbour-Joining. There are nine species examined, namely BurkholderiavietnamiensisG. (1995), Sinorhizobiummedicae R. (1996), S. meliloti L. (1994), Mesorhizobiumciceri J. (1997),M.. huakuii J. (1997), M. plurifarium L. (1998), M.septentrionale G. (2004),M.temperatum, G. (2004), and Bradyrhizobium japonicum J. (1982). Rhizobia species in one genushas higher similaritas value in nifD genecompared with species from different genera. Thehigher the value of the nifD gene between similaritas species of Rhizobia, the higher the kinship.The higher the level of nifD genes similarities, the more similarities of enzyme nitrogenase. Theresults of the tree phylogeny analysis indicates that Rhizobia are classified into three groups,namely the fast-growing Rhizobia, meso growing Rhizobia and slow-growing Rhizobia. Fastgrowing Rhizobia potential as biological fertiliser. Slow-growing Rhizobia can be combined withfast-growing Rhizobia as biological fertilizer on acidic soils.

Novel, non-symbiotic isolates ofNeorhizobiumfrom a dryland agricultural soil

Semi-selective enrichment, followed by PCR screening, resulted in the successful direct isolation of fast-growing Rhizobia from a dryland agricultural soil. Over 50% of these isolates belong to the genusNeorhizobium, as concluded from partialrpoBand near-complete 16S rDNA sequence analysis. Further genotypic and genomic analysis of five representative isolates confirmed that they form a coherent group withinNeorhizobium, closer toN. galegaethan to the remainingNeorhizobiumspecies, but clearly differentiated from the former, and constituting at least one new genomospecies withinNeorhizobium.All the isolates lackednodandnifsymbiotic genes but contained arepABCreplication/maintenance region, characteristic of rhizobial plasmids, within large contigs from their draft genome sequences. TheserepABCsequences were related, but not identical, torepABCsequences found in symbiotic plasmids fromN. galegae, suggesting that the non-symbiotic isolates have the potential to harbor symbiotic plasmids. This is the first report of non-symbiotic members ofNeorhizobiumfrom soil.

Novel, non-symbiotic isolates of Neorhizobium from a dryland agricultural soil

Semi-selective enrichment, followed by PCR screening, resulted in the successful direct isolation of fast-growing Rhizobia from a dryland agricultural soil. Over 50% of these isolates belong to the genus Neorhizobium, as concluded from partial rpoB and near-complete 16S rDNA sequence analysis. Further genotypic and genomic analysis of five representative isolates confirmed that they form a coherent group within Neorhizobium, closer to N. galegae than to the remaining Neorhizobium species, but clearly differentiated from the former, and constituting at least one new genomospecies within Neorhizobium. All the isolates lacked nod and nif symbiotic genes but contained a repABC replication / maintenance region, characteristic of rhizobial plasmids, within large contigs from their draft genome sequences. These repABC sequences were related, but not identical, to repABC sequences found in symbiotic plasmids from N. galegae, suggesting that the non-symbiotic isolates have the potential to harbor symbiotic plasmids. This is the first report of non-symbiotic members of Neorhizobium from soil.

Novel, non-symbiotic isolates of Neorhizobium from a dryland agricultural soil

Semi-selective enrichment, followed by PCR screening, resulted in the successful direct isolation of fast-growing Rhizobia from a dryland agricultural soil. Over 50% of these isolates belong to the genus Neorhizobium, as concluded from partial rpoB and near-complete 16S rDNA sequence analysis. Further genotypic and genomic analysis of five representative isolates confirmed that they form a coherent group within Neorhizobium, closer to N. galegae than to the remaining Neorhizobium species, but clearly differentiated from the former, and constituting at least one new genomospecies within Neorhizobium. All the isolates lacked nod and nif symbiotic genes but contained a repABC replication / maintenance region, characteristic of rhizobial plasmids, within large contigs from their draft genome sequences. These repABC sequences were related, but not identical, to repABC sequences found in symbiotic plasmids from N. galegae, suggesting that the non-symbiotic isolates have the potential to harbor symbiotic plasmids. This is the first report of non-symbiotic members of Neorhizobium from soil.