Biochemical and Molecular Phylogenetic Study of Agriculturally Useful Association of a Nitrogen-Fixing Cyanobacterium and Nodule Sinorhizobium with Medicago sativa L.

E V Karaushu,E Omarova,O E Lazebny,N A Vorobey,N Yu Taran,D A Kiriziy,S Ya Kots,O A Koksharova,T R Kravzova,I V Lazebnaya,A A Popova,O P Olkhovich

doi:10.1155/2015/202597

Abstract

Seed inoculation with bacterial consortium was found to increase legume yield, providing a higher growth than the standard nitrogen treatment methods. Alfalfa plants were inoculated by mono- and binary compositions of nitrogen-fixing microorganisms. Their physiological and biochemical properties were estimated. Inoculation by microbial consortium of Sinorhizobium meliloti T17 together with a new cyanobacterial isolate Nostoc PTV was more efficient than the single-rhizobium strain inoculation. This treatment provides an intensification of the processes of biological nitrogen fixation by rhizobia bacteria in the root nodules and an intensification of plant photosynthesis. Inoculation by bacterial consortium stimulates growth of plant mass and rhizogenesis and leads to increased productivity of alfalfa and to improving the amino acid composition of plant leaves. The full nucleotide sequence of the rRNA gene cluster and partial sequence of the dinitrogenase reductase (nifH) gene of Nostoc PTV were deposited to GenBank (JQ259185.1, JQ259186.1). Comparison of these gene sequences of Nostoc PTV with all sequences present at the GenBank shows that this cyanobacterial strain does not have 100% identity with any organisms investigated previously. Phylogenetic analysis showed that this cyanobacterium clustered with high credibility values with Nostoc muscorum.

Highlights

Continuous anthropogenic impact on the environment of different chemicals, fertilizers, herbicides, plant protection from pests and diseases, plant growth regulators, and so forth that are used in agriculture, makes it necessary to develop an alternative to agricultural production, which would be based on the use of cost-effective and environmentally friendly systems for land application of fertilizers and plant protection
The goals of this research were the study of the effect of artificial stable microbial consortium based on nitrogenfixing cyanobacterium Nostoc PTV and Tn5-mutant of nodule bacteria Sinorhizobium meliloti T17, on the physiological and biochemical characteristics of growth and development of alfalfa, and, on its yield and product quality and the molecular typing and phylogenetic analysis of this new cyanobacterial isolate Nostoc PTV
PTV and S. meliloti [29], we found stimulation of cell growth area of nodule bacteria around the colonies of cyanobacterium N

Summary

Introduction

Continuous anthropogenic impact on the environment of different chemicals, fertilizers, herbicides, plant protection from pests and diseases, plant growth regulators, and so forth that are used in agriculture, makes it necessary to develop an alternative to agricultural production, which would be based on the use of cost-effective and environmentally friendly systems for land application of fertilizers and plant protection. Cyanobacteria are never found in the form of cell populations of one species They are in a close relationship with the microbial community, located in the mucus of the surrounding cells. Axenic cultures of cyanobacteria exist only in the laboratories In nature, they form a community and, being the edificators of microbial communities, cyanobacteria can change the microbial composition [4]. Nitrogen-fixing activity (NFA) of soil compositions of diazotrophic microorganisms can be an effective way to supply the crop by environmentally friendly biological nitrogen. Use of this approach requires in-depth study of the relationship between bacteria, cyanobacteria, and plants, as well as compatibility of microorganisms-partners in created artificial associations. It is necessary to select an optimal quantitative ratio of microorganisms and methods of their implantation into the rhizosphere

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