Isolation and identification of root nodule bacteria from guar cyamopsis tetragonoloba (L.) Taub. Sel'skokhozyaistvennaya Biologiya, 53(6):1285-1293, 2018. cited By 0
Isolation and identification of root nodule bacteria from guar cyamopsis tetragonoloba (L.) Taub [link]Paper  doi  abstract   bibtex   
Cyamopsis tetragonoloba (guar) belongs to the family Fabaceae and is one of the promising crops for cultivation in Russia. Beans contain a large number of protein and fatty oil content, green beans can serve as a valuable source of food and feeds (as seed flour and not ground granulated feeds), but the plant is more in demand as a source of guar gum, which is a polysaccharide formed by galactose and mannose (galactomannan) and is contained in the endosperm of the seeds of this plant. Guar gum is widely used in various industries: food, textile, cosmetic, oil and other. Guar comes from India, where approximately 80 % of the world's production of guar gum is obtained. However, due to high demand, the plant is cultivated throughout the world in areas with a suitable climate (the USA, Sudan, Kenya, Pakistan, Australia), including in the south of the Russian Federation. It is known that the productivity of leguminous crops depends not only on climatic conditions, but also on the effectiveness of symbiosis of plants with nodule bacteria (rhizobia), which is determined by the nitrogen-fixing activity and competitiveness of strains, as well as their complementarity to a particular variety. The use of rhizobia for inoculation of plants is especially important when they are introduced to new habitats, so knowledge of its microsymbionts is necessary for successful cultivation of guar in Russia. This paper is the first to report on isolation of the nodule bacteria of the species Bradyrhizobium elkanii from root nodules of the guar plants grown in a pot experiment with the use of soil samples from India. We determined the taxonomic position and genetic heterogeneity of the isolated strains. The 16S rRNA gene (rrs), ITS-region between the 16S and 23S rDNA and three “housekeeping” genes atpD, dnaK and recA of 10 isolates of nodule bacteria were sequenced. According to the results of the rrs sequence analysis, all isolates are assigned to the species Bradyrhizobium elkanii (family Bradyrhizobiaceae), whose representatives are microsymbionts of a wide range of leguminous plants, including the tribe Indigofereae, to which the guar belongs. However, the representatives of the species were not previously described as a microsymbiont of Сyamopsis tetragonoloba. Sequencing of the ITS-region and the “housekeeping” genes confirmed the species identity of the isolates and demonstrated their genetic heterogeneity. Thus, the study of nodule bacteria from guar has expanded our knowledge of the phylogeny of its microsymbionts and will allow us in the future to select the most effective strains that improve nitrogen nutrition and plant growth. Knowledge of the rhizobial microsymbionts of guar will help maximize the symbiotic potential of this agronomically valuable culture for its stable and highly productive cultivation. © 2018 Russian Academy of Agricultural Sciences. All rights reserved.

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