Diversity of Sinorhizobium meliloti from the Central Asian Alfalfa Gene Center

Sinorhizobium meliloti was isolated from nodules and soil from western Tajikistan, a center of diversity of the host plants (Medicago, Melilotus, and Trigonella species). There was evidence of recombination, but significant disequilibrium, between and within the chromosome and megaplasmids. The most frequent alleles matched those in the published genome sequence

Symbiotic and genetic diversity of Rhizobium galegae isolates collected from the Galega orientalis gene center in the Caucasus

This paper explores the relationship between the genetic diversity of rhizobia and the morphological diversity of their plant hosts. Rhizobium galegae strains were isolated from nodules of wild Galega orientalis and Galega officinalis in the Caucasus, the center of origin for G. orientalis. All 101 isolates were characterized by genomic amplified fragment length polymorphism fingerprinting and by PCR-restriction fragment length polymorphism (RFLP) of the rRNA intergenic spacer and of five parts of the symbiotic region adjacent to nod box sequences. By all criteria, the R. galegae bv. officinalis and R. galegae bv. orientalis strains form distinct clusters. The nod box regions are highly conserved among strains belonging to each of the two biovars but differ structurally to various degrees between the biovars. The findings suggest varying evolutionary pressures in different parts of the symbiotic genome of closely related R. galegae biovars. Sixteen R. galegae bv. orientalis strains harbored copies of the same insertion sequence element; all were isolated from a particular site and belonged to a limited range of chromosomal genotypes. In all analyses, the Caucasian R. galegae bv. orientalis strains were more diverse than R. galegae bv. officinalis strains, in accordance with the gene center theory

Optimum ratio of complex biological product and fertilize (NPK) and the contribution of fungi and bacteria to the general decomposition and mulching of coniferous wood waste

Received: August 7th, 2021 ; Accepted: December 15th, 2021 ; Published: September 12th, 2022 ; Corresponding author: Loskutov Svyatoslav [email protected] use of a complex biological product (CBP) based on native microbiological consortiums of coniferous forest litter accelerated the composting process of coniferous wood waste. The contribution of micromycetes and bacteria to the activation of coniferous wood waste composting processes using the different fertilizers rates was studied. A fractal analysis has confirmed the formation of a micromycetes-bacterial system in the treatment with optimal rates of NPK and CBP. In this case the better decomposition of wood waste was observed. It was noted that micromycetes of the genus Penicillium dominated in the composts obtained with CBP addition. This compost was not phytotoxic. Thus, for coniferous sawdust decomposition and its further humification, it is necessary to use both micromycetes and bacteria. The use of organic material resulting from wood waste decomposition with CBP and optimal rates of NPK is an effective way to increase the content of organic substances in soils and their potential fertility