Inoculum Concentration and Mineral Fertilization: Effects on the Endophytic Microbiome of Soybean.

Soybean crops are of great economic importance worldwide and in Brazil. This crop is a commodity that provides large amounts of financial resources to the country. Soybean productivity is influenced by several biotic and abiotic factors, and most of these factors cannot be controlled by agricultural practices. Due to the soybean cultivars used and their required yields, the soybean crop, similar to other agriculturally important crops, requires large amounts of mineral fertilizers. There are several microorganisms that colonize soybean plant roots without causing symptoms or damage. These microorganisms that colonize plant tissues are called endophytes and can often promote plant growth and development. Little is known about the factors that influence endophyticism. The aim of the present study was to evaluate whether Bacillus subtilis inoculant concentrations and levels of mineral fertilization recommended for the crop have any influence on the endophytic microbiome of soybean plant roots. The results show that B. subtilis inoculations did not affect the endophytic community of the roots; however, the evaluation of the microbial community structure according to the alpha diversity metrics observed richness, Chao1 index, Shannon index and Simpson index showed that microbial diversity of endophytes was higher at fertilization levels of 50 and 100%, with a significant difference (p < 0.05) between 0 and 50% and 0 and 100% fertilization.

Microorganisms in cryopreserved semen and culture media used in the in vitro production (IVP) of bovine embryos identified by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS).

Commercial cattle breeders produce their own herd offspring for the dairy and beef market using artificial insemination. The procedure involves sanitary risks associated with the collection and commercialization of the germplasm, and the in vitro production and transfer of the bovine embryos must be monitored by strict health surveillance. To avoid the spreading of infectious diseases, one must rely on using controlled and monitored germplasm, media, and reagents that are guaranteed free of pathogens. In this article, we investigated the use of a new mass spectrometric approach for fast and accurate identification of bacteria and fungi in bovine semen and in culture media employed in the embryo in vitro production process. The microorganisms isolated from samples obtained in a commercial bovine embryo IVP setting were identified in a few minutes by their conserved peptide/protein profile, obtained applying matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), matched against a commercial database. The successful microorganisms MS identification has been confirmed by DNA amplification and sequencing. Therefore, the MS technique seems to offer a powerful tool for rapid and accurate microorganism identification in semen and culture media samples.