Investigating the effects of Brachiaria (Syn. Urochloa) varieties on soil properties and microbiome

Abstract

Background and Aims The Brachiaria sp. (synonymous with Urochloa) is one of Brazil’s main grass species used in livestock production and has become the focus of breeding genetic programs to enhance its resistance to drought, flooding, and pests, as well as improving its palatability to animals. However, there is a limited understanding of how genetic breeding can affect the soil microbiome and its potential functions. Thus, this study aimed to investigate the impact of four different Brachiaria varieties on the soil prokaryotic and fungal communities, particularly emphasizing their potential functions related to the N-cycle. Methods We combined molecular techniques, such as quantitative PCR and amplicon sequencing, to target prokaryotic and fungi communities and traditional soil and plant chemical analyses. Results Our findings revealed that all varieties improved soil porosity, P content, and organic carbon. Soil acidity, nutrient availability, and porosity were the main drivers of the microbial communities. The Nitrososphaeraceae, Gaiellales, Conexibacter, Sphingomonas, Hydnophlebia meloi, Conocybe, and Cladosporium were the main taxa associated with the dissimilarities between the Brachiaria varieties and the Control. In addition, the presence of the plants increased potential microbial functions such as Chemoheterotroph, Aerobic-Chemoheterotroph, and Pathotroph-Saprotroph groups. The study also identified the ability of each variety to recruit nitrogen-fixing and bacterial and archaeal ammonia-oxidizing communities. Conclusion Our findings suggest that selecting an efficient Brachiaria variety could positively impact soil quality, improving agricultural systems and increasing food production.