On-Farm Consortium Increases Vigor in Native Plant Seedlings

Abstract

This study aimed to test the hypothesis that native microbial consortia, particularly arbuscular mycorrhizal fungi (AMF) assembled on-farm, would enhance seedling vigor and restructure rhizosphere microbiomes of Atlantic Forest tree species more effectively than bacterial consortia alone. Thus, the microbial shifts and growth responses were evaluated in Schizolobium parahyba , Caesalpinia peltophoroides , and Albizia niopoides in greenhouse experiments comparing two inoculants: (i) a bacterial consortium (Consortium B) composed of isolates with multiple plant growth-promoting traits, and (ii) an on-farm AMF consortium (Consortium F) both derived from native forest soils. Seedlings were monitored for 85–280 days, assessing growth parameters, mycorrhizal colonization, and rhizosphere microbial diversity via 16S/ITS metataxonomics and functional predictions. Consortium F consistently improved seedling performance, with increases exceeding 50% in height, diameter, and biomass across species. Mycorrhizal colonization reached 27.8% in C. peltophoroides and 68.9% in A. niopoides . In contrast, Consortium B showed negligible effects. Metataxonomic analysis revealed that F inoculation enriched beneficial bacterial genera ( Streptomyces , Bifidobacterium , Cellulomonas ) and decomposer fungi ( Microascus , Podospora ), while reducing saprophytic fungi taxa; functional predictions indicated enhanced organic matter decomposition and nutrient cycling. Native AMF consortia assembled on-farm are effective bioinoculants, simultaneously boosting seedling vigor and restructuring rhizosphere microbiomes toward plant-beneficial functions. These findings highlight their potential as scalable tools for producing resilient seedlings in ecological restoration of degraded tropical landscapes.