Interactions between Bacterial Inoculants and Native Soil Bacterial Community: the Case of Spore-forming Bacillus spp

• Published in: FEMS microbiology ecology Vol. 98; no. 12
• Main Authors: Mawarda, Panji Cahya, Mallon, Cyrus A, Le Roux, Xavier, van Elsas, Jan Dirk, Salles, Joana Falcão
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 22.11.2022; Wiley-Blackwell
• Subjects: Agricultural Inoculants; Bacillus; Bacteria; Competition; Ecology; Life Sciences; Microbiology; Microbiology and Parasitology; Microbiomes; Microorganisms; Niches; Propagules; Soil; Soil Microbiology; Soil microorganisms; Soils; Spore-forming bacteria; Spores; Sporulation; Survival; invasion impact; soil functioning; diversity-invasion relationship; microbial invasion; resource competition; oil functioning; resource competitions
• ISSN: 1574-6941; 0168-6496; 1574-6941
• DOI: 10.1093/femsec/fiac127

Abstract Microbial diversity can restrict the invasion and impact of alien microbes into soils via resource competition. However, this theory has not been tested on various microbial invaders with different ecological traits, particularly spore-forming bacteria. Here we investigated the survival capacity of two introduced spore-forming bacteria, Bacillus mycoides (BM) and B. pumillus (BP) and their impact on the soil microbiome niches with low and high diversity. We hypothesized that higher soil bacterial diversity would better restrict Bacillus survival via resource competition, and the invasion would alter the resident bacterial communities’ niches only if inoculants do not escape competition with the soil community (e.g. through sporulation). Our findings showed that BP could not survive as viable propagules and transiently impacted the bacterial communities’ niche structure. This may be linked to its poor resource usage and low growth rate. Having better resource use capacities, BM better survived in soil, though its survival was weakly related to the remaining resources left for them by the soil community. BM strongly affected the community niche structure, ultimately in less diverse communities. These findings show that the inverse diversity-invasibility relationship can be valid for some spore-forming bacteria, but only when they have sufficient resource use capacity. This study evaluates the diversity-invasibility relationship of spore-forming Bacillus spp, and the impact of such invasion on the soil bacterial communities' niches.