Long-Term Rock Phosphate Fertilization Impacts the Microbial Communities of Maize Rhizosphere

Abstract

Phosphate fertilization is a common practice in agriculture worldwide, and several commercial products are widely used. Triple superphosphate (TSP) is an excellent soluble phosphorus (P) source. However, its high cost of production makes the long-term use of crude rock phosphate (RP) a more attractive alternative in developing countries, albeit its influence on plant-associated microbiota remains unclear. Here, we compared long-term effects of TSP and RP fertilization on the structure of maize rhizosphere microbial community using next generation sequencing. Proteobacteria were dominant in all conditions, whereas Oxalobacteraceae (mainly Massilia and Herbaspirillum) was enriched in the RP-amended soil. Klebsiella was the second most abundant taxon in the RP-treated soil. Burkholderia sp. and Bacillus sp. were enriched in the RP-amended soil when compared to the TSP-treated soil. Regarding fungi, Glomeromycota showed highest abundance in RP-amended soils, and the main genera were Scutellospora and Racocetra. These taxa are already described as important for P solubilization/acquisition in RP-fertilized soil. Maize grown on TSP and RP-treated soil presented similar productivity, and a positive correlation was detected for P content and the microbial community of the soils. The results suggest changes of the microbial community composition associated to the type of phosphate fertilization. Whilst it is not possible to establish causality relations, our data highlights a few candidate taxa that could be involved in RP solubilization and plant growth promotion. Moreover, this can represent a shorter path for further studies aiming the isolation and validation of the taxa described here concerning P release on the soil plant system and their use as bioinoculants.

Contrasting P acquisition strategies of the bacterial communities associated with legume and grass in subtropical orchard soil

“…Silva et al . () found that Burkholderia was enriched by the amendment of crude rock phosphate in the rhizosphere of maize plants, supporting our results. However, some less described taxa (e.g., Candidatus Pelagibacter , Trichodesmium , Neorickettsia ) have yet to be explored.…”

“…More importantly, our data indicated that Candidatus Pelagibacter, Trichodesmium, Neorickettsia, Nitrobacter, Paraburkholderia, Candidatus Solibacter and Burkholderia were the major taxa contributing to stronger capacity of solubilizing sparingly soluble Pi in bahiagrass soil. Silva et al (2017) found that Burkholderia was enriched by the amendment of crude rock phosphate in the rhizosphere of maize plants, supporting our results. However, some less described taxa (e.g., Candidatus Pelagibacter, Trichodesmium, Neorickettsia) have yet to be explored.…”

The rhizosphere microbiome of common bean (<i>Phaseolus vulgaris</i> L.) and the effects on phosphorus uptake

“…In both genotype, RPB additions promote a higher diversity of microorganisms compared to TSP and no phosphorus additions. This was already observed in long term studies (SILVA et al, 2017). These findings, together with the previous observations regarding genotype effect, provide evidences to support the proposed hypothesis that there is a correlation between the plant efficiency in phosphorus uptake and its rhizosphere microbiome in phosphorus mobilization and that this recruitment is potentialized in phosphorus depleted conditions.…”

“…The rhizosphere of IAC Imperador with L50 of RPB, showed an increase in several phyla, like Bacteroidetes, Acidobacteria, Planctomycetes and Proteobacteria compared to phosphorus depleted conditions. Changes in rhizosphere microbial community of maize was already described, showing a significant enrichment of Oxalobacteriacea (Betaproteobacteria), Burkholderiacea (Betaproteobacteria) and Bacillaceae (Firmicutes) was observed in maize rhizosphere (SILVA et al, 2017). However, considering the involvement of the rhizosphere microbiome in phosphorus mobilization a significant enrichment of binding and transport proteins is promoted under phosphorus limiting conditions in the IAC Imperador genotype.…”

Research Article Isolation, diversity, and biotechnological potential of maize (<i>Zea</i> <i>mays</i>) grains bacteria

“…Ikeda et al (2013) have only found the genera Pantoea, Bacillus, Burkholderia, and Klebsiella to occur in commercial maize seeds from the east region of the Paraná state, indicating a higher diversity of bacteria associated with maize grains in the North Central part of the same state (this work). The occurrence of the genera Massilia and Ochrobactrum have been reported in maize roots and rhizosphere (Niu et al, 2017;Silva et al, 2017). The occurrence of Modestobacter and Isoptericola genera isolates have not been described yet in maize grains.…”