Impact of Elemental Sulfur on the Rhizospheric Bacteria of Durum Wheat Crop Cultivated on a Calcareous Soil

Abstract

Previous experiments have shown that the application of fertilizer granules containing elemental sulfur (S0) as an ingredient (FBS0) in durum wheat crops produced a higher yield than that produced by conventional ones (F), provided that the soils of the experimental fields (F vs. FBS0) were of comparable quality and with the Olsen P content of the field’s soil above 8 mg kg−1. In this experiment the FBS0 treatment took place in soil with Olsen P at 7.8 mg kg−1, compared with the F treatment’s soil with Olsen P of 16.8 mg kg−1, aiming at reducing the imbalance in soil quality. To assess and evaluate the effect of FBS0 on the dynamics of the rhizospheric bacteria in relation to F, rhizospheric soil at various developmental stages of the crops was collected. The agronomic profile of the rhizospheric cultivable bacteria was characterized and monitored, in connection with the dynamics of phosphorus, iron, organic sulfur, and organic nitrogen, in both the rhizosoil and the aerial part of the plant during development. Both crops were characterized by a comparable dry mass accumulation per plant throughout development, while the yield of the FBS0 crop was 3.4% less compared to the F crop’s one. The FBS0 crop’s aerial part showed a transient higher P and Fe concentration, while its organic N and S concentrations followed the pattern of the F crop. The incorporation of S0 into the conventional fertilizer increased the percentage of arylsulfatase (ARS)-producing bacteria in the total bacterial population, suggesting an enhanced release of sulfate from the soil’s organic S pool, which the plant could readily utilize. The proportion of identified ARS-producing bacteria possessing these traits exhibited a maximum value before and after topdressing. Phylogenetic analysis of the 68 isolated ARS-producing bacterial strains revealed that the majority of the isolates belonged to the Pseudomonas genus. A large fraction also possessed phosphate solubilization, and/or siderophore production, and/or ureolytic traits, thus improving the crop’s P, Fe, S, and N balance. The aforementioned findings imply that the used FBS0 substantially improved the quality of the rhizosoil at the available phosphorus limiting level by modulating the abundance of the bacterial communities in the rhizosphere and effectively enhancing the microbially mediated nutrient mobilization towards improved plant nutritional dynamics.

Advances in Plant Sulfur Research

“…In order to assess and evaluate the effect of fertilizer granules enriched with ES on the dynamics of the rhizospheric bacteria in relation to the corresponding conventional ones, Bouranis et al (2019) [12] performed comparative experiments. The enriched fertilization scheme was applied to a soil with Olsen-P at 7.8 mg kg −1 , and to a control treatment where Olsen-P accounted for 16.8 mg kg −1 in the soil.…”

Multi-Trait Wheat Rhizobacteria from Calcareous Soil with Biocontrol Activity Promote Plant Growth and Mitigate Salinity Stress

“…Sixty-eight arylsulfatase (ARS)-producing bacterial isolates used in this study were isolated from the rhizosphere of durum wheat on calcareous soil after treatment with fertilizer granules containing elemental sulphur (S 0 ) and characterized with respect to their phylogenetic affiliation as well as their traits associated with plant nutrition [ 48 ]. Briefly, the rhizospheric bacterial strains were isolated from rhisopshaeric soil at different sampling time points through the cultivation period.…”

“…Microbial colonies possessing arylsulphatase activity were detected by their blue colour on Petri dishes. Apart from the arylsulfatase activity of the selected strains, we investigated other possible PGP traits, such as phosphate solubilization on Pikovskaya agar [ 50 ] and siderophore production on chrome azurol-S (Sigma-Aldrich®, Merk KGaA, Burlington, MA, USA) agar medium [ 51 ], and urease production ability was tested by inoculating Urea Base Christensen ISO 6579, ISO 19250 (Conda, Madrid, Spain) medium [ 48 ]. All assays were done in triplicate.…”

“…We demonstrated that the field application of fertilizer granules with incorporated elemental sulphur (FBS 0 ) affected the abundance of wheat rhizospheric arylsulfatase (ARS)-producing bacteria communities and effectively enhance the microbially mediated nutrient mobilization towards improved plant nutritional dynamics [ 48 ].…”

Indicadores de qualidade do solo em sistemas agroecológicos no Cerrado Mineiro

“…A arilsulfatase, por exemplo, hidrolisa ésteres de sulfato e é uma enzima essencial para a mineralização de enxofre orgânico do solo. Por esse motivo, é utilizada com frequência como um indicador de fertilidade do solo (BOURANIS et al, 2019).…”