Nitrifying Microbes in the Rhizosphere of Perennial Grasses Are Modified by Biological Nitrification Inhibition

Abstract

Soil nitrification (microbial oxidation of ammonium to nitrate) can lead to nitrogen leaching and environmental pollution. A number of plant species are able to suppress soil nitrifiers by exuding inhibitors from roots, a process called biological nitrification inhibition (BNI). However, the BNI activity of perennial grasses in the nutrient-poor soils of Australia and the effects of BNI activity on nitrifying microbes in the rhizosphere microbiome have not been well studied. Here we evaluated the BNI capacity of bermudagrass (Cynodon dactylon L.), St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze), saltwater couch (Sporobolus virginicus), seashore paspalum (Paspalum vaginatum Swartz.), and kikuyu grass (Pennisetum clandestinum) compared with the known positive control, koronivia grass (Brachiaria humidicola). The microbial communities were analysed by sequencing 16S rRNA genes. St. Augustinegrass and bermudagrass showed high BNI activity, about 80 to 90% of koronivia grass. All the three grasses with stronger BNI capacities suppressed the populations of Nitrospira in the rhizosphere, a bacteria genus with a nitrite-oxidizing function, but not all of the potential ammonia-oxidizing archaea. The rhizosphere of saltwater couch and seashore paspalum exerted a weak recruitment effect on the soil microbiome. Our results demonstrate that BNI activity of perennial grasses played a vital role in modulating nitrification-associated microbial populations.

Transferred Bacterial Community on the Potentially Pathogenic Bacteria among Aquatic Water, Plant Root, and Sediment When Planting with Chinese Herbs

“…in pond water [21]. Plant roots with stronger dissolved oxygen levels and biological nitrification inhibition capacities suppress the populations of Nitrospira in the rhizosphere, which may exert a weak recruitment effect on the soil microbiome [22]. Nitrospirae sig-nificantly increased and decreased in the HcT1 and Jr root groups, respectively, in the present study, with our previous study results showing that HcT1 and Jr are involved in nitrogen and phosphorus removal.…”

Biogeographical survey of soil microbiomes across sub-Saharan Africa: structure, drivers, and predicted climate-driven changes

“…p -value < 0.01), namely pH, nutrient and cation concentration, spatial distance, vegetation cover, MAP, and precipitation seasonality. Surprisingly, nitrogen content was not predicted to be a driver of archaeal community structure, despite previous work having identified nitrogen as an important factor in shaping archaeal soil communities [ 77 – 80 ]. This result could be explained by the fact that the taxon in the archaeal population to be most affected by nitrogen content (i.e., Nitrososphaeria) was identified as a ubiquitous fraction of the archaeal population across the sample set.…”

Nitrogen acquisition and retention pathways in sustainable perennial bioenergy grass cropping systems

“…Enhanced N uptake, for example, occurs through the prolonged growing seasons of perennial grasses (Di & Cameron, 2002) or via grasses facilitating the colonization of arbuscular mycorrhizal fungi (AMF) (Nuccio et al., 2022; Sarr et al., 2021; Wattenburger et al., 2020). Other pathways include biological nitrification inhibition (BNI), a mechanism where plants actively produce root exudates to inhibit the microbial transformation of ammonium to nitrate—a trait that is found in sorghum and several wild grasses such as Guinea grass, Bermuda grass, and koronivia grass (O'Sullivan et al., 2016; Subbarao et al., 2007; Subbarao, Nakahara, et al., 2013; Subbarao, Rao, et al., 2013; Villegas et al., 2020; Zhou et al., 2020). In addition to mitigating N loss, perennial grass cultivation also expands the mineral N pool in soil (Davis et al., 2015), potentially through enhanced biological N fixation (BNF) and mineralization (Bahulikar et al., 2014; Cadoux et al., 2012; Davis et al., 2010; Kämpfer et al., 2015; Keymer & Kent, 2014; Minamisawa et al., 2004; Soman et al., 2018).…”