Nitrogen- and phosphorus-starved Triticum aestivum show distinct belowground microbiome profiles

Abstract

Many plants have natural partnerships with microbes that can boost their nitrogen (N) and/or phosphorus (P) acquisition. To assess whether wheat may have undiscovered associations of these types, we tested if N/P-starved Triticum aestivum show microbiome profiles that are simultaneously different from those of N/P-amended plants and those of their own bulk soils. The bacterial and fungal communities of root, rhizosphere, and bulk soil samples from the Historical Dryland Plots (Lethbridge, Canada), which hold T . aestivum that is grown both under N/P fertilization and in conditions of extreme N/P-starvation, were taxonomically described and compared (bacterial 16S rRNA genes and fungal Internal Transcribed Spacers—ITS). As the list may include novel N- and/or P-providing wheat partners, we then identified all the operational taxonomic units (OTUs) that were proportionally enriched in one or more of the nutrient starvation- and plant-specific communities. These analyses revealed: a) distinct N-starvation root and rhizosphere bacterial communities that were proportionally enriched, among others, in OTUs belonging to families Enterobacteriaceae , Chitinophagaceae , Comamonadaceae , Caulobacteraceae , Cytophagaceae , Streptomycetaceae , b) distinct N-starvation root fungal communities that were proportionally enriched in OTUs belonging to taxa Lulworthia , Sordariomycetes , Apodus , Conocybe , Ascomycota , Crocicreas , c) a distinct P-starvation rhizosphere bacterial community that was proportionally enriched in an OTU belonging to genus Agrobacterium , and d) a distinct P-starvation root fungal community that was proportionally enriched in OTUs belonging to genera Parastagonospora and Phaeosphaeriopsis . Our study might have exposed wheat-microbe connections that can form the basis of novel complementary yield-boosting tools.

Inorganic Chemical Fertilizer Application to Wheat Reduces the Abundance of Putative Plant Growth-Promoting Rhizobacteria

“…We combined both CI and -dependent methods to study the impact of fertilizer on microbiome community composition and diversity. Our CI results confirmed previous studies showing that fertilizer alters community structure and reduces bacterial alpha diversity in the root environment ( Jorquera et al, 2014 ; Zhu et al, 2016 ; Cui et al, 2018 ; Kavamura et al, 2018 ; Lian et al, 2018 ; Chen et al, 2019 ; Pagé et al, 2019 ; Liang et al, 2020 ). Our CD results support this as beta diversity was influenced and alpha diversity reduced by fertilizer.…”

Interactions between plants and soil shaping the root microbiome under abiotic stress

“…However, in both bulk soil and roots, low rates of N fertilization supported an increased relative abundance of fungi from the genera Clonostachys and Resinicium , both of which have species demonstrating biological antagonism against pathogens [129]. Thus, reduced N availability in soil influences communities of root-associated fungi other than AMF— a conclusion also supported by recent findings in root-associated fungal communities of N-starved wheat [130], and the possibility that these fungi may be implicated in providing plant-beneficial services under low N certainly merits further investigation.…”

“…Shifts in root exudation profiles have also been hypothesized to drive observed changes in root microbial communities. An increase in bacterial abundance in the barley rhizosphere under high N growth conditions [153], shifts in root endosphere bacteria community structure in sorghum grown in +N or −N conditions [154], and enrichment of certain bacterial families in the root microbiome of N-starved wheat [130] were hypothesized to be at least partly the result of changes in quality and/or quantity of root exudates under different levels of N availability. However, exudates were not specifically characterized in any of these cases.…”

Proteomic analysis reveals how pairing of a Mycorrhizal fungus with plant growth‐promoting bacteria modulates growth and defense in wheat

“…Together with rice and corn, wheat is one of the most important crops worldwide (Fernie & Yan, 2019). Recently, many studies have been conducted on wheat-associated microbes, providing a detailed list of bacteria and fungi associated with wheat plants under natural conditions (Kuźniar et al, 2020;Mahoney, Yin, & Hulbert, 2017;Naylor, DeGraaf, Purdom, & Coleman-Derr, 2017;Pagé, Tremblay, Masson, & Greer, 2019) or describing the core microbiome of wheat (Simonin et al, 2020), thus revealing the ecological rules that regulate microbial assembly (Hassani, Özkurt, Seybold, Dagan, & Stukenbrock, 2019). Ecological studies suggest that higher soil microbial diversity results in a greater resilience of the plant population (Van der Heijden et al, 1998).…”