Populus root exudates are associated with rhizosphere microbial communities and symbiotic patterns

Abstract

IntroductionMicrobial communities in the plant rhizosphere are critical for nutrient cycling and ecosystem stability. However, how root exudates and soil physicochemical characteristics affect microbial community composition in Populus rhizosphere is not well understood.MethodsThis study measured soil physiochemistry properties and root exudates in a representative forest consists of four Populus species. The composition of rhizosphere bacterial and fungal communities was determined by metabolomics and high-throughput sequencing.ResultsLuvangetin, salicylic acid, gentisic acid, oleuropein, strigol, chrysin, and linoleic acid were the differential root exudates extracted in the rhizosphere of four Populus species, which explained 48.40, 82.80, 48.73, and 59.64% of the variance for the dominant and key bacterial or fungal communities, respectively. Data showed that differential root exudates were the main drivers of the changes in the rhizosphere microbial communities. Nitrosospira, Microvirga, Trichoderma, Cortinarius, and Beauveria were the keystone taxa in the rhizosphere microbial communities, and are thus important for maintaining a stable Populus microbial rhizosphere. The differential root exudates had strong impact on key bacteria than dominant bacteria, key fungi, and dominant fungi. Moreover, strigol had positively effects with bacteria, whereas phenolic compounds and chrysin were negatively correlated with rhizosphere microorganisms. The assembly process of the community structure (keystone taxa and bacterial dominant taxa) was mostly determined by stochastic processes.DiscussionThis study showed the association of rhizosphere microorganisms (dominant and keystone taxa) with differential root exudates in the rhizosphere of Populus plants, and revealed the assembly process of the dominant and keystone taxa. It provides a theoretical basis for the identification and utilization of beneficial microorganisms in Populus rhizosphere.

Microbial community and network differently reshaped by crushed straw or biochar incorporation and associated with nitrogen fertilizer level

“…A previous study also suggested that the effect of straw return on the RA of Proteobacteria was related to the nitrogen level (Du, Zhang, et al, 2022). The sufficient air and organic nutrient conditions provided by BC might be responsible for the increase in Sphingomonas (Li, Song, et al, 2022; Li, Zheng, et al, 2022).…”

“…The RAs of Acremonium and Trichoderma were increased by SD (at the N0 level) and BC (at the N100 level), respectively (Figure 3 and Table S2). As a well‐known plant growth‐promoting fungus, Trichoderma can activate the plant immune system against pathogens (Fernández‐González et al, 2020; Li, Song, et al, 2022; Li, Zheng, et al, 2022). Acremonium was also considered to be a beneficial fungus and was found to be dominant in soils treated with organic residues (Hernández‐Lara et al, 2023).…”

“…In the current study (Figure 4 and Table S3), Glomus , Chaetomium , Mucor , and Gaiella in SD‐M0, Pseudozyma and Nitrospira in SD‐M1, and Mrakia in SD‐M2 were identified as the main KT in the SD network, while Fusarium in BC‐M0, Mrakia in BC‐M1, Massilia in BC‐M2, and Solirubrobacter and Ramicandelaber in BC‐M3 were identified as KT in the BC network, indicating their potential as indicators and the shifting of their ecological roles by different SRMs. Gaiella likely serves a role in nitrogen cycling in cultivated farm ecosystems (Li, Song, et al, 2022; Li, Zheng, et al, 2022). Nitrosospira are main ammonia‐ and nitrite‐oxidizing bacteria and function as soil N cycle (Xu et al, 2022; Yang, Jing, et al, 2019; Yang, Ma, et al, 2019).…”

Microbe tree metabolite interactions in the soil - phyllosphere continuum of poplar tree: when microbes rewire poplar root exudate and metabolome

“…Furthermore, most studies have been conducted on herbaceous plants or shrubs, whereas similar studies with trees are limited to a few species and involve very few forest trees (Vives-Peris et al, 2020). To our knowledge, only one study has attempted to characterize poplar root exudates, and it focused more on rhizospheric soil metabolomes rather than on actual exudates (Li et al, 2022). Even less is known regarding feedback effects of rhizospheric microbiota on tree exudation.…”

Geographical variation of Geochemistry and Bacteriome of Maize Rhizosphere in Agricultural Farmlands

“…Quintessentially, Microvirga species have been described as keystone taxon in biocontrol of crop diseases(Li et al, 2022;Xing et al, 2022) and equally enhance crop growth upon degrading pesticide and making nutrient available (Castellano-Hinojosa and Strauss, 2020). Abundance of Streptomyces OTUs exerts negative antagonistic interaction with microbial pathogen to confer protection to maize by suppressing root diseases.…”