Genotype-Dependent Rhizosphere Microbiome Assembly Improves Potassium Use Efficiency in Pear Rootstocks Under Low Potassium Stress.
Xu H, Yang H, Shi Y, Hu X, Zhang L
Summary
8.0/10Certain pear rootstock varieties naturally recruit beneficial bacteria that significantly boost potassium absorption and utilization, especially under nutrient-scarce conditions. Deliberately introducing these bacteria increased plant biomass by 106%, potassium accumulation by 165%, and improved fruit quality.
Key Findings
P. betulaefolia recruits distinct Bacillaceae-dominated microbiomes that upregulate potassium transport genes, resulting in superior K accumulation and fruit quality compared to P. ussuriensis under low-K stress
Synthetic bacterial communities from five Bacillaceae strains increased plant biomass by 105.86%, K accumulation by 164.99%, and aboveground K utilization by 125.91%
Genotype-driven enrichment of Bacillaceae microbiomes provides mechanistic insights for developing microbiome-based bioinoculants and breeding microbiome-responsive rootstocks for sustainable fruit production under K limitation
Original Abstract
Potassium (K) is a vital nutrient for fruit quality in pears (Pyrus spp.), and rhizosphere microbes play a critical role in enhancing plant K uptake and utilization. To investigate the genotype-dependent influences of the rhizosphere microbiome on potassium use efficiency (KUE) in pears, we compared two rootstocks with contrasting KUE (Pyrus betulaefolia and Pyrus ussuriensis) using integrated pot and long-term field experiments, 16S rRNA amplicon sequencing, and metagenomic analyses. Synthetic community (SynCom) inoculation and transcriptome profiling were employed to elucidate the mechanisms underlying enhanced K acquisition. Under low-K conditions, P. betulaefolia recruited distinct microbial communities, which significantly improved K accumulation by upregulating genes (e.g., ATP1A, kdPB, and COG3158) associated with K transport and homoeostasis. Field trials further confirmed that P. betulaefolia-grafted trees sustained higher Bacillaceae abundance, superior fruit quality, and elevated K content than P. ussuriensis under K-deficient conditions. SynComs constructed from five Bacillaceae strains enhanced low-K tolerance by promoting root metabolic activity, stimulating root hair development, modulating K⁺ transporter (e.g., NRT2.4) expression, and activating calcium-dependent signalling pathways. Inoculation with SynComs led to substantial improvements under K limitation, including a 105.86% increase in plant biomass, a 164.99% increase in K accumulation, and a 125.91% enhancement in the aboveground K utilisation index. These findings reveal that genotype-driven enrichment of Bacillaceae-dominated microbiomes significantly enhances pear KUE, offering mechanistic insights to guide the development of microbiome-based bioinoculants and breeding of "microbiome-responsive" rootstocks for sustainable fruit production under K-limiting conditions.
Species Mentioned
Pears are a genus of trees, Pyrus, in the family Rosaceae, that bear an edible apple-like fruit of the same name. Several species of pears are cultivated for their fruit and juices, while others are grown as ornamental flowering trees.
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