The combined phytoremediation strategy using arbuscular mycorrhizal fungi, rhizobia, and biochar enhances lead tolerance and growth of white clover (Trifolium repens L.).

Enhancing copper and arsenic phytoextraction from calcareous soil through the synergistic interaction of ethylenediaminetetraacetic acid application timing and metal-resistant plant growth-promoting rhizobacteria inoculation.

Remediating calcareous soils co-contaminated with copper and arsenic remains a major challenge due to low metal bioavailability and the risk of chelator-induced phytotoxicity, which can severely limit phytoremediation success. This study investigated a synergistic strategy combining heavy metal-resistant plant growth-promoting rhizobacteria (PGPR) with precisely timed ethylenediaminetetraacetic acid (EDTA) application to improve phytoextraction efficiency in corn (Zea mays). Eight PGPR isolates were obtained from contaminated soil, and three strains (Stenotrophomonas sp. A22, Pseudomonas sp. A2 and A5) were selected based on their high resistance to Cu (up to 400 mg L-1) and As (up to 250 mg L-1), as well as multiple plant growth-promoting traits. In a controlled pot experiment, we evaluated bacterial inoculation and EDTA application at 20, 35, or 45 days after planting on plant growth, physiological performance, and metal uptake. Early EDTA addition (day 20) caused severe phytotoxicity, markedly reducing root and shoot biomass and depressing photosynthetic efficiency (Fv/Fm). In contrast, delaying EDTA application to days 35 or 45 substantially alleviated these adverse effects. PGPR inoculation, particularly with strain A5, further mitigated EDTA-induced stress and improved biomass production and physiological status. The combined PGPR-EDTA treatments significantly increased soil metal bioavailability and enhanced plant uptake, with maximum shoot Cu (214 mg kg-1) and As (99 mg kg-1) concentrations observed with strains A5 or A2 and EDTA application at day 20. Sequential extraction confirmed that these PGPR-EDTA treatments shifted metals from residual and oxide-bound pools into more soluble and exchangeable/carbonate-bound fractions. The findings support a mechanistically informed, optimized phytoremediation strategy for calcareous soils, based on the optimal timing of EDTA application and inoculation with metal-resistant PGPR.

Arbuscular mycorrhizal fungi combined with mycorrhizal helper bacteria synergistically enhance cadmium stress resistance of cucumber seedlings and change soil bacterial community.

It is suggested that FS treatment enhances the resistance of cucumber seedlings to Cd stress, and this effect may be associated with changes in the rhizosphere microbial community, activation of soil nutrients, and enhanced plant nutrient uptake.

Synergistic Effects of Arbuscular Mycorrhizal Fungi and Rhizobia on Nutrient Acquisition, Growth Promotion, and Protein Profile Optimization in Alfalfa

Arbuscular mycorrhizal fungi (AMF) and rhizobia establish mutualistic symbioses with plant roots. This study focused on their effects on alfalfa (Medicago sativa L.) growth, root morphology, nutritional quality, photosynthetic characteristics, and protein fractions; eight treatments were established: single inoculation with three AMF strains (Funneliformis mosseae, Claroideoglomus etunicatum, Glomus versiforme) or Sinorhizobium meliloti (Sm), dual co-inoculation of each AMF with Sm, and a non-inoculated control (CK). Results showed that all AMF successfully colonized alfalfa roots, with co-inoculation increasing both mycorrhizal colonization rate and nodule number. The F. mosseae × Sm treatment achieved the highest colonization (83.3%) and nodule count (76 per plant). Across two years, this treatment significantly increased aboveground biomass, plant height, and stem diameter (p < 0.05). C. etunicatum × Sm significantly reduced acid detergent fiber content, while dual inoculation markedly improved net photosynthetic rate and light-use efficiency. All inoculations increased rapidly (PB1) and intermediate-degradable protein (PB2) but decreased non-protein nitrogen (PA) and bound protein (PC). In conclusion, AMF and rhizobia exhibit significant synergistic effects. Co-inoculation (F. mosseae × Sm and C. etunicatum × Sm) enhances alfalfa productivity by optimizing root structure, improving photosynthesis, and regulating nitrogen metabolism.

Synergistic Effects of Triple Superphosphate, Mycorrhizal Fungi, and Phosphate-Solubilizing Bacteria on Cotton Yield, Fiber Quality, and Stress Tolerance under Variable Water Availability and Plant Density

Arbuscular Mycorrhizal Fungi and Azospirillum brasilense Enhance Growth and Resource Use Efficiency of Tomato Under Resource‐Limited Peat‐Reduced Cultivation

The transition towards peat‐reduced and resource‐efficient horticultural systems presents challenges for maintaining crop productivity because of altered nutrient dynamics and reduced microbial diversity within soilless substrates. Beneficial microbial inoculants may provide a sustainable approach to improve plant performance under reduced‐input cultivation; however, their effectiveness in peat‐reduced hydroponic environments remains poorly understood. This study evaluated the effects of arbuscular mycorrhizal fungi (AMF; Rhizophagus irregularis) and nitrogen‐fixing bacteria (NFB; Azospirillum brasilense), applied individually and in combination, on growth, productivity, resource‐use efficiency, and substrate nutrient dynamics of tomato grown under restricted fertigation in a peat‐reduced hydroponic system. NFB primarily enhanced vegetative growth, increasing leaf number by 11.7% and shoot fresh weight by 40%. AMF increased total fruit weight by 46% and exerted a significant positive main effect on WUE and NUE. Co‐inoculation produced the highest numerical responses, increasing shoot and root fresh biomass by 48% and 74%, fruit number by 80%, fruit weight by 77% and co‐inoculation increased substrate nitrate (NO3−) and potassium (K+) concentrations by 45% and 21%, respectively, compared with the control. Although co‐inoculation frequently produced the greatest numerical responses, interaction effects were generally limited, indicating complementary rather than strongly synergistic functions between the two microbial groups. Fruit quality characteristics, including total soluble solids and marketable fruit percentage, were not significantly affected by microbial treatments. Overall, these findings demonstrate complementary roles of AMF and A. brasilens under peat‐reduced cultivation, highlighting the potential of microbial inoculants to support more sustainable, low‐input greenhouse production systems.

Strigolactone (GR24) promotes arbuscular mycorrhizal colonization and wheat root growth