Increased soil salinization is among the main factors that limits safe rice production. Arbuscular mycorrhizal fungi (AMF) have been shown to alleviate the toxic effects of salt stress in plants. However, more studies on AMF combined with other functional microorganisms are needed to further improve salt tolerance in rice. Therefore, the compound inoculum Funneliformis mosseae (Fm) together with two functional microorganisms, Piriformospora indica (Pi) and Agrobacterium rhizogenes (Ar) was evaluated for their effect on the rice growth, photosynthetic gas exchange parameters, ion homeostasis, and the expression of salt tolerance-related genes under 0, 80, 120 and 160 mM salt stress conditions. The results showed that: (1) the rice seedling biomass of the AMF compound inoculant treatment group was significantly higher than that of the non-inoculation treatment group (P < 0.05); (2) under NaCl stress, inoculation with AMF compound inoculants can activate the rice antioxidant enzyme system and improve osmoregulation ability; (3) AMF compound inoculants can increase the concentration of K⁺ in the plant and inhibit the transfer of Na⁺ to rice leaves, maintaining a high K⁺/Na⁺; and (4) AMF compound inoculants could induce and regulate the overexpression of genes related to salt tolerance, photosynthesis and ion homeostasis in rice, and improve the tolerance of rice under salt stress. Our study showed that AMF compound inoculants could improve the adaptability of rice under NaCl stress and promote plant growth by regulating the photosynthetic gas exchange parameter, reactive oxygen species (ROS) scavenging ability, and ion homeostasis of plants. These results suggest that AMF compound inoculants may play an important role in improving rice productivity in salinized soil. Graphical Abstract

In order to further clarify the growth-promoting effect of the non-core Metarhizium sp. Marquandomyces marquandii on plants, M. marquandii SGSF043, which was obtained via pre-screening in the laboratory, was selected as a test strain and the seed soaking method was adopted. The effects of a fermentation broth obtained from this strain on the seed germination, seedling growth, and rhizosphere soil enzyme activity of maize were studied. The results were as follows: In seed germination tests, M. marquandii SGSF043 fermentation liquid had a certain inhibitory effect on corn seed germination, and the germination rate was only 15%. When the fermentation solution was diluted 10 times, the germination rate reached 97%. After the germination test, the growth of maize plumules was promoted in the groups treated with 10-times and 1000-times dilutions. In the field community experiment, based on the comprehensive evaluation of seedling biomass indicators, the solution diluted 100 times had the best growth-promoting effect. The aboveground fresh weight was increased by 127.13% compared with the control group. The results show that M. marquandii SGSF043 has the potential to promote the growth of maize and improve the soil environment, which provides a theoretical basis for the research on and the application of M. marquandii in farmland.

Albic soil is acidic and nutrient-deficient, resulting in low soil fertility that significantly limits the sustainable utilization of arable land. Microbial inoculants have emerged as promising biotechnological interventions to enhance soil quality by stimulating microbial activity and facilitating nutrient accumulation. This study focused on improving the characteristics of albic soil through the incorporation of straw residues combined with inoculation treatments involving arbuscular mycorrhizal fungi (AMF) and Trichoderma. Four experimental treatments were established: a Control (CK), single inoculation with AMF (AM), single inoculation with Trichoderma (TL), and a combined inoculation of both (AT). The investigation focused on assessing the synergistic effects of the AT treatment on albic soil chemical characteristics and its microbial community structure. The AT treatment significantly elevated rhizosphere soil pH, TN, and TP by 3.8%, 19.2%, and 10.9%, respectively, relative to the Control. The AT treatment markedly enhanced soil cellulase, β-glucosidase, and lignin peroxidase activities by 24.9%, 77.6%, and 36.7%, respectively, and increased the SQI by 78.9% compared to CK. Furthermore, the AT treatment led to a higher correlation abundance of Sphingomonas and aerobic chemoheterotrophs taxa. Structural equation modeling (SEM) uncovered that the interactions between AMF and Trichoderma modulated microbial community functions, augmented soil enzyme activities, promoted nutrient accumulation, and consequently improved albic soil quality. This study elucidates arbuscular mycorrhizal and Trichoderma longibrachiatum interactions with the soil environment, providing insights for improving albic soil health and microbial community structure.

Straw return is considered an effective strategy for its improvement. However, in regions where albic soil is predominantly distributed, low temperatures s

In order to further clarify the growth-promoting effect of non-core Metarhizium spp. M. marquandii on plants, M. marquandii SGSF043, which was obtained from the pre-screening in the laboratory, was selected as a test strain, and the effects of the fungus fermentation broth during the stabilization period of the growth of this strain on the growth and growth of maize seeds were investigated by using fermentation broth as a submerged seed. germination, seedling growth, and inter-root soil enzyme activity of seedlings. The results are as follows: In the seed germination test, M. marquandii SGSF043 fermentation liquid had a certain inhibitory effect on the germination of maize seeds, and the 10-times dilution of the fermentation liquid significantly promoted the seed germination, and the effect was the best; After the germination test, the growth of maize germ was promoted by the treatment groups of 10 times and 1,000 times diluent; In the field plot experiment, the 100-fold dilution had the best growth promotion effect, which could promote the growth of cabbage seedlings and increase the seedling biomass. The results show that M. marquandii SGSF043 has the potential to promote the growth of maize and improve the soil environment, which provides a theoretical basis for the research and application of M. marquandii in farmland.