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Plants can recruit beneficial microbes to enhance their ability to resist disease. It is well established that selenium is beneficial in plant growth, but its role in mediating microbial disease resistance remains poorly understood. Here, we investigated the correlation between selenium, oilseed rape rhizosphere microbes, and Sclerotinia sclerotiorum. Soil application of 0.5 and 1.0 mg kg–1 selenium [selenate Na2SeO4, Se(VI) or selenite Na2SeO3, Se(IV)] significantly increased the resistance of oilseed rape to Sclerotinia sclerotiorum compared with no selenium application, with a disease inhibition rate higher than 20% in Se(VI)0.5, Se(IV)0.5 and Se(IV)1.0 mg kg–1 treatments. The disease resistance of oilseed rape was related to the presence of rhizosphere microorganisms and beneficial bacteria isolated from the rhizosphere inhibited Sclerotinia stem rot. Burkholderia cepacia and the synthetic community consisting of Bacillus altitudinis , Bacillus megaterium , Bacillus cereus , Bacillus subtilis , Bacillus velezensis , Burkholderia cepacia , and Flavobacterium anhui enhanced plant disease resistance through transcriptional regulation and activation of plant-induced systemic resistance. In addition, inoculation of isolated bacteria optimized the bacterial community structure of leaves and enriched beneficial microorganisms such as Bacillus , Pseudomonas , and Sphingomonas. Bacillus isolated from the leaves were sprayed on detached leaves, and it also performed a significant inhibition effect on Sclerotinia sclerotiorum. Overall, our results indicate that selenium improves plant rhizosphere microorganisms and increase resistance to Sclerotinia sclerotiorum in oilseed rape. [ABSTRACT FROM AUTHOR]

The prolonged utilization of copper (Cu)-containing fungicides results in Cu accumulation and affects soil ecological health. Thus, a pot experiment was conducted using Citrus reticulata cv. Shatangju with five Cu levels (38, 108, 178, 318, and 388 mg kg−1) to evaluate the impacts of the soil microbial processes, chemistry properties, and citrus growth. These results revealed that, with the soil Cu levels increased, the soil total Cu (TCu), available Cu (ACu), organic matter (SOM), available potassium (AK), and pH increased while the soil available phosphorus (AP) and alkali-hydrolyzable nitrogen (AN) decreased. Moreover, the soil extracellular enzyme activities related to C and P metabolism decreased while the enzymes related to N metabolism increased, and the expression of soil genes involved in C, N, and P cycling was regulated. Moreover, it was observed that tolerant microorganisms (e.g., p_Proteobacteria, p_Actinobacteria, g_Lysobacter, g_Sphingobium, f_Aspergillaceae, and g_Penicillium) were enriched but sensitive taxa (p_Myxococcota) were suppressed in the citrus rhizosphere. The citrus biomass was mainly positively correlated with soil AN and AP; plant N and P were mainly positively correlated with soil AP, AN, and acid phosphatase (ACP); and plant K was mainly negatively related with soil β−glucosidase (βG) and positively related with the soil fungal Shannon index. The dominant bacterial taxa p_Actinobacteriota presented positively correlated with the plant biomass and plant N, P, and K and was negatively correlated with plant Cu. The dominant fungal taxa p_Ascomycota was positively related to plant Cu but negatively with the plant biomass and plant N, P, and K. Notably, arbuscular mycorrhizal fungi (p_Glomeromycota) were positively related with plant P below soil Cu 108 mg kg−1, and pathogenic fungi (p_Mortierellomycota) was negatively correlated with plant K above soil Cu 178 mg kg−1. These findings provided a new perspective on soil microbes and chemistry properties and the healthy development of the citrus industry at increasing soil Cu levels. [ABSTRACT FROM AUTHOR]

Due to the essential role of nano-fertilizers in crop production, studies have yet to be conducted to evaluate nano-molybdenum (Mo) application on winter wheat (Triticum aestivum L.). The present study assessed the efficacy of nano-Mo on the Mo-uptake, plant growth, and winter wheat yield. Wheat was grown in the pot experiment using four experimental groups (deionized water: C, nano potassium molybdate: NMoK, potassium molybdate: MoK, and ammonium molybdate: MoA), each with six replicate samples applied-foliar three times in a 30-day interval. The results revealed that NMoK improved Mo accumulation in grains, stomatal conductance, root dry weight, yield, and the number of spikes per pot of wheat compared with MoK. Additionally, NMoK treatment significantly increased wheat grain yield by 46.29%, 13.94%, and 17.70% compared with C, MoK, and MoA treatments, respectively. These results demonstrated that the nano-Mo application may enhance Mo-inefficient wheat growth, thus, increasing its productivity under acidic soil conditions. The principal component analysis (PCA) elucidates that all variables reside within the positively correlated variable domain. This encompasses parameters related to yield, photosynthetic machinery, and Mo uptake by various plant organs. Through cluster analysis, the nano-Mo group exhibited a more pronounced influence on the variables than the without-Mo and non-nano-Mo groups. Based on our findings, nano-Mo could be a suitable alternative to non-nano molybdenum fertilizers. This recommendation is particularly relevant for enhancing the growth of winter wheat crops cultivated in acidic soil conditions. [ABSTRACT FROM AUTHOR]

Molybdenum (Mo) is an essential element for higher plants. Recent research indicated that Mo application enhanced cold-resistance of winter wheat. In order to improve our understanding of the mechanisms of cold resistance enhanced by molybdenum application in winter wheat, liquid nutrient culture experiments were conducted to investigate the effects of molybdenum on endogenesis hormone in winter wheat (Mo efficient cv. 97003 and Mo inefficient cv. 97014) under low temperature stress. The results showed that Mo application increased the AO activities, the contents of abscisic acid (ABA) and indole-3-acetic acid (IAA) in the leaves of +Mo winter wheat under low temperature stress. No significant difference in the contents of GA3 and Z was detected between -Mo and +Mo winter wheat at the earlier stage of low temperature stress, whereas the contents of gibberellin (GA3) increased significantly, and zeatin (Z) decreased significantly in the leaves of +Mo winter wheat at the later stage of low temperature stress. Mo-deficiency also induced the drastic decrease of the ABA/GA in the leaves of winter wheat under low temperature stress. These results indicated that Mo regulated the ABA and IAA biosynthesis via AO in winter wheat and the response of ABA and IAA to Mo deficiency was prior to that of GA3 and ZT. The dramatic decrease in ABA and IAA levels in Mo deficient winter wheat may affect the homeostasis of endogenous hormones and Mo regulated cold resistance via the levels and balance of endogenous hormone in winter wheat.