Symbiotic Effectivity of Dual and Tripartite Associations on Soybean (Glycine max L. Merr.) Cultivars Inoculated With Bradyrhizobium japonicum and AM Fungi

Abstract

Soybean (Glycine max L. Merr.) is regarded worldwide as indisputably one of the most important crops for human food and animal feed. The presence of symbiotic bacteria and fungi is essential for soybean breeding, especially in low-input agricultural systems. Research on the cooperation between different microbial symbionts is a key to understanding how the health and productivity of the plant is supported. The symbiotic effectivity of dual and tripartite symbiotic agents was investigated in two pot experiments on different soybean cultivars with special regard to compatibility. In the Selection experiment, two out of sixteen soybean cultivars (Aliz, Emese) were chosen on the basis of their drought tolerance and used in all the other investigations. In the Compatibility experiment, the compatible coupling of symbiotic partners was selected based on the efficiency of single and co-inoculation with two Bradyrhizobium japonicum strains and two commercial arbuscular mycorrhizal fungal (AMF) products. Significant differences were found in the infectivity and effectivity of the microsymbionts. The rhizobial and AMF inoculation generally improved plant production, photosynthetic efficiency and root activity, but this effect depended on the type of symbiotic assotiation. Despite the low infectivity of AMF, inocula containing fungi were more beneficial than those containing only rhizobia. In the Drought Stress (DS) experiment, co-inoculated and control plants were grown in chernozem soil originating from organic farms. Emese was more resistant to drought stress than Aliz and produced a bigger root system. Under DS, the growth parameters of both microbially inoculated cultivars were better than that of control, proving that even drought tolerant genotypes can strengthen their endurance due to inoculation with AMF and nitrogen fixing bacteria. Root electrical capacitance (CR) showed a highly significant linear correlation with root and shoot dry mass and leaf area. The same root biomass was associated with higher CR in inoculated hosts. As CR method detects the absorptive surface increasing due to inoculation, it may be used to check the efficiency of the microbial treatment.

Potential of Native Rhizobia to Improve Cowpea Growth and Production in Semiarid Regions of Kenya

“…Rhizobia inoculation has been regarded as a sustainable and cost-effective technology to augment the plants' N needs (Ondieki et al, 2017). Several studies have reported that inoculation with rhizobia improves legume growth, nutrition, and production (Takács et al, 2018;Aserse et al, 2020). However, inoculation with proven rhizobia inoculants as well as some commercial inoculants has at times failed to yield positive results when inoculation is done in regions with different agroenvironmental conditions to the original habitat.…”

The effects of mycorrhizal colonization on phytophagous insects and their natural enemies in soybean fields

“…Legumes can form tripartite symbiotic associations with nodule-inducing rhizobia and AMF, that may benefit growth, development, and the uptake of both phosphorous and nitrogen [16][17][18][19]. It was shown in soybean and common bean (Phaseolus vulgaris L.) that the co-inoculation of AMF and rhizobium improved production, efficiency of photosynthesis, nodulation and, especially, an increase in both phosphorus and nitrogen concentrations [20,21]. In addition, some studies showed that co-inoculation of soybean with PGPR of Bacillus species and the rhizobia Bradyrhizobium japonicum, increases nodulation and nitrogen fixation [9,22].…”

Interaction with Soil Bacteria Affects the Growth and Amino Acid Content of Piriformospora indica

“…Garbaye proposed five potential mechanisms underlying the MHB effect: (i) Enhancement of plant susceptibility to mycorrhizal colonization, (ii) enhancement of the root-fungus recognition process, (iii) nutritional improvement of fungal growth, (iv) a beneficial change in the composition of the rhizosphere soil, and (v) stimulation of fungal propagules germination [7]. It has been proposed that active bacterial attachment and colonization of the mycorrhizal surfaces are required for MHB to influence mycorrhizal plant growth and health [8,9]. Streptomycetes studies demonstrated that the exudation of bacterial compounds can both inhibit pathogenic fungi growth and support symbiotic fungi growth [10,11].…”