Bacillus subtilisCP4, isolated from native soil in combination with arbuscular mycorrhizal fungi promotes biofortification, yield and metabolite production in wheat under field conditions

Abstract

Aims The aim of this study was to identify the best combination of plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) for biofortification and enhancing yield in wheat as well as improve soil health under field conditions. Another aim was to get insights into metabolite dynamics in plants treated with PGPB and AMF. Methods and Results Different combinations of PGPB and AMF that gave good results in greenhouse study were used in a field study. The combined application of Bacillus subtilis CP4 (native PGPB) and AMF gave the best results with a significant increase in biomass, macronutrient and micronutrient content in wheat grains and improvement in yield‐related parameters relative to the untreated control. PGPB and AMF treatment increased antioxidant enzymes and compounds and decreased the level of an oxidation marker. Metabolite profiling performed using Gas Chromatography–Mass Spectrometry (GC‐MS) showed significant upregulation of specific organic acids, amino acids, sugars and sugar alcohols in plants treated with CP4 and AMF. The altered pathways due to CP4 and AMF inoculation mainly belong to carbohydrate and amino acid metabolism. A positive correlation was observed between some organic acids, sugars and amino acids with wheat growth and yield parameters. The activities of soil enzymes increased significantly with the best results shown by native PGPB and AMF combination. Conclusions A native bacterial isolate Bacillus subtilis CP4 in combination with AMF showed exceptional ability for biofortification and yield enhancement under field conditions. The upregulation of a number of metabolites showed correlation plant growth promotion and nutrients. Significance and Impact of the Study The combined application of native B. subtilis CP4 and AMF could offer a more sustainable approach for the development of a biofertilizer to enhance wheat nutrient content and production and soil health thereby advancing agriculture.

Plant Growth Promoting Rhizobacteria, Arbuscular Mycorrhizal Fungi and Their Synergistic Interactions to Counteract the Negative Effects of Saline Soil on Agriculture: Key Macromolecules and Mechanisms

“…Table 4 shows examples of the beneficial interaction between PGPR and AMF to boost plant growth. The efficacy of co-inoculation of AMF and PGPR have been shown in sorghum [ 160 ], wheat [ 161 , 162 ], swamp oak [ 163 ], bean [ 164 ], and watermelon [ 146 ], and several other plants to promote growth and/or improve stress tolerance. Although an increase in plant growth and grain yield was observed when PGPR and AMF are used in combination, several factors such as environmental conditions, soil quality, and the microbial strains used, contribute to variable results.…”

Microbial-Assisted Wheat Iron Biofortification Using Endophytic Bacillus altitudinis WR10

“…For example, in all tissues, the contents of N and K were higher along with a higher abundance of Bacillus spp. In contrast, Fe content was higher in the root but lower in leaves when having more Bacillus spp; however, the complex and different regulation of nutrient content in different wheat tissues by microbial inoculants are frequently reported in previous studies (13,(22)(23)(24)43).…”

“…Indeed, the relative abundance of WR10 is always much higher in the root than in the sprout at the same time point and effective colonization of AMF, as well as other PGPB, has also been reported in the root of wheat (24,44); however, this experiment provided more information regarding the quantitative or dynamic distribution of microbial inoculants in different tissues of wheat. It was also shown that exogenous WR10 reached a plateau in both the root and the sprout after a certain number of hours (e.g., 10 or 12 hpi).…”

“…As high as a 70% increase in Fe content in wheat grains after inoculation with B. pichinotyi or B. subtilis has been reported (22,23). In another study, B. subtilis CP4 and AMF in combination increased Fe content in wheat grains by more than 44% (24). To fully discover the effect of WR10 application on grain nutrients, we evaluated three macronutrients and four micronutrients in grains.…”

“…Field studies have demonstrated as high as a 70% increase of Fe content in wheat grains after inoculation with B. pichinotyi or B. subtilis ( 22 , 23 ). In another study, the values of tillers per plant (TTP) and thousand-grain weight (TGW) increased more than 20%, and the levels of grain Fe increased more than 44% ( 24 ).…”