Effect of mycorrhizae, Thiobacillus and sulfur nutrition on the chemical composition of soybean [Glycine max (L.)] Merr. seed

Regional analysis of planting date and cultivar maturity recommendations that improve soybean oil yield and meal protein concentration

Planting date and cultivar maturity group (MG) are major management factors affecting soybean [Glycine max (L.) Merr.] yield, but their effect on seed oil and protein concentration, and in particular meal protein concentration, is less understood. We quantified changes in seed oil and protein, and estimated meal protein concentration, and total oil and protein yield in response to planting date and cultivar MG ranging from 3 to 6 and across locations comprising a 8.3° range in latitude in the U.S. Midsouth. Our results show that delayed planting date and later cultivar maturity reduced oil concentration, and this was partially associated with a decrease in temperature during the seed fill phase. Thus, optimum cultivar MG recommendations to maximize total oil yield (in kg ha-1) for planting dates in May and June required relatively earlier cultivar MGs than those recommended to maximize seed yield. For planting dates in April, short-season MG 3 cultivars did not increase oil yield compared to full-season MG 4 or 5 cultivars due to a quadratic yield response to planting date at most locations. Planting date and cultivar maturity effects on seed protein concentration were not always consistent with the effects on estimated meal protein concentration after oil extraction. Meal protein concentration decreased with lower temperatures during seed fill, and when the start of seed fill occurred after August 15, but relatively short-season cultivar MGs reduced the risk of low meal protein concentration. Meal protein concentration is a trait of interest for the feed industry that would be beneficial to report in future studies evaluating genetic, management, and environmental effects on seed protein concentration.

Fungal communities in European alpine soils are not affected by short-term in situ simulated warming than bacterial communities

The impact of global warming on biological communities colonizing European alpine ecosystems was recently studied. Hexagonal open top chambers (OTCs) were used for simulating a short-term in situ warming (estimated around 1°C) in some alpine soils to predict the impact of ongoing climate change on resident microbial communities. Total microbial DNA was extracted from soils collected either inside or outside the OTCs over 3 years of study. Bacterial and fungal rRNA copies were quantified by qPCR. Metabarcoding sequencing of taxonomy target genes was performed (Illumina MiSeq) and processed by bioinformatic tools. Alpha- and beta-diversity were used to evaluate the structure of bacterial and fungal communities. qPCR suggests that, although fluctuations have been observed between soils collected either inside and outside the OTCs, the simulated warming induced a significant (p < 0.05) shift only for bacterial abundance. Likewise, significant (p < 0.05) changes in bacterial community structure were detected in soils collected inside the OTCs, with a clear increase of oligotrophic taxa. On the contrary, fungal diversity of soils collected either inside and outside the OTCs did not exhibit significant (p < 0.05) differences, suggesting that the temperature increase in OTCs compared to ambient conditions was not sufficient to change fungal communities.

Novel sulphur-oxidizing bacteria consummate sulphur deficiency in oil seed crop

Plants absorb sulphate, the oxidized form of elemental sulphur (S°), from soil. Sulphur-oxidizing bacteria play a key role in transformation of sulphur in soil. Oil seed crops require high amount of sulphur and it plays an important role in the formation of proteins, vitamins and enzymes. It increases yield, oil content and protein content in oil seed crops. Sulphur is the important constituent of amino acids, viz. methionine, cystine, and cysteine. It necessitates various enzymatic, metabolic processes such as photosynthesis and nitrogen fixation. In the last few years, the prominence of sulphur in oil seed crop nutrition has been accepted as widespread occurrence of its inadequacy in agricultural soil. Approximately 41% of Indian soil is deficient in sulphur. The soil microbial population is the major enforcement behind sulphur transformation. They mineralize, immobilize, oxidize and reduce the elemental and other reduced forms of sulphur. The main step in transformation is oxidation carried out by microorganisms to convert sulphur into sulphate. The chemolithotrophic bacteria belonging to genus Thiobacillus are of primary importance; there are heterotrophic bacteria also which can oxidize sulphur in soil. The pH reduction at the time of oxidation helps in mineralization and absorption of other essential nutrients also. This property of sulphur-oxidizing bacteria (SOB) shows their potential to be used as bioinoculants. Bioformulations prepared using carrier-based formulations, immobilization, biostimulation, etc., are sustainable forms of fertilizers. These SOB inoculants can be used to increase the fertility and sulphate production in soil.

Mycorrhizal Fungi and Thiobacillus Co-inoculation Improve the Physiological Indices of Lallemantia iberica Under Salinity Stress

Salinity, a serious environmental pressure on crop production, might be counteracted by free-living and symbiotic inoculants entailing positive synergistic effects. Enhancement in nutrient uptake and/or production of antioxidants under the stress condition, can improve plant growth and yield. In this study, inoculation of Lallemantia iberica with Funneliformis mosseae and the sulfur solubilizing bacterium (Thiobacillus sp. T95 and T40) was evaluated under two salinity levels (6.72 dS/m and 0.91 dS/m as control). The root colonization, spore density, seed and biological yield, total soluble sugars, and nutrients were reduced by salt stress. Antioxidant enzyme activity (catalase, superoxide dismutase, peroxidase and ascorbate peroxidase), proline, contents of sodium and sulfur have increased under salt stress. The enzyme activities as well as the concentrations of nitrogen, phosphorus, potassium, sodium, and sulfur were dropped at the flowering stage (75 days after sowing). Seed and biological yield, antioxidant enzymes activity, proline content, and nutrients were significantly improved in mycorrhizal treatments. Inoculation of Thiobacillus exhibited the positive effect on root colonization, spore density, enzymes activity, and nutrients. Bacterial treatments (dual and single) significantly increased the sulfur and total soluble sugars. Totally, the mycorrhizal plants accumulated more enzymatically produced antioxidants, osmolytes, and showed improved nutrient uptake. Our results provide new insights into the relationship among arbuscular mycorrhizal fungi (AMF), biosulfur bacteria, and plant growth under saline conditions. In conclusion, the Lallemantia iberica inoculation with mycorrhizal fungi, either alone, or in combination with Thiobacillus, is indicated for optimum plant yield through alleviation of the salinity stress.