Foliar application of fertilizers and biostimulant has a strong impact on the olive (Olea europaea) rhizosphere microbial community profile and the abundance of arbuscular mycorrhizal fungi

Abstract Background Increasing the presence of beneficial soil microorganisms is a promising sustainable alternative to support conventional and organic fertilization and may help to improve crop health and productivity. If the application of single bioeffectors has shown satisfactory results, further improvements may arise by combining multiple beneficial soil microorganisms with natural bioactive molecules. Methods In the present work, we investigated in a pot experiment under greenhouse conditions whether inoculation of two phosphate-solubilizing bacteria, Pseudomonas spp. (B2) and Bacillus amyloliquefaciens (B3), alone or in combination with a humic acids (HA) extracted from green compost and/or a commercial inoculum (M) of arbuscular mycorrhizal fungi (AMF), may affect maize growth and soil microbial community. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) fingerprinting analysis were performed to detect changes in the microbial community composition. Results Plant growth, N and P uptake, and mycorrhizal root colonization were found to be larger in all inoculated treatments than in the uninoculated control. The greatest P uptake was found when B. amyloliquefaciens was applied in combination with both HA and arbuscular mycorrhizal fungi (B3HAM), and when Pseudomonas was combined with HA (B2HA). The PLFA-based community profile revealed that inoculation changed the microbial community composition. Gram+/Gram− bacteria, AMF/saprotrophic fungi and bacteria/fungi ratios increased in all inoculated treatments. The greatest values for the AMF PLFA marker (C16:1ω5) and AMF/saprotrophic fungi ratio were found for the B3HAM treatment. Permutation test based on DGGE data confirmed a similar trend, with most significant variations in both bacterial and fungal community structures induced by inoculation of B2 or B3 in combination with HA and M, especially in B3HAM. Conclusions The two community-based datasets indicated changes in the soil microbiome of maize induced by inoculation of B2 or B3 alone or when combined with humic acids and mycorrhizal inoculum, leading to positive effects on plant growth and improved nutrient uptake. Our study implies that appropriate and innovative agricultural management, enhancing the potential contribution of beneficial soil microorganisms as AMF, may result in an improved nutrient use efficiency in plants.

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Effects of temperature rise (+5°C) on millet growth and mycorrhization and soil microbial community of culture

10.5194/egusphere-egu21-16406 ◽

2021 ◽

Author(s):

Sally Diatta ◽

Hassna Mboup-Founoune ◽

Sidy Diakhaté ◽

Diégane Diouf

Keyword(s):

Microbial Community ◽

Arbuscular Mycorrhizal Fungi ◽

Mycorrhizal Fungi ◽

Crop Yields ◽

Pennisetum Glaucum ◽

Agricultural Practices ◽

Arbuscular Mycorrhizal ◽

Sub Saharan Africa ◽

Soil Fertility Management ◽

Vegetation Growth

Our planet is marked by significant climatic variations, particularly with the warming of temperatures and the variation in rainfall. In sub-Saharan Africa, the impacts of climate change are more pronounced because agriculture is highly dependent on climate, hence its vulnerability to climate variability (Vanluwe et al., 2011). In the context of changing environmental conditions, the use of innovative agricultural practices to contribute to plant adaptation is necessary to support food security challenges. Agroecological practices to improve crop yields and sustainable soil fertility management. Soil is the main reservoir of biodiversity as it hosts a very high diversity of interacting living species, which can be distinguished according to their size, macrofauna, mesofauna and microorganisms that constitute a particularly important component of soil (Brady and Weil, 2002), particularly for the provision of ecosystem services to humans. This work is therefore interested in studying the contribution of arbuscular mycorrhizal fungi (AMF) to the growth of millet (Pennisetum glaucum) under warmer temperature conditions and the behaviour of microbial community in soil of millet growing.Millet is grown in a plant climate chamber and inoculated with a selected mycorrhizal strain.&#160; These millet growing conditions were carried out in two different temperatures: 32&#176;C (normal temperature) and 37&#176;C (warmer temperature).The results showed that in conditions of warmer temperature the inoculation induced a significant vegetative growth of millet even with a low intensity of mycorrhization and so it improves microbial nutrient mineralization mediate vegetation growth.In soil of millet growing, a significant increase in microbial biomass with 42.7 in warmer temperature condition compared to control temperature 16.7. Results of DGGE shows also a soil abundance and SMB diversity of the total fungal community was noted under warmer temperature condition.This study showed that climate variation may affect soil symbiosis but not the potential for promoting plant growth of fungi. The use of arbuscular mycorrhizal fungi on the one hand as a biofertilizer can be an alternative in the context of reducing chemical inputs in agriculture and developing ecologically intensive agriculture (EIA) and on the other hand an adaptive practice&#160; to apprehend the predicted climate changes.

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