Arbuscular mycorrhizae: Effect of rhizosphere and relation with carbon nutrition

More than 90 % of terrestrial plants form symbiotic association with mycorrhizae which develop and promote cooperation belowground in rhizosphere. Mycorrhizal fungi produces spores in the soil and vegetative propagules in root fragments which respond to stimulation of root exudates in the rhizosphere. As a result, symbiotic relationship takes place where physiology and morphology of both participants rely on each other. Mycorrhizae are present in a range of horticultural, agricultural, forestry and other plant species. Along with mycorrhizae, other beneficial microbes also add in plant growth promotion, nutrient and uptake and stress tolerance either biotic or abiotic. The presence of bacteria in rhizosphere synchronizes with mycorrhizae termed as 'mycorrhizae helper bacteria' and increases plant growth by focusing on N and P in particular while micronutrients in general. Besides that, carbon has important structural and functional role in symbiotic association, because of mycorrhizal reliance on plants for food. Additionally, movement of C to the roots is an interesting area for exploration due to recent global focus on addressing climate change and carbon mitigation approaches particularly for sustainable agriculture. AM symbiosis can influence soil CO2 emissions and soil in ecosystems dominated by mycorrhizal plants that contain 70 % more carbon per unit nitrogen than soil in ecosystems dominated by non-AM-associated plants. Absorption of CO2 by mycorrhizae is contributing in climate change mitigation and translated as plant biomass production. © Springer Nature Singapore Pte Ltd. 2016