Synergistic Effects of Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria for Sustainable Agricultural Production

Abstract

Soil microorganisms play a major role in improving soil fertility and plant health. Symbiotic arbuscular mycorrhizal fungi (AMF) form a key component of the soil microbial populations. AMF form a mutualistic association with the host plant and exert a positive influence on its growth and nutrient uptake. The establishment of mycorrhizal symbioses with the host plant can positively be influenced by plant growth promoting rhizobacteria through various mechanisms such as increased spore germination and hyphal permeability in plant roots. Though there are evidences that combined interactions between AMF and PGPR can promote the plant growth however mechanisms of these interactions are poorly understood. Better understanding of the interactions between AMF and other microorganisms is necessary for maintaining soil fertility and enhancing crop production. This paper reviews current knowledge concerning the interactions between AMF and PGPR with plants and discusses on enhanced nutrient availability, biocontrol, abiotic stress tolerance and phytoremediation in sustainable agriculture.

EFFECT OF MYCORRHIZAE AND ACTINOMYCETES ON GROWTH AND BIOPROTECTION OF Capsicum annuum L. AGAINST Phytophthora capsici

“…These microorganisms increased the foliar uptake of phosphorus levels in Trifolium repens (white clover) plants, which stimulated the production of biomass and mycorrhizal colonization compared with the inoculation of each individual organism. According to Ramasamy et al (2011), plant growth-promoting rhizobacteria, such as actinomycetes, could positively influence the development of mycorrhizal symbiosis through different mechanisms of action. In this regard, Carpenter-Boggs et al (1995) found 19 actinomycetes capable of stimulating in vitro germination of G. margarita by producing volatile compounds that could benefit the plant in terms of greater growth.…”

Beneficial microorganisms for soybean (Glycine max (L.) Merr), with a focus on low root-zone temperatures

“…While mycorrhizae transport phosphorus throughout the soil, it may not be available to the host plant without the P-solubilizing activity of certain rhizobacteria; thus, both symbionts play important roles. Fungi may facilitate colonization of the host by rhizobia and fluorescent pseudomonads (Bianciotto et al 1996), and some bacteria may improve spore colonization in turn (Ramasamy et al 2011). In addition, VAM improve rhizobial nodulation and nitrogen fixation (Table 2).…”

“…Phosphorus-solubilizing bacteria, including representatives of Rhizobium, Pseudomonas, Bacillus, and Burkholderia, increase the availability of soil P to the host plant (Barka et al 2006;Hayat et al 2010;Ramasamy et al 2011). This is often achieved by releasing organic acids, such as the 2-ketoglutonic acid produced by Rhizobium meliloti, to dissolve mineral phosphates (Halder and Chakrabartty 1993;Hayat et al 2010).…”

“…Mycorrhizal colonization increases nitrogen bioavailability and local phosphorus concentration, supplementing the capabilities of diazotrophic and P-solubilizing bacteria (Ramasamy et al 2011). While mycorrhizae transport phosphorus throughout the soil, it may not be available to the host plant without the P-solubilizing activity of certain rhizobacteria; thus, both symbionts play important roles.…”

“…Bacteria that produce the compound 1-aminocyclopropane-1-carboxylate (ACC) deaminase can increase resistance to environmental stress such as salinity or drought by modifying ethylene levels (Hayat et al 2010). ACC deaminase hydrolyzes the ethylene precursor ACC to ammonium and α-ketobutyrate, lowering ACC and therefore ethylene levels in the plant (Ramasamy et al 2011;Glick 2012;Ahemad and Kibret 2013).…”