Spore Associated Bacteria (SAB) of Arbuscular Mycorrhizal Fungi (AMF) and Plant Growth Promoting Rhizobacteria (PGPR) Increase Nutrient Uptake and Plant Growth Under Stress Conditions

Abstract

Microorganisms present in the rhizosphere soil plays a vital role in improving the plant growth and soil fertility. Many kinds of fertilizers including chemical and organic has been approached to improve the productivity. Though some of them showed significant improvement in yield, they failed to maintain the soil properties. Rather they negatively affected soil eventually, the land became unsuitable for agricultural. To overcome these problems, microorganisms have been used as effective alternative. For past few decades, plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) have been used as effective inoculants to enhance the plant growth and productivity. PGPR improves the plant growth and helps the plant to withstand biotic and abiotic stresses. AM fungi are known to colonize roots of plants and they increase the plant nutrient uptake. Spore associated bacteria (SAB) are attached to spore wall or hyphae and known to increase the AMF germination and root colonization but their mechanism of interaction is poorly known. Better understanding the interactions among AMF, SAB and PGPR are necessary to enhance the quality of inoculants as a biofertilizers. In this paper, current knowledge about the interactions between fungi and bacteria are reviewed and discussed about AMF spore associated bacteria.

Plant, Soil and Microbes

“…This prophylactic activity of AMF is also endorsed to some root pathogen antagonists such as Trichoderma , Gliocladium , and PGPR like Pseudomonas and Bacillus (Kloepper et al 1991 ;Barea et al 1996 ). Growth-promoting bacteria and fungi work in collaboration with AMF by improvement in plant rooting, enhancement of plant growth and nutrition (Gopal et al 2012 ;, abiotic stress tolerance (Xun et al 2015 ), and biological control of pathogens; they also improve as well as facilitate symbiosis (Barea et al 1996 ). That means the presence of microbial community in soil rhizosphere or changes in rhizosphere enhances AMF-assisted antagonism to root pathogens.…”

Bacteria from Arbuscular Mycorrhizal Fungi Spores Gigaspora sp. and Glomus sp. : Their Antagonistic Effects towards Soilborne Fungal Pathogens and Growth Stimulation of Gigaspora sp. in vitro

“…Bacteria have been observed to live in close association with AMF (Gopal 2012), and have been isolated from different AMF spores (Xavier & Germida 2003;Roesti 2005;Horii & Ishii 2006;Cruz 2008;Bharadwaj 2008;, KSC_SF9c isolated from surface sterilized AMF spores . Xavier and Germida (2003) found 5 bacteria, , sp.…”

“…Certain Arbuscular Mycorrhizal Fungi hyphae produce hydrolytic enzymes which hydrolyses the biopolymers such as protein, chitin and cellulose that will help the AMF to degrade and infect the plant cell walls (Gopal . 2012).…”

The Study of Electrolyte Leakage from Barley (<i>Hordeum vulgare L</i>) and Pearlmillet Using Plant Growth Promotion (PGPR) and Reverse Osmosis

“…Even though plant cell membranes in trials treated with PGPRs, were found having less electron leakage, compared to control one treated irrigated with brackish water. In this tale, implicate PGPR in protection of plant cell membranes was possible by promoting the synthesis of lipids, that considered as structural constituents of most cellular membrane [14,15,16,17].…”