Plant growth stimulating actinomycetes: Isolation,identification and varies of usage

Nowadays bacteria are one of the most frequently studied microorganisms in terms of plant growth-promoting and fighting against different pathogens. Actinomycetes are prokaryotic organisms that produce mycelium, spores and are capable of producing secondary metabolites. Although many studies are demonstrating the importance of actinomycetes in the Bacteria domain, especially in the production of antibiotics there are fewer studies on the regulatory-stimulating properties of plant growth. In this study, free-living and endophytic actinomycetes were isolated from rhizosphere soil and plant parts of olive (Olea europaea L.) and walnut (Juglans regia L.) trees which are commercially important agricultural products for Turkey. Some of the properties of purified actinomycetes that regulate the plant growth; phosphate solubilization, indole-3-acetic acid, siderophore, ammonia, chitinase, protease, and beta-galactosidase production potentials and antagonistic activities against various plant-pathogen molds were investigated. As a result, a total of 422 actinomycetes were isolated and 89 actinomycetes determined to be in possible plant biofertilizers were identified as Streptomyces spp., Amycolatopsis spp., Micromonospora spp. and Nocardiopsis spp. after the sequencing of their 16S rRNA gene regions. The potential of the EA12 encoded actinomycete to be a "new type species" had been proved by polyphasic taxonomy tests. Moreover, some actinomycetes had been used in hydroponic germination of wheat seeds and it had been shown to improve plant growth in terms of root and stem parts.