Characterization of actinomycetes isolates for plant growth promoting traits and their effects on drought tolerance in maize

Drought is a major cause of the present decrease in crop yield and agricultural productivity around the globe. The disastrous effects of drought on plants call for a renewed concern on effective strategies to improve plant growth and yield under drought stress. This study was designed to evaluate the effectiveness of Arthrobacter arilaitensis and Streptomyces pseudovenezuelae to improve maize growth under drought stress at three soil moisture levels using two inoculation methods. Seven rhizosphere actinomycetes isolates were screened for the production of plant growth promoting (PGP) traits and it was observed that all isolates produced one or more PGP properties. The inoculated plants were not only protected from the deleterious effects of drought, but also showed significant increases in the physiological parameters measured. The findings of this study suggest that these isolates are important tools capable of being developed into bio-inoculants to effectively improve drought tolerance in plants.