Induction of resistance and biocontrol of rhizoctonia in cotton against damping-off disease by rhizosphere microorganisms.

Abstract

Addition of fishmeal to the soil infested with the pathogen led to a remarkable reduction in the percentage of disease compared to the soil non-amended with fishmeal. 28 fungal isolates, 22 yeast isolates, 43 isolates of actinomycetes and 8 isolates of bacteria were isolated from the rhizosphere associated soil of cotton plant. Three fungal isolates, 3 yeast isolates, 4 isolates of actinomycetes and 4 isolates of bacteria were characterized by their potent and remarkable antagonistic activities, and were identified as: Eupenicillium senticosum, Penicillium herquer, Trichoderma viride, Hansenula arabitolgenes, Candida incommunis and Candida steatolytica, Streptomyces erumpens, S. purpureus, S. aurantiacus, S. microflavus , Arthrobacter ramosus, Aureobacterium terregens, Curtobacterium pusillum and Pseudomonas putida respectively. The use of a mixture of fungal, yeast, actinomycete and bacterial species led to an increase in inhibition of the pathogen, an increase in induction of resistance of cotton plant and an increase in growth measurements of cotton plant than each of them alone. Candida incommunis, S. purpueus and A. ramosus have the ability of solubilizing phosphate and have the ability for production of indolacetic acid (IAA) and siderophores.

New Egyptian Journal of Microbiology Vol. 17 (2) 2007: pp. 148-168