ABSTRACT
A total of 104 actinomycete isolates were recovered from farming soil samples collected from 11 states in Sudan. Upon screening for potential antifungal activity, an actinomycete isolate (R92) was found to be highly antagonistic against all of the tested phytopathogenic fungi. It was identified as Streptomyces rochei on the basis of its morphology, chemotaxonomy and 16S rDNA sequence analysis. In vivo antagonistic activities of the nbutanol extract of R92 culture were significant since the progress of Drechslera halodes leaf spot on sorghum and Alternaria alternata early blight on tomato was highly restricted and incidence of both diseases was greatly suppressed. Trials to evaluate the In vivo control efficacy of this extract under field conditions is recommended.
ABSTRACT
Laboratory experiments were conducted to isolate and identify Benlate- (Benomyl) degrading microorganisms from two soil types collected from different locations in Khartoum State, Sudan. Benomyl degradation was studied at two temperatures (28 and 40ºC) in soil treated with three Benomyl concentrations (0.032, 3.2 and 8.0mg Benomyl/g soil) and incubated for 360 days. Potential degraders were also tested in mineral salt liquid medium using Benomyl as a sole carbon source. Degradation percentages were then determined and the most efficient Benomyl degraders were identified by amplification with 16S rRNA gene, sequencing and alignment with deposited sequences in the international gene bank. A total of 64 isolates were recovered from the two soil types, with 59 (92.2%) isolates recovered from the clay soil. Thirty four isolates were recovered from clay soil treated with 8.0mg Benomyl/g soil and incubated at 28ºC. The most efficient Benomyl degraders, with degradation percentages in the range of 44-59, were identified as Pseudomonas stutzeri (Two different isolates), Pseudomonas putida, Acinetobacter johnsonii, Brevibacillus invocatus, Bacillus clausii, Lysinibacillus sp. and Agrobacterium radiobacter.