Control of Phytophthora sojae and Macrophomina phaseolina in soybean by biological agents

Soybean is one of the most important oilseed crops, supplying half of the protein and vegetable oil by humans. Charcoal rot disease and soybean crown and root rot caused by Macrophomina phaseolina and Phytophthora sojae, respectively, are among the most important soybean pathogens that cause a reduction in crop yield. A biocontrol strategy using Actinobacteria, especially different species of Streptomyces, and Hypocreaceae especially different species of Trichoderma, is considered a method for the management of disease and pests. In this study, biological control of these pathogens was investigated using Streptomyces sp. isolate 23 and Trichoderma sp. isolates 1 and their volatile metabolites. The activity of Streptomyces isolates and a Trichoderma isolate taken from the soil of Kerman was evaluated against pathogenic fungi, M. phaseolin, and P. sojae. Experiments in the laboratory were conducted based on a completely randomized design with three replications. Sequence analysis of 16s rDNA and ITS region showed Streptomyces sp. isolate 23 and Trichoderma sp. isolate 1 belong to S. bacillaris and T. longibrachiatum, respectively. The results of the double culture method and volatile metabolites test showed that S. bacillaris isolate 23 and T. longibrachiatum isolate 1, significantly inhibited the growth of M. phaseolina and P. sojae. In both tests, the two biocontrol agents used showed more inhibitory effects on P. sojae compared to M. phaseolina. The results of the dual culture and volatile metabolites tests showed that S. bacillaris isolate 23 and T. longibrachiatum isolate 1 had a high inhibitory effect on M. phaseolina and P. sojae.