Archivio Journal of Plant Pathology

Abstract:

Understanding the environmental factors and their impediments to commercialization of microbial biocontrol agents is an essential step for improving biocontrol efficiency. One of these impediments is the lack of liquid culture technology for cost-effective mass production of biocontrol agents and their insufficient longevity during storage. Pseudomonas fluorescens UTPF61 is a biocontrol agent against sclerotinia wilt of sunflower, an important disease caused by Sclerotinia sclerotiorum. This strain was originally isolated from rice rhizosphere and was selected out of 47 strains. In this work liquid culture assays were made to identify nitrogen sources that had a differential influence on the biocontrol activity of UTPF61. Rapid growth in flask was observed in media containing M1+peptone, M1+2-ammonium hydrogen phosphate, M1+ammonium sulfate and M1+ urea+ammonium sulfate, respectively. Medium containing M1+urea or M1+ammonium phosphate had the best effect on the antagonistic efficiency. The best effect on plant growth was observed in treatments with M1+2- ammonium hydrogen phosphate under greenhouse conditions since, compared to the control, it significantly increased the length of roots and stems by 124.18% and 168.25%, respectively, as well as the wet weight (by 222.3%) and dry weight (by 246.15%) of the plants.