BIOASSAY, CHARACTERIZATION AND ESTIMATION OF SIDEROPHORES FROM SOME IMPORTANT ANTAGONISTIC FUNGI

Abstract

The primary mechanisms of plant disease suppression by biological control agents are by production of antimicrobial secondary metabolites like siderophores, antibiotics, volatile substances etc. Siderophores are low molecular iron chelating compounds produced by fungi and bacteria under iron stress condition. The present study is focused on the detection, estimation and characterisation of siderophores from different soil borne fungal biocontrol agents like Trichoderma spp., Beauveria spp. and Metarhizium spp. Isolates of Trichoderma have shown positive results in CAS agar plate whereas Beauveria and Metarhizium have shown negative results. The isolates with positive results were opted for characterization and quantitative estimation of siderophore. T. harzianum produced a maximum percentage of siderophore (85.00%), followed by T. viride (65.50%), T. asperellum (60.27%) and T. longibrachiatum (45.50%). While studying the typification of siderophores, it was found that T. harzianum recorded with maximum hydroxymate and carboxylate production whereas T. viride, T. asperellum and T. longibrachiatum recorded with lesser production of hydroxymate and carboxylate as confirmed by color intensity. But none of the isolates was recorded with catecholate production. Through spectrophotometric analysis, it has been found that slightly alkaline pH was more favorable for the siderophore production for different spp. of Trichoderma. The productions of siderophore from Trichoderma spp. not only scavenge iron which lead to inactivation of those enzymes of the pathogen where iron plays the critical role as cofactor which supplies that iron to the host plant resulting in plantgrowth promotion. Siderophore also has a high degree of influence on medical science in MRI imaging. So mapping of different strains of Trichoderma with high antagonistic efficacy along with profound potency of siderophore production will encourage eco friendly management of fungal diseases on crops, crop improvement and enrichment of medical science