Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium oxysporum
The development of reliable, eco-friendly processes for the synthesis of nanomaterials is a crucial aspect of nanotechnology today. One approach that shows immense potential is predicated on the biosynthesis of nanoparticles using biological micro-organisms like bacteria. during this laboratory, we’ve targeting the utilization of fungi within the intracellular production of metal nanoparticles. As a part of our investigation, we’ve observed that aqueous silver ions when exposed to the fungus Fusarium oxysporum are reduced in solution, thereby resulting in the formation of a particularly stable silver hydrosol. [1]
Fusarium oxysporum and its biocontrol
Fusarium oxysporum is well represented among the rhizosphere microflora. While all strains exist saprophytically, some are well‐known for inducing wilt or root rots on plants whereas others are considered as nonpathogenic. Several methods supported phenotypic and genetic traits are developed to characterize F. oxysporum strains. Results showed the good diversity affecting the soil‐borne populations of F. oxysporum. In suppressive soils, interactions between pathogenic and nonpathogenic strains end in the control of the disease. Therefore nonpathogenic strains are developed as biocontrol agents. The nonpathogenic F. oxysporum strains show several modes of action contributing to their biocontrol capacity. [2]
Mutation of an Arginine Biosynthesis Gene Causes Reduced Pathogenicity in Fusarium oxysporum f. sp. melonis
Restriction enzyme-mediated integration (REMI) mutagenesis was wont to tag genes required for pathogenicity of Fusarium oxysporum f. sp. melonis. Of the 1,129 REMI transformants tested, 13 showed reduced pathogenicity on susceptible melon cultivars. one among the mutants, FMMP95–1, was an arginine auxotroph. Structural analysis of the tagged site in FMMP95-1 identified a gene, designated ARG1, which possibly encodes argininosuccinate lyase, catalyzing the last step for arginine biosynthesis. Complementation of FMMP95–1 with the ARG1 gene caused a recovery in pathogenicity, indicating that arginine auxotrophic mutation causes reduced pathogenicity during this pathogen. [3]
Sesquiterpene emissions from Alternaria alternata and Fusarium oxysporum: Effects of age, nutrient availability and co-cultivation
Alternaria alternata is one among the foremost studied fungi so far due to its impact on human life – from plant pathogenicity to allergenicity. However, its sesquiterpene emissions haven’t been systematically explored. Alternaria regularly co-occurs with Fusarium fungi, which are common plant pathogens, on withering plants. We analyzed the range and determined absolutely the quantities of volatile organic compounds (VOCs) within the headspace above mycelial cultures of A. alternata and Fusarium oxysporum under different conditions (nutrient rich and poor, single cultures and co-cultivation) and at different mycelial ages. [4]
Cultural, Morphological and Pathogenic Variability among Fusarium oxysporum f. sp. phaseoli Causing Wilt in French Bean (Phaseolus vulgaris L.)
Aim: This study aimed toward evaluating cultural, morphological and pathogenic variability among Fusarium oxysporum f. sp. phaseoli strains isolated from French beans.
Study Design: Cross-sectional study.
Methodology: The French beans showing wilt symptoms were obtained from different fields in Kabaa irrigation scheme in Machakos County, Kenya. The diseased plants were washed and dig 5 mm pieces which were surface sterilized before plating on Fusarium-selective medium. They were incubated for 10 days at 25-26°C. The developing colonies were transferred on Potato Dextrose Agar (PDA), Carnation Leaf Agar (CLA) and Spezieller Nahrstoffarmer Agar (SNA) media for cultural and morphological characterization. Pathogenicity was assessed using on haricot vert ‘Amy’ variety. [5]
Reference
[1] Ahmad, A., Mukherjee, P., Senapati, S., Mandal, D., Khan, M.I., Kumar, R. and Sastry, M., 2003. Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium oxysporum. Colloids and surfaces B: Biointerfaces, 28(4), (Web Link)
[2] Fravel, D., Olivain, C. and Alabouvette, C., 2003. Fusarium oxysporum and its biocontrol. New phytologist, 157(3), (Web Link)
[3] Namiki, F., Matsunaga, M., Okuda, M., Inoue, I., Nishi, K., Fujita, Y. and Tsuge, T., 2001. Mutation of an arginine biosynthesis gene causes reduced pathogenicity in Fusarium oxysporum f. sp. melonis. Molecular plant-microbe interactions, 14(4), (Web Link)
[4] Sesquiterpene emissions from Alternaria alternata and Fusarium oxysporum: Effects of age, nutrient availability and co-cultivation
Fabian Weikl, Andrea Ghirardo, Jörg-Peter Schnitzler & Karin Pritsch
Scientific Reports volume 6, (Web Link)
[5] K. Maina, P., M. Wachira, P., A. Okoth, S. and W. Kimenju, J. (2017) “Cultural, Morphological and Pathogenic Variability among Fusarium oxysporum f. sp. phaseoli Causing Wilt in French Bean (Phaseolus vulgaris L.)”, Journal of Advances in Microbiology, 2(4), (Web Link)
