Genetic Improvement of Fungal Pathogens

Potential Entomopathogenic Fungi a. Metarhizium spp. b. Beauveria spp. c. Verticillium lecanii d. Nomuraea rileyi e. Hirsutella spp. f. Paecilomyces spp. Genetic Improvement of EPF a) Chemical mutagenesis b) Parasexual cycle c) Protoplast fusion d) Direct genetic manipulation Mutagen In genetics, a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations cause cancer, mutagens are therefore also likely to be carcinogens. Not all mutations are caused by mutagens: so-called “spontaneous mutations” occur due to spontaneous hydrolysis, errors in DNA replication, repair and recombination. Parasexual cycle The Parasexual cycle (or para sexuality), a process peculiar to fungi and single-celled organisms, is a nonsexual mechanism for transferring genetic material without meiosis or the development of sexual structures [1]. It was first described by Italian geneticist Guido Pontecorvo in 1956 during studies on Aspergillus nidulans (also called Emericella nidulans when referring to its sexual form, or teleomorph). A Parasexual cycle is initiated by the fusion of hyphae (anastomosis) during which nuclei and other cytoplasmic components occupy the same cell (heterokaryosis and plasmogamy). Fusion of the unlike nuclei in the cell of the heterokaryon results in formation of a diploid nucleus (karyogamy), which is believed to be unstable and can produce segregants by recombination involving mitotic crossing over and Volume 8 Issue 1 2018