Abstract:The characterization of entomopathogenic microorganisms is important for the selection of more effective strains for use in integrated pest-control programs. Five Nomuraea rileyi strains (SA86101, GU87401, SR86151, CG128 and VA9101) were characterized using random amplified polymorphic DNA (RAPD) analysis, virulence studies and assessment of chitinolytic and proteolytic activity. RAPD analysis divided the strains into two groups with a similarity coefficient of 0,76%, group 1 consisting of strains SA86101, GU8… Show more
“…In order to better understand the pathogen-host relationships of this mycopathogen, various molecular methods have been used to delineate strains of N. rileyi. For example, DNA extracted from diVerent pools of N. rileyi isolates have been subjected to random ampliWed polymorphic DNA (RAPD) (Tigano and Aljanabi, 2000;Vargas et al, 2003), inter-simple sequence repeat (ISSR) analysis (Han et al, 2002) and ampliWed fragment length polymorphism (AFLP) (Boucias et al, 2000a,b). Vargas et al (2003) were unable to link the results of RAPD analysis conducted on a series of N. rileyi isolates to phenotypic traits (virulence, enzyme levels).…”
Section: Introductionmentioning
confidence: 99%
“…For example, DNA extracted from diVerent pools of N. rileyi isolates have been subjected to random ampliWed polymorphic DNA (RAPD) (Tigano and Aljanabi, 2000;Vargas et al, 2003), inter-simple sequence repeat (ISSR) analysis (Han et al, 2002) and ampliWed fragment length polymorphism (AFLP) (Boucias et al, 2000a,b). Vargas et al (2003) were unable to link the results of RAPD analysis conducted on a series of N. rileyi isolates to phenotypic traits (virulence, enzyme levels). Tigano and Aljanabi (2000) using RAPDs were able to clearly delineate N. rileyi into two phenetic groups that were associated with the insect host.…”
“…In order to better understand the pathogen-host relationships of this mycopathogen, various molecular methods have been used to delineate strains of N. rileyi. For example, DNA extracted from diVerent pools of N. rileyi isolates have been subjected to random ampliWed polymorphic DNA (RAPD) (Tigano and Aljanabi, 2000;Vargas et al, 2003), inter-simple sequence repeat (ISSR) analysis (Han et al, 2002) and ampliWed fragment length polymorphism (AFLP) (Boucias et al, 2000a,b). Vargas et al (2003) were unable to link the results of RAPD analysis conducted on a series of N. rileyi isolates to phenotypic traits (virulence, enzyme levels).…”
Section: Introductionmentioning
confidence: 99%
“…For example, DNA extracted from diVerent pools of N. rileyi isolates have been subjected to random ampliWed polymorphic DNA (RAPD) (Tigano and Aljanabi, 2000;Vargas et al, 2003), inter-simple sequence repeat (ISSR) analysis (Han et al, 2002) and ampliWed fragment length polymorphism (AFLP) (Boucias et al, 2000a,b). Vargas et al (2003) were unable to link the results of RAPD analysis conducted on a series of N. rileyi isolates to phenotypic traits (virulence, enzyme levels). Tigano and Aljanabi (2000) using RAPDs were able to clearly delineate N. rileyi into two phenetic groups that were associated with the insect host.…”
“…Resulting products are separated by gel electrophoresis, which provides RAPD-banding profiles that allow to analyze presence or absence of bands. This profiling technique has been widely employed to study intraspecific variation within species like Entomophaga grylli (Entomophthoromycotina: Entomophthorales) (Bidochka et al 1995), E. muscae (Jensen et al 2001), P. neoaphidis (Rohel et al 1997;Nielsen et al 2001;Tymon and Pell 2005), Zoophthora phytonomi (Entomophthoromycotina: Entomophthorales) (Hajek et al 1996), Z. radicans (Hodge et al 1995), B. bassiana (Maurer et al 1997;Fernandes et al 2006), B. brongniartii (Cravanzola et al 1997Piatti et al 1998), Hirsutella thompsonii (Ascomycota: Hypocreales) (Mozes-Koch et al 1995;Aghajanzadeh et al 2007), L. lecanii (Mor et al 1996), M. anisopliae (Fegan et al 1993;Leal et al 1994;Velásquez et al 2007), N. rileyi (Boucias et al 2000Vargas et al 2003), and Paecilomyces farinosus (=Isaria farinosus) (Ascomycota: Hypocreales) (Chew et al 1998). Studies have focused for instance on associations of fungal genotypes with specific hosts (Hodge et al 1995;Bridge et al 1997;Maurer et al 1997;Jensen et al 2001) or on correlations between RAPD profiles and geographical origin of a species (Leal et al 1994;Hajek et al 1996;Boucias et al 2000;Nielsen et al 2001).…”
The power of molecular genetic techniques to address ecological research questions has opened a distinct interdisciplinary research area collectively referred to as molecular ecology. Molecular ecology combines aspects of diverse research fields like population and evolutionary genetics, as well as biodiversity, conservation biology, behavioural ecology, or species-habitat interactions. Molecular techniques detect specific DNA sequence characteristics that are used as genetic markers to discriminate individuals or taxonomic groups, for instance in analyses of population and community structures, for elucidation of phylogenetic relationships, or for the characterization and monitoring of specific strains in the environment. Here, we summarize the PCR-based molecular techniques used in molecular ecological research on fungal entomopathogens and discuss novel techniques that may have relevance to the studies of entomopathogenic fungi in the future. We discuss the flow chart of the molecular ecology approaches and we highlight some of the critical steps involved. There are still many unresolved questions in the understanding of the ecology of fungal entomopathogens. These include population characteristics and relations of genotypes and habitats as well as hostpathogen interactions. Molecular tools can provide substantial support for ecological research and offer insight into this far inaccessible systems. Application of molecular ecology approaches will stimulate and accelerate new research in the field of entomophathogen ecology.
“…The full potential of entomopathogenic fungi has not been approached. However, previous studies indicate that the insect mycopathogen N. rileyi a dimorphic hypomycete causes fungal epizootics in population of several noctuid pests (14,28,31). Moreover, previous bioassays have shown that N. rileyi isolates from different geographical locations and different hosts vary in their virulence and specificity (3,12,30,34).…”
The entomopathogenic fungus Nomuraea rileyi was isolated from Spodoptera litura and Helicoverpa armigera insect cadavers collected from different sampling sites. Pathogenicity of ten N. rileyi isolates against Spodoptera litura was studied by exposing third instars to topical application of a spore concentration of 10 8 conidia/ml. All ten isolates of N rileyi were active against third instars of S. litura, resulting in 85 to 97% mortality. However, there were statistically no significant differences among the isolates with respect to the pathogenicity levels. Median lethal time (LT 50 ) values of N. rileyi isolates against third instars of S. litura ranged from 5.5 to 6.6 days, which were not statistically different. This strongly suggests that the isolates from different geographical locations are equally pathogenic against S. litura.
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