ENTOMOPATHOGENIC LECANICILLIUM FUNGI FOR APHID BIOCONTROL: GENETIC CHARACTERIZATION, FUNGICIDE SUSCEPTIBILITY, AND STRAIN-SPECIFIC DIAGNOSIS

SCHUSTER, C.; SAAR, K.; MANFRINO, R.; AGUILERA, J.; TORNESELLO, J.; GARCIA, J.J.; LOPEZ LASTRA, C.C.; LECLERQUE, A.

Maastricht

Congreso; 6to. Congreso Europeo de Microbiologos; 2015

Federación Europea de Sociedades Microbiológicas

Keywords:Lecanicillium; aphids; biocontrol; molecular taxonomy; fungicide susceptibility; group-I intron diagnosisBackground:Mitosporic fungal entomopathogens of the genus Lecanicillium (Ascomycota; Hypocreales) are of particular interest as biological control agents for phloem-sucking plant pests including aphids. Bioprospection for these fungi in Argentina has given rise to a set of Lecanicillium isolates from a wide range of hosts.Reliable molecular taxonomic markers and diagnostic tools for Lecanicillium fungi are highly solicited.Fungicide susceptibility of Lecanicillium fungi is of interest for both their co-applicability with agro-fungicides and the development of selection markers for basic research.Objectives:Lecanicillium isolates from Argentina should be solidly characterized at the species level, and susceptibilities to a set of fungicides should be determined. For promising biocontrol isolates, a strain-specific identification tool should be developed.Methods:A set of five genetic markers comprising mitochondrial (NMS) and nuclear (ITS, IGS) rRNA operon together with mitochondrial (nad1) and nuclear (ef1) protein-encoding sequences has been employed for molecular taxonomic classification.The development of strain-specific diagnostics has been based on self-splicing group-I introns located within rRNA encoding genes.Susceptibilities to several fungicides were determined using a semi-quantitative test on solid media containing the respective compound.Conclusions:A subset of markers permitting the unequivocal distinction of the three Lecanicillium core species, L. lecanii, L. muscarium, and L. longisporum, was defined. Most, but not all of the Argentinian isolates belong to these species.Feasibility of strain-specific identification was demonstrated.Between-strain differences in susceptibilities to most fungicides were found important. The fungicide soraphen is of outstanding activity against a wide variety of isolates from all species investigated.