Caratterizzazione e utilizzo di nematodi entomopatogeni presenti in Georgia e in Italia.

Responsabili di progetto

Francesca Deluca, Medea Burjanadze

Accordo

GEORGIA - SRNSF - Shota Rustaveli National Science Foundation

Bando

CNR-SRNSF 2016-2017

Dipartimento

Scienze bio-agroalimentari

Area tematica

Scienze bio-agroalimentari

Stato del progetto

Nuovo

Proposta di ricerca

Surveys on Biological Control Agents (BCA) in Europe carried out during the past years, provided important data about their presence and natural occurrence and distribution in many of the European Regions. Entomopathogenic nematodes (EPNs) are widely distributed throughout the world and have a wide range of insect hosts (Hominick, 2002). The genetic and phenotypic isolates analysis from around the world have shown that this distribution is widespread and associated with high biological diversity from strong speciation nematodes and their symbionts (Nguyen & Hunt, 2007). Genetic diversity and biological properties of the nematode-bacterium complex, with fundamental considerations on their geographical distribution (Hominick et al., 1996), constitute an interesting biological resource and have a great potential as qualitative soil bioindicators.
According to a ''bio-rational approach'' for selecting microbial control agents (Yeo et al. 2003), selection of EPN strains have to be based not only on their intrinsic virulence to the target host revealed by laboratory bioassays, but also on their ability to operate over the range of abiotic conditions that they could find in the agro-ecosystem. It is necessary, in fact, to select strains that combine the best characteristics for killing the target insects (high virulence against target organisms) and their ability to persist and infect in the environment in which the pest is occurring.
Georgia is among the richest country with natural resources in Eurasia and is wealthy with the unique representatives of Caucasian flora.
In 60's of the past century, Georgia intensively started to establish biological means in agricultural forest protection. Extensive research by study of EPNs and their practical use, at the laboratory of nematology of the Institute of Zoology of Ilia State University and Department of Forest Protection, Vasil Gulisashvili Forest institute, Agricultural University of Georgia was carried out (Kakulia, 1966; 1983; Devdariani, 1975; 1980; Gorgadze, 1990; 2000; 2014; Kakulia, Lortkipanidze, 2000; Kakulia, Lortkipanidze, Swanishvili, 2002; Gorgadze, Lortkipanidze, Devdariani, Kokhia, 2003; Lortkipanidze et al , 2004 ; Burdjanadze et al., 2009; 2011, 2012, 2015).
At present four local species of Steinernematidae are registered in Georgia: Steinernema georgica (Kakulia & Veremchuk, 1965), S. thesami (Gorgadze, 1988), S. disparica (Gorgadze, 2001),and S. gurgistana (Gorgadze & Lortkipanidze, 2006).
The bio-efficiency of nematode-bacterial complex of the local species (Steinernema disparica, Steinernema thezami and Steinernema gurgistana) against the major harmful insects of the agricultural and forest plants, spread in Georgia such as: Hyphanthria cunea, Ocneria dispar, Leptinotarsa desemlineata, Operopthera brumata, Erannis defoliaria, Pieris brassicae Ips typographus, Ips secdentatus etc. has been established (Gorgadze & Lortkipanidze, 2004; Burjanadze, et al., 2005; 2011; Lortkipanidze et al., 2011; Gorgadze et al., 2013; 2015).
Nowadays, there is an increase interest to innovative technology of mass-production of BCAs. Search for new possibilities and optimal parameters for the successful formulation, their storage and application is very important in biological control strategy.
In Italy, the occurrence and distribution of EPNs have been carried out in most of the Italian regions following a large-scale biogeographic approach with respect to different vegetation levels and habitats (Tarasco et al., 2015) in order to create a comprehensive map of the Italian EPN biodiversity. Currently the EPNs isolated from different habitats are almost 140 indigenous strains belonging to 13 species: Heterorhabditis bacteriophora, H. downesi, H. megidis, Steinernema feltiae, S. affine, S. kraussei, S. apuliae, S. ichnusae, S. carpocapsae, S. vulcanicum, Steinernema "isolate S.sp.MY7" of "S. intermedium group", S. arenarium and Oscheius onirici.
In Italy, endogenous EPN formulations have been effectively tested and applied to control pests, i.e. Thaumetopoea pityocampa Denis & Schiffermüller (Lepidoptera: Thaumetopoeidae) on pine Curculio elephas Gyll. and Curculio glandium Mars. (Coleoptera: Curculionidae), Pammene fasciana L., Cydia splendana Hüb. and Cydia fagiglandana (Zeller) (Lepidoptera: Tortricidae) on chestnut, Capnodis tenebrionis L. (Coleoptera: Buprestidae) on apricot, Xanthogaleruca luteola Müller (Coleoptera: Chrysomelidae) on elm; Corythucha ciliata Say (Hemiptera: Tingidae) on plane tree; Rhynchophorus ferrugineus Oliver (Coleoptera: Curculionidae) on palm; Rhytidoderes plicatus Oliv. (Coleoptera: Curculionidae) on savoy cabbage.
The aim of the present research program is to characterize EPNs from Georgia and Italy at molecular level by using ribosomal and mitochondrial markers in order to establish phylogenetic relationships. Moreover, for the most promising EPN strains as biological control agents, will be studied genes (aquaporin, hsp90, hsp70) that are involved in stresses tolerance (heat or cold temperature). The molecular characterization of these genes may facilitate an estimation of these organism's potential as a biocontrol agents. If a correlation between or among traits can be established, the relationships may assist further in predicting which strains or species of EPNs are most suitable for the environmental conditions associated with a particular target system.
In particular, the hsp90 gene will be amplified by using degenerate primers. The amplified products will be sequenced and specific primers for each EPN will be designed. The expression of the hsp90 gene will be determined by real time PCR in order to compare the expression of this stress gene among the different species. Expression experiments will be carried out after exposure of EPNs at different temperatures in order to establish which species or strains are more tolerant.

Obiettivi della ricerca

To elaborate new biological control technique, many species and strains of potential control organisms have to be evaluated and identified at morphological and molecular level. In Georgia, the lack of detailed and reliable biogeographic data and the lack of a usable strain collection seriously restrict research on biological control techniques.
The objectives that our research aims to achieve are:
- Eco-morphological and molecular comparison among endogenous EPN strains in Georgia and Italy
- Establish and maintain a collection of endogenous EPN strains in both Countries
- Evaluate the EPN strains with laboratory bioassays to identify tolerant strains to be used as Biological Control Agent against agricultural, urban and forest pests.

Ultimo aggiornamento: 08/07/2025