FRUIT FLIES S MICROFLORA

Transcription

1 FRUIT FLIES S MICROFLORA First Meeting of TEAM. Palma of Mallorca. 7-8 th April Genome dynamics of Wolbachia in Rhagoletis cerasi WOLFGANG ARTHOFER 1, DANIELA SCHNEIDER 2, MARTIN KRAMMER 2, MARKUS RIEGLER 3, WOLFGANG J. MILLER 2 and CHRISTIAN STAUFFER 1 1 Department of Forest & Soil Sciences, Boku, University of Natural Resources & Applied Life Sciences, Vienna, Austria. 2 Centre of Anatomy & Cell Biology, Medical University of Vienna, Austria. 3 School of Integrative Biology, The University of Queensland, St. Lucia QLD 4072, Australia. christian.stauffer@boku.ac.at Wolbachia is a powerful intracellular manipulator of insect s reproduction causing effects like cytoplasmic incompatibility (CI). However, theory predicts that these parasites will tend to evolve towards a more mutualistic association with their hosts because of maternal inheritance. Here we present the restructuring of Wolbachia genomes in different hosts species over time and their effects on the phenotype. The double infection wcer1&wcer2 in the cherry fruit fly Rhagoletis cerasi expresses high CI. Populations experience an expansion of wcer1&wcer2 in the south-western Europe, while the north-eastern part of the continent harbours only wcer1. wcer2 was successfully transferred to Drosophila simulans in 2000, establishing six D. simulans lines expressing different levels of CI. Since then the wcer2 infection has coevolved with its novel host over more than 150 fly generations. The recently published Wolbachia genome revealed a high number of genes encoding ankyrin domain (ANK) repeats highly variable between different strains. ANK genes are candidate genes for Wolbachia-host interactions. We evaluate the hypothesis if upon arrival of Wolbachia in a novel host and its successful establishment in the germ line, the parasitic genome will be restructured over time in order to adapt to the new environment. We mapped the genome of wcer2 (i) in six independent D. simulans lines, (ii) in the original donor populations of R. cerasi collected in 2000 and (iii) in field populations of R. cerasi from Further data on Variable Number Tandem Repeat (VNTRs) loci with size differences ranging from one to seven 141bp repeats will be presented. This comparative genomic approach will reveal the integrity and dynamics of Wolbachia genomes in different host species over time. Key: 1721

2 Medfly-Bacteria Interactions MICHAEL BEN-YOSEF 1, ADI BEHAR 1, EDOUARD JURKEVITCH 2 and BOAZ YUVAL 1 1 Department of Entomology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, 76100, Israel. 2 Department of Microbiology and Plant diseases, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, 76100, Israel. benyosef@agri.huji.ac.il Mediterranean fruit flies (Ceratitis capitata Wiedemann, Diptera: Tephritidae), harbor a diverse community of bacteria in their digestive system. This associated microbiota may have important functions impacting on the fly's fitness. Molecular and culture based techniques show that members of the Enterobacteriaceae form the dominant populations in the medfly s gut. Among them, many are diazotrophs and actively fix nitrogen in vivo. Most prominent are Klebsiella spp, Enterobacter spp., Pectobacterium spp. Citrobacter freundii and Providencia stuartii. Additionally, we found that pseudomonads, some of which are known entomopathogens, constitute a minor, yet common and stable community in the medfly's gut. A marked shift in community composition was observed between different developmental stages: in larvae, the pectinolytic Pectobacterium were most abundant, suggesting that pectinolysis plays a role early during the fly's life. Eliminating the bacterial population by using antibiotics had several effects on fitness components of males and females: bacterial activity in the gut did not affect the fecundity of females. However, it significantly delayed the oviposition rate when females were nutritionally stressed. Additionally, bacteria provided males with a significant mating advantage (a shorter latency to mate) only when they were not nutritionally stressed. Moreover, longevity was prolonged in antibiotic-treated flies only when nutritionally stressed. In conclusion, the medfly harbors an enterobacterial community of pectinolytic and nitrogen fixing bacteria. The removal of these bacteria affects measurable physiological and behavioral parameters related to fitness in a diet dependent fashion. This community may contribute to the fly s nitrogen and carbon metabolism, and also play a role in inhibiting potentially deleterious microbial populations. Key: 1727

3 What bacterial species constitute the symbiotic flora of the olive fly, Bactrocera oleae? ILIAS KOUNATIDIS 1, ELENA CROTTI 2, PANAGIOTIS SAPOUNTZIS 3, LUCIANO SACCHI 4, BESSEM CHOUAIA 5, CLAUDIO BANDI 5, ALBERTO ALMA 6, DANIELE DAFFONCHIO 2, PENELOPE MAVRAGANI-TSIPIDOU 1 and KOSTAS BOURTZIS 3 1 Department of Biology, Aristotle University of Thessaloniki (AUTH), GR Thessaloniki, Greece. 2 Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, Italy. 3 Department of Environmental and Natural Resources Management, University of Ioannina, 2 Seferi Street, Agrinio, Greece. 4 Department of Biology, University of Pavia, Italy. 5 DIPAV Sezione di Patologia Generale e Parassitologia Università degli Studi di Milano, Italy. 6 Dipartimento di Valorizzazione e Protezione delle Risorse Agroforestali, Università degli Studi di Torino, Italy. kbourtz@uoi.gr Insects have been reported to establish symbiotic associations with a variety of microorganisms which affect many aspects of host biology and physiology. Insect symbionts are separated into two main groups: primary and secondary symbionts. Primary symbionts (the best studied example is Buchnera, the primary symbiont of aphids) reside within specific host organs called bacteriomes and have the capacity to provide their hosts with nutrients such as essential amino acids, vitamins and other cofactors. Secondary symbionts, also known as guest microbes, usually establish facultative symbiotic associations that range from deleterious to beneficial. Petri described in 1909 the first bacterial symbiotic association in Diptera, that of the olive fly Bactrocera oleae. Since then, a number of researchers have reported the presence of several bacterial symbionts in this important pest species. In the present study we report on the symbiotic flora of the laboratory strain Aghia Triada-84 of the olive fly Bactrocera oleae using electron microscopy, molecular biology and classical microbiology approaches. Our results indicate the presence of an acetic acid bacterium, Acetobacter tropicalis, in the laboratory strain Aghia Triada-84 as well as in Greek natural populations of Bactrocera oleae. Besides several other bacterial isolates we were able to get in culture in cell-free media the A. tropicalis symbiont. Molecular typing experiments on different isolates indicated that different A. tropicalis strains inhabit the Aghia Triada-84 laboratory strain. Key: 1729

4 Wolbachia symbiosis in Tephritidae PANAGIOTIS SAPOUNTZIS 1, KLEOPATRA MORAITI 2, ILIAS KOUNATIDIS 3, STEFANOS SIOZIOS 1, PENELOPE MAVRAGANI-TSIPIDOU 3, NIKOS T. PAPADOPOULOS 2 and KOSTAS BOURTZIS 3 1 Department of Environmental and Natural Resources Management, University of Ioannina, 2 Seferi Street, Agrinio, Greece. 2 Department of Agriculture, Crop Production and Agricultural Environment, University of Thessaly, Fytokou Street, Nea Ionia Magnisias, Greece. 3 Department of Biology, Aristotle University of Thessaloniki (AUTH), GR Thessaloniki, Greece. kbourtz@uoi.gr Wolbachia is an obligatory maternally transmitted bacterium which infects numerous invertebrate species (insects, isopods, mites, arachnids, nematodes). The widespread distribution of this bacterium is due to its unique ability to control the reproductive properties of its hosts by inducing parthenogenesis, feminization, malekilling and, mainly, cytoplasmic incompatibility. There is an increasing interest in the use of Wolbachia infections in an applied context. It has been proposed that they might be used either as a tool to drive desirable genotypes into natural populations of insects or alternatively to directly suppress insect populations. The population suppression approach, known as Incompatible Insect Technique (I.I.T.) has been successfully used in the past for the population control of mosquito and lepidopteran pest species. This approach is based on the mechanism of cytoplasmic incompatibility (CI) which is expressed as embryonic mortality in crosses between an infected male and a female of different infection status. It is well known that the family Tephritidae includes major pest species. In the present study we present data regarding the presence and the biological role of Wolbachia in tephritid species. Wolbachia has been detected and/or characterized in species of the genera Bactrocera, Anastrepha, Rhagoletis and Ceratitis. We also show how the reproductive parasite Wolbachia can be used in environment-friendly approaches for the population control of tephritid pest species. Key: 1730

5 Bacteria-olive fly interactions ANTONIO BELCARI, PATRIZIA SACCHETTI, AURELIO GRANCHIETTI, SERENA LANDINI and ALESSANDRA CAMERA Department of Agricultural Biotechnology, University of Firenze, Italy. The olive fly, Bactrocera oleae (Rossi) is one of the most injurious pest of the olive ecosystems in the Mediterranean basin, where the majority of the world s olives are produced. Nutritional requirements for reared adults are well known, whereas very little is known about the feeding behaviour of wild populations. Culturable epiphytic bacteria were isolated from twigs, leaves and fruits of olive trees in order to relate bacteria population density to the number of the olive flies caught in traps. The results obtained show a high degree of correlation between the presence of bacteria on the phylloplane of the olive tree and the size of the olive fly population in the olive grove during the different periods. This suggests that epiphytic bacteria may play an essential role for fly fitness in the olive system as confirmed by morphological investigations of the mouth apparatus. Labellar structures indicate B. oleae adults are fluid feeders showing a substantial difference with tropical Dacinae. As a matter of fact, pseudotracheae micropores do not allow the assumption of bacteria trough a filtering apparatus. Epiphytic bacteria are fed trough the midline, then stored in prestomium and finally housed in the oesophageal bulb. Morphology of both mouth structures and oesophageal bulb are presented. Molecular characterisation of associated bacteria found in different tracts of the adult gut are also presented and discussed. Key: 1782

6 Bacterial microbiota associated with a Bactrocera oleae population from eastern Spain FRANCISCO J. SILVA 1,2, ANDRÉS MORET 1, ALEXANDER NEEF 1 and EUGENI BELDA 1,2 1 Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Apartat 22085, València, Spain. 2 Departament de Genètica, Universitat de València, C/ Dr. Moliner 50, Burjassot, Spain. francisco.silva@uv.es Many bacterial species live in symbiotic association with insects. Sometimes they are mutualists and contribute to the fitness of the host by producing beneficial effects on its growth and development. The diversity of bacterial species associated with Bactrocera oleae was analysed through the PCR amplification with bacterial universal primers of a fragment of the 16S ribosomal RNA gene. Four types of samples corresponding to bulk adult heads, headless male bodies, headless female bodies and larval gut were characterized by cloning the PCR products and sequencing a set of 96 clones derived from each sample type. Bacterial sequences were identified through sequence similarity and the proportion of each type quantified. In adult heads and larval gut, only a bacterial species was detected (Erwinia dacicola). The diversity associated with male and female headless bodies was higher. However, E. dacicola was not the most frequent sequence, although, in each sex, more than 20% of clones belonged to this species. In headless male bodies, two species belonging to the phylum Bacteroidetes were detected in more than 20% of the clones. In headless female bodies the most frequent type of sequence belonged to the genus Ralstonia (ca. 40%) with a less frequent species (ca. 10%) belonging to Xanthomonadaceae. The presence/absence of the most frequent sequence types has been characterized in single individuals grown on two types of olive trees. Pairs of 16S rrna primers were designed with the previous sequences. They were designed on variable 16S rrna regions with the aim to be species, or at least genus, specific primers. POSTER SUBMISSION Key: 1728 Panel: Fruit Fly's Associate Microflora