Publications

4369

AbstractBackgroundThe olive fly,Bactrocera oleae, is the most important insect pest in olive production, causing economic damage to olive crops worldwide. In addition to extensive research onB. oleaecontrol methods, scientists have devoted much effort in the last century to understanding olive fly endosymbiosis with a bacterium eventually identified asCandidatusErwinia dacicola. This bacterium plays a relevant role in olive fly fitness. It is vertically transmitted, and it benefits both larvae and adults in wild populations; however, the endosymbiont is not present in lab colonies, probably due to the antibiotics and preservatives required for the preparation of artificial diets. Endosymbiont transfer from wildB. oleaepopulations to laboratory-reared ones allows olive fly mass-rearing, thus producing more competitive flies for future Sterile Insect Technique (SIT) applications.ResultsWe tested the hypothesis thatCa.E. dacicola might be transmitted from wild, naturally symbiotic adults to laboratory-reared flies. Several trials have been performed with different contamination sources ofCa.E. dacicola, such as ripe olives and gelled water contaminated by wild flies, wax domes containing eggs laid by wild females, cages dirtied by faeces dropped by wild flies and matings between lab and wild adults. PCR-DGGE, performed with the primer set 63F-GC/518R, demonstrated that the transfer of the endosymbiont from wild flies to lab-reared ones occurred only in the case of cohabitation.ConclusionsCohabitation of symbiotic wild flies and non-symbiotic lab flies allows the transfer ofCa.E. dacicola through adults. Moreover, PCR-DGGE performed with the primer set 63F-GC/518R was shown to be a consistent method for screeningCa.E. dacicola, also showing the potential to distinguish between the two haplotypes (htA and htB). This study represents the first successful attempt at horizontal transfer ofCa.E. dacicola and the first step in acquiring a better understanding of the endosymbiont physiology and its relationship with the olive fly. Our research also represents a starting point for the development of a laboratory symbiotic olive fly colony, improving perspectives for future applications of the Sterile Insect Technique.

AbstractThe newly discoveredCandidatus‘Methanoperedens nitroreducens’ (M.nitroreducens), mediating nitrate-dependent anaerobic oxidation of methane, is an important microorganism in linking carbon and nitrogen cycles. In order to explore the diversity ofM.nitroreducens-like archaea in various environmental niches with advanced high-throughput sequencing, new primers based on alpha subunit of methyl-coenzyme M reductase gene were designed. The PCR results demonstrated that the new primers could effectively detectM.nitroreducens-like archaea from an enrichment culture dominated byM.nitroreducensas well as samples collected from a natural freshwater lake and a full-scale wastewater treatment plant (WWTP). By high-throughput sequencing, more than 30,000M.nitroreducens-like sequences were obtained. Phylogenetic analysis of these sequences along with published sequences showed thatM.nitroreducens-like archaea could be divided into three sub-branches (named as Group A, Group B and Group C in this study). Clear geographical difference was observed, with Group A and Group B dominating samples in Queensland (Australia) and in European ecosystems, respectively. Further quantitative PCR revealed that theM.nitroreducens-like archaea were more abundant in WWTP than the freshwater lake. The study provided a large number of sequences forM.nitroreducens-like archaeal communities, thus expanded our understanding on the ecological diversity ofM.nitroreducens-like archaea.


 
 
 El “permanente del tomate”, “manchado del tubérculo” o “zebra chip” en papa y “brotes cloróticos” del chile, son tres enfermedades descritas en México con signos coincidentes de aborto de flor, oscurecimiento de tejido vascular en la base del tallo y raíz de las plantas. Se ha mencionado la asociación entre estas enfermedades y la bacteria emergente Candidatus Liberibacter solanacearum (CLs) así como al psílido Bactericera cockerelli como su vector. Estas enfermedades, que en inicio se localizaban en tres estados de México se han diseminado a las principales regiones productoras de solanáceas, tanto en condiciones de campo como en invernadero. El objetivo del estudio fue conocer la presencia de CLs asociado a enfermedades que afectan los cultivos de tomate, para y chile en México. La bacteria se identificó por PCR del gen 16S de ADNr, clonación y secuenciación. La alineación de secuencias nucleotídicas se realizó con el método Clustal W y el árbol filogenético se construyó con el algoritmo de Neighbor-Joining a partir de distancias calculadas con el método de Tajima-Nei y un índice de Felsenstein de 1 000 réplicas, utilizando el software MEGA versión 5.05. En total se analizaron 167 muestras, de las cuales 86 resultaron positivas, provenientes de 14 estados de México. Se obtuvieron cinco secuencias nucleotídicas de Guanajuato, San Luis Potosí y Sinaloa correspondientes al tomate, papa y chile, adultos y huevecillos de B. cockerelli. El análisis de las secuencias mostró una identidad de 99.4% al comparase entre estas y hasta 99.8% con accesiones del GenBank descritas para CLs en EUA, Nueva Zelanda y Canadá.
 
 

ABSTRACT “ Candidatus Phycosocius bacilliformis” is an alphaproteobacterial ectosymbiont of the hydrocarbon-producing green alga Botryococcus braunii . We sequenced the whole genome of “ Ca. P. bacilliformis” BOTRYCO-2, isolated from a two-membered culture with B. braunii . The genome contains approximately 3.3 Mb, with an average G+C content of 56.91% and 3,125 predicted protein-coding genes.