Draft genome sequence of Photorhabdus luminescens strain DSPV002N isolated from Santa Fe, Argentina

Here, we report the draft genome sequence of Photorhabdus luminescens strain DSPV002N, which consists of 177 contig sequences accounting for 5,518,143 bp, with a G+C content of 42.3% and 4,701 predicted protein-coding genes (CDSs). From these, 27 CDSs exhibited significant similarity with insecticidal toxin proteins from Photorhabdus luminescens subsp. laumondii TT01.This research was supported by the Spanish Ministry of Economy and Competitiveness (grant AGL2015-70584-C2-2-R)

The insecticidal-protein repertory of 14 xenorhabdus strains isolated from Argentina

Entomopathogenic nematodes belonging to the genus Steinernema are able to infest and kill insect hosts in association with their resident, entomopathogenic symbiont bacteria in the gram-negative genus Xenorhabdus (Enterobacteriaceae). However, only a few species of Xenorhabdus have been isolated from their hosts and their insecticidal properties reported. Here we performed the genome sequence analysis of 14 Xenorhabdus strains isolated from Steinernema nematodes in Argentina, able to kill 6th instar Galleria mellonella (Lepidoptera) larvae. The 14 draft genome sequences encoded 110 putative insecticidal toxins (Tc, Pir and Mcf toxin homologs) plus other virulence factors with similarity to putative nematicidal toxins and chitinases. The genome sequences of strains Flor, 5, PSL, Reich, 42, Vera, M, 18, Cul, DI, 12, 38, 3 and ZM exhibited 4, 9, 2, 10, 9, 5, 7, 10, 10, 7, 3, 18, 8 and 8 putative insecticidal toxin genes, respectively. Strains 5, Reich, 42, 18, DI, 38, 3 and ZM carried their predicted insecticidal toxin genes arranged into putative pathogenicity islands whereas strains Flor, PSL, Vera, M, Cul and 12) showed them spread thorough different contigs. Multigene phylogenetic analysis and average nucleotide identity (ANI) calculations were also performed and allowed the identification of three strains (PSL, Reich and 12) that should be considered as novel Xenorhabdus genomospecies. In this work, we provide a dual insight into the diversity of the species belonging to the Xenorhabdus genus and into their predicted insecticidal toxin repertory, which is currently under investigation

Genome sequence analysis and insecticidal characterization of Bacillus thuringiensis Bt-UNVM_94, a strain showing dual insecticidal activity against lepidopteran and coleopteran pests

Bacillus thuringiensis is a gram-positive and spore-forming bacterium that synthesizes a wide diversity of proteins with insecticidal activity and which has demonstrated its potential and safety as a biocontrol agent for more than four decades. However, several susceptible insect species have been reported for evolving resistance, which demands screening for strains exhibiting novel insecticidal properties. In this work, we performed the genome sequence analysis and the insecticidal characterization of B. thuringiensis strain Bt-UNVM_94 isolated from Argentina. This strain produced quasi symmetric bipyramidal parasporal crystals as shown using Scanning Electron Microscopy. Its genomic sequence harbours one coding sequence showing homology to the crystal toxin Cry7Ga2 and another, with similarity to the Mpp2Aa3 (Mtx2) toxin. Known Cry7A and Cry7B are known to be active against some coleopteran and lepidopteran larvae, respectively. However, bioassays performed with spore-crystal mixtures of strain Bt-UNVM_94 exhibited dual toxicity with 50% and 91% mortality against Cydia pomonella (Lepidoptera: Tortricidae) and Anthonomus grandis (Coleoptera: Curculionidae), respectively. No toxicity was detected against the free-living nematode Panagrellus redivivus (Rhabditidae: Panagrolaimidae). This strain also showed no PCR amplification of the type I b-exotoxin thuE gene, consistent with the absence of mortality in b-exotoxin bioassays with Musca domestica (Diptera: Muscidae). Screenings of novel B. thuringiensis strains may provide toxins with novel insecticidal properties that can be used to suppress insect resistance to the most used B. thuringiensis-crops in the field

Primer reporte de Ceroplastes grandis (Hemiptera: Coccidae) en plantas ornamentales de Duranta erecta var. lemon L. (Verbenaceae) en la provincia de Entre Ríos, Argentina

The present investigation carried out a survey of soft scales belonging to thegenus Ceroplastes Gray associated with Duranta erecta var. lemon L. for ornamental use in Paraná city (Entre Ríos, Argentina). These insects damagethe growth of plants, can cause their decay and affect their ornamental value.Through the analysis of microscope slides, the species Ceroplastes grandisHempel (Hemiptera: Coccomorpha: Coccidae) was identified in all the plantssurveyed. The slides were storedin the Coccomorpha Collection InstitutoFundación Miguel Lillo –IFML- (Tucumán, Argentina). The association betweenC. grandis and plants of D. erecta var. lemon is reported for the first time inArgentina.Se realizó un relevamiento de cochinillas blandas pertenecientes al género Ceroplastes Gray, asociadas a Duranta erecta var. lemon L. en la ciudad de Paraná, Entre Ríos, Argentina. Estos insectos afectan el crecimiento de las plantas, provocando su decaimiento y disminuyendo su valor ornamental. Se realizaron preparaciones microscópicas y se identificó a la especie Ceroplastes grandis Hempel (Hemiptera: Coccomorpha: Coccidae) en la totalidad de las plantas relevadas. Las preparaciones microscópicas fueron depositadas en la Colección de Coccomorpha del Instituto Fundación Miguel Lillo –IFML- (Tucumán, Argentina). Se reporta por primera vez en Argentina la asociación de C. grandis y plantas de D. erecta var. lemon

Biological activity of soils cultivated with yacón (Smallanthus sonchifolius Poep. & Endl) H. Robinson, inoculated with Azospirillum brasilense and native mycorrhizal fungi

The soil is influenced by the roots of plants because the exudate radicals affect its physical, chemical, and biological processes. The aim of this research was to evaluate the microbial activity of soils cultivated with yacón (Smallanthus sonchifolius Poep. & Endl) H. Robinson and inoculated with microorganisms which promote plant growth. The experimental design used was randomized blocks with three repetitions per treatment. Each repetition corresponded to a 3m x 3m plot with 25 plants, in 5 cultivation lines with a distance of 70 cm apart. Four treatments were applied at the time of plantation. These consisted of yacón propagules inoculated with Azospirillum brasilense (T1) and native mycorrhizal fungi (T2) inoculated with the microbial consortium (T3). In the control treatments, the propagules were not inoculated with these microorganisms (T0). Soil samples were collected in lots cultivated with yacón located in the Province of Catamarca, in the northwest of Argentina. The samples were collected at the time of implantation and harvest during three agricultural cycles. The total Biological Activity (TBA) of the collected samples was determined by Fluorescein Diacetate Hydrolysis. The TBA of the soil was affected by the different crop treatments, which rose in the analyzed soils and was statistically different from the control treatments. Significant differences were also observed between the TBA of the soils at the beginning of the crops in comparison with the recorded values of the crop at the time of harvest. The inoculation of yacón propagules with A. brasilense and native mycorrhizal fungi affects the TBA of the cultivated soils marking a significant increase.El suelo está influenciado por las raíces de las plantas, ya que los exudados radicales afectan los procesos físicos, químicos y biológicos del suelo. El objetivo de la investigación fue evaluar la actividad microbiana en suelos donde se ha cultivado yacón (Smallanthus sonchifolius), inoculado con microorganismos promotores del crecimiento de las plantas. El diseño experimental empleado fue bloques al azar con tres repeticiones por tratamiento. Cada repetición correspondió a una parcela de 3 x 3m con 25 plantas, en 5 líneas de cultivo distanciadas a 70 cm. Se aplicaron cuatro tratamientos en el momento de la plantación y consistieron en la inoculación de propágulos de yacón con Azospirillum brasilense (T1), hongos micorrícicos nativos (T2), con el consorcio microbiano (T3) y en los tratamientos testigos los propágulos sin inocular con estos microorganismos (T0). Muestras de suelo fueron colectadas en lotes cultivados con yacón situados en la Provincia de Catamarca, al noroeste de Argentina, al momento de implantación y de cosecha durante tres ciclos agrícolas. Se determinó la Actividad Biológica Total (ABT) por Hidrólisis del Diacetato de Fluoresceína a las muestras colectadas. La ABT del suelo fue afectada por los diferentes tratamientos del cultivo, la cual se elevó en los suelos estudiados, difiriendo estadísticamente con los testigos. También se observaron diferencias significativas entre la ABT de los suelos al inicio de los cultivos con los valores registrados a la cosecha de este. La inoculación de propágulos de yacón con A. brasilense y hongos micorrícicos nativos afecta la ABT de los suelos cultivados, aumentando significativamente

Arbuscular mycorrhizal and native dark septate fungus in jerusalem artichoke (Helianthus tuberosus L.) in Catamarca, Argentina

In order to determine and evaluate the fungal root infection it was studied the colonization by native fungal symbionts in roots of jerusalem artichoke (Helianthus tuberosus L.) cultivated in the Central Valley of the province of Catamarca, an arid region at the Northwest of Argentina. The studies were made by: microscope observation of the stained root fungal structures. The infection quantification was made by clarification methodologies and count under magnifying glass. Endomycorrhizal structures of the vesicle arbuscular type were observed (MVA; hyphae, arbuscules and vesicles) and of septate dark endophytic fungi (DES; melanized septate hyphae and with numerous microesclerotia). A high level of fungi colonization was determined with simultaneous occurrence of vesicle arbuscular mycorrhizae (VAM) and fungi (DES). This study is the first report of the colonization by VAM and DES in roots of jerusalem artichoke.Para determinar y valorar la infección fúngica radicular, se estudió la colonización por simbiontes fúngicos nativos en raíces de Topinambur (Helianthus tuberosus L.), cultivado en el Valle Central de la provincia de Catamarca, región árida del Noroeste Argentino. Los estudios se efectuaron mediante observación microscópica de estructuras fúngicas teñidas dentro de la raíz. La cuantificación de la infección se efectuó mediante metodologías de clarificación y conteo sobre cuadricula bajo lupa. Se observaron estructuras endomicorrícicas como hifas, arbúsculos y vesículas del tipo vesículo arbuscular (MVA) y de hongos endofíticos septados oscuros (ESO) con hifas tabicadas, melanizadas y con numerosos microesclerocios. Se determinó un alto nivel de colonización fúngica con ocurrencia simultánea de MVA y hongos ESO. Este estudio es el primer informe sobre colonización por MVA y ESO en raíces de topinambur

Biological control of Alphitobius diaperinus with Steinernema rarum CUL and Heterorhabditis bacteriophora SMC and feasibility of application in rice hull

Chemical insecticides often are not efficient in reducing Alphitobius diaperinus populations in poultry farms and have induced insect resistance. Entomopathogenic nematodes (EPNs) appear as an alternative to pest biocontrol agents; however, their efficiency on rice hull litter is still unknown. The aim of this study was to evaluate the potential of Steinernema rarum (CUL isolate), Heterorhabditis bacteriophora (SMC isolate) and their symbiotic bacteria as biocontrol agents of A. diaperinus larvae and adults in rice hull litter. Mortality of insect adults and fifth- and seventh-instar larvae was determined in Petri dishes containing filter paper or rice hull. The effect of Xenorhabdus szentirmaii and Photorhabdus luminescens on L7 and adults in rice hull substrate was also evaluated. Moreover, the effectiveness of the EPNs was assessed in bags in an environment simulating the prevailing conditions in a broiler chicken farm. Under laboratory conditions, insect mortality was significantly affected by EPN species, substrate, insect stage and time after application. Mortality of L5 and L7 caused by EPNs in rice hulls reached a peak of 64 and 57.3 %, respectively, whereas symbiotic bacteria applied on rice hull showed low mortality rate at both insect stages. In the simulated poultry farm conditions, S. rarum and H. bacteriophora caused up to 40.8 and 50.4 % mortality of A. diaperinus larvae, respectively, but with adult mortality being low for both species. We conclude that infective juveniles from S. rarum CUL and H. bacteriophora SMC isolates can be used as biological control agents of A. diaperinus larvae in chicken litter containing rice hulls.Fil: del Valle, Eleodoro Eduardo. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Frizzo, Laureano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Malmierca, Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Zbrun, María Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Lax, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; ArgentinaFil: Doucet, Marcelo Edmundo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin