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Rapid evolution of weed biological control agents (BCAs) to new biotic and abiotic conditions is poorly understood and so far only little considered both in pre-release and post-release studies, despite potential major negative or positive implications for risks of nontargeted attacks or for colonizing yet unsuitable habitats, respectively. Provision of genetic resources, such as assembled and annotated genomes, is essential to assess potential adaptive processes by identifying underlying genetic mechanisms. Here, we provide the first sequenced genome of a phytophagous insect used as a BCA, that is, the leaf beetle Ophraella communa , a promising BCA of common ragweed, recently and accidentally introduced into Europe. A total 33.98 Gb of raw DNA sequences, representing ∼43-fold coverage, were obtained using the PacBio SMRT-Cell sequencing approach. Among the five different assemblers tested, the SMARTdenovo assembly displaying the best scores was then corrected with Illumina short reads. A final genome of 774 Mb containing 7,003 scaffolds was obtained. The reliability of the final assembly was then assessed by benchmarking universal single-copy orthologous genes (>96.0% of the 1,658 expected insect genes) and by remapping tests of Illumina short reads (average of 98.6 ± 0.7% without filtering). The number of protein-coding genes of 75,642, representing 82% of the published antennal transcriptome, and the phylogenetic analyses based on 825 orthologous genes placing O. communa in the monophyletic group of Chrysomelidae, confirm the relevance of our genome assembly. Overall, the genome provides a valuable resource for studying potential risks and benefits of this BCA facing environmental novelties. [ABSTRACT FROM AUTHOR]

The release of large quantities of microorganisms to soil for purposes such as pest control or plant growth promotion may affect the indigenous soil microbial communities. In our study, we investigated potential effects of Metarhizium brunneum ART2825 on soil fungi and prokaryota in bulk soil using high-throughput sequencing of ribosomal markers. Different formulations of this strain, and combinations of the fungus with garlic as efficacy-enhancing agent, were tested over 4 months in a pot and a field experiment carried out for biological control of Agriotes spp. in potatoes. A biocontrol effect was observed only in the pot experiment, i.e. the application of FCBK resulted in 77% efficacy. Colony counts combined with genotyping and marker sequence abundance confirmed the successful establishment of the applied strain. Only the formulated applied strain caused small shifts in fungal communities in the pot experiment. Treatment effects were in the same range as the effects caused by barley kernels, the carrier of the FCBK formulation and temporal effects. Garlic treatments and time affected prokaryotic communities. In the field experiment, only spatial differences affected fungal and prokaryotic communities. Our findings suggest that M. brunneum may not adversely affect soil microbial communities. [ABSTRACT FROM AUTHOR]

Aims The goal was to determine the effect of temperature, light and incubation period on production, germination and bioactivity of Trichoderma atroviride LU132 against Rhizoctonia solani. Methods and Results The incubation temperatures of 20, 25 or 30°C were assessed on the production of T. atroviride conidia under constant light over a 25 and 50 days periods. The resulting conidia were also studied for germination and bioactivity. Conidium production was maximum at 25°C after 20 days. The second peak of conidium production occurred at 45-50 days. Incubation at 25°C after 15 days showed optimum production of T. atroviride LU132. Conidia produced at 30°C gave the greatest germination and bioactivity in comparison with incubation at 20 or 25°C. Conclusion This study indicates that the temperature at which conidia of T. atroviride are produced affects germination and bioactivity. Formulations based on production of the high conidia yield may not result in optimal bioactivity and there is a trade-off between quantity and quality of T. atroviride LU132 conidia. Conidium production was shown to be a continuous process, and increased under a dark/light regime. This is the first report of bimodal conidium production in a Trichoderma biological control agent (BCA), which is likely to be on 20 days cycle, and is dependent on colony age rather than abiotic factors. Conidia produced after 15 days are likely to be the most suitable for use in commercial production of this strain as a BCA. Significance and Impact of the Study Most studies on Trichoderma-based BCA have only shown the effect of culture conditions on the high conidia yield regardless of conidium quality. This study is the first report on conidium quality affected by principal culture conditions for Trichoderma biological control formulations. [ABSTRACT FROM AUTHOR]

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a classic glycolytic enzyme that plays important roles in various cellular processes. Here, we report the sequence and transcriptional analyses of a regulated gene ( gpdh1) encoding GAPDH in the entomopathogenic fungus Metarhizium anisopliae, a well-characterized biocontrol agent of a wide range of arthropod pests. Transcript and protein analyses of the gpdh1 showed a carbohydrate-dependent expression pattern in response to different carbon sources. A demonstration that GAPDH is localized at the cell surface is presented, and assays with insect wings show that this protein has adhesion-like activity. These results imply that GAPDH adhesion to the wing surface is specific and may play a role in the binding of conidia to a host. Our observations indicate new roles for GAPDH both physiologically and during the entomopathogen-host interaction. [ABSTRACT FROM AUTHOR]

Aims: To characterize the volatile antifungal compound produced by Oxyporus latemarginatus EF069 and to examine in vitro and in vivo fumigation activity of the fungus. Methods and Results: An antifungal volatile-producing strain, O. latemarginatus EF069 inhibited the mycelial growth of Alternaria alternata, Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. lycopersici, and Rhizoctonia solani by mycofumigation. An antifungal volatile compound was isolated from the hexane extract of wheat bran–rice hull cultures of O. latemarginatus EF069 by repeated silica gel column chromatography and identified as 5-pentyl-2-furaldehyde (PTF). The purified PTF inhibited mycelial growth of R. solani in a dose-dependent manner. The mycofumigation with solid cultures of EF069 also reduced effectively the development of postharvest apple decay caused by B. cinerea and Rhizoctonia root rot of moth orchid caused by R. solani. Conclusions: Oxyporus latemarginatus EF069 showed in vitro and in vivo fumigation activity against plant pathogenic fungi by producing 5-pentyl-2-furaldehyde. Significance and Impact of the Study: Oxyporus latemarginatus EF069 producing an antifungal volatile compound may be used as a biofumigant for the control of fungal plant diseases. [ABSTRACT FROM AUTHOR]

Aims: Production of the mosquito biolarvacide Lagenidium giganteum in solid culture has been proposed as an economic alternative to production in liquid culture because of observations of improved shelf life and efficacy upon storage. Understanding the differences between these production systems and estimating growth rate in solid culture are important for commercialization. In order to address these needs a logistic model was developed to describe the growth kinetics of L. giganteum produced in solid and liquid cultures. Methods and Results: Kinetic parameters in the logistic model were estimated by nonlinear regression of CO2 evolution rate (CER) and biomass data from solid and liquid cultivation experiments. Lagenidium giganteum biomass was measured using DNA extracted directly from samples. The logistic model was fit to experimental biomass and CER data with low standard errors for parameter estimates. The model was validated in two independent experiments by examining prediction of biomass using on-line CER measurements. Conclusions: There were significant differences between maximum biomass density, maintenance coefficients, and specific growth rates for liquid and solid cultures. The maximum biomass density (mg dw ml−1) was 11 times greater for solid cultivation compared with liquid cultivation of L. giganteum; however, the maintenance coefficient (mg CO2 h−1 (mg dw)−1) was six times greater for liquid cultivation than in solid cultivation. The specific growth rate at 30°C was approximately 30% greater in liquid cultivation compared with solid cultivation. Slower depletion of substrate and lower endogenous metabolism may explain the longer shelf life of L. giganteum produced in solid culture. Significance and Impact of the Study: A simple logistic model was developed which allows real-time estimation of L. giganteum biomass from on-line CER measurements. Parameter estimates for liquid and solid cultivation models also elucidated observations of longer shelf life for production in solid culture. [ABSTRACT FROM AUTHOR]

We report on laboratory hybridization between the indigenous Chrysoperla nipponensis and its close relative, C. carnea, which has been imported since 2001 from Germany to Japan as a biological control agent. Interspecific hybrids were obtained, and fully viable and fertile F1 and F2 generations were produced. Crosses between C. carnea females and C. nipponensis males showed 41.3% fertility, but the reciprocal cross showed only 9.5% fertility. Despite the low fertility of interspecific crosses, most F1 hybrids were fertile and were successfully backcrossed to both parental species. However, F1 males from C. carnea females ⊗ C. nipponensis males showed low fertility (zero except for 20% in one ease) when crossed with any females (F1 or backcross), In the one combination resulting in 20% fertility, an extremely long preoviposition period was observed, caused presumably by a mating delay. The absence of change in hatchability, adult emergence rate, total developmental period, or deviation from the 50:50 sex ratio from parents to the F2 generation of hybrids suggests that there is no genetic incompatibility between C. carnea and C. nipponensis resulting from hybrid breakdown. Because the courtship songs of the introduced C. carnea and the indigenous C. nipponensis are quite different, interspecific mating between the two close relatives may not occur under natural conditions. It will be necessary to monitor the establishment of the introduced C. carnea and its possible hybrids with the indigenous C. nipponensis in the wild to minimize any irreversible ecological risks, such as loss of genetic identity. [ABSTRACT FROM AUTHOR]

Microorganisms have knowingly been used during the last century to control plant diseases. During the last decades, research and application of biological control agents (BCAs) as a pest control strategy have gained increasing attention. This review focuses specifically on non-target effects of bacterial BCAs that are used to suppress root pathogenic fungi. It attempts to critically evaluate the strengths and weaknesses of non-target effect studies published to date and relate them to the success of the BCA in fungal pathogen control. Significant non-target effects of BCAs have indeed been observed, but these are generally small in scale and limited to a growth season, and have not been proven to affect soil health. We discuss these studies and point out what we believe are notable deficiencies. Among the modes of disease suppression by BCAs, antibiotic production is believed to be of major importance. But assurances that in situ antibiotic production actually occurs in environmental samples are lacking in the non-target effect studies. Also the effectiveness of the BCA on the target pathogen, the absence of appropriate controls for inoculation effects, and the presence of pathogenic fungi are missing in most studies. In future non-target effect studies we recommend focusing on proven effective BCAs and clearly distinguishing effects of antimicrobial compounds from effects of general microbial activity. [Copyright &y& Elsevier]

Pseudomonas putida and closely-related species such as Pseudomonas fluorescens and Pseudomonas brassicacearum have been reported as potential biocontrol agents and plant growth-promoters. Recently, we have described the biocontrol activity of P. putida B2017 against several phytopathogens of agricultural relevance. In this study, its ability to produce potential antibiotic / toxic metabolites was assessed by functional, chromatography-mass spectrometry and genomic analysis. Our results show that B2017 is not able to synthesize surfactants and common antibiotics produced by Pseudomonas spp., i.e. pyrrolnitrin, 2,4-diacetylphloroglucinol, pyoluteorin and pyocyanin, but it produces pyoverdine, a siderophore which is involved in its biocontrol activity. The non-production of other metabolites, such as cyanide, safracin, promysalin and lipopeptides between others, is also discussed. Our data suggest that the mode of action of B2017 is not mainly due to the production of antimicrobial / toxic metabolites. Moreover, these features make P. putida B2017 a promising biocontrol microorganism for plant protection without side effects on environment, non-target organisms and human health. [ABSTRACT FROM AUTHOR]