Ivan Dubovskiy

Novosibirsk State Agricultural University · Department of Plant Protection

Although many insects successfully live in dangerous environments exposed to diverse communities of microbes, they are often exploited and killed by specialist pathogens. Studies of host-pathogen interactions (HPI) provide valuable insights into the dynamics of the highly aggressive coevolutionary arms race between entomopathogenic fungi (EPF) and...

Evolution of the insect immune system led to the creation of a comprehensive cellular defense system, not only involving phagocytosis, but also encapsulation and nodulation (both often referred to as capsule formation) allowing the isolation and neutralization of invading pathogens and parasites. Such reactions are closely related to the anatomical...

Microevolutionary mechanisms of resistance to a bacterial pathogen were explored in a population of the Greater wax moth, Galleria mellonella, selected for an 8.8-fold increased resistance against the entomopathogenic bacterium Bacillus thuringiensis (Bt) compared with a non-selected (suspectible) line. Defense strategies of the resistant and susce...

Epigenetic mechanisms have been proposed to translate environmental stimuli into heritable transgenerational phenotypic variations that can significantly influence natural selection. An intriguing example is exposure to pathogens, which imposes selection for host resistance. To test this hypothesis, we used larvae of the greater wax moth Galleria m...

Dopamine (DA) is known as a hormone neurotrasnmitter molecule involved in several stress reactions in both vertebrates and invertebrates. Following infections with the fungi Metarhizium robertsii or Beauveria bassiana and the bacterium Bacillus thuringiensis, dopamine the concentration was measured at different time points in the haemolymph of the...

Abstract book

Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most dangerous pests in the world and one of the most pesticide-resistant species ever. Complex biological preparations are of great interest for the acaricide market because they do not poison ecosystems and do not bioaccumulate in food products, simultaneously,...

Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most dangerous pests in the world and one of the most pesticide-resistant species ever. Complex biological preparations are of great interest for the acaricide market because they do not poison ecosystems and do not bioaccumulate in food products, simultaneously,...

The current progress in genetic technologies (methodologies) allows to create crops with the modified genome to counter different pest species. Genome editing is the most popular and efficient approach to increase crop defense against harmful insects, mites, and nematodes. During the first decades of the twenty-first century, the methodology of pes...

Since Agostino Bassi first isolated the fungal pathogenic agent of the white muscardine in insects (later named Beauveria bassiana in his honor), and Ilya Mechnikov cultivated Metarhizium anisopliae as a first approach to use fungi as pest control agents, many other entomopathogenic fungi have been studied over the last two centuries [...]

The bacteria Bacillus thuringiensis subsp. aizawai ( B. thuringiensis subsp. aizawai ) are entomopathogenic microorganisms that are used to control the abundance of insect pests, in particular members of the Lepidoptera and Diptera orders. The growth-stimulating effect of the bacterium B. thuringiensis subsp. aizawai on potatoes. In particular, an...

Black scurf and stem canker caused by Rhizoctonia solani is a significant disease problem of potatoes. Currently, chemical methods are the primary means of controlling this pathogen. This study sought to explore an alternative approach by harnessing the biocontrol potential of a bacterial mix of Bacillus subtilis and Bacillus amyloliquefaciens agai...

Plant protection faces a growing number of challenges, partly stemming from intensification of plant cultivation to ensure food security for a rapidly growing global population [...]

Chaetoceros sp. is widely used in aquaculture due to its high nutritional value. However, the low growth rate and poor light adaptability of Chaetoceros sp. limit their applications as aquatic food. In this study, the effects of different carbon and nitrogen sources on the growth of algal cells were studied. The highest algal cell density was 5.25*...

Bacillus thuringiensis (Bt) is one of the most common entomopathogenic bacteria used as a biopesticide, and source of endotoxin genes for generating insect-resistant transgenic plants. The mechanisms underpinning an insect's susceptibility or resistance to B. thuringiensis are diverse. The bacterial lifecycle does not end with the death of a host,...

In the article, the authors showed the effectiveness of bacterization of winter barley variety Basalt with a complex microbial preparation BakSib. The authors used a semi-dry method of seed treatment (10 l/t of working solution) and a single treatment of vegetative plants on the southern chernozem together with chemical pesticides and without them....

How invasive species cope with novel selective pressures with limited genetic variation is a fundamental question in molecular ecology. Several mechanisms have been proposed, but they can lack generality. Here, we addressed an alternative solution, polygenic adaptation, wherein traits that arise from multiple combinations of loci may be less sensit...

In order to find effective and safe ways to prevent the weakening and death of honey bee colonies from various stress factors, it is necessary to focus on the stimulation of physiological processes in the bee's body, activating their own mechanisms of resistance. Bacteria Bacillus subtilis and Bacillus licheniformis produce important digestive enzy...

Three types of modified silicon dioxide nanoparticles (SiO2, 10–20 nm) with additives of epoxy, silane and amino groups, used independently and in combination with the entomopathogenic bacteria Bacillus thuringiensis subsp. morrisoni and fungus Metarhizium robertsii were tested against Colorado potato beetle (Leptinotarsa decemlineata) and cabbage...

Estimation of the effectiveness and potential mechanism of action of biological agents on various soil profiles and crops allows more accurate recommendations for their application, and ultimately leads to an increase in crop yields. In the article is researched the composition and structure of the soil microbial community during pre-planting inocu...

Bacillus thuringiensis (Bt) is one of the most common entomopathogenic bacteria used as a biopesticide, and source of endotoxin genes for generating insect-resistant transgenic plants. The mechanisms underpinning an insect’s susceptibility or resistance to B. thuringiensis are diverse. The bacterial lifecycle does not end with the death of a host,...

How invasive species cope with novel selective pressures with limited genetic variation is a fundamental question in molecular ecology. Several mechanisms have been proposed, but they can lack generality. Here, we addressed an alternative solution, polygenic adaptation, wherein traits that arise from multiple combinations of loci may be less sensit...

The insect integument (exoskeleton) is an effective physiochemical barrier that limits disease-causing agents to a few portals of entry, including the gastrointestinal and reproductive tracts. The bacterial biopesticide Bacillus thuringiensis (Bt) enters the insect host via the mouth and must thwart gut-based defences to make its way into the body...

The co-evolutionary arms race between disease-causing agents and their insect victims is ancient and complex – leading to the development of specialised attack and defence strategies. Among such strategies is the capacity of fungal and oomycete pathogens to deploy degradative enzymes, notably proteases, to facilitate infection directly across the i...

Although many insects successfully live in dangerous environments exposed to diverse communities of microbes, they are often exploited and killed by specialist pathogens [...]

Juvenile hormone has been suggested to be a potential mediator in the trade-off between mating and insects' immunity. Studies on various insect taxons have found that juvenile hormone interferes with humoral and cellular immunity. Although this was shown experimentally, studies using highly virulent parasites or pathogens are lacking so far. In thi...

The crystallogenic bacteria Bacillus thuringiensis, which is immobile and does not form flagella, was found in the permafrost of Magadan oblast. In the isolated culture of the bacteria, crystals were not separated from the spore. These bacteria were detected in 80% of the soil samples. The number of bacteria reached 4 × 103 cfu/g of dry soil. The s...

The efficacy of the fungus Lecanicillium lecanii and two bacteria, Bacillus thuringiensis and Streptomyces avermitilis against the two-spotted spider mite Tetranychus urticae Koch and side effects on its predatory mite Phytoseiulus persimilis A.-H. was studied under laboratory conditions. Both S. avermitilis and B. thuringiensis based biopesticides...

Полученные при токсикологическом анализе данные о чувствительности имаго колорадского жука Leptinotarsa decemlineata Say (Coleoptera, Chrysomelidae) на территории Новосибирской области свидетельствуют о наличии множественной резистентности к препаратам из классов фосфорорганических соединений (ФОС), неоникотиноидов и нереистоксинов. Особенностью но...

Background: Genetic modification of plants is one of the promising strategies to increase their resistance to insect pests. The development of metabolic or RNA interference systems for plant protection requires appropriate models of host-insect interactions. Nicotiana tabacum L. is a classical model plant, used in molecular and metabolic engineerin...

In order for entomopathogenic fungi to colonize an insect host, they must first attach to, and penetrate, the cuticle layers of the integument. Herein, we explored the interactions between the fungal pathogen Metarhizium brunneum ARSEF 4556 and two immunologically distinct morphs, melanic (M) and non-melanic (NM), of the greater wax moth Galleria m...

Some mechanisms of resistance to Bacillus thuringiensis, including esterase activity in the midgut, can appear in laboratory and field insect populations. We found that B. thuringiensis infection significantly reduced the esterase activity in the midgut of greater wax moth Galleria mellonella 48 h post infection. Esterase activity was inhibited 1.5...

An analysis of the influence of the sum of effective temperatures (SET) that embryos of gypsy moth (Lymantria dispar (L.)) from populations of different latitude origins receive in the midsummer—autumn period until overwintering on the diapause duration and the SET of eclosion, as well as an assessment of the effect of short-term temperature rise d...

Recent concepts in evolutionary biology suggest that epigenetic mechanisms can translate environmental selection pressures into heritable changes in phenotype. To determine whether experimental selection for a complex trait in insects involves epigenetic modifications, we carried out a generation-spanning experiment using larvae of the greater wax...

Galleria mellonella fed 3 million Nosema pyrausta spores per larva showed 0 and 5% infestation rate at 30°C and 24°C, respectively. N. pyrausta virulence did not increase after passage through G. mellonella for three generations. When larvae were pretreated with phenylthiourea, Bacillus thuringiensis or combination of both, infection rates were 11%...

For the first time the causes of mass death of embryos in a population of gypsy moth Lymantria dispar L. (Lepidoptera: Erebidae, Lymantriidae) with biochemical and molecular methods are investigated. In this study egg masses were collected in the territory of Russia from two populations: with low (the West Siberian population) and high (Trans-Ural)...

Host innate immunity is one of the factors that determines the resistance of insects to their entomopathogens. In the research reported here we studied whether or not phenoloxidase (PO), a key enzyme in the melanogenesis component of humoral immunity of insects, plays a role in the protection of Lymantria dispar larvae from infection by L. dispar m...

Initial dataset of all experiments described within the article. (XLS)

The effect of a number of plant extracts on the susceptibility of experimental insects to enthomopathogenic microorganisms has been studied. It is shown that the weight of the wax moth Galleria mellonella larvae tends to decrease by 30–50% under the treatments of polar and nonpolar extracts from the ledum sprouts and the reindeer lichen, while the...

The synergistic effect between the entomopathogenic fungus Metarhizium robertsii and a sublethal dose of the bacterium Bacillus thuringiensis ssp. morrisoni var. tenebrionis was studied in terms of immune defense reactions and detoxification system activity of the Colorado potato beetle, Leptinotarsa decemlineata, fourth instar larvae. Bacterial in...

This study examines how the dynamics of fungus – insect interactions can be modulated by temperature. The wax moth, Galleria mellonella, is a well-studied and important model insect whose larvae in the wild develop optimally at around 34°C in beehives. However, surprisingly little research on wax moths has been conducted at relevant temperatures. I...

The phenological synchrony between the emergence of overwintering herbivorous insects and the budding of host plants is considered a crucial factor in the population dynamics of herbivores. However, the mechanisms driving the interactions between the host plant, herbivores, and their pathogens are often obscure. In the current study, an artificiall...

On page 258, right column, the final line of the ACKNOWLEDGMENTS should read: The study was financially supported by the Russian Scientific Foundation (project no. 15-14-10014).

The interaction between the entomopathogenic fungus Metarhizium robertsii and natural avermectin metabolites of the actinomycete Streptomyces avermitilis were investigated on Colorado potato beetle larvae. A synergy in the mortality of larvae was detected after simultaneous treatment with half-lethal doses of avermectins (commercial name actarophit...

Bacteria Bacillus thuringiensis var. tenebrionis (Bt) are naturally occurring bacterial disease and effective agent for biological control of important pest Colorado potato beetle (Leptinotarsa decemlineata). In this study we used Siberian population of Colorado potato beetle collected from the field that had never been sprayed with Bt -based biope...

Development of mycoses and progress of humoral and cellular immune responses were compared in larvae of the Colorado potato beetle Leptinotarsa decemlineata infected with entomopathogenic fungi Metarhizium robertsii, M. brunneum and M. pemphigi. The larvae were found to be highly susceptible to the strains of M. robertsii and M. brunneum but weakly...

The synergistic effect in mortality of the greater wax moth Galleria mellonella larvae was recorded after combined treatment with the entomopathogenic fungi Cordyceps militaris (L.: Fr.) Link and Beauveria bassiana (Bals.-Criv.) Vuill. Treatment with C. militaris resulted in development arrest and some changes in immune response (a sharp decrease i...

The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects' fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenomenon. However, the spreading of this phenomenon through the food chain, and espec...

In addition to nutritional conditions experienced by individuals themselves, those experienced by their parents can affect their immune function. Here, we studied the intra- and trans-generational effects of larval diet on susceptibility to an entomopathogenic fungus, Beauveria bassiana, in the greater wax moth, Galleria mellonella. In the first pa...

Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the al...

Several aspects of immune response in insects treated with an organophosphate (pirimiphosmethyl) have been assessed. Both humoral (phenoloxidase activity) and cellular (hemocyte count and encapsulation rate) immunity changes have been studied in larvae of the representatives of two insect orders, the Colorado potato beetle Leptinotarsa decemlineata...

The immunosuppressive and insecticidal activity of culture of the entomopathogenic fungus Cordyceps militaris on the larvae of the Colorado potato beetle Leptinotarsa decemlineata has been established for the first time. It was found that the peroral effect of the fungal culture resulted in dose�dependent decrease in survival, delayed in developmen...

The mortality rate of Anopheles messeae Fll. and Culex pipiens pipiens L. mosquito larvae infected with entopathogenic fungi Metarhizium brunneum and M. robertsii has been studied in laboratory conditions. It was shown that C. pipiens larvae are more susceptible to a water suspension of fungal conidia treatment while A. messeae larvae are more susc...

In this study the cellular and humoral immune reactions of the Greater wax moth Galleria mellonella have been investigated during bacterial infection caused by oral administration of Bacillus thuringiensis. Two different dose strengths were investigated to assess the contribution of immune parameters to induced Bt resistance. Low-dose (sublethal LC...

Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to...

A 'dark morph' melanic strain of the greater wax moth, Galleria mellonella, was studied for its atypical, heightened resistance to infection with the entomo-pathogenic fungus, Beauveria bassiana. We show that these insects exhibit multiple intraspecific immunity and physiological traits that distinguish them from a non-melanic, fungus-susceptible m...