Entomopathogenic Fungi Research Articles

INTEGRATED PEST MANAGEMENT AND ENTOMOPATHOGENIC FUNGAL BIOTECHNOLOGY IN THE LATIN AMERICAS: II. KEY RESEARCH AND DEVELOPMENT PREREQUISITES

In the first part of this review article (Valencia & Khachatourians, 1998) we presented the special opportunity that entomopathogenic fungi (EPF) offer for integrated pest management (IPM) in the Latin Americas. As expected, along with the opportunities, there are challenges for the use of EPF. First that there are only two fungi, Beauveria bassiana and Metarhizium anisopliae, for which sorne prerequisite knowledge of basic and applied mycology for industrial research and development (R & D) are in place. Because of precedent setting leadership in the development of certain EPF, e.g., B. bassiana in 1PM, Latin America stands to contribute to and gain from future discovery research coupled to a strong and dependable industrialization effort. There is also need to develop the framework for public acceptance, newer commercialization potential and widespread use of EPF in 1PM. Here we examine issues that are prerequisites for industrial R & D.

Field appraisal of entomopathogenic fungi horizontal transmission device for entomo-vectoring of Beauveria bassiana and Metarhizium anisopliae in bitter gourd field against Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae)

BackgroundBactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) infestation poses a serious risk to bitter gourd cultivation. Traditionally, B. cucurbitae has been controlled using synthetic pesticides, which have drawbacks such as non-target toxicity and pest resistance. Entomopathogenic fungi (EPF) provide concentrated ecological alternatives, which support ongoing pest reduction and sustainable agriculture by adhering to Integrated Pest Management principles. Therefore, EPF provides a viable alternative for chemical control of B. cucurbitae, addressing its shortcomings and promoting environmentally friendly pest control technology. This study evaluated the effectiveness of entomo-vectored horizontal transmission devices (EV-HTD) against B. cucurbitae in bitter gourd fields, focusing on GF-120 and Butanone acetate. Assessment parameters include converting fruit infestation data into yield loss per plant, marketable fruit yield per plant, marketable yield per hectare, and yield loss per hectare.ResultsThe highest mean percentage of entomo-vectored B. cucurbitae (70.50%) was found in plots treated with Butanone acetate + B. bassiana-based EV-HTD. This was followed by GF-120 + B. bassiana-based EV-HTD (66.18%), Butanone acetate + M. anisopliae-based EV-HTD (58.95%), and GF-120 + M. anisopliae-based EV-HTD (54.78%). The Butanone acetate + B. bassiana-based EV-HTD produced the highest mean number of spores per B. cucurbitae (7.80 spores/cm2), while the other treatments produced low spore counts. Plots treated with Butanone acetate + B. bassiana-based EV-HTD had the highest percentage mortality of B. cucurbitae (81.20%). The percentage of fruit infestation varied between 9.00 and 34.00%, with the least amount of infestation seen in plots treated with B. bassiana + Butanone acetate. There were minimal yield losses in Butanone acetate. The Butanone acetate + B. bassiana-based EV-HTD showed the lowest yield losses (66.66 g/plant), while the other treatments showed high losses. Plots treated with Butanone acetate + B. bassiana-based EV-HTD had the highest marketable yield per plant (673.87 g/plant), while yields in control treatments were low. Plots treated with Butanone acetate + B. bassiana-based EV-HTD had the highest marketable yield (2217.85 kg/ha). Lastly, plots treated with Butanone acetate + B. bassiana-based EV-HTD (219.40 kg/ha) showed the lowest yield losses per hectare.ConclusionsAccording to the study’s findings, Butanone acetate-based EV-HTD was more successful than GF-120. Furthermore, B. bassiana was more effective at controlling B. cucurbitae than M. anisopliae. With a maximum cost–benefit ratio of 14.99, the treatment Butanone acetate + B. bassiana was shown to be the most advantageous economically, suggesting its potential for use in practical pest management techniques.

INTEGRATED PEST MANAGEMENT AND ENTOMOPATHOGENIC FUNGAL BIOTECHNOLOGY IN THE LATIN AMERICAS: I-OPPORTUNITIES IN A GLOBALAGRICULTURE

Entomopathogenic fungi (EPF) have been used as insect biocontrol agents separately and in integrated pest management (1PM) worldwide including in the Latin Americas. The proper use of these agents along with other elements and concepts of 1PM has significant impact on the provision of crops. fruits and other agricultura! products Entomopathogenic fungi can play a significant role in the preservation of the natural delicate balance of beneficia! biota and their active spreading from the surrounding natural habitats, such as the tropical rain forest, the humid cloudy forest in the Andes and other important ecosystems, to the agricultura} lands in Central and South America. Of ali known EPF, there are only about half a dozen for which prerequisite aspects of fungal biotechnology for industrial R and D are in place. Because of its precedent setting leadership in the use ofEPF in 1PM and agroecological practices, LatinAmerica stands to gain irnrnensely here and more so if the concept of rational design of bioinsecticides (RADBIO) is employed. The future prospects will depend on a balance of discovery research coupled to a strong and dependable industrialization effort to develop the framework for illustrating public acceptance, commercialization potential and widespread use of EPF in 1PM. The potential for the next generation of mycoinsecticides is now loorning on the horizon.

The basic leucine zipper domain (bZIP) transcription factor BbYap1 promotes evasion of host humoral immunity and regulates lipid homeostasis contributing to fungal virulence in Beauveria bassiana.

Entomopathogenic fungi (EPF) offer an effective and eco-friendly alternative to curb insect populations in biocontrol strategy. When EPF enter the hemolymph of their host, they encounter a variety of stress reactions, such as immunological and oxidative stress. Basic leucine zipper domain transcription factors, of which yeast activator protein (Yap) is a significant class, have diverse biological functions related to metabolism, development, reproduction, conidiation, stress responses, and pathogenicity. This study demonstrates that BbYap1 of Beauveria bassiana regulates cellular enzyme lipid homeostasis and fungal virulence by eluding host humoral defense, which contributes to fungal chemical stress and vegetative development. These findings offer fresh perspectives for comprehending molecular roles of YAP in EPF.

The endophytic entomopathogenic fungus Metarhizium robertsii alters sugarcane plant defenses, reducing Diatraea saccharalis oviposition and enhancing the attraction of Cotesia flavipes

The use of endophytic entomopathogenic fungi (EEF) represents a promising strategy to boost plant resistance in crops against both biotic and environmental stresses. However, the mechanisms by which this inoculation influences constitutive and herbivore-induced defenses to protect plants against pest insects remain unclear. To address this gap, we investigated whether the inoculation of the EEF Metarhizium robertsii can modulate sugarcane plant defenses and their resistance against the sugarcane borer Diatraea saccharalis. Specifically, we examined the endogenous levels of jasmonic acid (JA) and salicylic acid (SA), as well as the volatile emissions in sugarcane, in the absence and presence of infestation caused by D. saccharalis. We also explored how these inoculations might affect the oviposition preference of D. saccharalis (direct defense) and the chemotaxis of its main natural enemy, the parasitoid Cotesia flavipes (indirect defense), commonly used in biological control programs. Our findings revealed that M. robertsii inoculation alters sugarcane plant chemical traits, affecting their resistance differently against D. saccharalis infestation. In non-infested plants, the inoculation of M. robertsii increased JA and SA phytohormones, suppressed volatile emissions, and reduced egg-laying by D. saccharalis, while exhibiting no effect on C. flavipes attraction. Conversely, in D. saccharalis-infested plants, M. robertsii increased JA content and reduced SA levels, resulting in quantitatively different volatile emissions. These changes increased attraction of C. flavipes compared to infested plants without fungal inoculation. Our results demonstrate that M. robertsii inoculations can enhance sugarcane plants' constitutive defenses against D. saccharalis while improving their herbivore-induced indirect defenses in sugarcane.

Potential of entomopathogenic fungi to control insect pests and disease at lettuce and arugula crops

The lettuce (Lactuca sativa L.) (Asteraceae) and arugula (Eruca sativa Miller) (Brassicaceae) crops are attacked by various pests and diseases, but the control is usually done with agrochemicals. We evaluate the control of pests and diseases by systematic applications of the entomopathogenic fungi strains Metarhizium anisopliae IBCB425 and Beauveria bassiana IBCB66 both 300g c.p. in the planting groove and 200 g c.p. ha-1 on the foliage, in weekly applications at lettuce and arugula crops planted in association. For the evaluation of pests and diseases, 15 plants were evaluated at random in three beds per treatment. In the lettuce crop occurred the presence of aphids (Myzus persicae Hemiptera:Aphididae), whiteflies (Bemisia tabaci Hemiptera: Aleyrodidae), thrips (Frankliniella schultzei Thysanoptera:Thripidae), leafhoppers Agallia albidula (Hemiptera: Cicadellidae) and septoria disease (Septoria lactucae). In the arugula crop the same pests occurred, but with any disease. The fungi B. bassiana and M. anisopliae controlled F. schultzei and S. lactucae at lettuce crop, B. tabaci in both crops, but did not control M. persicae and A. albidula in both crops. The fungus B. bassiana decreased the mean number of leaves per plant and the mean of dry mass weight of arugula plants in relation to the control treatment, but the sample size may have interfered with these results. The two fungi could be used as biological control agents of pests and diseases at lettuce and arugula crops, especially in organic farming.

Safety of the Entomopathogenic Fungus Beauveria bassiana for Wild and Laboratory-Reared Chrysoperla lucasina Strains.

The need to reduce the impact of plant protection products on agroecosystems fosters the use of augmentative biological control involving the release of beneficial species into the field, the employment of entomopathogenic microbials, and the protection of naturally occurring biocontrol agents. This study aimed to investigate the compatibility of the entomopathogenic fungus Beauveria bassiana with the generalist insect predator Chrysoperla lucasina, in comparative experiments involving a laboratory-reared and a wild chrysopid strain. The larvae of the predators were exposed to different concentrations of fungal conidia up to a concentration of 107 conidia/mL by contact and ingestion. The treated insects showed only slight differences in terms of survival and immature development time compared to the untreated control insects. A significant decrease in the proportion of the male adults of C. lucasina that emerged from the laboratory-reared larvae that were exposed to higher concentrations of the fungus suggested a potentially different susceptibility between the sexes. A slightly lower adult emergence rate was observed in the wild strain, while no significant differences were recorded in the adult reproductive performance. These findings indicate that the B. bassiana strain ATCC 74040, at concentrations commonly used in the field, did not pose a significant risk to C. lucasina and can be safely used in combination with this predator for sustainable pest management.

Genomic and Pathogenic Characterization of Akanthomyces muscarius Isolated from Living Mite Infesting Hazelnut Big Buds.

The capability of entomopathogenic fungi to live as plant endophytes is well established. However, their presence in undiscovered environmental niches represents the beginning of a new challenging research journey. Recently, Akanthomyces muscarius (Ascomycota, Cordycipitaceae) (Petch) Spatafora, Kepler & B. Shrestha was isolated from hazelnut buds infested by the big bud mite pest Phytoptus avellanae Nalepa, which makes the buds swollen, reddish, and unable to further develop. Gall formation is known to be regulated by a consortium of microbes and mites, and to better understand the possible role of A. muscarius within the infested gall, its whole genome sequence was obtained using a hybrid approach of Illumina and Nanopore reads. The functional and comparative genomics analysis provided within this study may help answer questions related to the ecology and the entomopathogenicity of this fungus.

Oleic Acid and Linoleic Acid Enhances the Biocontrol Potential of Metarhizium rileyi.

Metarhizium rileyi is a wide spread insect fungi with a good biocontrol potentiality to various pests, particularly noctuid insects. However, it is characterized by its slow growth, its sensitivity to abiotic stress, and the slow speed of kill to pests, which hinder its use compared with other entomopathogenic fungi. In this study, the responses of M. rileyi to eight types of lipids were observed; among the lipids, oleic acid and linoleic acid significantly promoted the growth and development of M. rileyi and enhanced its stress tolerances and virulence. An additional mechanistic study demonstrated that exogenous oleic acid and linoleic acid significantly improved the conidial germination, appressorium formation, cuticle degradation, and cuticle infection, which appear to be largely dependent on the up-regulation of gene expression in growth, development, protective, and cuticle-degrading enzymes. In conclusion, exogenous oleic acid and linoleic acid enhanced the stress tolerances and virulence of M. rileyi via protecting conidial germination and promoting cuticle infection. These results provide new insights for the biopesticide development of M. rileyi.

Histopathological Alterations in Nilaparvata lugens (Hemiptera: Delphacidae) after Exposure to Cordyceps javanica.

The brown planthopper (BPH), Nilaparvata lugens (Stål, 1854), is a pest of rice plants worldwide. Cordyceps javanica is a destructive entomopathogenic fungus known to attack leafhoppers or BPHs specifically. Live adult BPH samples were inoculated with isolated C. javanica PSUC002, and their interaction was morpho-histologically examined from 0 to 120 h post-inoculation (pi). We observed that the mortality of BPH continuously increased until 120 h pi (Day 5). Tissue alterations in the host were examined after infection using morphological and histological methods, including the Grocott Methenamine Silver stain test (GMS). Filamentous fungi were first found on the external integument at 12 h pi, and fungal conidia attached to the integument at 24 h pi. However, the initial degeneration of BPHs was identified by histology at 6 h pi especially in the integument and adipose tissue. We identified the degeneration and loss of integument and adipose tissue of infected BPHs at 12 h pi, and their necrosis was completed at 96 h pi. The enzymatic index of the sampled fungi (chitinase and protease) peaked at 7 days of incubation. This study demonstrated that C. javanica PSUC002 is useful to control the BPHs as an eco-friendly practice and will possibly be applied in agriculture.

Eco-friendly and sustainable approaches against aphids management (Myzus persicae) and dissipation studies of imidacloprid in important cash crop capsicum under protected and open condition

Capsicum is generally infested with many biotic agents mainly sucking insects, among them the major is aphid (Myzus persicae). Chemical management is one of the most common strategies for their management. However, there are no recommended insecticides for insect management in polyhouse. An experiment was designed to assess the bio-potency of four popularly used insecticides (Imidacloprid-17.8SL, Acephate-75SP, Dimethoate-30EC and Buprofezin-25SC), a botanical (Neem oil 10000 ppm) and two entomopathogenic fungi (Metarhizium anisopliae 1.15%WP and Lecanicillium lecanii 1.15%WP) for two consecutive seasons. Most effective and the highest reduction of aphid population (78.14–81.92 %) were found in imidacloprid (17.8SL) treated plots. This effective molecule imidacloprid was further studied for its dissipation pattern under polyhouse and open condition and found that the imidacloprid residues in capsicum fruit dissipated below quantification limit (BQL) within 10days after final spray and the residues in the soil sampled at harvest time were found below the detection level. The half-lives of imidacloprid were 1.88 and 2.61 days under polyhouse and 1.07 and 1.52 days in open field at recommended doses (25 g a.i. ha−1) and double doses (50 g a.i. ha−1) of application respectively. The dietary exposure of imidacloprid on capsicum fruit under both conditions exposed that hazard quotient (HQ) values obtained from the different treatment doses have not exceeded the upper limit of toxicity (HQ < 1) and imidacloprid residues in the fruits were found below the existing MRL (Maximum Residue Limit) values (0.5 mg/kg) at 3 days after its final applications. Thus, imidacloprid may be considered as the effective chemical management option against aphids in capsicum under polyhouse and open field having no harmful effect on human consumption.

Endophytic entomopathogenic fungi as biological control agents of insect pests.

Entomopathogenic fungi capable of establishing mutualistic endophytic relationships with plants have a tremendous potential as biocontrol agents of insect pests. While fungi have long played an important and highly effective role in pest suppression, the utility of endophytic entomopathogenic fungi in pest management is a relatively new and emerging topic of biocontrol. Here we discuss the relevance of endophytic fungi to plant health in general, synthesize the current knowledge of the effectiveness of endophytic entomopathogenic fungi against diverse insect pests, discuss the indirect plant-mediated effects of endophytic entomopathogenic fungi on arthropods, and describe the diverse benefits of endophytic fungi to plants that are likely to affect herbivores and plant pathogens as well. Lastly, we consider major challenges to incorporating endophytic entomopathogenic fungi in biocontrol, such as their non-target effects and field efficacy, which can be variable and influenced by environmental factors. Continued research on endophyte-insect-plant-environment interactions is critical to advancing our knowledge of these fungi as a sustainable pest management tactic. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Role of Endophytic Entomopathogenic Fungi in Mediating Host Selection, Biology, Behavior, and Management of Tarnished Plant Bug, Lygus lineolaris (Hemiptera: Miridae).

Non-insecticidal control strategies using entomopathogens, nematodes, and endophytes provide sustainable and safer alternatives for managing crop pests. This study investigated the potential of different fungal endophytes, specifically Beauveria bassiana strains, in colonizing cotton plants and their efficacy against tarnished plant bug, Lygus lineolaris. The effect of endophytes on plant growth parameters and cotton yield were measured during different plant growth stages. The entomopathogenicity of these fungi was studied in diet cup bioassays using L. lineolaris adults. The behavior of adult males and females toward endophytic cotton squares was analyzed using olfactometer assays. The experiments showed that the fungal endophytes colonized the plant structures of cotton plants, which resulted in an increase in the number of cotton squares, plant height, and weight compared to control plants. B. bassiana strains/isolates such as GHA, NI-8, and JG-1 caused significant mortality in Lygus adults compared to controls. Also, male and female Lygus adults exhibited repellence behavior towards endophytic cotton squares containing JG-1 isolate of B. bassiana and to other B. bassiana strains such as NI-8, GHA, and SPE-120. No differences were observed in the survival and development of L. lineolaris second-instar nymphs on endophytic cotton, and no yield differences were observed in the field experiments.

Leptoglossus occidentalis Heidemann, 1910 (Hemiptera Coreidae) in Türkiye Its distribution, life cycle, and fungal associations

In this study, the distribution, life cycle and associations with fungi of the alien invasive species Leptoglossus occidentalis Heidemann, 1910 (Hemiptera: Coreidae) in Türkiye were investigated. During the study between 2019 and 2021, we found that the pest has spread almost all over Türkiye. We recorded the presence of the species in 35 provinces. The biological data obtained in the study were divided into ecologically similar sub-regions (Ankara-Çankırı-Kırşehir, Artvin, Isparta-Burdur, Izmir-Aydın-Manisa-Muğla-Antalya) in order to reveal the life cycle of the species. Additionally, host plant and insect samples were examined for the presence of Diplodia sapinea (Fr.) Fuckel (pine shoot blight agent) and entomopathogenic fungi species through morphological and molecular identification methods. Consequently, we found that L. occidentalis has two generations in Türkiye. Timing of the first flight was in early May-mid June and the second generation was from mid-July to late August. Although D. sapinea was detected in some of the sampled host plant tissues, it could not be isolated from L. occidentalis individuals. Accordingly, we did not find any evidence that L. occidentalis vectors D. sapinea although the insect and the fungus cooccurs in sampling areas. On the other hand, its vector potential cannot be ruled out especially during rainy periods. This potential remains as a hypothesis for future studies. Although we detected 25 fungal species isolated from L. occidentalis adults, none of them were entomopathogenic fungal species.

Microbial preparations for controlling the number of pests (phytophages): mechanisms of action and benefits of use

The article demonstrates environmentally safe and effective ways to control insect pests with the help of biological products. The main representatives of biological products producers, their mechanisms of action on pests, as well as advantages and features of their application are described. The mechanism of action of preparations based on Bacillus thuringiensis is explained in detail and the issue of using this microorganism to create resistant GM crops is touched upon. The details of the mechanism of action of entomopathogenic fungi on insect pests and the scheme of infection, reproduction and their distribution are demonstrated. It is noted that entomopathogenic viruses are the most specific among all entomopathogenic microorganisms. They are characterized by extreme selectivity of pathogenic action, i.e. the ability to infect one or more arthropod species without harming others. This feature is a guarantee of safety for non-target organisms, but despite their success in pest control, their difficulty in mass production and easy degradation in the environment makes them less popular among farmers. The main producers of biological products, their mechanisms of action on pests, as well as their advantages and peculiarities in application are described. The importance of integrating different methods of pest control and combining different biological products to obtain maximum yields in environmentally friendly plant cultivation is shown

Role of chitinase expression in the virulence of Lecanicillium lecanii against citrus black aphid (Toxoptera aurantii)

Chitinase plays a vital role in the virulence of entomopathogenic fungi (EPF) when it infects host insects. We used gene recombination technology to express chitinase of three strains of Lecanicillium lecanii: Vl6063, V3450, and Vp28. The ORF of ChitVl6063, ChitV3450 and ChitVp28 were inserted into the fungal expression vector pBARGPE-1, which contained strong promoter and terminator, respectively, to construct a chitinase overpressing plasmid, then transformed the wild-type strain with blastospore transformation method. The virulence of the three recombinant strains against Toxoptera aurantii was improved by overproduction of ChitVl6063, ChitV3450, and ChitVp28, as demonstrated by significantly lower 3.43 %, 1.72 %, and 1.23 % fatal doses, respectively, according to an insect bioassay. Similarly, lethal times of recombinants (ChitVl6063, ChitV3450 and ChitVp28) were also decreased up to 29.51 %, 30.46 % and 33.90 %, respectively, compared to the wild-type strains. Improving the expression of chitinase is considered as an effective method for the enhancement of the EPF value. The efficacy could be enhanced using recombinant technology, which provides a prospecting view for future insecticidal applications.

Evaluation of endophytic colonization and establishment of entomopathogenic fungi against Tuta absoluta (Lepidoptera: Gelechiidae) in tomato plants.

The tomato, Solanum lycopersicum L., is one of the most important horticultural crops that can be consumed fresh or after being processed worldwide. The tomato leaf miner (Tuta absoluta) is one of the most devastating pest to tomato plants due to its mine-feeding nature in the mesophyll tissue of the plant. Fungal entomopathogens can exist naturally in plants as an asymptote. This study aimed to detect the endophytic colonization of Beauveria bassiana and Metarhizium robertsii within tomato plants via artificial inoculation and their virulence effects on Tuta absoluta. Isolates with the highest percent germination and virulence against T. absoluta were selected for endophytic evaluation within tomato plants by different artificial inoculation techniques. This study revealed that, isolates with the highest percent germination and virulent to Tuta absoluta had the potential to colonize tomato plants. The result showed that, the maximum mortality rate (97.5%) of Tuta absoluta larvae was achieved by Metarhizium robertsii isolate K-61 at a concentration of 1x10 8conidial/ml at 7 days post inoculated. However, the highest cumulative mortality (100%) was recorded by Beauveria bassiana isolate APPRC-27 at 10 days post inoculated through the direct contact method. The highest endophytic colonization was registered by isolate APPRC-27 (76.67%) at 7 days post-inoculated using the leaf spray technique, but it declined to 11.67% after 28 days of inoculated. In the case of the seedling inoculation technique, the highest endophytic colonization was obtained in the root tissues of tomatoes at 28 days of inoculated by isolate K-61. This study revealed that the leaf spray inoculation technique was the most effective method, followed by seedling inoculation, for the deployment of Beauveria bassiana and Metarhizium robertsii endophytes in tomato plant tissues. Therefore, virulent Beauveria bassiana and Metarhizium robertsii, are promising bioagents for the control of Tuta absoluta if deployed as endophytes.

Evaluation of some techniques for drying conidiated rice culture of the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. with a bioassay evaluating their eligibility

BackgroundProduction of entomopathogenic fungi on a solid substrate, mostly on rice, is preferred by many producers due to its low technological requirements. Drying may be needed after fermentation to preserve the viability of the conidia until use. This study aimed to introduce some uncomplicated drying techniques and study their effectiveness in terms of drying time and extent, as well as their impact on the quantity of conidia produced and their biological activity. Four techniques were studied, i.e., condensing water vapor (by cooling), desiccant (using NaOH), air drying on a net, and air drying on a solid (impermeable) surface.ResultsCondensing water vapor and desiccant techniques were the fastest and most efficient, resulting in the lowest moisture content, ranging between 12 and 13%. While drying on a solid surface was the slowest and resulted in the highest moisture content of 32.98%. All of the dried samples yielded a lower quantity of conidia compared to the fresh samples. Samples of condensing water vapor, desiccant, and net techniques yielded approximately a similar quantity of conidia, ranging between 74 and 71% of the yield of the fresh sample. The solid surface sample yielded the lowest quantity of conidia, representing 63.78% of the fresh sample yield. A bioassay test on the mite, Tetranychus urticae Koch (Acari: Tetranychidae), showed that conidia dried via condensing water vapor and desiccant techniques kept their pathogenicity similar to the fresh sample, while samples dried on a net and solid surface significantly lost part of their pathogenicity.ConclusionThe condensing water vapor and desiccant techniques were the most efficient regarding the time needed, conidia yield, and pathogenicity. Drying on a solid surface was the least effective regarding the same factors.

Identification of a novel member of the genus Laulavirus (family Phenuiviridae) from the entomopathogenic ascomycete fungus Cordyceps javanica.

The virus family Phenuiviridae (order Hareavirales, comprising segmented negative-sense single stranded RNA viruses) has highly diverse members that are known to infect animals, plants, protozoans, and fungi. In this study, we identified a novel phenuivirus infecting a strain of the entomopathogenic fungus Cordyceps javanica isolated from a small brown plant hopper (Laodelphax striatellus), and this virus was tentatively named "Cordyceps javanica negative-strand RNA virus 1" (CjNRSV1). The CjNRSV1 genome consists of three negative-sense single stranded RNA segments (RNA1-3) with lengths of 7252, 2401, and 1117 nt, respectively. The 3'- and 5'-terminal regions of the RNA1, 2, and 3 segments have identical sequences, and the termini of the RNA segments are complementary to each other, reflecting a common characteristic of viruses in the order Hareavirales. RNA1 encodes a large protein (∼274 kDa) containing a conserved domain for the bunyavirus RNA-dependent RNA polymerase (RdRP) superfamily, with 57-80% identity to the RdRP encoded by phenuiviruses in the genus Laulavirus. RNA2 encodes a protein (∼79 kDa) showing sequence similarity (47-63% identity) to the movement protein (MP, a plant viral cell-to-cell movement protein)-like protein (MP-L) encoded by RNA2 of laulaviruses. RNA3 encodes a protein (∼28 kDa) with a conserved domain of the phenuivirid nucleocapsid protein superfamily. Phylogenetic analysis using the RdRPs of various phenuiviruses and other unclassified phenuiviruses showed CjNRSV1 to be grouped with established members of the genus Laulavirus. Our results suggest that CjNRSV1 is a novel fungus-infecting member of the genus Laulavirus in the family Phenuiviridae.

Transcriptome and proteome analyses reveal genes and signaling pathways involved in the response to two insect hormones in the insect-fungal pathogen Hirsutella satumaensis.

The insect hormones ecdysone (20E) and juvenile hormone III (JH) have been demonstrated to stimulate the secretion of conidia mucilage and pigments in Hirsutella satumaensis. However, the underlying mechanisms remain elusive. Here, comparative transcriptome and proteome analyses were performed to identify the fungal genes and proteins of H. satumaensis that are up- or downregulated in response to insect hormones. A total of 17,407 unigenes and 1,016 proteins in conidia mucilage were identified. The genes involved in response to the hormones were classified into four functional groups: (1) stress response-related genes that are required for the removal of reactive oxygen species (glutathione synthetase, c7144) and genes involved in the response to osmotic stress in the hemocoel, such as those encoding proteins involved in the G, mTOR, and MAPK signaling pathways (2); insect hormone metabolic genes, including genes encoding ecdysteroid UDP-glucosyltransferase, ecdysteroid-22-kinase, and a key aldehyde dehydrogenase in a juvenile hormone synthesis pathway (3); secretory proteins that share homology with those of the host Bombyx mori, including fibrohexamerin, sericin 1, metalloprotease 1 protein, and silk gum protein, which were revealed by the omics data; and (4) proteins related to amino sugar metabolism and oxidative phosphorylation that were specifically expressed in mucilage in response to 20E and JH, respectively. These findings revealed that H. satumaensis can mount effective responses by modulating the expression of genes involved in the detoxification, adaptation, and evasion of insect hormone-mediated immune responses, providing fresh insights into fungal pathogen-host insect interactions.IMPORTANCEInsect hormones are highly important for the regulation of insect growth, development, and immune system function. Thus, the expansion of entomopathogenic fungi (EPF) could be affected by these hormones when they inhabit the host hemocoel. However, the molecular basis of EPF in response to insect hormones has yet to be determined. Our results revealed that EPF are impacted by 20E and JH, both of which act as signals, as these hormones lead to changes in metabolic pathways of the fungus, thus demonstrating a direct relationship between the fungus and the hormones. Furthermore, adaptive strategies, such as the use of ecdysone-inactivating enzymes and secreted filamentous proteins in H. satumaensis, which strongly resemble those of the host insect, have been discovered, thus illustrating the importance of adaptation to insect hormones for a better understanding of the interaction between insects and EPF.