Entomopathogenic Beauveria Bassiana Research Articles

A novel fungal sensor (Ngs1) of N-acetylglucosamine (GlcNAc) mediates the fungal response to GlcNAc in the interaction between entomopathogenic Beauveria bassiana and insect host

As N-acetylglucosamine (GlcNAc) ubiquitously exists in both insect cuticle and fungal cell walls, the GlcNAc sensor (Ngs1) potentially plays important roles in the interactions between entomopathogenic fungi and their insect hosts. However, the roles of the Ngs1 derived from the entomopathogens in response to the host’s cuticle remain completely unexplored. In this study, a putative Ngs1 homolog was identified in the entomopathogenic fungus Beauveria bassiana. Deletion of Ngs1 significantly reduced virulence towards Galleria mellonella larvae either through cuticle infection (by 23%) or by bypassing the cuticle (by 44%). To investigate the role of Ngs1 in fungal virulence, an analysis of the transcriptome induced by Locusta migratoria exoskeleton was conducted, highlighting the regulatory mechanism of Ngs1 in carbohydrate metabolic process, particularly chitin metabolism and GlcNAc metabolism. Consistent with the transcriptomic data, Ngs1-deletion mutants showed reduced activities of both secreted chitinase (17% reduction) and Pr1 protease (35% reduction). Loss of Ngs1 down-regulated the transcript levels of GlcNAc-catabolism genes, resulting in a 17% decrease in fungal growth on GlcNAc-supported media. Furthermore, Ngs1 deficiency attenuated the fungal response to GlcNAc, leading to the alteration of fungal resistance to diverse stress cues. All of these changes contribute to the reduction in virulence in Ngs1-deficient B. bassiana. These findings support that Ngs1 plays a critical role in responding to insect-derived GlcNAc, affecting the production of cuticle-degrading enzymes to penetrate insect epidermis, GlcNAc-induced changes of stress resistance, and contribute to the fungal virulence against insects.

A Test of Immune Priming in the Kissing Bug Rhodnius pallescens (Hemiptera: Reduviidae) against the Entomopathogenic Fungus Beauveria bassiana (Hypocreales: Cordycipitaceae) in Panama

Abstract The assumption that the invertebrate immune system lacks memory and specificity has changed over time: many studies now indicate that a primary exposure of the host to a pathogen increases its resistance to a subsequent lethal challenge, a phenomenon known as immune priming. One group of insects in which immune priming has been little investigated is the hematophagous triatomine bugs. Herein, we tested the capability of the kissing bug Rhodnius pallescens Barber (Hemiptera: Reduviidae; hereafter kissing bugs), the vector of Chagas disease, to resist entomopathogenic fungi. Laboratory kissing bugs free of Wolbachia and Trypanosoma spp. as well as kissing bugs collected from the wild were used for tests with the entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae). Against laboratory kissing bugs, the fungus remained virulent for 94 d, indicating long-term viability. Kissing bugs collected from the wild that were exposed to a nonlethal dose of the fungus did not show increased survival against a lethal dose compared with controls inoculated with the lethal dose. However, kissing bugs inoculated with a nonlethal dose had higher levels of total phenoloxidase than control kissing bugs. Although the fungus activates the immune system of the kissing bugs, other variables may influence survival in the face of infection. Moreover, the lethality of the same strain was lower against wild kissing bugs, suggesting that the presence of symbionts or parasites influence the fungus–triatome (host) interaction. This work is one of the few studies that have investigated the fungus–host interaction in terms of immune priming in a hematophagous insect of public health importance. Implications are discussed.

Fungi associated with ambrosia beetle Xylosandrus germanus in Slovakia

The black timber bark beetle (Xylosandrus germanus) is a strongly invasive ambrosia beetle and an important forest pest in Slovakia. This pest is closely associated with symbiotic fungi used as its food source. We investigated the fungi associated with X. germanus adults in Slovakia. In this study, Beauveria bassiana, B. pseudobassiana, Clonostachys rosea, Fusarium oxysporum, Ophiostoma quercus, Phaeoacremonium scolyti, and Talaromyces amestolkiae were isolated and identified by morphological and molecular analyses. The fungus Ophiostoma quercus was most frequently isolated from living beetles, while the entomopathogenic Beauveria bassiana was the most commonly isolated from dead beetles. The morphological descriptions of fungi based on isolates from the surface of X. germanus adults are provided.

Molecular taxonomic characterization and infra-specific diversity of entomopathogenic Beauveria bassiana fungi from Argentina

It has been the aim of this study to molecular-taxonomically identify 15 Beauveria isolates collected from different geographical regions and insect hosts in Argentina and to investigate the levels of inter- and intra-specific diversity across this set of isolates. Based on phylogenetic analyses of EF1A-RPB1-RPB2 concatenated genes and BLOC markers, all Beauveria strains were identify as Beauveria bassiana. Within the B. bassiana clades of both phylogenies, isolates from Argentina were not clustered according to geographic origin or host. The 15 fungal isolates were further analyzed by PCR amplification of the intron insertion hot spot region of the nuclear 28S rRNA encoding sequence. By intron sequence and position, seven different group-I intron combinations termed variants A, B1, B2, C, D, E and F were found in the 15 isolates under study. Variants B1/B2 consisting of a single 28Si2 intron were found in ten isolates, whereas variant A occurred twice and variants C through F were unique across the set of isolates under study. The determination of the different introns and intron combinations in the 28S rRNA gene is a powerful tool for achieving infraspecific differentiation of B. bassiana isolates from Argentina.

Ecological Insights and First Confirmed Record of Ooencyrtus nezarae (Hymenoptera: Encyrtidae) on Eggs of Megacopta cribraria (Hemiptera: Plataspidae) in Tennessee and Georgia1

Abstract The kudzu bug, Megacopta cribraria (F.) (Heteroptera: Plataspidae), is native to Asia, was first detected in Georgia, USA, in 2009, and has since been recognized as a damaging pest of soybean (Glycine max (L.) Merrill; Fabales: Fabaceae) in several southeastern states. Megacopta cribraria dispersed rapidly from 2009 to 2013, after which its spread rate declined sharply. Despite this decline, established populations have remained stable. This decline may be partially attributed to natural enemies of kudzu bug. For example, the exotic egg parasitoids Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Paratelenomus saccharalis (Dodd) (Hymenoptera: Platygastridae) have been occasionally detected in the United States since 2016 and 2013, respectively. We recovered O. nezarae from M. cribraria eggs collected from wild patches of kudzu (Pueraria montana Lour. (Merrill) var. lobata (Willd.)) throughout summer 2017. Although the occurrence of O. nezarae in southern Georgia has been suggested based on exit holes from kudzu bug eggs, to our knowledge, this report is the first to document and confirm recovery of O. nezarae from kudzu bug eggs in both Tennessee and Georgia. In addition, at the time of collection in 2017, this recovery was the first confirmation of this species from kudzu in North America. This early-season natural enemy combined with the later-occurring entomopathogen Beauveria bassiana (Balsamo-Crivelli) Vuillemin may reduce and maintain kudzu bug densities, which could lessen economic impacts on soybean producers.

Harmful and Harmless Soil-Dwelling Fungi Indicate Microhabitat Suitability for Off-Host Ixodid Ticks.

Following blood meals or questing bouts, hard ticks (Ixodidae) must locate moist off-host microhabitats as refuge. Soil-dwelling fungi, including entomopathogenic Beauveria bassiana (Bb), thrive in moist microhabitats. Working with six species of ixodid ticks in olfactometer bioassays, we tested the hypothesis that ticks avoid Bb. Contrary to our prediction, nearly all ticks sought, rather than avoided, Bb-inoculated substrates. In further bioassays with female black-legged ticks, Ixodes scapularis, ticks oriented towards both harmful Bb and harmless soil-dwelling fungi, implying that fungi-regardless of their pathogenicity-signal habitat suitability to ticks. Only accessible Bb-inoculated substrate appealed to ticks, indicating that they sense Bb or its metabolites by contact chemoreception. Bb-inoculated substrate required ≥24 h of incubation before it appealed to ticks, suggesting that they respond to Bb metabolites rather than to Bb itself. Similarly, ticks responded to Bb-inoculated and incubated cellulose but not to sterile cellulose, indicating that Bb detection by ticks hinges on the Bb metabolism of cellulose. 2-Methylisoborneol-a common fungal metabolite with elevated presence in disturbed soils-strongly deterred ticks. Off-host ticks that avoid disturbed soil may lower their risk of physical injury. Synthetic 2-methylisoborneol could become a commercial tick repellent, provided its repellency extends to ticks in diverse taxa.

SfMBP: A novel microbial binding protein and pattern recognition receptor in the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda, poses a significant threat as a highly destructive agricultural pest in many countries. Understanding the complex interplay between the insect immune system and entomopathogens is critical for optimizing biopesticide efficacy. In this study, we identified a novel microbial binding protein, SfMBP, in S. frugiperda. However, the specific role of SfMBP in the immune response of S. frugiperda remains elusive. Encoded by the LOC118269163 gene, SfMBP shows significant induction in S. frugiperda larvae infected with the entomopathogen Beauveria bassiana. Consisting of 115 amino acids with a signal peptide, an N-terminal flexible region and a C-terminal β-sheet, SfMBP lacks any known functional domains. It is expressed predominantly during early larval stages and in the larval epidermis. Notably, SfMBP is significantly induced in larvae infected with bacteria and fungi and in SF9 cells stimulated by peptidoglycan. While recombinant SfMBP (rSfMBP) does not inhibit bacterial growth, it demonstrates binding capabilities to bacteria, fungal spores, peptidoglycan, lipopolysaccharides, and polysaccharides. This binding is inhibited by monosaccharides and EDTA. Molecular docking reveals potential Zn2+-interacting residues and three cavities. Furthermore, rSfMBP induces bacterial agglutination in the presence of Zn2+. It also binds to insect hemocytes and SF9 cells, enhancing phagocytosis and agglutination responses. Injection of rSfMBP increased the survival of S. frugiperda larvae infected with B. bassiana, whereas blocking SfMBP with the antibody decreased survival. These results suggest that SfMBP acts as a pattern recognition receptor that enhances pathogen recognition and cellular immune responses. Consequently, this study provides valuable insights for the development of pest control measures.

Compatibility of essential oils with Beauveria bassiana (Balls.) Vuil

Insect pests are a primary agricultural concern, as they can cause productivity losses. The use of pesticides has been the main means of controlling pests. Despite its significant contribution to agriculture, its indiscriminate use harms the environment. The awareness about the risks of agrochemicals using natural enemies such as fungi and alternative controls, such as essential oils, can be an alternative control. The objective of this work was to evaluate the fungicidal activity of oils essentials of Cymbopogon citratus, Cinnamomum camphora var. linaloolifera, and Thymus vulgaris on the entomopathogen Beauveria bassiana. Bioassays followed a completely randomized design in a 3x6 factorial scheme, in which one factor was the essential oils of C. camphora, C. citratus, and T. vulgaris, and the other factor was the four essential oil concentrations, plus two controls. The evaluations took place on the 3rd, 7th, and 14th day. Each treatment had five repetitions, and each repetition was a plate. When assessing compatibility with the entomopathogenic fungus, it was verified that the essential oils showed antifungal activity at all concentrations tested for that non-target organism. Thus, it is advised against the concomitant use of this entomopathogen and the tested essential oils. However, both control tools can be used at different times, with rotation and intercalation of the two methods, following the IPM practices.

Dual RNA Sequencing of Beauveria bassiana-Infected Spodoptera frugiperda Reveals a Fungal Protease with Entomopathogenic and Antiphytopathogenic Activities.

Insect pests and phytopathogens significantly impact crop yield and quality. The fall armyworm (FAW) Spodoptera frugiperda and the phytopathogen Fusarium graminearum cause substantial economic losses in crops like barley and wheat. However, the entomopathogen Beauveria bassiana shows limited efficacy against FAW, and its antiphytopathogenic activities against F. graminearum remain unclear. Here, dual RNA sequencing was performed to identify differentially expressed genes in B. bassiana-infected FAW larvae. We found that the BbAorsin gene was significantly upregulated at 36 and 48 h post-infection. BbAorsin encodes a serine-carboxyl protease and is mainly expressed in blastospores and hyphae. Overexpression of BbAorsin in B. bassiana ARSEF2860 enhanced virulence against Galleria mellonella and FAW larvae and inhibited F. graminearum growth. The recombinant BbAorsin protein induced apoptosis and necrosis in FAW hemocytes and inhibited F. graminearum spore germination. These findings shed light on transcriptomic mechanisms governing insect-pathogen interactions, which could aid in developing dual-functional entomopathogens and anti-phytopathogens.

Potency of entomopathogen Beauveria bassiana fungus as biofertilizer and biostimulant to increase the plant growth of Cayenne pepper (Capsicum frutescens L.)

This research aimed to determine the Beauveria bassiana entomopathogen fungus as a biofertilizer and biostimulant. The research was conducted at the Biological Control laboratory and Wire House, Universitas Andalas. The potency of B. bassiana produced the IAA hormone was carried out by a This was qualitative research by observing a pink color change in the Salkowsky solution while the potency of B. bassiana to dissolve phosphate by using Pikovskaya medium. The test results on Pikovskaya media showed that all tested isolates had the potential to dissolve phosphate at 7, 10, and 14 days. The largest clear zone area was in the 14 days, found in Bb WS isolates (5.42 mm) followed by TD312 isolates (5.28mm). To test of plant growth in the laboratory was carried out by testing the germination of seeds by blotter test and test on paper. The design used was a non-factorial Completely Randomized. The results showed that the highest percentage of germination was found in TD312 and BbWS isolates. The potency of B. bassiana isolates as growth promoters can be seen from an increase in plant height and the number of chili leaves. All of the results indicated that entomopathogen fungus can be applied as biological fertilizers and biostimulants on cayenne pepper plants.

Natural occurrence of fungal endophytes in cultivated cucumber plants in Syria, with emphasis on the entomopathogen Beauveria bassiana

A survey was conducted to investigate endophytic Beauveria spp. and associated fungi in the tissues of cucumber plants (Cucumis sativus L.) cultivated in open fields and greenhouses in some regions of Syria during 2018–2019. Cultures of fungal endophytes belonging to nine genera were obtained (frequency %): Aspergillus (87.1%), Penicillium (41.23%), Fusarium (38.15%), Beauveria (12.83%), Trichoderma (9.87%), Colletotrichum (4.36%), Cladosporium (3.54%), Alternaria (2.79%), and Chaetomium (2.2%). Only Beauveria and Trichoderma cultures were entomopathogenic. Beauveria bassiana isolates were identified morphologically and molecularly from the stems, leaves, petioles, and fruits of cucumber plants collected at seven agricultural sites. Their ability to artificially colonize all cucumber plant parts was confirmed in the laboratory using soil drench. In this study, the natural association between the endophytic entomopathogenic fungus B. bassiana and cucumber plants is newly reported. In addition, a checklist of plant species reported in the literature to harbor this fungus is also provided.

Effect of relative humidity on the efficacy of entomopathogen Beauveria bassiana-based mycopesticide against red spider mite Tetranychus macfarlanei

Tetranychus macfarlanei is a potential threat to various economically important crops. Chemical control is widely used to control this spider mite, but the exclusive reliance on chemical acaricides is now being questioned, and entomopathogens are emerging as a promising alternative. The efficacy of the entomopathogens largely depends on abiotic factors like temperature, humidity, rainfall etc. The experiments were conducted to determine the effect of relative humidity on the efficacy of the entomopathogen Beauveria bassiana (strain GHA), marketed as BotaniGard ES, against the adult female and egg stages of T. macfarlanei under laboratory conditions. Adult females and eggs of T. macfarlanei were treated with three concentrations of BotaniGard (1×106, 1×107, and 1×108 conidia/ml), and virulence was assessed on mites held at three relative humidity levels (55, 75, and 95 ± 2% RH) at 25 ± 1 °C. The results showed that the mortalities of adult females and eggs of T. macfarlanei were dose-dependent, and there is certainly a synergistic effect of relative humidity on the efficacy. When the eggs were treated under the above laboratory conditions, highest egg mortalities of 86.4 and 91% were recorded at a concentration of 1×108 conidia/mL at 75 and 95 ± 2% RH, respectively, after six days of treatment. The LT50 values on adult females were 28.7 h and 33.4 h at 95 and 75 ± 2% RH in a concentration of 1×108 conidia/ml, respectively, which was significantly lower than values for other concentrations and RH levels. This study identified 1×108 conidia/ml of B. bassiana at 75 to 95 ± 2% RH as the best possible combination than other lower RH to manage the spider mite.

Dual Action of Beauveria bassiana (Hypocreales; Cordycipitaceae) Endophytic Stains as Biocontrol Agents against Sucking Pests and Plant Growth Biostimulants on Melon and Strawberry Field Plants.

Entomopathogenic fungi (EPF) can colonize plant tissues and serve crops not only as biopesticides but also as biostimulants that promote plant growth and trigger defense mechanisms. In this context, field trials were conducted evaluating two commercial strains of the entomopathogen Beauveria bassiana (Hypocreales: Cordycipitaceae), GHA (Botanigard) and PPRI 5339 (Velifer® ES) and a wild strain (AP0101) isolated from Achaia, Greece. The three strains were investigated in the field for their endophytic effects on melon Cucumis melo (Cucurbitales: Cucurbitaceae) and strawberry Fragaria sp. (Rosales: Rosaceae) plants and in particular for their ability to colonize plant tissues, control infestations of sucking insects Aphis gossypii (Hemiptera: Aphididae), Chaetosiphon fragaefolii (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae), and improve plant growth parameters (plant height, number of flowers and fruits). All experimental fungal strains successfully colonized both plants. A significant decrease in the aphid and thrip populations was observed in the treated plants compared to the untreated control. As for plant growth, the number of flowers and fruits was significantly increased in plants treated with B. bassiana strains AP0101 and PPRI 5339. Our results clearly indicate that fungal endophytes can efficiently act as dual action agents demonstrating both insecticidal and growth-promoting effects.

Characterization and biological activity of two new entomopathogenic Beauveria bassiana strains isolated from Hyphantria cunea larvae in Turkey

In this study, two fungal strains (HC-Z1 and HC-Z2) from Hyphantria cunea (fall webworm) larvae were evaluated for their potential as biocontrol agents against the H. cunea larvae. Based on morphological and molecular (ITS1-5.8S-ITS2 region) characterization, the strains were identified as Beauveria bassiana (HC-Z1: OP415530 and HC-Z2: OP415531). To determine the biological activities of the two fungal strains, a concentration-response assay (1 × 104-8 conidia/ml) was performed against third stage H. cunea larvae. In addition, two B. bassiana strains were tested on five (1-5) larval stages at 1 × 107 conidia/ml concentration. Both isolates produced mortalities over 96% within 7 days for the first larval stage of H. cunea. The LC50 and LT50 of HC-Z1 and HC-Z2 strains against third instar H. cunea larvae were calculated as 0.6 × 104 and 1.2 × 104 conidia/ml, respectively. LT50 values were obtained in 2.82 and 3.44 days for HC-Z1 and HC-Z2 isolates, respectively. As a result, it can be concluded that HC-Z1 and HC-Z2 strains can potentially be used as biological control agents against H. cunea.

Associated bacteria of a pine sawyer beetle confer resistance to entomopathogenic fungi via fungal growth inhibition

BackgroundThe entomopathogenic Beauveria bassiana is a popular fungus used to control the Japanese pine sawyer, Monochamus alternatus Hope, the key vector of pine wood nematode (Bursaphelenchus xylophilus) that is the causal agent of pine wilt disease, resulting in devastating losses of pines in China and Portugal. However, recent studies have demonstrated that some insect-associated bacteria might decrease fungal toxicity and further undermine its biological control efficacy against M. alternatus. Thus, it is of great significance to uncover whether and how associated bacteria of M. alternatus become involved in the infection process of B. bassiana.ResultsHere, we show that axenic M. alternatus larvae died significantly faster than non-axenic larvae infected by four increasing concentrations of B. bassiana spores (Log-rank test, P < 0.001). The infection of B. bassiana significantly changed the richness and structure of the beetle-associated bacterial community both on the cuticle and in the guts of M. alternatus; meanwhile, the abundance of Pseudomonas and Serratia bacteria were significantly enriched as shown by qPCR. Furthermore, these two bacteria genera showed a strong inhibitory activity against B. bassiana (One-way ANOVA, P < 0.001) by reducing the fungal conidial germination and growth rather than regulating host immunity.ConclusionsThis study highlights the role of insect-associated bacteria in the interaction between pest insects and entomopathogenic fungi, which should be taken into consideration when developing microbial-based pest control strategies.

Comparative analysis of the immune system and expression profiling of Lymantria dispar infected by Beauveria bassiana

Lymantria dispar is one of the most devastating forest pests worldwide. Fungal biopesticides have great potential as alternatives owing to their high lethality to pests and eco-friendly feature, which is, however, often severely compromised by the pests' innate immunity. A better understanding of the antifungal immune system in L. dispar would significantly facilitate the development of the biopesticide. Here, we investigated phylogenetic characteristics of immunity-related genes as well as the tissue expression patterns in L. dispar after the infection of an entomopathogen Beauveria bassiana using RNA-sequencing data. Results showed most immune genes remain at a low level of response after 24 h post-infection (HPI). Almost all genes in the Toll pathway were significantly up-regulated at 48 HPI, and SPH1, SPN6, Toll6, Toll12, Myd88, pelle, and Drosal were significantly down-regulated at 72 HPI. Immunoblotting analysis revealed that the protein levels of βGRP3 and PPO1 were significantly upregulated at 24 and 48 HPI, while Myd88 was downregulated at 24 HPI, which was further confirmed by Quantitative real-time PCR experiments. Moreover, the relative content of H2O2, a potent reactive oxygen species (ROS), was significantly increased with the decrease of the total antioxidant capacity, indicating that oxidative stress system positively participates in the clearance of the pathogenic fungus. Together, our study provides detailed genetic characteristics of antifungal immunity as well as profiling of the host defense against entomopathogenic infection, and comprehensive insight into molecular interaction between L. dispar and the entomopathogen.

Assessing the Endophytic Potential of a Commercially Available Entomopathogenic Beauveria bassiana Strain in Various Citrus Rootstocks

The citrus industry is challenged by numerous arthropods, yet extensive research has not been conducted to determine the potential use of entomopathogenic fungi as endophytes in pest management strategies. Two inoculation methods (i.e., soil drench and foliar spray) using a suspension of Beauveria bassiana (strain PPRI 5339 contained in Velifer®) containing 4 × 107 conidia mL−1 in 0.01% Tween 80 were conducted on three commercially available citrus rootstocks (i.e., ‘US-942’, ‘US-812’, ‘Swingle’). Seedlings were grown under greenhouse-controlled conditions over a 7-week observation period. Similarly, a third inoculation method (seed soaking) was conducted using seeds from the same three rootstocks. The fungus was re-isolated post-inoculation from ‘US-942’ and ‘US-812’ in the foliar spray and seed soaking treatments. In addition, the fungus was recovered from root tissue in the foliar-sprayed seedlings, suggesting possible systemic movement from leaves to roots. The fungus was not recovered from soil-drench-treated seedlings, nor from any of the ‘Swingle’ cultivars. This study assessed the potential of B. bassiana to endophytically colonize certain citrus rootstocks in planta.

Effect of antipyretic phenidone on the nodulation response and mortality of locust infected with fungus

The use of eicosanoids biosynthesis inhibitors (EBIs) as immune disruptors in host-pathogen interaction is a promising tool in insect pest control. In this study, co-applying the dual cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor phenidone (104 µg/larva) with the entomopathogen Beauveria bassiana (108 spores/mL) on Locusta migratoria manilensis, sharply declined the nodulation response. The reduction of nodulation response by phenidone proved that the dual COX/LOX is involved in nodules formation in L. migratoria manilensis. We investigated the effect of the antipyretic drug on the fungus virulence under different thermal conditions (thermoregulation and non-thermoregulation). Interestingly, a significant increase in the mortality rate of fungus-phenidone treated locusts was recorded. The drug suppressed the therapeutic effect of thermoregulation in infected locusts combined with phenidone tailoring a mortality rate of 70% by 14 days post-infection. Whereas 40% of the mortality rate was observed in those infected locusts under the same thermal condition but not treated with phenidone. These findings indicated that phenidone can cripple the immune defense of L. migratoria manilensis and additionally increase the virulence of B. bassiana under certain ecological conditions.

Development of fungal entomopathogen Beauveriabassiana (Balsamo) formulations for control ofmosquito larvae in the field

Till date, malaria remains a major global problem, exacting an unacceptable toll on the health and economic welfare of the world’s poorest communities. To overcome the problem, application of chemical insecticides, has been in use for decades, but it has met with tremendous setbacks in the light of the development of vector resistance and some attendant environmental hazards. In our study, we have focused on an ecofriendly entomopathogenic fungus to know its efficacy to control mosquito larvae in field trial. To evaluate the efficacy of the entomopathogenic fungus Beauveria bassiana (Balsamo) on malaria causing mosquitoes in the field, outdoor trials were undertaken in Udaipur city. The entomopathogenic fungus Beauveria bassiana (Balsamo) have demonstrated effectiveness against anopheline larvae in the laboratory. Laboratory reared Anopheles stephensi (L.) second instar larvae were selected for field studies. The powdered form of fungus mixed with CMC (Carboxy Methyl Cellulose) (5 g/kg) were obtained. In the field bioassay, doses i.e., 1 g, 2.5 g and 5 g of fungal conidia were tested. The data clearly revealed the effectiveness of Beauveria bassiana (Balsamo) in field conditions. The study demonstrated that the entomopathogenic fungus Beauveria bassiana (Balsamo) caused high impact on the survival of Anopheles stephensi (L.) in outdoor trials, when formulated in CMC (Carboxy Methyl Cellulose).

Myco-Synergism Boosts Herbivory-Induced Maize Defense by Triggering Antioxidants and Phytohormone Signaling.

BackgroundBiocontrol strategies are the best possible and eco-friendly solution to develop resistance against O furnacalis and improve the maize yield. However, the knowledge about underlying molecular mechanisms, metabolic shifts, and hormonal signaling is limited.MethodsHere, we used an axenic and a consortium of entomopathogenic Beauveria bassiana OFDH1-5 and a pathogen-antagonistic Trichoderma asperellum GDFS1009 in maize and observed that consortium applications resulted in higher chlorophyll contents and antioxidants activities [superoxide dismutase (SOD), peroxidase (POD), proline, protease, and polyphenol oxidase (PPO)] with a decrease in O. furnacalis survival. We performed a comprehensive transcriptome and an untargeted metabolome profiling for the first time at a vegetative stage in fungal inoculated maize leaves at 0-, 12-, 24-, 48-, and 72-h post insect infestation.ResultsThe consortium of B. bassiana and T. asperellum leads to 80–95% of O. furnacalis mortality. A total of 13,156 differentially expressed genes were used for weighted gene coexpression network analysis. We identified the six significant modules containing thirteen candidate genes [protein kinase (GRMZM2G025459), acyl-CoA dehydrogenase (GRMZM5G864319), thioredoxin gene (GRMZM2G091481), glutathione S-transferase (GRMZM2G116273), patatin-like phospholipase gene (GRMZM2G154523), cytochrome P450 (GRMZM2G139874), protease inhibitor (GRMZM2G004466), (AC233926.1_FG002), chitinase (GRMZM2G453805), defensin (GRMZM2G392863), peroxidase (GRMZM2G144153), GDSL- like lipase (AC212068.4_FG005), and Beta-glucosidase (GRMZM2G031660)], which are not previously reported that are highly correlated with Jasmonic acid - Ethylene (JA-ET) signaling pathway and antioxidants. We detected a total of 130 negative and 491 positive metabolomic features using a ultrahigh-performance liquid chromatography ion trap time-of-flight mass spectrometry (UHPLC-QTOF-MS). Intramodular significance and real time-quantitative polymerase chain reaction (RT-qPCR) expressions showed that these genes are the true candidate genes. Consortium treated maize had higher jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) levels.ConclusionOur results provide insights into the genetics, biochemicals, and metabolic diversity and are useful for future biocontrol strategies against ACB attacks.