Journal of Fungi

Editorial

3 pages, 152 KiB

Open AccessEditorial

Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol

by Jiaqin Xie and Nicolás Pedrini

J. Fungi 2025, 11(4), 289; https://doi.org/10.3390/jof11040289 (registering DOI) - 7 Apr 2025

Insects are the largest animal group in nature, with significant effects on ecology, human health, and indigenous flora and fauna [...] Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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14 pages, 1487 KiB

Open AccessArticle

Can Metarhizium anisopliae Reduce the Feeding of the Neotropical Brown Stink Bug, Euschistus heros (Fabricius, 1798), and Its Damage to Soybean Seeds?

by André Cirilo de Sousa Almeida, Mayara Alves Rodrigues, Heloiza Alves Boaventura, Angélica Siqueira Vieira, José Francisco Arruda e Silva, Flávio Gonçalves de Jesus and Eliane Dias Quintela

J. Fungi 2025, 11(4), 247; https://doi.org/10.3390/jof11040247 - 25 Mar 2025

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Abstract

The fungus Metarhizium anisopliae is under development as a bioinsecticide for Euschistus heros. To further elucidate the effect of this fungus on E. heros behavior, we monitored the feeding activities of adults treated with the fungus at 1 × 10⁸ conidia [...] Read more.

The fungus Metarhizium anisopliae is under development as a bioinsecticide for Euschistus heros. To further elucidate the effect of this fungus on E. heros behavior, we monitored the feeding activities of adults treated with the fungus at 1 × 10⁸ conidia mL⁻¹ on soybean in the pod-filling stage (R5) through electropenetrography (EPG) AC-DC. We also determined the virulence of M. anisopliae to adults and its damage to soybean seeds. M. anisopliae displayed high levels of virulence to adults even at low concentrations of 5 × 10⁶ conidia mL⁻¹ (98% mortality). E. heros females were more susceptible to M. anisopliae than males, exhibiting a lower LT₅₀ for mycosed adults (7.1 and 9.7 days, respectively). The EPG experiment showed that fungus-treated adults spent significantly less time on probing activities (reduced by 86% at day four and ceased at day five) than untreated insects, and the number of waveform events per insect significantly decreased. This information is valuable for managing stink bugs at the field level, as it shows that even though the insect is alive, its feeding is compromised, consequently minimizing the damage inflicted to the crop. This study paves the way for further research employing entomopathogenic fungi in pest control. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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13 pages, 1878 KiB

Open AccessArticle

Beauveria bassiana Induces Strong Defense and Increases Resistance in Tomato to Bemisia tabaci

by Mengying Liu, Dong Xiang, Heikki M. T. Hokkanen, Tiandi Niu, Junjie Zhang, Jinlin Yang, Qiuyang Wei, Hanqiu Chen, Huai Liu and Yaying Li

J. Fungi 2025, 11(2), 141; https://doi.org/10.3390/jof11020141 - 13 Feb 2025

Viewed by 636

Abstract

Pre-stimulation of plants can change their resistance mechanisms, thereby enhancing their defense responses. Beauveria bassiana, a broad-spectrum entomogenous fungi, can also induce plant defenses, but it received little attention. Here, we show that B. bassiana can act as a stimulus to prime [...] Read more.

Pre-stimulation of plants can change their resistance mechanisms, thereby enhancing their defense responses. Beauveria bassiana, a broad-spectrum entomogenous fungi, can also induce plant defenses, but it received little attention. Here, we show that B. bassiana can act as a stimulus to prime tomato defense responses, improving resistance in the plant to herbivore stress. The results illustrated that four defense genes (PIN2, PR2, PAL, and MPK3) were upregulated in all B. bassiana treatments, especially the phenylalanine deaminase (PAL) gene, which was highly expressed in tomato plants after B. bassiana inoculation. Feeding through Bemisia tabaci resulted in a weak upregulation of defense genes. However, in combined fungal inoculation and B. tabaci feeding, a total of nine defense genes were upregulated, among which five genes—PAL, PPO, PIN2, PR2, and PR1—were closely related to the phenol synthesis. The results of tomato plant metabolism showed that B. bassiana mainly activates tomato phenylpropane metabolic pathways, with this modulation being influenced by jasmonate. Further explorations revealed a significant enhancement in the antioxidant capacity of the plants, as evidenced by the determination of their antioxidant compounds and the coloration of leaf phenolic substances. Thus, entomopathogenic fungi can act as an exogenous substance to activate the defense responses of tomatoes without damaging the plant, indicating a good potential for developing applications using B. bassiana to promote resistance in tomatoes for pest management. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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19 pages, 7059 KiB

Open AccessArticle

The Inevitable Fate of Tetranychus urticae on Tomato Plants Treated with Entomopathogenic Fungi and Spinosad

by Waqas Wakil, Maria C. Boukouvala, Nickolas G. Kavallieratos, Aqsa Naeem, Dionysios Ntinokas, Muhammad Usman Ghazanfar and Pasco B. Avery

J. Fungi 2025, 11(2), 138; https://doi.org/10.3390/jof11020138 - 12 Feb 2025

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Abstract

Tetranychus urticae (Acari: Tetranychidae) is a pervasive and damaging mite pest of tomato crops, leading to important economic losses globally. This study evaluated the acaricidal efficacy of spinosad, alone and in combination with Beauveria bassiana (Bb) WG-21 and Metarhizium robertsii ( [...] Read more.

Tetranychus urticae (Acari: Tetranychidae) is a pervasive and damaging mite pest of tomato crops, leading to important economic losses globally. This study evaluated the acaricidal efficacy of spinosad, alone and in combination with Beauveria bassiana (Bb) WG-21 and Metarhizium robertsii (Mr) WG-04, in the laboratory (application to tomato leaf discs) and greenhouse (application to tomato plants), considering mortality and establishment, respectively. The combination treatments of Bb WG-21 or Mr WG-04 with spinosad achieved 100% mortality of T. urticae nymphs within 2 days on leaf discs, while individual applications of each control agent resulted in lower mortalities, ranging between 62.91 and 86.25% after 3 days. The paired treatment of Mr WG-04 + spinosad killed all exposed adults within 5 d, while that of Bb WG-21 + spinosad achieved the same results after 7 d. However, spinosad, Mr WG-04, and Bb WG-21 alone killed ≥77.08% of adults after 7 d. In the greenhouse, the combination treatment of WG-04 + spinosad deterred the presence of T. urticae (adults, immatures, and eggs) on either surface of the tomato leaves, while Bb WG-21 + spinosad suppressed the populations only on the adaxial surface. These findings indicate that combined treatments of the tested EPF + spinosad, especially Mr WG-04, on tomato plants under greenhouse conditions can provide substantially enhanced control of T. urticae life stages compared to each treatment applied alone. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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14 pages, 2528 KiB

Open AccessArticle

The Susceptibility of Two Beauveria bassiana Strains on Rice Pests Nilaparvata lugens and Sogatella furcifera

by Zhongwei Chen, Hanqing Mu, Yifan Peng, Rui Huo and Jiaqin Xie

J. Fungi 2025, 11(2), 128; https://doi.org/10.3390/jof11020128 - 8 Feb 2025

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Abstract

Entomopathogenic fungi represent a valuable natural resource with significant potential as biological agents for pest management. However, different species or strains of fungi demonstrate varying effectiveness against specific targets. In this study, we assessed the impact of two fungal strains, Beauveria bassiana KN801 [...] Read more.

Entomopathogenic fungi represent a valuable natural resource with significant potential as biological agents for pest management. However, different species or strains of fungi demonstrate varying effectiveness against specific targets. In this study, we assessed the impact of two fungal strains, Beauveria bassiana KN801 and KN802, on the rice planthoppers Ninaparvata lugens and Sogatella furcifera, in combination with insecticides. Our findings indicate that both B. bassiana strains can effectively infect the nymphs and adults of N. lugens and S. furcifera, resulting in a significantly higher mortality rate compared to the control groups. Notably, the B. bassiana strain KN801 demonstrated greater virulence than B. bassiana KN802 against these pests. However, no significant differences were observed when using different concentrations of the same fungal strain (B. bassiana KN801 or B. bassiana KN802) against these targets. Additionally, both fungi showed a germination rate of over 90% after treatment when combined with several common insecticides like chlorfenapyr and dinotefuran. The combined application of B. bassiana with chlorfenapyr or dinotefuran could improve pest control efficacy for these two pests. This study suggests that the two B. bassiana strains have the potential to infect rice planthoppers N. lugens and S. furcifera, indicating their promise as agents for the control of these pests. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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21 pages, 1982 KiB

Open AccessArticle

Temperature-Dependent Modeling and Spatial Predictions for Identifying Geographical Areas in Brazil Suitable for the Use of Cordyceps javanica in Whitefly Control

by Heloiza A. Boaventura, Lidiane A. Queirós, José Francisco A. Silva, Tarryn A. Goble, Kelly Pazolini, Allan F. Marciano and Eliane D. Quintela

J. Fungi 2025, 11(2), 125; https://doi.org/10.3390/jof11020125 - 8 Feb 2025

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Abstract

Lalguard C99 WP, based on the Cordyceps javanica BRM 27666 strain, is registered in Brazil for whitefly control. Spatial prediction is crucial for optimizing its field use and efficacy. In this study, the optimal temperature for mycelial growth and conidial production of C. [...] Read more.

Lalguard C99 WP, based on the Cordyceps javanica BRM 27666 strain, is registered in Brazil for whitefly control. Spatial prediction is crucial for optimizing its field use and efficacy. In this study, the optimal temperature for mycelial growth and conidial production of C. javanica is 25–30 °C, with no growth at 33–35 °C. The highest nymphal mortality occurred at 25 and 30 °C, showing lower LT₅₀ values at 30 °C. Mycelial growth was similar at 15, 20, 25, 30, and 35 °C when the fungus was exposed for 6 h and then transferred to a 27.4 °C environment; however, growth was slower at 35 °C with daily 6 h exposure alternating over 18 h at room temperature (mean of 28.5 °C). When the second instar whitefly nymphs were exposed for 6 h or 6 h daily at 15, 20, 25, 30, and 35 °C, followed by 7 days at fluctuating temperatures (mean of 28.4–30.2 °C), nymphal mortality was similar across temperatures. Although other abiotic factors (solar radiation, humidity, rainfall, etc.) must be considered for fungal efficacy, spatial predictions based on fluctuating temperatures indicated that C. javanica is suitable for use throughout Brazil, though its performance varied at constant temperatures in different locations. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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17 pages, 4397 KiB

Open AccessArticle

MaNrtB, a Putative Nitrate Transporter, Contributes to Stress Tolerance and Virulence in the Entomopathogenic Fungus Metarhizium acridum

by Jia Wang, Yuneng Zou, Yuxian Xia and Kai Jin

J. Fungi 2025, 11(2), 111; https://doi.org/10.3390/jof11020111 - 1 Feb 2025

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Abstract

Nitrogen is an essential nutrient that frequently determines the growth rate of fungi. Nitrate transporter proteins (Nrts) play a crucial role in the cellular absorption of nitrate from the environment. Entomopathogenic fungi (EPF) have shown their potential in the biological control of pests. [...] Read more.

Nitrogen is an essential nutrient that frequently determines the growth rate of fungi. Nitrate transporter proteins (Nrts) play a crucial role in the cellular absorption of nitrate from the environment. Entomopathogenic fungi (EPF) have shown their potential in the biological control of pests. Thus, comprehending the mechanisms that govern the pathogenicity and stress tolerance of EPF is helpful in improving the effectiveness and practical application of these fungal biocontrol agents. In this study, we utilized homologous recombination to create MaNrtB deletion mutants and complementation strains. We systematically investigated the biological functions of the nitrate transporter protein gene MaNrtB in M. acridum. Our findings revealed that the disruption of MaNrtB resulted in delayed conidial germination without affecting conidial production. Stress tolerance assays demonstrated that the MaNrtB disruption strain was more vulnerable to UV-B irradiation, hyperosmotic stress, and cell wall disturbing agents, yet it exhibited increased heat resistance compared to the wild-type strain. Bioassays on the locust Locusta migratoria manilensis showed that the disruption of MaNrtB impaired the fungal virulence owing to the reduced appressorium formation on the insect cuticle and the attenuated growth in the locust hemolymph. These findings provide new perspectives for understanding the pathogenesis of EPF. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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19 pages, 11996 KiB

Open AccessArticle

Visualizing Oral Infection Dynamics of Beauveria bassiana in the Gut of Tribolium castaneum

by Lautaro Preisegger, Juan Cruz Flecha, Fiorella Ghilini, Daysi Espin-Sánchez, Eduardo Prieto, Héctor Oberti, Eduardo Abreo, Carla Huarte-Bonnet, Nicolás Pedrini and Maria Constanza Mannino

J. Fungi 2025, 11(2), 101; https://doi.org/10.3390/jof11020101 - 28 Jan 2025

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Abstract

The ability of entomopathogenic fungi, such as Beauveria bassiana, to infect insects by penetrating their cuticle is well documented. However, some insects have evolved mechanisms to combat fungal infections. The red flour beetle (Tribolium castaneum), a major pest causing significant [...] Read more.

The ability of entomopathogenic fungi, such as Beauveria bassiana, to infect insects by penetrating their cuticle is well documented. However, some insects have evolved mechanisms to combat fungal infections. The red flour beetle (Tribolium castaneum), a major pest causing significant economic losses in stored product environments globally, embeds antifungal compounds within its cuticle as a protective barrier. Previous reports have addressed the contributions of non-cuticular infection routes, noting an increase in mortality in beetles fed with conidia. In this study, we further explore the progression and dynamics of oral exposure in the gut of T. castaneum after feeding with an encapsulated B. bassiana conidia formulation. First, we characterized the formulation surface using atomic force microscopy, observing no significant topological differences between capsules containing and not containing conidia. Confocal microscopy confirmed uniform conidia distribution within the hydrogel matrix. Then, larvae and adult insects fed with the conidia-encapsulated formulation exhibited B. bassiana distributed throughout the alimentary canal, with a higher presence of conidia before the pyloric chamber. More conidia were found in the larval midgut and hindgut compared to adults, but no germinated conidia were observed in the epithelium. These results suggest that the presence of conidia obstructs the gut, impairing the insect’s ability to ingest, process, and absorb nutrients. This disruption may weaken the host, increasing its susceptibility to infections and, ultimately, leading to death. By providing the first direct observation of fungal conidia within the alimentary canal of T. castaneum, this study highlights a novel aspect of fungal–host interaction and opens new avenues for advancing fungal-based pest control strategies by exploiting stage-specific vulnerabilities. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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11 pages, 1346 KiB

Open AccessArticle

In Vitro Response of Two Strains of Cordyceps javanica to Six Chemical Pesticides

by Ruixia Mao, Xiaoxia Cai, Tengyu Wang, Ziyang Liu, Peixiang Xing, Guisen Zhang, Wenwen Zhou, Hongliang Diao and Ruiyan Ma

J. Fungi 2024, 10(12), 852; https://doi.org/10.3390/jof10120852 - 10 Dec 2024

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Abstract

To determine the compatibility of two new biocontrol fungi with common chemical pesticides, this study examined the effects of three insecticides, namely, avermectin, imidacloprid, and acetamiprid, and three fungicides, namely, chlorogenonil, boscalid, and kasugamycin, on the mycelial growth and spore germination of Cordyceps [...] Read more.

To determine the compatibility of two new biocontrol fungi with common chemical pesticides, this study examined the effects of three insecticides, namely, avermectin, imidacloprid, and acetamiprid, and three fungicides, namely, chlorogenonil, boscalid, and kasugamycin, on the mycelial growth and spore germination of Cordyceps javanica strains IF-1106 and IJ-tg19. The insecticidal effects of mixed insecticides or fungicides with good compatibility with C. javanica IJ-tg19 against Myzus persicae were tested. The results showed that the six chemical pesticides exerted different degrees of inhibition on the mycelial growth of both C. javanica strains, with an obvious dose-dependent effect. The inhibitory effect of chlorothalonil on the mycelial growth of IF-1106 and IJ-tg19 was greater than 75%. Different kinds and concentrations of chemical pesticides had significant effects on spore germination. Among them, acetamiprid had little inhibitory effect on C. javanica spores. Therefore, the two C. javanica strains exhibited good compatibility with the insecticide acetamiprid and had some compatibility with avermectin and imidacloprid. Among the fungicides, the compatibility of the two strains of biocontrol fungi was the best with kasugamycin, followed by boscalid, while their compatibility with chlorothalonil showed the least compatibility. The median lethal time (LT₅₀) of five concentrations of C. javanica IJ-tg19 (1 × 10³, 1 × 10⁴, 1 × 10⁵, 1 × 10⁶, and 1 × 10⁷ spore/mL) mixed with acetamiprid against M. persicae were 5.28, 4.56, 3.80, 2.73, and 2.13 days, respectively, and the insecticidal rate was higher than that of fungus treatment alone (5.19, 4.59, 4.05, 3.32, and 2.94 days, respectively) or chemical pesticide treatment (5.36 days). This study provides data support and a theoretical basis for reducing the use of chemical pesticides, improving the efficiency of C. javanica-based insecticides, and optimizing the synergistic use of fungi and chemical pesticides. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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13 pages, 3950 KiB

Open AccessArticle

MaAzaR Influences Virulence of Metarhizium acridum against Locusta migratoria manilensis by Affecting Cuticle Penetration

by Geng Hong, Siqing Wang, Yuxian Xia and Guoxiong Peng

J. Fungi 2024, 10(8), 564; https://doi.org/10.3390/jof10080564 - 9 Aug 2024

Cited by 1 | Viewed by 1154

Abstract

The entomopathogenic fungus (EPF) Metarhizium acridum is a typical filamentous fungus and has been used to control migratory locusts (Locusta migratoria manilensis). This study examines the impact of the Zn(II)2Cys6 transcription factor, MaAzaR, in the virulence of M. acridum. Disruption [...] Read more.

The entomopathogenic fungus (EPF) Metarhizium acridum is a typical filamentous fungus and has been used to control migratory locusts (Locusta migratoria manilensis). This study examines the impact of the Zn(II)2Cys6 transcription factor, MaAzaR, in the virulence of M. acridum. Disruption of MaAzaR (ΔMaAzaR) diminished the fungus’s ability to penetrate the insect cuticle, thereby decreasing its virulence. The median lethal time (LT₅₀) for the ΔMaAzaR strain increased by approximately 1.5 d compared to the wild-type (WT) strain when topically inoculated, simulating natural infection conditions. ΔMaAzaR compromises the formation, turgor pressure, and secretion of extracellular hydrolytic enzymes in appressoria. However, the growth ability of ΔMaAzaR within the hemolymph is not impaired; in fact, it grows better than the WT strain. Moreover, RNA-sequencing (RNA-Seq) analysis of ΔMaAzaR and WT strains grown for 20 h on locust hindwings revealed 87 upregulated and 37 downregulated differentially expressed genes (DEGs) in the mutant strain. Pathogen–host interaction database (PHI) analysis showed that about 40% of the total DEGs were associated with virulence, suggesting that MaAzaR is a crucial transcription factor that directly regulates the expression of downstream genes. This study identifies a new transcription factor involved in EPF cuticle penetration, providing theoretical support and genetic resources for the developing highly virulent strains. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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19 pages, 4535 KiB

Open AccessArticle

The Forkhead Box Gene, MaSep1, Negatively Regulates UV- and Thermo-Tolerances and Is Required for Microcycle Conidiation in Metarhizium acridum

by Tiantian Song, Chan Li, Kai Jin and Yuxian Xia

J. Fungi 2024, 10(8), 544; https://doi.org/10.3390/jof10080544 - 2 Aug 2024

Cited by 1 | Viewed by 1025

Abstract

Insect pathogenic fungi have shown great potential in agricultural pest control. Conidiation is crucial for the survival of filamentous fungi, and dispersal occurs through two methods: normal conidiation, where conidia differentiate from mycelium, and microcycle conidiation, which involves conidial budding. The conidiation process [...] Read more.

Insect pathogenic fungi have shown great potential in agricultural pest control. Conidiation is crucial for the survival of filamentous fungi, and dispersal occurs through two methods: normal conidiation, where conidia differentiate from mycelium, and microcycle conidiation, which involves conidial budding. The conidiation process is related to cell separation. The forkhead box gene Sep1 in Schizosaccharomyces pombe plays a crucial role in cell separation. Nevertheless, the function of Sep1 has not been clarified in filamentous fungi. Here, MaSep1, the homolog of Sep1 in Metarhizium acridum, was identified and subjected to functional analysis. The findings revealed that conidial germination of the MaSep1-deletion strain (ΔMaSep1) was accelerated and the time for 50% germination rate of conidial was shortened by 1 h, while the conidial production of ΔMaSep1 was considerably reduced. The resistances to heat shock and UV-B irradiation of ΔMaSep1 were enhanced, and the expression of some genes involved in DNA damage repair and heat shock response was significantly increased in ΔMaSep1. The disruption of MaSep1 had no effect on the virulence of M. acridum. Interestingly, ΔMaSep1 conducted the normal conidiation on the microcycle conidiation medium, SYA. Furthermore, 127 DEGs were identified by RNA-Seq between the wild-type and ΔMaSep1 strains during microcycle conidiation, proving that MaSep1 mediated the conidiation pattern shift by governing some genes associated with conidiation, cell division, and cell wall formation. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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13 pages, 1734 KiB

Open AccessArticle

The Catalase Gene MrCat1 Contributes to Oxidative Stress Tolerance, Microsclerotia Formation, and Virulence in the Entomopathogenic Fungus Metarhizium rileyi

by Yu Su, Xuyi Wang, Yuanli Luo, Huan Jiang, Guiting Tang and Huai Liu

J. Fungi 2024, 10(8), 543; https://doi.org/10.3390/jof10080543 - 2 Aug 2024

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Abstract

Catalases play a crucial role in the metabolism of reactive oxygen species (ROS) by converting H₂O₂ into molecular oxygen and water. They also contribute to virulence and fungal responses to various stresses. Previously, the MrCat1-deletion mutant (ΔMrCat1) [...] Read more.

Catalases play a crucial role in the metabolism of reactive oxygen species (ROS) by converting H₂O₂ into molecular oxygen and water. They also contribute to virulence and fungal responses to various stresses. Previously, the MrCat1-deletion mutant (ΔMrCat1) was generated using the split-marker method in Metarhizium rileyi. In this study, the Cat1 gene was identified, and its function was evaluated. Under normal culture conditions, there were no significant differences in colony growth or dimorphic switching between ΔMrCat1 and the wild-type (WT) strains. However, under oxidative stress, the colony growth was inhibited, and the yeast–hyphal transition was suppressed in the ΔMrCat1 strain. Hyperosmotic stress did not differ significantly between the two strains. In the ΔMrCat1 strain, microsclerotia (MS) formation was delayed, resulting in less uniform MS size and a 76% decrease in MS yield compared to the WT strain. Moreover, the ΔMrCat1 strain exhibited diminished virulence. Gene expression analysis revealed up-regulation of ΔMrCat1, MrCat2, MrCat4, and MrAox in the ΔMrCat1 strain. These findings indicate that the MrCat1 gene in M. rileyi is essential for oxidative stress tolerance, MS formation, and virulence. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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18 pages, 4949 KiB

Open AccessArticle

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

by Guang Wang, Xu Zhang, Guangzu Du, Wenqian Wang, Yunhao Yao, Sitong Jin, Haosheng Cai, Yuejin Peng and Bin Chen

J. Fungi 2024, 10(8), 521; https://doi.org/10.3390/jof10080521 - 26 Jul 2024

Cited by 2 | Viewed by 1403

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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12 pages, 707 KiB

Open AccessArticle

A Countermeasure Strategy against Peramine Developed by Chilesia rudis in the Endophyte–Ryegrass–Herbivore Model

by Manuel Chacón-Fuentes, Daniel Martínez-Cisterna, Marcelo Lizama, Valeria Asencio-Cancino, Ignacio Matamala and Leonardo Bardehle

J. Fungi 2024, 10(8), 512; https://doi.org/10.3390/jof10080512 - 23 Jul 2024

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Abstract

Exploitation of the symbiotic relationship between endophytic fungi and ryegrass is a crucial technique for reducing the incidence of insect pests. This is primarily due to the production of alkaloids, such as peramine, by the fungi. This alkaloid has been reported as both [...] Read more.

Exploitation of the symbiotic relationship between endophytic fungi and ryegrass is a crucial technique for reducing the incidence of insect pests. This is primarily due to the production of alkaloids, such as peramine, by the fungi. This alkaloid has been reported as both a deterrent and toxic to a variety of insects. However, insects have developed various strategies to counteract plant defenses. One of the most studied methods is their ability to sequester toxic compounds from plants. In this study, we examined the feeding preferences and adaptation to peramine in Chilesia rudis, a native Chilean larva. Using a no-choice assay, we assessed larval feeding preferences and mass gain on seven experimental lines and two commercial cultivars of endophyte-infected and non-infected ryegrass. Pupal development time and adult performance were evaluated post-assay. Additionally, we measured peramine content in larval carcasses, feces, and ryegrass leaves. Jumbo was the most preferred cultivar with 32 mm² of leaf tissues consumed. The longest pupal development time was observed in L161 and ALTO AR1, both at 28 days. Wing length in adults was greatest in the Jumbo and L163 cultivars, measuring 1.25 cm and 1.32 cm, respectively. Peramine concentrations were detected in the bodies of C. rudis. In conclusion, this larva can adapt to endophyte-infected ryegrass and develop counter-adaptation mechanisms to mitigate the effects of peramine. Full article

(This article belongs to the Special Issue Fungi and Insect Interactions: Pathogenicity, Immune Defenses and Biocontrol)

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