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Invasive species are a growing global threat to forest ecosystems. In North America, previous invasions have functionally eliminated the American chestnut (Castanea dentata), a keystone and commercially important species in eastern North American forests, and currently threaten to eliminate other important species, such as ash (Fraxinus spp.), redbay (Persea borbonia), and eastern hemlock (Tsuga canadensis). Invasive species, particularly invasive insects, pathogens, and plants, threaten forest ecosystem integrity and put commercial forestry at risk. However, as the threat from invasive species grows due to expanding international trade, the scientific workforce with specialized expertise and training to mitigate current threats and, more importantly, avoid future threats, has been declining over the past 40 years. Research funding and administrative capacity to respond have also not kept pace with increased frequency and risk of species introductions. Herein, we review the nature of this ongoing challenge by examining contributing factors, including documenting trends in expertise and funding. In addition, we make recommendations for resources needed and information gaps that should be addressed and justify the need for increased support for basic biological research and further exploration of techniques to identify and treat potential threats (e.g. sentinel studies). Study Implications: The US faces an invasive species crisis. Major tree species are already being decimated. The forest products industry relies primarily on a hand full of species. A new insect or disease could thus decimate the industry. We show that the pace of introductions has accelerated due to greater and faster shipping volume. Port screening and sanitation need considerable improvement, especially for live plants, which harbor insects and pathogens. Interior monitoring and overseas sentinal studies need enhancement for better detection of threats. More research and control staff are needed at government and university posts, especially to enable rapid response. Finally, research is needed on new detection and control technologies. [ABSTRACT FROM AUTHOR]

Co-infection of plants by pathogens is common in nature, and the interaction of the pathogens can affect the infection outcome. There are diverse ways in which viruses and bacteria are transmitted from infected to healthy plants, but insects are common vectors. The present review aims to highlight key findings of studies evaluating the co-transmission of plant pathogens by insects and identify challenges encountered in these studies. In this review, we evaluated whether similar pathogens might compete during co-transmission; whether the changes in the pathogen titer in the host, in particular associated with the co-infection, could influence its transmission; and finally, we discussed the pros and cons of the different approaches used to study co-transmission. At the end of the review, we highlighted areas of study that need to be addressed. This review shows that despite the recent development of techniques and methods to study the interactions between pathogens and their insect vectors, there are still gaps in the knowledge of pathogen transmission. Additional laboratory and field studies using different pathosystems will help elucidate the role of host co-infection and pathogen co-transmission in the ecology and evolution of infectious diseases. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) symbiosis can provide multiple benefits to the host plant, including improved nutrition and protection against biotic stress. Mycorrhiza induced resistance (MIR) against pathogens and insect herbivores has been reported in different plant systems, but nutrient availability may influence the outcome of the interaction. Phosphorus (P) is a key nutrient for plants and insects, but also a regulatory factor for AM establishment and functioning. However, little is known about how AM symbiosis and P interact to regulate plant resistance to pests. Here, using the tomato-Funneliformis mosseae mycorrhizal system, we analyzed the effect of moderate differences in P fertilization on plant and pest performance, and on MIR against biotic stressors including the fungal pathogen Botrytis cinerea and the insect herbivore Spodoperta exigua. P fertilization impacted plant nutritional value, plant defenses, disease development and caterpillar survival, but these effects were modulated by the mycorrhizal status of the plant. Enhanced resistance of F. mosseae-inoculated plants against B. cinerea and S. exigua depended on P availability, as no protection was observed under the most P-limiting conditions. MIR was not directly explained by changes in the plant nutritional status nor to basal differences in defense-related phytohormones. Analysis of early plant defense responses to the damage associated molecules oligogalacturonides showed primed transcriptional activation of plant defenses occurring at intermediate P levels, but not under severe P limitation. The results show that P influences mycorrhizal priming of plant defenses and the resulting induced-resistance is dependent on P availability, and suggest that mycorrhiza fine-tunes the plant growth vs defense prioritization depending on P availability. Our results highlight how MIR is context dependent, thus unravel molecular mechanism based on plant defence in will contribute to improve the efficacy of mycorrhizal inoculants in crop protection. [ABSTRACT FROM AUTHOR]

Plants interact with a large diversity of microbes and insects, both below and above ground. While studies have shown that belowground microbes affect the performance of plants and aboveground organisms, we lack insights into how belowground microbial communities may shape interactions between aboveground pathogens and insects. We investigated how soil microbiomes and aboveground organisms affect plant growth and development, and whether differences in soil microbiomes influence interactions between aboveground organisms. We conducted a growth‐chamber experiment with oak seedlings Quercus robur growing in three soils with similar abiotic soil properties but with distinct natural soil microbiomes. Seedlings were subjected to single or dual attack by powdery mildew Erysiphe alphitoides and aphids Tuberculatus annulatus, either in the presence or absence of prior attack by a free‐feeding caterpillar Phalera bucephala. Soil microbiomes were associated with differences in seedling height, and seedlings with multiple aboveground organisms had more but smaller leaves than healthy seedlings. The soil microbiome affected the severity of powdery mildew infection, and mediated the impact of co‐occurring aboveground organisms on aphid population size. Our study highlights that plant performance is affected by natural soil microbiomes as well as aboveground organisms, and that natural soil microbiomes can affect interactions between pathogens and insects. These findings are important to understand species interactions in natural systems, as well as for practical applications, such as manipulation of soil microbiomes to manage agricultural pests and diseases. [ABSTRACT FROM AUTHOR]

Non‐native pests in North America are a growing threat to native trees and forest communities. Theory suggests that a less specialised niche, as reflected by a pest's broad host range, may facilitate successful pest invasions. Incorporating a pest's host range characteristics along with life‐history traits may thus help us better predict future invasions and impacts.We quantified the host range of North American tree pests using indices of host taxonomic richness and the standard effect size of the mean pairwise distance between hosts, then compared the host ranges of non‐native and native pests. We next examined whether non‐native and native pests tended to be associated with phylogenetically distinct sets of host tree lineages. Finally, we evaluated whether pest impacts were associated with pest host ranges, nativity or pest type (i.e. insect vs. pathogen).We found that the set of tree hosts impacted by non‐native pests was phylogenetically distinct from hosts of native pests, and that non‐native insect pests had significantly broader host ranges than native insect pests, perhaps due to an innate ability to associate with diverse tree species. We also found that pathogens generally had broader host ranges than insect pests—possibly a result of more frequent host range expansion. While severity was not associated with pest nativity per se, non‐native pathogens had the greatest impact on their hosts across all pest subsets.Synthesis. We identified important differences in the host ranges of native and non‐native pests, with non‐native pests associated with a broader range of hosts, and this difference was most evident in comparisons between insect pests. We suggest a broad host range might facilitate non‐native pest establishment. We also highlight the need for further research on pest life histories and impacts to better understand the consequences of pest invasions. [ABSTRACT FROM AUTHOR]

Curated databases of species interactions are instrumental to exploring and understanding the spatial distribution of species and their biotic interactions. In the process of conducting such projects, data development and curation efforts may give rise to a data product with utility beyond the scope of the original work, but which becomes inaccessible over time. Data describing insect host–pathogen interactions are fairly rare, and should thus be preserved and curated with appropriate metadata. Here, we introduce the insectDisease R package, a mechanism for curating, updating and distributing data from the Ecological Database of the World's Insect Pathogens, a database of insect host–pathogen associations, including attempted inoculations and infection outcomes for insect hosts and pathogens (bacteria, fungi, nematodes, protozoans and viruses). This dataset has been utilized for several projects since its inception, but without a well‐defined, curated and permanent repository, its existence and access have been limited to word‐of‐mouth connections. The current effort presented here aims to provide a means to preserve, augment and disseminate the database in a documented and versioned format. This project is an example of the type of effort that will be necessary to maintain valuable databases after the original funding disappears. [ABSTRACT FROM AUTHOR]

Insect vector and phytopathogen interactions are mediated by host plants. Insects interact with pathogens directly or indirectly and they may prefer host plants based on infection status. Performance on infected hosts varies depending on the type of pathogen involved. Species specific studies of economically important insects and phytopathogens are needed to understand how these interactions impact crop yields. Onion thrips, Thrips tabaci Lindeman (Thysanoptera:Thripidae), is an economically devastating insect pest of onions (Allium cepa L., Asparagales: Amaryllidaceae) worldwide and it co-occurs simultaneously with many different pathogens. Colletotrichum coccodes (Wallr) (Glomerellales: Glomerellaceae) is a generalist fungal pathogen that attacks onion foliage, causing tan lesions and decreasing yield. Onion thrips and C. coccodes represent two important pests of onions, but the relationship between onion thrips and C. coccodes infected onions has not been studied, and it is unclear if onion thrips contribute to the spread of C. coccodes in onion fields. A four-choice test with control, artificially injured, artificially injured + symptomatic, and inoculated-symptomatic onion suggests that onion thrips distinguish between hosts based on health status. Furthermore, a two-choice test with control, inoculated-asymptomatic, and inoculated-symptomatic onion pairings revealed that onion thrips distinguish between hosts based on infection status and prefer inoculated-symptomatic hosts. In a no-choice test, onion thrips numbers increased on inoculated-symptomatic plants compared to control or inoculated-asymptomatic plants. Overall, we found that onion thrips preferred and performed best on C. coccodes infected plants. [ABSTRACT FROM AUTHOR]

We reviewed recent literature to identify the positive and negative effects of thinning on both stand- and tree-level resistance and resilience to four stressors that are expected to increase in frequency and/or severity due to global change: (1) drought, (2) fire, (3) insects and pathogens, and (4) wind. There is strong evidence that thinning, particularly heavy thinning, reduces the impact of drought and also the risk and severity of fire when harvest slash is burned or removed. Thinning also increases the growth and vigor of residual trees, making them less susceptible to eruptive insects and pathogens, while targeted removal of host species, susceptible individuals and infected trees can slow the spread of outbreaks. However, the evidence that thinning has consistent positive effects is limited to a few insects and pathogens, and negative effects on root rot infection severity were also reported. At this point, our review reveals insufficient evidence from rigorous experiments to draw general conclusions. Although thinning initially increases the risk of windthrow, there is good evidence that thinning young stands reduces the long-term risk by promoting the development of structural roots and favouring the acclimation of trees to high wind loads. While our review suggests that thinning should not be promoted as a tool that will universally increase the resistance and resilience of forests, current evidence suggests that thinning could still be an effective tool to reduce forest vulnerability to several stressors, creating a window of opportunity to implement longer term adaptive management strategies such as assisted migration. We highlight knowledge gaps that should be targeted by future research to assess the potential contribution of thinning to adaptive forest management. One of these gaps is that studies from boreal and tropical regions are drastically underrepresented, with almost no studies conducted in Asia and the southern hemisphere. Empirical evidence from these regions is urgently needed to allow broader-scale conclusions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Spodoptera frugiperda is one of the significant migratory pests in the Global Alert issued by the Food and Agriculture Organization of the United Nations. As an insect‐specific microbial insecticide, baculovirus has been used to control various pests. MicroRNA‐34‐5p (miR‐34‐5p) is involved in regulating growth, reproduction and innate immunity to pathogens in insects, playing an essential role in host–virus interactions. In this study, we explored the critical function of miR‐34‐5p encoded by S. frugiperda in the anti‐Autographa californica multiple nucleopolyhedrovirus (AcMNPV), providing a reference for the design of a miR‐34‐5p target biopesticide against S. frugiperda and a theoretical basis for the wide application of microRNAs (miRNAs) in green pest control technology. RESULTS: We focused on miR‐34‐5p identified as downregulated in Sf9 cells and S. frugiperda larvae infected by AcMNPV. The regulatory function of miR‐34‐5p in AcMNPV–S. frugiperda interactions was studied by transfecting synthetic mimics and inhibitors, and constructing recombinant bacmids with miR‐34‐5p overexpression. miR‐34‐5p inhibited the production of infectious budded virions at the cellular and insect levels, inhibited the replication of the viral DNA and glucose metabolism, and increased the transcription of the antimicrobial peptide gloverin. Furthermore, the virus genes odv‐e66, ac78 and ie2 were shown to be direct targets. CONCLUSION: We systematically revealed the mechanism by which miR‐34‐5p is involved in the insect antiviral process. miR‐34‐5p inhibited the replication and infection of AcMNPV by directly targeting AcMNPV genes, especially ac78 and ie2. Our study provides a new direction and thinking for the prevention and green control of lepidopteran pests. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors" published in the journal Parasites & Vectors. The correction addresses an incorrect reference in the original article and provides the correct reference for readers to access. The correction has been made to the original article. The publisher, Springer Nature, maintains a neutral stance on jurisdictional claims and institutional affiliations. The authors of the original article are Norman A. Ratcliffe, Joao P. Furtado Pacheco, Paul Dyson, Helena Carla Castro, Marcelo S. Gonzalez, Patricia Azambuja, and Cicero B. Mello. [Extracted from the article]

[Display omitted] • Studying bed bug immunity can help us understand why they are not pathogen vectors. • Bed bug immune effector genes are upregulated in response to an insect pathogen. • Bed bug immune effector genes are upregulated in response to environmental bacteria. • Immune effector genes are not upregulated when bed bugs are fed Borrelia duttoni. • This human pathogen may not be detected by the bed bug molecular immune system. Bed bugs (Hemiptera: Cimicidae) are widely distributed, obligately blood-feeding insects, but they have never been linked to pathogen transmission in humans. Most other hematophagous insects that frequently bite humans transmit pathogens, and it is unclear why bed bugs do not. One hypothesis is that bed bugs have evolved a highly robust immune system because their mating system, traumatic insemination, exposes females to consistent wounding and bacterial infections. Although this has been proposed, very little is known about the bed bug immune system and how bed bugs respond to microbial challenges introduced by wounding. Similarly, there is little known about how the bed bug immune system responds to human pathogens. Understanding the bed bug immune system could give insight to why bed bugs appear not to transmit disease and under what circumstances they could, while also facilitating biological control efforts involving microbes. To investigate the transcriptomic response of bed bugs to immune challenges, we exposed female bed bugs to three bacterial challenges. 1.) Pseudomonas fluorescens , an entomopathogen known to have harmful effects to bed bugs, 2.) bacteria cultured from a bed bug enclosure (99.9 % Bacillus spp.), likely encountered during traumatic insemination, and 3.) Borrelia duttoni , a human vector-borne pathogen that causes relapsing fever. We compared the transcriptomes of infected bed bugs with uninfected matched controls in a pairwise fashion, focusing on immune-related genes. We found many known antimicrobial effector genes upregulated in response to P. fluorescens and traumatic insemination-associated bacteria, but interestingly, not in response to B. duttoni. In the differentially expressed genes that were shared between experiments, we found significant overlap in the P. fluorescens treatment and the traumatic insemination bacteria treatment, and between the P. fluorescens and B. duttoni treatments, but not between the traumatic insemination bacteria treatment and the B. duttoni treatment. Finally, we identify previously overlooked candidates for future studies of immune function in bed bugs, including a peroxidase-like gene, many putative cuticle-associated genes, a laccase-like gene, and a mucin-like gene. By taking a comprehensive transcriptomic approach, our study is an important step in understanding how bed bugs respond to diverse immune challenges. [ABSTRACT FROM AUTHOR]

Various microbiota including beneficial symbionts reside in the insect gut. Infections of pathogens cause dysregulation of the microflora and threaten insect survival. Reactive oxygen species (ROS) have been used in the gut immune responses, in which its production is tightly regulated by controlling dual oxidase (Duox) activity via Ca2+ signal to protect beneficial microflora and gut epithelium due to its high cytotoxicity. However, it was not clear how the insects discriminate the pathogens from the various microbes in the gut lumen to trigger ROS production. An entomopathogenic nematode (Steinernema feltiae) infection elevated ROS level in the gut lumen of a lepidopteran insect, Spodoptera exigua. Dorsal switch protein 1 (DSP1) localized in the nucleus in the midgut epithelium was released into plasma upon the nematode infection and activated phospholipase A2 (PLA2). The activated PLA2 led to an increase of PGE2 level in the midgut epithelium, in which rising Ca2+ signal up-regulated ROS production. Inhibiting DSP1 release by its specific RNA interference (RNAi) or specific inhibitor, 3-ethoxy-4-methoxyphenol, treatment failed to increase the intracellular Ca2+ level and subsequently prevented ROS production upon the nematode infection. A specific PLA2 inhibitor treatment also prevented the up-regulation of Ca2+ and subsequent ROS production upon the nematode infection. However, the addition of PGE2 to the inhibitor treatment rescued the gut immunity. DSP1 release was not observed at infection with non-pathogenic pathogens but detected in plasma with pathogenic infections that would lead to damage to the gut epithelium. These results indicate that DSP1 acts as a damage-associated molecular pattern in gut immunity through DSP1/PLA2/Ca2+/Duox. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes are used as biological control agents against a broad range of insect pests. We ascribed the pathogenicity of these organisms to the excretory/secretory products (ESP) released by the infective nematode. Our group characterized different virulence factors produced by Steinernema carpocapsae that underlie its success as an insect pathogen. A novel ShK-like peptide (ScK1) from this nematode that presents high sequence similarity with the ShK peptide from a sea anemone was successfully produced recombinantly in Escherichia coli. The secondary structure of ScK1 appeared redox-sensitive, exhibiting a far-UV circular dichroism spectrum consistent with an alpha-helical secondary structure. Thermal denaturation of the ScK1 allowed estimating the melting temperature to 59.2 ± 0.1 °C. The results from toxicity assays using Drosophila melanogaster as a model show that injection of this peptide can kill insects in a dose-dependent manner with an LD50 of 16.9 µM per adult within 24 h. Oral administration of the fusion protein significantly reduced the locomotor activity of insects after 48 h (p < 0.05, Tukey's test). These data show that this nematode expresses insecticidal peptides with potential as next-generation insecticides. [ABSTRACT FROM AUTHOR]

Cases of sand fly-borne diseases in the Emilia-Romagna region, such as meningitis caused by Toscana virus and human leishmaniasis, are reported annually through dedicated surveillance systems. Sand flies are abundant in the hilly part of the region, while the lowland is unsuitable habitat for sand flies, which are found in lower numbers in this environment with respect to the hilly areas. In this study, we retrieved sand flies collected during entomological surveillance of the West Nile virus (from 2018 to 2021) to assess their abundance and screen them for the presence of pathogens. Over the four-year period, we collected 3022 sand flies, more than half in 2021. The most abundant sand fly species was Phlebotomus (Ph.) perfiliewi, followed by Ph. perniciosus; while more rarely sampled species were Ph. papatasi, Ph. mascittii and Sergentomyia minuta. Sand flies were collected from the end of May to the end of September. The pattern of distribution of the species is characterized by an abundant number of Ph. perfiliewi in the eastern part of the region, which then falls to almost none in the western part of the region, while Ph. perniciosus seems more uniformly distributed throughout. We tested more than 1500 female sand flies in 54 pools to detect phleboviruses and Leishmania species using different PCR protocols. Toscana virus and Leishmania infantum, both human pathogens, were detected in 5 pools and 7 pools, respectively. We also detected Fermo virus, a phlebovirus uncharacterized in terms of relevance to public health, in 4 pools. We recorded different sand fly abundance in different seasons in Emilia-Romagna. During the season more favorable for sand flies, we also detected pathogens transmitted by these insects. This finding implies a health risk linked to sand fly-borne pathogens in the surveyed area in lowland, despite being considered a less suitable habitat for sand flies with respect to the hilly areas. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.), a major crop in Argentina and a staple food around the world, is affected by the emergence and re‐emergence of foliar diseases. Agrochemicals are the main control strategy nowadays; however, they can cause resistance in insects and microbial pathogens and have negative effects on the environment and human health. An emerging alternative is the use of living organisms, i.e. microbial biocontrol agents, to suppress plant pathogen populations. This is a risk‐free approach when the organisms acting as biocontrol agents come from the same ecosystem as the foliar pathogens they are meant to antagonize. Some epiphytic microorganisms may form biofilm by becoming aggregated and attached to a surface, as is the case of spore‐forming bacteria from the genus Bacillus. Their ability to sporulate and their tolerance to long storage periods make them a frequently used biocontrol agent. Moreover, the biofilm that they create protects them against different abiotic and biotic factors and helps them to acquire nutrients, which ensures their survival on the plants they protect. This review analyzes the interactions that the phyllosphere‐inhabiting Bacillus genus establishes with its environment through biofilm, and how this lifestyle could serve to design effective biological control strategies. [ABSTRACT FROM AUTHOR]

BrlA and AbaA are key activators of the central developmental pathway (CDP) that controls asexual development in Aspergillus but their roles remain insufficiently understood in hypocerealean insect pathogens. Here, regulatory roles of BrlA and AbaA orthologs in Metarhizium robertsii (Clavicipitaceae) were characterized for comparison to those elucidated previously in Beauveria bassiana (Cordycipitaceae) at phenotypic and transcriptomic levels. Time-course transcription profiles of brlA, abaA, and the other CDP activator gene wetA revealed that they were not so sequentially activated in M. robertsii as learned in Aspergillus. Aerial conidiation essential for fungal infection and dispersal, submerged blastospore production mimicking yeast-like budding proliferation in insect hemocoel, and insect pathogenicity via cuticular penetration were all abolished as a consequence of brlA or abaA disruption, which had little impact on normal hyphal growth. The disruptants were severely compromised in virulence via cuticle-bypassing infection (intrahemocoel injection) and differentially impaired in cellular tolerance to oxidative and cell wall-perturbing stresses. The ΔbrlA and ΔabaA mutant shad 255 and 233 dysregulated genes (up/down ratios: 52:203 and 101:122) respectively, including 108 genes co-dysregulated. These counts were small compared with 1513 and 2869 dysregulated genes (up/down ratios: 707:806 and 1513:1356) identified in ΔbrlA and ΔabaA mutants of B. bassiana. Results revealed not only conserved roles for BrlA and AbaA in asexual developmental control but also their indispensable roles in fungal adaptation to the insect-pathogenic lifecycle and host habitats. Intriguingly, BrlA- or AbaA-controlled gene expression networks are largely different between the two insect pathogens, in which similar phenotypes were compromised in the absence of either brlA or abaA. [ABSTRACT FROM AUTHOR]

Niche breadth coevolution between biotic partners underpins theories of diversity and co‐existence and influences patterns of disease emergence and transmission in host‐parasite systems. Despite these broad implications, we still do not fully understand how the breadth of parasites' infectivity evolves, the nature of any associated costs, or the genetic basis of specialization. Here, we serially passage a granulosis virus on multiple inbred populations of its Plodia interpunctella host to explore the dynamics and outcomes of specialization. In particular, we collect time series of phenotypic and genetic data to explore the dynamics of host genotype specialization throughout the course of experimental evolution and examine two fitness components. We find that the Plodia interpunctella granulosis virus consistently evolves and increases in overall specialization, but that our two fitness components evolve independently such that lines can specialize in productivity or infectivity. Furthermore, we find that specialization in our experiment is a highly polygenic trait best explained by a combination of evolutionary mechanisms. These results are important for understanding the evolution of specialization in host‐parasite interactions and its broader implications for co‐existence, diversification, and infectious disease management. [ABSTRACT FROM AUTHOR]

Plants are exposed to varied biotic stresses, including sequential or simultaneous attack by insects and pathogens. To overcome these complex stresses, plants must perceive each of the stresses, then integrate and relay the information throughout the plant body and eventually activate local and systemic resistance responses. Previous molecular genetic studies identified jasmonic acid and salicylic acid as key plant hormones of wound and immune responses. These hormones, combined with their antagonistic interaction, play critical roles in the initiation and regulation of defense responses against insects and pathogens. Aside from molecular and genetic information, the latest in vivo imaging technology has revealed that plant defense responses are regulated spatially and temporally. In this review, we summarize the current knowledge of local and systemic defense responses against wounding and diseases with a focus on past and recent advances in imaging technologies. We discuss how imaging-based multiparametric analysis has improved our understanding of the spatiotemporal regulation of dynamic plant stress responses. We also emphasize the importance of compiling the knowledge generated from individual studies on plant wounding and immune responses for a more seamless understanding of plant defense responses in the natural environment. [ABSTRACT FROM AUTHOR]

SQUINT (SQN) regulates plant maturation by promoting the activity of miR156, which functions primarily in the miR156–SQUAMOSA PROMOTER BINDING PROTEIN-LIKE9 (SPL9) module regulating plant growth and development. Here, we show that SQN acts in the jasmonate (JA) pathway, a major signaling pathway regulating plant responses to insect herbivory and pathogen infection. Arabidopsis thaliana sqn mutants showed elevated sensitivity to the necrotrophic fungus Botrytis cinerea compared with wild type. However, SQN is not involved in the early pattern-triggered immunity response often triggered by fungal attack. Rather, SQN positively regulates the JA pathway, as sqn loss-of-function mutants treated with B. cinerea showed reduced JA accumulation, JA response and sensitivity to JA. Furthermore, the miR156–SPL9 module regulates plant resistance to B. cinerea: mir156 mutant, and SPL9 overexpression plants displayed elevated sensitivity to B. cinerea. Moreover, constitutively expressing miR156a or reducing SPL9 expression in the sqn-1 mutant restored the sensitivity of Arabidopsis to B. cinerea and JA responses. These results suggest that SQN positively modulates plant resistance to B. cinerea through the JA pathway, and the miR156–SPL9 module functions as a bridge between SQN and JA to mediate plant resistance to this pathogen. [ABSTRACT FROM AUTHOR]

Traditional foliar spray and soil drench applications of crop protection compounds have been ineffective at managing huanglongbing (HLB) in citrus. Trunk injection is a technique that delivers crop protection compounds directly into the tree vasculature, which optimizes compound availability while minimizing drift, runoff, and damage to non-target organisms. Five-year-old HLB-affected 'Valencia' sweet orange (Citrus sinensis) trees were injected with the insecticide imidacloprid or the antibacterial oxytetracycline in October 2020 and April 2021. Trees were monitored for tree health, psyllid colonization, bacterial titers, fruit quality, fruit drop, and yield for two production seasons. Imidacloprid injection caused 63% mortality of psyllid adults within one week and reduced progeny survival by 80%, though the efficacy waned within two months. Injection with oxytetracycline significantly improved tree health, reduced bacterial titers, and reduced preharvest fruit drop by more than 3-fold with corresponding increases in yield. Residue dynamics varied by injected compound and tissue analyzed. These results suggest trunk injection could be an effective delivery method for existing or novel therapeutics targeting either the insect vector or the pathogen causing HLB. [ABSTRACT FROM AUTHOR]

Plant growth and response to environmental cues are largely driven by hormones. Salicylic acid (SA)- and jasmonic acid (JA)-mediated defenses have been shown to be effective against different types of attackers. SAmediated defense is mainly effective against biotrophic pathogens and phloem-feeding insects, whereas JA-mediated defense is effective against necrotrophic pathogens and tissue-damaging insects. Cytokinins (CKs) are classic growth hormones that have also emerged as plant immunity modulators. Evidence pointed out that CKs contribute to the defense responses mediated by SA and JA, acting as hormone modulators of the SA/JA signaling backbone. Recently, we identified in Arabidopsis a type-B response regulator 11 (ARR 11) involved in cytokinin-mediated responses as a novel regulator of the SA/JA cross-talk. Here we investigated plant fitness and resistance against the fungal necrotrophic pathogen Botrytis cinerea in Arabidopsis wild-type Col-8 and defective arr11 mutant following SA, JA, CK single or combined treatment. Our results demonstrated that the CK and SA/JA/CK combination has a positive outcome on plant fitness in both Arabidopsis Col-8 and arr11 mutant,. The triple hormone treatment is efficient in increasing resistance to B. cinerea in Col-8 and this effect is stronger in arr11 mutant. The results will provide not only new background knowledge, corroborating the role of ARR11 in plant-defense related processes, but also new potential opportunities for alternative ways of protecting plants from fungal diseases. [ABSTRACT FROM AUTHOR]

Plants attacked by insects commonly mobilize various defense mechanisms, including the biosynthesis and release of so-called herbivore-induced plant volatiles (HIPVs). Entomopathogenic nematodes (EPNs) can be attracted to these belowground HIPVs, which can enhance biocontrol services from EPNs. However, recent research has also demonstrated that HIPVs can induce and initiate insect immune responses, decreasing the insect's susceptibility to pathogens and parasites. Therefore, experiments were conducted to test the impact of HIPVs on insects and EPNs during the initial stage of EPN infection. Compounds that can impact EPN attraction and infectivity such as pregeijerene, β-caryophyllene, and α-pinene, and compounds that have been determined to increase or decrease susceptibility of insects to pathogens, such as (Z)-3- hexenyl acetate, linalool, and β-ocimene, were selected. Exposure of Galleria mellonella larvae to pregeijerene, linalool, β-ocimene and α-pinene during invasion significantly increased mortality of Steinernema diaprepesi and Heterorhabditis bacteriophora after 48 h. Larval treatment with βcaryophyllene only increased mortality for Heterorhabditis bacteriophora. (Z)-3-hexenyl acetate did not cause differential mortality from the controls for either nematode species. In additional experiments, we found that EPNs exposed to α-pinene and linalool were more readily recognized by the insects' immune cells compared to the control treatment, thus the observed increased mortality was likely due to HIPVs-EPN interactions with the insect's immune system. These results show that the presence of HIPVs can impact EPN survival in the model host, G. mellonella. [ABSTRACT FROM AUTHOR]

Interspecific niche complementarity is a key mechanism posited to explain positive species richness–productivity relationships in plant communities. However, the exact nature of the niche dimensions that plant species partition remains poorly known.Species may partition abiotic resources that limit their growth, but species may also be specialized with respect to their set of biotic interactions with other trophic levels, in particular with enemies including pathogens and consumers. The lower host densities present in more species‐diverse plant communities may therefore result in smaller populations of specialized enemies, and in a smaller associated negative feedback these enemies exert on plant productivity.To test whether such host density‐dependent effects of enemies drive diversity–productivity relationships in young forest stands, we experimentally manipulated leaf fungal pathogens and insect herbivores in a large subtropical forest biodiversity–ecosystem functioning experiment in China (BEF‐China).We found that fungicide spraying of tree canopies removed the positive tree‐species richness–productivity relationship present in untreated control plots. The tree species that contributed the most to this effect were the ones with the highest fungicide‐induced growth increase in monoculture. Insecticide application did not cause comparable effects.Synthesis. Our findings suggest that tree species diversity may not only promote productivity by interspecific resource‐niche partitioning but also by trophic niche partitioning. Most likely, partitioning occurred with respect to enemies such as pathogenic fungi. Alternatively, similar effects on tree growth would have occurred if fungicide had eliminated positive effects of a higher diversity of beneficial fungi (e.g. mycorrhizal symbionts) that may have occurred in mixed tree species communities. [ABSTRACT FROM AUTHOR]

Lignin is a complex phenolic compound that can enhance the stiffness, hydrophobicity, and antioxidant capacity of the cell wall; it thus provides a critical barrier against pathogen and insect invaders. Caffeoyl shikimate esterase (CSE) is a key novel enzyme involved in lignin biosynthesis that is associated with genetic improvements in lignocellulosic biomass; however, no research thus far have revealed the role of CSE in resistance to pathogenic stress. CsCSE1 (Cucsa.134370) has previously been shown to highly associated with the response of cucumber to attack by Podosphaera xanthii through RNA sequencing. Here, we detected the exactly role of CsCSE1 in the defence of cucumber to P. xanthii infection. Homologous sequence alignment revealed that CsCSE1 contains two highly conserved lyase domains (GXSXG), suggesting that CsCSE1 possesses CSE activity. Subcellular localization analysis manifested that CsCSE1 was localized to the plasma membrane and endoplasmic reticulum (ER). Functional analysis demonstrated that the transient silencing of CsCSE1 in cucumber dramatically attenuated resistance to P. xanthii , whereas overexpression of CsCSE1 in cucumber markedly increased resistance to P. xanthii. Further investigation of the abundance of lignin in transient transgenic plants revealed that CsCSE1 might actively mediate the disease resistance of cucumber by promoting lignin biosynthesis. CsCSE1 also affects the expression of its downstream lignin biosynthesis-related genes, like CsLAC , CsCOMT , CsCCR , and CsCAD. The results of this study provide targets for the genetic breeding of tolerant cucumber cultivars as well as new insights that could aid the control of plant diseases. • CsCSE1 is involved in the immune defense of cucumber against Podosphaera xanthii. • CsCSE1 positively regulates lignin biosynthesis. • CsCSE1 activates the expression of CsLAC , CsCOMT , CsCCR , and CsCAD. [ABSTRACT FROM AUTHOR]

The geographical distributions of non-native forest insects and pathogens (pests) result from a multitude of interacting abiotic and biotic factors. Following arrival, the presence of suitable host trees and environmental conditions are required for pests to establish and spread, but the role of forest biodiversity in this process is not well-understood. We analyzed county-level data for 22 non-native forest pests in the conterminous United States, developing species-specific models to investigate the effects of spatial contagion, human activities, and host and non-host tree biomass or richness on the occurrence of pest species. Species-specific models indicated that (i) the spatial contagion of invasions was the most common driver of invasion incidence, (ii) facilitation effects from host biomass and richness were present in approximately half of the invasions and almost entirely observed in invasions by sap-feeding insects or pathogens, and (iii) there was substantial variation in the direction and magnitude of the effects of non-host tree biomass and richness on invasion. Our analyses highlighted the prominent role of spatially derived propagule pressure in driving intracontinental invasions whereas effects of forest biodiversity were variable and precluded broad generalizations about facilitation and dilution effects as drivers of forest pest invasions at large spatial scales. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes (EPNs) have emerged as a promising tool for controlling soil-dwelling crop pests. However, their efficacy varies according to EPN populations and targeted hosts. Wireworms are polyphagous insects causing significant crop losses, especially since the ban on pesticides previously used for their control. They are highly resistant to EPN populations and require high number of infective juveniles (IJs) to achieve optimal mortality rates. In this research, we collected and compared the virulence of 16 EPN populations, of foreign origin, purchased or collected from wireworms infested fields. Then, we have tested two hypotheses: (i) smaller nematodes induce heightened mortality rates against wireworms; (ii) virulence levels can be linked to nematodes-bacteria complex. Mortality rates scaled from three to 43 % after 56 days of continuous exposure across the 16 tested EPN populations (Heterorhabditis spp. and Steinernema spp.). Morphometric analysis of IJs revealed both intra- and interspecific variations in length and diameter among populations. Interestingly, while EPN length influence mortality at three days post-inoculation. We found leaner IJs (< 25 µm) to induce higher mortality rates at 56 days post-inoculation. To better determine the structure and dimensions of the primary entry routes utilized by EPNs, we provide optical microscope micrographs of wireworm Agriotes spp. spiracle, anal sclerotized coating anus and anal muscles. Symbiotic bacteria of each EPN population were identified, and a biochemical characterization was performed using Analytical Profile Index tests. The symbiotic bacteria belong to the species Photorhabdus antumapuensis, P. laumondii subsp. laumondii, P. thracensis, Xenorhabdus bovienii and X. nematophila. Bacteria biochemical profiles did not reflect the differences in virulence of nematodes-bacteria complex against wireworms. These findings highlight the importance of considering EPN morphometry and intraspecific variability in designing applications to control wireworms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Abstract The relationship between entomopathogenic fungi and their insect hosts is a classic example of the co-evolutionary arms race between pathogen and target host. The present review describes the entomopathogenic potential of Chytridiomycota and Blastocladiomycota fungi, and two groups of fungal allies: Oomycota and Microsporidia. The Oomycota (water moulds) are considered as a model biological control agent of mosquito larvae. Due to their shared ecological and morphological similarities, they had long been considered a part of the fungal kingdom; however, phylogenetic studies have since placed this group within the Straminipila. The Microsporidia are parasites of economically-important insects, including grasshoppers, lady beetles, bumblebees, colorado potato beetles and honeybees. They have been found to display some fungal characteristics, and phylogenetic studies suggest that they are related to fungi, either as a basal branch or sister group. The Blastocladiomycota and Chytridiomycota, named the lower fungi, historically were described together; however, molecular phylogenetic and ultrastructural research has classified them in their own phylum. They are considered parasites of ants, and of the larval stages of black flies, mosquitoes and scale insects.

This correction notice addresses errors in a publication titled "Trunk Injection as a Tool to Deliver Plant Protection Materials—An Overview of Basic Principles and Practical Considerations." The mistake in Figure 1 is corrected, as the Q-Connect device was inaccurately described as a high-pressure application device. The correction clarifies that the Arborjet Quik-Jet Air and similar high-pressure systems, such as ENDOplant, are examples of high-pressure application devices. These devices use plastic plugs as injection ports and specialized metal injection tips to deliver materials at pressures of 60-100 psi. The correction emphasizes that plugging tree core wounds may interfere with the natural healing capabilities of the tree. The authors assure that the scientific conclusions remain unaffected. [Extracted from the article]

Plants need to survive with changing environmental conditions, be it different accessibility to water or nutrients, or attack by insects or pathogens. Few of these changes, especially heavy metal stress, can become more stressful and needed strong countermeasures to ensure survival of plants. Priming, a pre-sowing hydration treatment, involves pre-exposure of plants to an eliciting component which enhance the plant's tolerance to later stress events. By considering the role of micronutrients in aiding plants to cope up under adverse conditions, this review addresses various aspects of micronutrient seed priming in attenuating heavy metal stress. Priming using micronutrients is an adaptive strategy that boosts the defensive capacity of the plant by accumulating several active or inactive signaling proteins, which hold considerable importance in signal amplification against the triggered stimulus. Priming induced 'defence memory' persists in both present generation and its progeny. Therefore, it is considered a promising approach by seed technologist for commercial seed lots to enhance the vigour in terms of seed germination potential, productivity and strengthening resistance response against metalloid stress. The present review provides an overview regarding the potency of priming with micronutrient to ameliorate harmful effects of heavy metal stress, possible mechanism how attenuation is accomplished, role of priming in enhancing crop productivity and inducing defence memory against the metalloid stress stimulus. [ABSTRACT FROM AUTHOR]

Summary: Many plant species produce multiple leaf flushes during the growing season, which might have major consequences for within‐plant variation in chemistry and species interactions. Yet, we lack a theoretical or empirical framework for how differences among leaf flushes might shape variation in damage by insects and diseases.We assessed the impact of leaf flush identity on leaf chemistry, insect attack and pathogen infection on the pedunculate oak Quercus robur by sampling leaves from each leaf flush in 20 populations across seven European countries during an entire growing season.The first leaf flush had higher levels of primary compounds, and lower levels of secondary compounds, than the second flush, whereas plant chemistry was highly variable in the third flush. Insect attack decreased from the first to the third flush, whereas infection by oak powdery mildew was lowest on leaves from the first flush. The relationship between plant chemistry, insect attack and pathogen infection varied strongly among leaf flushes and seasons.Our findings demonstrate the importance of considering differences among leaf flushes for our understanding of within‐tree variation in chemistry, insect attack and disease levels, something particularly relevant given the expected increase in the number of leaf flushes with climate change. [ABSTRACT FROM AUTHOR]

Plants interact with a multitude of microorganisms and insects, both belowand above ground, which might influence plant metabolism. Despite this, we lack knowledge of the impact of natural soil communities and multiple aboveground attackers on the metabolic responses of plants, and whether plant metabolic responses to single attack can predict responses to dual attack. We used untargeted metabolic fingerprinting (gas chromatographymass spectrometry, GC-MS) on leaves of the pedunculate oak, Quercus robur, to assess the metabolic response to different soil microbiomes and aboveground single and dual attack by oak powdery mildew (Erysiphe alphitoides) and the common oak aphid (Tuberculatus annulatus). Distinct soil microbiomes were not associated with differences in the metabolic profile of oak seedling leaves. Single attacks by aphids or mildew had pronounced but different effects on the oak leaf metabolome, but we detected no difference between the metabolomes of healthy seedlings and seedlings attacked by both aphids and powdery mildew. Our findings show that aboveground attackers can have species-specific and non-additive effects on the leaf metabolome of oak. The lack of a metabolic signature detected by GC-MS upon dual attack might suggest the existence of a potential negative feedback, and highlights the importance of considering the impacts of multiple attackers to gain mechanistic insights into the ecology and evolution of species interactions and the structure of plant-associated communities, as well as for the development of sustainable strategies to control agricultural pests and diseases and plant breeding. [ABSTRACT FROM AUTHOR]

Biodiversity effects on ecosystem functioning can be partitioned into complementarity effects, driven by many species, and selection effects, driven by few. Selection effects occur through interspecific abundance shifts (dominance) and intraspecific shifts in functioning. Complementarity and selection effects are often calculated for biomass, but very rarely for secondary productivity, that is, energy transfer to higher trophic levels. We calculated diversity effects for three functions: aboveground biomass, insect herbivory and pathogen infection, the latter two as proxies for energy transfer to higher trophic levels, in a grassland experiment (PaNDiv) manipulating species richness, functional composition, nitrogen enrichment, and fungicide treatment. Complementarity effects were, on average, positive and selection effects negative for biomass production and pathogen infection and multiple species contributed to diversity effects in mixtures. Diversity effects were, on average, less pronounced for herbivory. Diversity effects for the three functions were not correlated, because different species drove the different effects. Benefits (and costs) from growing in diverse communities, be it reduced herbivore or pathogen damage or increased productivity either due to abundance increases or increased productivity per area were distributed across different plant species, leading to highly variable contributions of single species to effects of diversity on different functions. These results show that different underlying ecological mechanisms can result in similar overall diversity effects across functions. [ABSTRACT FROM AUTHOR]

Secondary metabolites/toxins produced by Purpeocillium lilacinum (Hypocreales; Phiocordycipitaceae), a well-known insect pathogen, can be used for the management of different insect pests. We report the lethal and sublethal effects of cyclosporin C (a toxin produced by P. lilacinum) against a major vegetable pest, Plutella xylostella, at specific organismal (feeding rate, larval growth, adult emergence, fecundity, and adult longevity) and sub-organismal levels (changes in antioxidant and neurophysiological enzyme activities). The toxicity of cyclosporin C against different larval instars of P. xylostella increased with increasing concentrations of the toxin and the maximum percent mortality rates for different P. xylostella larval instars at different times were observed for the 300 µg/mL cyclosporin C treatment, with an average mortality rate of 100% for all larval instars. The median lethal concentrations (LC50) of cyclosporin C against the first, second, third, and fourth larval instars of P. xylostella 72 h post-treatment were 78.05, 60.42, 50.83, and 83.05 μg/mL, respectively. Different concentrations of cyclosporin C caused a reduction in the average leaf consumption and average larval weight. Different life history parameters, such as the pupation rate (%), adult emergence (%), female fecundity, and female longevity were also inhibited when different concentrations of cyclosporin C were applied topically. The cyclosporin C concentrations inhibited the activities of different detoxifying (glutathione S-transferase, carboxylesterase, and acetylcholinesterase) and antioxidant enzyme (superoxide dismutase, catalase, and peroxidase) activities of P. xylostella when compared to the control. These findings can serve as baseline information for the development of cyclosporin C as an insect control agent, although further work on mass production, formulation, and field application is still required. [ABSTRACT FROM AUTHOR]

Alfalfa is one of the most important legume forages in the world and contributes greatly to the improvement of ecosystems, nutrition, and food security. Diseases caused by pathogens and pests severely restrict the production of alfalfa. Breeding resistant varieties is the most economical and effective strategy for the control of alfalfa diseases and pests, and the key to breeding resistant varieties is to identify important resistance genes. Plant innate immunity is the theoretical basis for identifying resistant genes and breeding resistant varieties. In recent years, the framework of plant immunity theory has been gradually formed and improved, and considerable progress has been made in the identification of alfalfa resistance genes and the revelation of the related mechanisms. In this review, we summarize the basic theory of plant immunity and identify alfalfa resistance genes to different pathogens and insects and resistance mechanisms. The current situation, problems, and future prospects of alfalfa resistance research are also discussed. Breeding resistant cultivars with effective resistance genes, together with other novel plant protection technologies, will greatly improve alfalfa production. [ABSTRACT FROM AUTHOR]

Oak decline presenting symptoms of tracheomycosis have been observed globally over long periods of time. Since the 1990s, oak decline has been considered to be a multifactorial process where abiotic predisposing factors play a significant role. Nevertheless, biotic factors, such as subcortical insects and fungal pathogens, may influence the decline process, as some insect species transmit spores of tracheomycotic pathogens. We investigated biotic agents (subcortical insects, Ophiostoma spp. and Phytophthora spp.) in six declining oak stands located within mesophytic and thermophytic zones in the Czech Republic, where five dry years occurred from 2015 to 2019. The spectrum of insect pests of oak stands was investigated using two methods: reared from logs from each stand and window traps. The presence of Ophiostoma fungi was assessed from cultivated woodblocks; Phytophthora pathogens were isolated from soil samples. In total, 2931 subcortical insect individuals were captured during the 2021 vegetation period. The most species-rich group of the subcortical insect complex involved in oak decline consisted of the families Cerambycidae: Xylotrechus antilope; Curculionidae: Scolytus intricatus, Xyleborus monographus; and Buprestidae: Agrilus biguttatus, A. sulcicollis. The presence of Ophiostoma was detected in all stands with different intensities between tree parts. Several important oak pests were positively correlated with the occurrence of Ophiostoma. On the contrary, from all soil samples, Phytophthora plurivora was found at only one studied oak stand. Based on the results, a new modified model of biotic and abiotic factors involved in the oak decline is proposed. [ABSTRACT FROM AUTHOR]

Plant resistance factors, such as secondary metabolites and proteins, are known to affect the viability of insect fungal pathogens. Different plant varieties can have different levels of plant pathogen resistance, which could potentially influence efficacy of insect pathogens. Leaves from twelve maize (Zea mays L.) inbreds with different reported resistance to Fusarium and/or Aspergillus pathogens were examined for their influence on the efficacy of two different commercial strains of Beauveria bassiana (Bals.-Criv.) Vuill. against corn earworms, Helicovepa zea (Boddie) and fall armyworms, Spodoptera frugiperda (J.E. Smith). For leaf assays with first instar caterpillars, mortality on day 2 ranged from an inbred dependent high of 92% to a low of 14% for corn earworms, and from a high of 84% to a low of 22% for fall armyworms. Leaves that caused the greatest inhibition of B. bassiana efficacy had the greatest amount of caterpillar damage compared to corresponding control leaves that were not treated with B. bassiana. Damage ratings due to Fusarium graminearum (Schwabe) infection were often correlated with the mortality levels of both species of B. bassiana treated caterpillars that fed on leaves, suggesting that maize resistance factors to F. graminearum were interfering with the efficacy of B. bassiana. The study suggests that the interaction between plant pathogen resistance factors and insect pathogens should be considered when developing both new plant varieties and biocontrol strains that may be used for insect pest management where possible. [ABSTRACT FROM AUTHOR]

Summary: Lenticels can be defined as pores that are the entrance of a continuous aeration system from the atmosphere via the living bark to the secondary xylem in the otherwise protective layers of the periderm. Most work on lenticels has had an anatomical focus but the structure-function relationships of lenticels still remain poorly understood. Gas exchange has been considered the main function of lenticels, analogous to the stomata in leaves. In this perspective review, we introduce novel ideas pertaining to lenticel functions beyond gas exchange. We review studies on lenticel structure, as this knowledge can give information about structure-function relationships. The number of species investigated to-date is low and we provide suggestions for staining techniques for easy categorization of lenticel types. In the follow-up sections we review and bring together new hypotheses on lenticel functioning in the daily "normal operation range", including regulative mechanisms for gas exchange and crack prevention, the "stress operation range" comprising flooding, drought and recovery from drought and the "emergency operation range", which includes infestation by insects and pathogens, wounding and bending. We conclude that the significance of dermal tissues and particularly of lenticels for tree survival has so far been overlooked. This review aims to establish a new research discipline called " Phytodermatology ", which will help to fill knowledge gaps regarding tree survival by linking quantitative and qualitative lenticel anatomy to tree hydraulics and biomechanics. A first step into this direction will be to screen more species from a great diversity of biomes for their lenticel structure. [ABSTRACT FROM AUTHOR]

Insects are important models for studying immunity in an ecological and evolutionary context. Yet, most empirical work on the insect immune system has come from phenotypic studies meaning we have a limited understanding of the genetic architecture of immune function in the sexes.We use nine highly inbred lines to thoroughly examine the genetic relationships between a suite of commonly used immune assays (haemocyte count, implant encapsulation, total phenoloxidase activity, antibacterial zone of inhibition and pathogen clearance) and resistance to infection by three generalist insect pathogens (the gram‐negative bacterium Serratia marcescens, the gram‐positive bacterium Bacillus cereus and the fungus Metarhizium robertsii) in male and female Gryllodes sigillatus.There were consistent positive genetic correlations between haemocyte count, antibacterial and phenoloxidase activity and resistance to S. marcescens in both sexes, but these relationships were less consistent for resistance to B. cereus and M. robertsii. In addition, the clearance of S. marcescens was genetically correlated with the resistance to all three pathogens in both sexes. Genetic correlations between resistances to the different pathogen species were inconsistent, indicating that resistance to one pathogen does not necessarily mean resistance to another. Finally, while there is ample genetic (co)variance in immune assays and pathogen resistance, these genetic estimates differed across the sexes and many of these measures were not genetically correlated across the sexes, suggesting that these measures could evolve independently in the sexes.Our finding that the genetic architecture of immune function is sex and pathogen specific suggests that the evolution of immune function in male and female G. sigillatus is likely to be complex. Similar quantitative genetic studies that measure a large number of assays and resistance to multiple pathogens in both sexes are needed to ascertain if this complexity extends to other species. [ABSTRACT FROM AUTHOR]

The alfalfa leafcutting bee Megachile rotundata Fabricius (HYMENOPTERA: Megachilidae) is an important pollinator for multiple agricultural seed commodities in the United States. M. rotundata is a solitary cavity nesting bee that forms brood nests where its larvae can develop. During the developmental stages of growth, brood can be preyed upon by multiple different fungal pathogens and insect predators and parasitoids, resulting in the loss of the developing larvae. Larval loss is a major concern for alfalfa (Medicago sativa L.) seed producers because they rely on pollination services provided by M. rotundata. Reduced pollination rates result in lower yields and increased production costs. In the present study, we examined the taxonomic composition of organisms found within M. rotundata brood cells using a multiplex PCR assay which was developed for the detection of bacterial, fungal, and invertebrate pests and pathogens of M. rotundata larvae. Known pests of M. rotundata were detected, including members of the fungal genus Ascosphaera , the causative agent of chalkbrood. The presence of multiple Ascosphaera species in a single brood cell was observed, with potential implications for chalkbrood disease management. The multiplex assay also identified DNA from more than 2,400 total species, including multiple predators and pathogenetic species not previously documented in association with M. rotundata brood cells. [ABSTRACT FROM AUTHOR]

• Insect pathogens enter hosts through natural openings or epithelial barriers • Pathogen infection routes regulate the insect immune response • This information is critical for understanding the evolution of innate immunity Recent advances in insect-pathogen interactions have started to reveal the role of insect tissues and organs as natural infection routes for parasites and microbial pathogens. Here we summarize this information highlighting the micro- and macro-parasites that enter insects through distinct infection routes and link them to innate immune activity. We also examine whether the infection route determines the insect immune response and if the resulting immunological and physiological processes underpinning these different routes of infection are clearly distinct. Understanding how the infection route is associated with the robustness in insect host defense will help us identify conserved evolutionary and ecological patterns in order to design novel strategies for the management of destructive agricultural pests and disease vectors. [ABSTRACT FROM AUTHOR]

Glandular trichomes of tobacco (Nicotiana tabacum) produce blends of acylsucroses that contribute to defence against pathogens and herbivorous insects, but the mechanism of assembly of these acylsugars has not yet been determined. In this study, we isolated and characterized two trichome-specific acylsugar acyltransferases that are localized in the endoplasmic reticulum, NtASAT1 and NtASAT2. They sequentially catalyse two additive steps of acyl donors to sucrose to produce di-acylsucrose. Knocking out of NtASAT1 or NtASAT2 resulted in deficiency of acylsucrose; however, there was no effect on acylsugar accumulation in plants overexpressing NtASAT1 or NtASAT2. Genomic analysis and profiling revealed that NtASAT s originated from the T subgenome, which is derived from the acylsugar-producing diploid ancestor N. tomentosiformis. Our identification of NtASAT1 and NtASAT2 as enzymes involved in acylsugar assembly in tobacco potentially provides a new approach and target genes for improving crop resistance against pathogens and insects. [ABSTRACT FROM AUTHOR]

Walking through a garden or a crop field, you may notice that plants damaged by pests (insects or pathogens) look smaller than the same kind of plants nearby that are not damaged. An obvious explanation would be that damaged plants may have lost substantial photosynthetic tissue due to insect and pathogen activities. As such, plants may have a reduced ability to capture light and perform photosynthesis, which fuels the growth of plants. While this is likely part of the reason why damaged plants look smaller, there is also another and perhaps more fascinating explanation that we would like to discuss here in this primer. It turns out that plants attacked by insects, pathogens and other biotic stressors may 'purposely' slow down their growth and that this response is often systemic, meaning that it occurs throughout the plant and beyond the tissue that is damaged by pests. Interestingly, some chemicals or plant genetic mutations that simulate insect or pathogen attacks without causing a loss of photosynthetic tissue can also slow plant growth, suggesting the physical loss of photosynthetic tissue per se is not always a prerequisite for slowing down plant growth. In contrast, there are conditions under which plants need to grow rapidly. For example, plants grow quickly when searching for light during germination or under a shaded canopy due to crowding from neighboring plants. Under these conditions, rapid plant growth is often accompanied by increased susceptibility to pests, presumably because growth is prioritized over defense. This inverse growth–defense relationship is commonly known as the 'growth–defense trade-off' and may be considered one of the most fundamental principles of 'plant economics' that allows plants to adjust growth and defense based on external conditions (Figure 1). As plants must both grow and defend in order to reproduce and survive in the natural world, growth–defense trade-offs have important ecological consequences. In agricultural settings, crops have often been bred to maximize growth-related traits, which could inadvertently result in the loss of useful genetic traits for biotic defenses. Thus, deciphering the molecular mechanisms underlying growth–defense trade-off phenomena could impact future crop breeding strategies aimed at designing superior crop plants with high yields as well as the ability to defend against biotic stressors. Here, we discuss some of the prevailing hypotheses about growth–defense trade-offs, our current understanding of the underlying mechanisms, and the ongoing efforts to optimize growth–defense trade-offs in crop plants. He et al. summarize hypotheses and molecular mechanisms behind trade-offs in plant growth and defense and describe how these have been exploited for crop improvement. [ABSTRACT FROM AUTHOR]

Small heat shock proteins (sHsps) containing conserved α-crystallin domain play important roles in many cellular processes, but little is known about the functions of sHsps in filamentous entomopathogens. Here, three sHsps of Hsp20, Hsp30a, and Hsp30b were characterized in Beauveria bassiana, a filamentous fungal insect pathogen that serves as the main source of wide-spectrum fungal insecticides. The results demonstrated that these three genes are interrelated at the transcriptional level under normal and heat-shocked conditions. Meanwhile, all the deletion mutants showed significant but differential changes in cell wall integrity, antioxidant activity, hyphal tolerance to carbendazim fungicide, conidial tolerance to 45 °C wet heat and virulence. However, only Δhsp30b showed growth defects on rich and minimal media at 25 °C and Δhsp30a displayed the reduction in conidiophores and conidia. Moreover, the single deletion of hsp30a and hsp30b caused the decreases in hyphal growth at 34 °C and conidial tolerance to UV-B irradiation. Our findings provide a global insight into vital roles of hsp20, hsp30a, and hsp30b in asexual development, environmental adaptation, and fungal virulence of B. bassiana. [ABSTRACT FROM AUTHOR]

Metarhizium is a genus of endophytic, insect-pathogenic fungi that is used as a biological control agent. The dual lifestyles of these fungi combine the parasitism of insect pests with the symbiotic association with plant roots. A major class of secreted metabolites by Metarhizium are cyclic depsipeptides called destruxins (DTXs). As prominent insecticidal compounds, their role during plant interactions is still largely unknown. Here, we examined the metabolomic profile of Metarhizium, with special emphasis on DTX production, using untargeted, liquid chromatography-tandem mass spectrometry (LC-MS/MS). Four Metarhizium species, two insect generalists (M. robertsii and M. brunneum), and two insect specialists (M. flavoviride and M. acridum) were inoculated onto agar plate cultures containing either bean (Phaseolus vulgaris) or corn (Zea mays) and grown for four and seven days. After methanol extraction, feature-based molecular networking (FBMN) was used to obtain DTX identification as defined by the Global Natural Products Social Molecular Networking (GNPS). A total of 25 DTX analogs were identified, with several DTX-like compounds in coculture that could not be identified. Metarhizium species differed in the amount and type of DTXs they produced, with the insect specialists producing far fewer amounts and types of DTXs than the insect generalists. The production of these metabolites varied between cultures of different ages and plant hosts. Conditions that influence the production of DTXs are discussed. As the genetic arsenal of natural products relates to the lifestyle of the organism, uncovering conditions with an ecological context may reveal strategies for producing novel compounds or precursors suitable for synthetic biology. [ABSTRACT FROM AUTHOR]

Insects and fungal pathogens pose constant problems to public health and agriculture, especially in resource-limited parts of the world; and the use of chemical pesticides continues to be the main methods for the control of these organisms. Photorhabdus spp. and Xenorhabdus spp., (Fam; Morganellaceae), enteric symbionts of Steinernema, and Heterorhabditis nematodes are naturally found in soil on all continents, except Antarctic, and on many islands throughout the world. These bacteria produce diverse secondary metabolites that have important biological and ecological functions. Secondary metabolites include non-ribosomal peptides, polyketides, and/or hybrid natural products that are synthesized using polyketide synthetase (PRS), non-ribosomal peptide synthetase (NRPS), or similar enzymes and are sources of new pesticide/drug compounds and/or can serve as lead molecules for the design and synthesize of new alternatives that could replace current ones. This review addresses the effects of these bacterial symbionts on insect pests, fungal phytopathogens, and animal pathogens and discusses the substances, mechanisms, and impacts on agriculture and public health. Key points: • Insects and fungi are a constant menace to agricultural and public health. • Chemical-based control results in resistance development. • Photorhabdus and Xenorhabdus are compelling sources of biopesticides. [ABSTRACT FROM AUTHOR]

Pinosylvin (3,5-dihydroxy-trans-stilbene), a natural pre-infectious stilbenoid toxin, is a terpenoid polyphenol compound principally found in the Vitaceae family in the heartwood of Pinus spp. (e.g., Pinus sylvestris) and in pine leaf (Pinus densiflora). It provides defense mechanisms against pathogens and insects for many plants. Stilbenoids are mostly found in berries and fruits but can also be found in other types of plants, such as mosses and ferns. This review outlined prior research on pinosylvin, including its sources, the technologies used for its extraction, purification, identification, and characterization, its biological and pharmacological properties, and its toxicity. The collected data on pinosylvin was managed using different scientific research databases such as PubMed, SciFinder, SpringerLink, ScienceDirect, Wiley Online, Google Scholar, Web of Science, and Scopus. In this study, the findings focused on pinosylvin to understand its pharmacological and biological activities as well as its chemical characterization to explore its potential therapeutic approaches for the development of novel drugs. This analysis demonstrated that pinosylvin has beneficial effects for various therapeutic purposes such as antifungal, antibacterial, anticancer, anti-inflammatory, antioxidant, neuroprotective, anti-allergic, and other biological functions. It has shown numerous and diverse actions through its ability to block, interfere, and/or stimulate the major cellular targets responsible for several disorders. [ABSTRACT FROM AUTHOR]

Monitoring systems based on artificial intelligence (AI) and wireless sensors are in high demand and give exact data extraction and analysis. The main objective of this paper is to detect the most appropriate plant development parameters. This paper has the concept of reducing the hazards in agriculture and promoting intelligent farming. Advancement in agriculture is not new, but the AI-based wireless sensor will push intelligent agriculture to a new standard. The research goal of this work is to improve the prediction state using image processing-based machine learning techniques. The main objective of the paper, as described above, is to detect and control cotton leaf diseases. This paper comprises several aspects, including leaf disease detection, remote monitoring system depending on the server, moisture and temperature sensing, and soil sensing. Insects and pathogens are typically responsible for plant diseases that reduce productivity if not timely. This paper presents a method to monitor the soil quality and prevent cotton leaf diseases. The proposed system suggested uses a regression technique of artificial intelligence to identify and classify leaf diseases. The information would be delivered to farmers through the Android app after infection identification. The Android app also allows soil parameter values like moisture, humidity, and temperature to be displayed along with the chemical level in a container. The relay may be on/off to regulate the motor and chemical sprinkler system as required by using the Android app. In the proposed system, the SVM algorithm delivers the best accuracy in detecting various diseases and demonstrates its efficiency in the detection and control by the improvement of cultivation for the farmers. [ABSTRACT FROM AUTHOR]

Understanding the types of haemocytes involved in the immune response in insects, and the mechanism involved in determining that response, can provide a scientific reference for developing effective microbial insecticides. Therefore, the current study examined haemocytes from Agrotis ipsilon (Hufnagel) larvae infected with Escherichia coli in terms of their morphology, total counts, and relative proportions at different time points post-infection by optical microscopy technology. The results revealed six types of haemocytes (prohemocytes, plasmatocytes, granulocytes, spherule cells, oenocytoids, and cystocytes) in the haemolymph of sixth-instar larvae. Haemocyte deformation, disruption, nuclear changes, and vacuoles were recorded after infection with different dosages of E. coli. At each time period post-infection, the total haemocyte count was significantly higher than in the controls, peaking at 24 h post-infection and then decreasing by 48 h post-infection. The proportion of prohemocytes decreased significantly until 24 h post-infection, and then began to increase. By contrast, the proportions of plasmatocytes, granulocytes, spherule cells, oenocytoids, and cystocytes relatively increased, and peaked by 24 h post-infection, and then decreased. This revealed that strong immune response was stimulated in larva of A. ipsilon in a short time after infection with E.coli, and the results shed addition light on the cellular immune response of insects to pathogens. [ABSTRACT FROM AUTHOR]

Unique CFP (cysteine-free protein; 120 aa) has been identified as an extraordinary virulence factor in Beauveria bassiana (Cordycipitaceae), a main source of wide-spectrum fungal insecticides. Its homologs exclusively exist in wide-spectrum insect pathogens of Hypocreales, suggesting their importance for a fungal insect-pathogenic lifestyle. In this study, all three CFP homologs (CFP1–3, 128–145 aa) were proven essential virulence factors in Metarhizium robertsii (Clavicipitaceae). Despite limited effects on asexual cycles in vitro, knockout mutants of cfp1,cfp2 and cfp3 were severely compromised in their capability for normal cuticle infection, in which most tested Galleria mellonella larvae survived. The blocked cuticle infection concurred with reduced secretion of extracellular enzymes, including Pr1 proteases required cuticle penetration. Cuticle-bypassing infection by intrahemocoel injection of ~250 conidia per larva resulted in a greater reduction in virulence in the mutant of cfp1 (82%) than of cfp2 (21%) or cfp3 (25%) versus the parental wild-type. Transcriptomic analysis revealed dysregulation of 604 genes (up/down ratio: 251:353) in the Δcfp1 mutant. Many of them were involved in virulence-related cellular processes and events aside from 154 functionally unknown genes (up/down ratio: 56:98). These results reinforce the essential roles of small CFP homologs in hypocrealean fungal adaptation to insect-pathogenic lifestyle and their exploitability for the genetic improvement of fungal insecticidal activity. [ABSTRACT FROM AUTHOR]