Configurable SNAP microresonators induced by axial pre-strain-assisted CO2 laser exposure.

Flexible engineering of the complex shapes of the surface nanoscale axial photonics (SNAP) bottle microresonators (SBMs) is challenging for future nanophotonic technology applications. Here, we experimentally propose a powerful approach for the one-step fabrication of SBMs with simultaneous negative and positive radius variations, exhibiting a distinctive "bump-well-bump" profile. It is executed by utilizing two focused and symmetrical CO2 laser beams exposed on the fiber surface for only several hundred milliseconds. The spectral characteristics of different eigenmodes are analyzed, providing deep insights into the complex physical processes during the CO2 laser exposure. The shapes of the SBMs can be flexibly adjusted by the exposure time, laser power, and applied pre-strains. As a proof of this technique, the developed approach enables the efficient production of a bat SBM, ensuring a uniform field amplitude of the bat mode over the length exceeding 120 µm with 7% deviation. Our proposed technique provides a powerful technique for the efficient fabrication of SBMs with predetermined shapes, laying the groundwork for its applications on microscale optical signal processing, quantum computing, and so on.

The transcriptome of Icerya aegyptiaca (Hemiptera: Monophlebidae) and comparison with neococcoids reveal genetic clues of evolution in the scale insects.

BACKGROUND: Scale insects are worldwide sap-sucking parasites, which can be distinguished into neococcoids and non-neococcoids. Neococcoids are monophyletic with a peculiar reproductive system, paternal genome elimination (PGE). Different with neococcoids, Iceryini, a tribe in non-neococcoids including several damaging pests, has abdominal spiracles, compound eyes in males, relatively abundant wax, unique hermaphrodite system, and specific symbionts. However, the current studies on the gene resources and genomic mechanism of scale insects are mainly limited in the neococcoids, and lacked of comparison in an evolution frame. RESULT: We sequenced and de novo assembled a transcriptome of Icerya aegyptiaca (Douglas), a worldwide pest of Iceryini, and used it as representative of non-neococcoids to compare with the genomes or transcriptomes of other six species from different families of neococcoids. We found that the genes under positive selection or negative selection intensification (simplified as "selected genes" below) in I. aegyptiaca included those related to neurogenesis and development, especially eye development. Some genes related to fatty acid biosynthesis were unique in its transcriptome with relatively high expression and not detected in neococcoids. These results may indicate a potential link to the unique structures and abundant wax of I. aegyptiaca compared with neococcoids. Meanwhile, genes related to DNA repair, mitosis, spindle, cytokinesis and oogenesis, were included in the selected genes in I. aegyptiaca, which is possibly associated with cell division and germ cell formation of the hermaphrodite system. Chromatin-related process were enriched from selected genes in neococcoids, along with some mitosis-related genes also detected, which may be related to their unique PGE system. Moreover, in neococcoid species, male-biased genes tend to undergo negative selection relaxation under the PGE system. We also found that the candidate horizontally transferred genes (HTGs) in the scale insects mainly derived from bacteria and fungi. bioD and bioB, the two biotin-synthesizing HTGs were exclusively found in the scale insects and neococcoids, respectively, which possibly show potential demand changes in the symbiotic relationships. CONCLUSION: Our study reports the first I. aegyptiaca transcriptome and provides preliminary insights for the genetic change of structures, reproductive systems and symbiont relationships at an evolutionary aspect. This will provide a basis for further research and control of scale insects.

Genomic insight into the scale specialization of the biological control agent Novius pumilus (Weise, 1892).

BACKGROUND: Members of the genus Novius Mulsant, 1846 (= Rodolia Mulsant, 1850) (Coleoptera, Coccinellidae), play important roles in the biological control of cotton cushion scale pests, especially those belonging to Icerya. Since the best-known species, the vedalia beetle Novius cardinalis (Mulsant, 1850) was introduced into California from Australia, more than a century of successful use in classical biological control, some species of Novius have begun to exhibit some field adaptations to novel but related prey species. Despite their economic importance, relatively little is known about the underlying genetic adaptations associated with their feeding habits. Knowledge of the genome sequence of Novius is a major step towards further understanding its biology and potential applications in pest control. RESULTS: We report the first high-quality genome sequence for Novius pumilus (Weise, 1892), a representative specialist of Novius. Computational Analysis of gene Family Evolution (CAFE) analysis showed that several orthogroups encoding chemosensors, digestive, and immunity-related enzymes were significantly expanded (P < 0.05) in N. pumilus compared to the published genomes of other four ladybirds. Furthermore, some of these orthogroups were under significant positive selection pressure (P < 0.05). Notably, transcriptome profiling demonstrated that many genes among the significantly expanded and positively selected orthogroups, as well as genes related to detoxification were differentially expressed, when N. pumilus feeding on the nature prey Icerya compared with the no feeding set. We speculate that these genes are vital in the Icerya adaptation of Novius species. CONCLUSIONS: We report the first Novius genome thus far. In addition, we provide comprehensive transcriptomic resources for N. pumilus. The results from this study may be helpful for understanding the association of the evolution of genes related to chemosensing, digestion, detoxification and immunity with the prey adaptation of insect predators. This will provide a reference for future research and utilization of Novius in biological control programs. Moreover, understanding the possible molecular mechanisms of prey adaptation also inform mass rearing of N. pumilus and other Novius, which may benefit pest control.

Horizontally acquired antibacterial genes associated with adaptive radiation of ladybird beetles.

BACKGROUND: Horizontal gene transfer (HGT) has been documented in many herbivorous insects, conferring the ability to digest plant material and promoting their remarkable ecological diversification. Previous reports suggest HGT of antibacterial enzymes may have contributed to the insect immune response and limit bacterial growth. Carnivorous insects also display many evolutionary successful lineages, but in contrast to the plant feeders, the potential role of HGTs has been less well-studied. RESULTS: Using genomic and transcriptomic data from 38 species of ladybird beetles, we identified a set of bacterial cell wall hydrolase (cwh) genes acquired by this group of beetles. Infection with Bacillus subtilis led to upregulated expression of these ladybird cwh genes, and their recombinantly produced proteins limited bacterial proliferation. Moreover, RNAi-mediated cwh knockdown led to downregulation of other antibacterial genes, indicating a role in antibacterial immune defense. cwh genes are rare in eukaryotes, but have been maintained in all tested Coccinellinae species, suggesting that this putative immune-related HGT event played a role in the evolution of this speciose subfamily of predominant predatory ladybirds. CONCLUSION: Our work demonstrates that, in a manner analogous to HGT-facilitated plant feeding, enhanced immunity through HGT might have played a key role in the prey adaptation and niche expansion that promoted the diversification of carnivorous beetle lineages. We believe that this represents the first example of immune-related HGT in carnivorous insects with an association with a subsequent successful species radiation.

Revealing the Mechanisms for Linalool Antifungal Activity against Fusarium oxysporum and Its Efficient Control of Fusarium Wilt in Tomato Plants.

Fusarium oxysporum f. sp. radicis-lycopersici (Forl) is a destructive soil-borne phytopathogenic fungus that causes Fusarium crown and root rot (FCRR) of tomato, leading to considerable field yield losses. In this study, we explored the antifungal capability of linalool, a natural plant volatile organic component, against Forl and its role in controlling FCRR symptoms in tomatoes. Our results showed that Forl mycelial growth was inhibited by the linalool treatment and that the linalool treatment damaged cell membrane integrity, enhanced reactive oxygen species levels, depleted glutathione, and reduced the activities of many antioxidant enzymes in Forl. Transcriptomic and proteomic analyses demonstrated that linalool also downregulated metabolic biosynthetic pathways at the transcript and protein levels, including redox, transporter activity, and carbohydrate metabolism in Forl. Moreover, linalool significantly decreased the expression of many Forl pathogenic genes, such as cell wall degrading enzymes (CWDEs) and G proteins, which is likely how a Forl infection was prevented. Importantly, exogenously applied linalool activated the salicylic acid (SA) and jasmonic acid (JA) defensive pathways to improve disease resistance and relieved the negative effects of Forl on plant growth. Taken together, we report that linalool is an effective fungicide against Forl and will be a promising green chemical agent for controlling FCRR.

Genomic insight into diet adaptation in the biological control agent Cryptolaemus montrouzieri.

BACKGROUND: The ladybird beetle Cryptolaemus montrouzieri Mulsant, 1853 (Coleoptera, Coccinellidae) is used worldwide as a biological control agent. It is a predator of various mealybug pests, but it also feeds on alternative prey and can be reared on artificial diets. Relatively little is known about the underlying genetic adaptations of its feeding habits. RESULTS: We report the first high-quality genome sequence for C. montrouzieri. We found that the gene families encoding chemosensors and digestive and detoxifying enzymes among others were significantly expanded or contracted in C. montrouzieri in comparison to published genomes of other beetles. Comparisons of diet-specific larval development, survival and transcriptome profiling demonstrated that differentially expressed genes on unnatural diets as compared to natural prey were enriched in pathways of nutrient metabolism, indicating that the lower performance on the tested diets was caused by nutritional deficiencies. Remarkably, the C. montrouzieri genome also showed a significant expansion in an immune effector gene family. Some of the immune effector genes were dramatically downregulated when larvae were fed unnatural diets. CONCLUSION: We suggest that the evolution of genes related to chemosensing, digestion, and detoxification but also immunity might be associated with diet adaptation of an insect predator. These findings help explain why this predatory ladybird has become a successful biological control agent and will enable the optimization of its mass rearing and use in biological control programs.

Changes in life history traits and transcriptional regulation of Coccinellini ladybirds in using alternative prey.

BACKGROUND: Ladybird beetles (Coleoptera, Coccinellidae) are highly diverse in their feeding habits. Most of them are specialist feeders, while some can have a broad spectrum of prey. As a representative group of generalists, the tribe Coccinellini includes many aphidophagous species, but members of this tribe also feed on other hemipterous insects including coccids, psyllids and whiteflies. As a result, several species are effective biological control agents or invasive species with serious non-target effects. Despite their economic importance, relatively little is known about how they adapt to new prey. RESULTS: In this study, comparisons of the life history traits and transcriptomes of ladybirds fed initial (aphids) and alternative prey (mealybugs) were performed in three Coccinellini species. The use of alternative prey greatly decreased performance, implied by the significantly prolonged development time and decreased survival rate and adult weight. Prey shifts resulted in a set of differentially expressed genes encoding chemosensory proteins and digestive and detoxifying enzymes. CONCLUSIONS: Our results suggest that these generalists do not perform well when they use alternative prey as the sole nutrition source. Although their capacity for predation might have created an opportunity to use varied prey, they must adapt to physiological obstacles including chemosensing, digestion and detoxification in response to a prey shift. These findings challenge the effect of Coccinellini predators on the biological control of non-aphid pests and suggest the possibility of non-target attacks by so-called specialists.

Population admixture can enhance establishment success of the introduced biological control agent Cryptolaemus montrouzieri.

BACKGROUND: Introduced biological control agents have opportunities of population admixture through multiple introductions in the field. However, the importance of population admixture for their establishment success often remains unclear. Previous studies based on genetic markers have suggested a history of population admixture in the predatory ladybird Cryptolaemus montrouzieri Mulsant in China. RESULTS: We tested whether population admixture may lead to fitness changes under laboratory conditions. We first found no mating barrier or strong bias between two parental populations, despite their differences in genetics and phenotypes. Then, our experimental evidence supported the hypothesis that admixed populations have a higher potential of establishment success, due to their superior reproductive ability, and hunger and cold tolerance inherited from one of the parental populations. CONCLUSIONS: We suggest that population admixture can be a breeding method to improve the performance of biological control agents, particularly when used in a classical biological control approach, but that consequences for potential invasiveness need to be considered.

Molecular phylogeny reveals food plasticity in the evolution of true ladybird beetles (Coleoptera: Coccinellidae: Coccinellini).

BACKGROUND: The tribe Coccinellini is a group of relatively large ladybird beetles that exhibits remarkable morphological and biological diversity. Many species are aphidophagous, feeding as larvae and adults on aphids, but some species also feed on other hemipterous insects (i.e., heteropterans, psyllids, whiteflies), beetle and moth larvae, pollen, fungal spores, and even plant tissue. Several species are biological control agents or widespread invasive species (e.g., Harmonia axyridis (Pallas)). Despite the ecological importance of this tribe, relatively little is known about the phylogenetic relationships within it. The generic concepts within the tribe Coccinellini are unstable and do not reflect a natural classification, being largely based on regional revisions. This impedes the phylogenetic study of important traits of Coccinellidae at a global scale (e.g. the evolution of food preferences and biogeography). RESULTS: We present the most comprehensive phylogenetic analysis of Coccinellini to date, based on three nuclear and one mitochondrial gene sequences of 38 taxa, which represent all major Coccinellini lineages. The phylogenetic reconstruction supports the monophyly of Coccinellini and its sister group relationship to Chilocorini. Within Coccinellini, three major clades were recovered that do not correspond to any previously recognised divisions, questioning the traditional differentiation between Halyziini, Discotomini, Tytthaspidini, and Singhikaliini. Ancestral state reconstructions of food preferences and morphological characters support the idea of aphidophagy being the ancestral state in Coccinellini. This indicates a transition from putative obligate scale feeders, as seen in the closely related Chilocorini, to more agile general predators. CONCLUSIONS: Our results suggest that the classification of Coccinellini has been misled by convergence in morphological traits. The evolutionary history of Coccinellini has been very dynamic in respect to changes in host preferences, involving multiple independent host switches from different insect orders to fungal spores and plants tissues. General predation on ephemeral aphids might have created an opportunity to easily adapt to mixed or specialised diets (e.g. obligate mycophagy, herbivory, predation on various hemipteroids or larvae of leaf beetles (Chrysomelidae)). The generally long-lived adults of Coccinellini can consume pollen and floral nectars, thereby surviving periods of low prey frequency. This capacity might have played a central role in the diversification history of Coccinellini.

Variation in life history traits and transcriptome associated with adaptation to diet shifts in the ladybird Cryptolaemus montrouzieri.

BACKGROUND: Despite the broad diet range of many predatory ladybirds, the mechanisms involved in their adaptation to diet shifts are not completely understood. Here, we explored how a primarily coccidophagous ladybird Cryptolaemus montrouzieri adapts to feeding on aphids. RESULTS: Based on the lower survival rate, longer developmental time, and lower adult body weight and reproduction rate of the predator, the aphid Megoura japonica proved being less suitable to support C. montrouzieri as compared with the citrus mealybug Planococcus citri. The results indicated up-regulation of genes related to ribosome and translation in fourth instars, which may be related to their suboptimal development. Also, several genes related to biochemical transport and metabolism, and detoxification were up-regulated as a result of adaptation to the changes in nutritional and non-nutritional (toxic) components of the prey. CONCLUSION: Our results indicated that C. montrouzieri succeeded in feeding on aphids by regulation of genes related to development, digestion and detoxification. Thus, we argue that these candidate genes are valuable for further studies of the functional evolution of ladybirds led by diet shifts.

Identification of two lineages of host-associated eriophyoid mites predisposed to different levels of host diversification.

Herbivorous arthropods can diversify as a consequence of evolutionary changes in response to their plant hosts. Current patterns of host association of herbivores are likely to reflect a long evolutionary history of herbivore-plant co-evolution. Here, we used molecular phylogenetics to track the evolutionary history of host shifts and diversification of 66 eriophyoid mites (Acari, Eriophyoidea), and linked past patterns of evolutionary diversification to more recent patterns of divergence by tracking population genetic variation in 13 of the eriophyoid mite species feeding on different gymnosperm hosts. This allowed us to explore the relationship between a past history of diversification and the current potential of mites to undergo host range shifts. We found that population-level diversity across gymnosperm hosts as measured by 28S rRNA markers was greater in species from the mite clade that had radiated across evolutionary time to utilize a variety of hosts including angiosperms, compared to species from the clade that has remained restricted to ancestral gymnosperm hosts. Species from the radiated clade exhibited higher variation in host use. Lineages of mites that have in the past been able to radiate and adapt to diverse plants may therefore be predisposed to continue their expansion on new hosts, although additional clades need to be tested.

Larval nutrition-induced plasticity affects reproduction and gene expression of the ladybeetle, Cryptolaemus montrouzieri.

BACKGROUND: Organisms may develop into multiple phenotypes under different nutritional environments by developmental plasticity, whereas the potential costs and mechanisms of such plasticity are poorly understood. Here we examined the fitness and gene expression of nutrition-induced phenotypes in the ladybeetle, Cryptolaemus montrouzieri after having experienced varying larval food regimes. RESULTS: We found that C. montrouzieri adults undergoing a variable larval food regime achieved a similar developmental time, survival, body mass and egg production as those undergoing a high larval food regime. The survival, developmental time, body mass and fecundity of the adults from a restricted larval food regime were inferior to those from the high and variable larval food regimes. However, the adults from this restricted larval food regime had a higher expression level of genes encoding immune- and antioxidant-related enzymes than those from the high and variable larval food regimes when exposed to starvation and pesticide conditions in adult life. CONCLUSIONS: These results suggest that larval food availability in C. montrouzieri not only triggers adult phenotypic differences but also affects reproduction and expression level of genes in adult life, indicating that the larval nutritional conditions can affect adult fitness and resistance to stressful conditions through developmental plasticity.

Genetic Differentiation in Native and Introduced Populations of Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) and Its Implications for Biological Control Programs.

Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) is an effective biological control agent of Australian origin, which has been introduced worldwide to control mealybugs. Although successfully used for >100 yr, its introduction in a new area may cause environmental risks should the populations become invasive. In the present study, a population genetics method was used to make predictions of the invasive potential of C. montrouzieri. Our results showed a similar level of genetic diversity among all populations. No significant genetic differentiation between native and introduced populations was observed, while three populations from the native region were significantly divergent. The fact that genetic diversity was not reduced in introduced areas suggests that no bottleneck effect has occurred during introduction. To avoid rapid evolution of the introduced C. montrouzieri, the introduction records of each population should be clearly traced and introductions from multiple sources into the same area should be avoided.

DNA barcoding reveals the protogyne and deutogyne of Tegolophus celtis sp. nov. (Acari: Eriophyidae).

A few eriophyoid mites have two forms of adult female, called protogyne and deutogyne. The latter form is thought to increase survival under unfavorable conditions. The two forms have distinct morphological characters, which often cause them to be recognized as different species. Molecular species delimitation provides a useful tool to solve these misunderstandings. Here we describe a new species of eriophyoid mite, Tegolophus celtis sp. nov., that has protogyne and deutogyne forms infesting Chinese hackberry, Celtis sinensis Pers. (Cannabaceae), an ornamental tree in China. The two forms can be easily differentiated by body shape (fusiform and triangular, respectively) and body color (light yellow and red, respectively). The putative protogyne and deutogyne forms of T. celtis were identified by using fragments of three genes, a mitochondrial gene (COI) and two nuclear genes (18S rRNA and 28S rRNA). Kimura-2-parameter distances of these three fragmental sequences were between 0.0% and 0.9%. Phylogenetic topologies strongly support the occurrence of the protogyne and deutogyne forms with high bootstrap and Bayesian values. The population structure of T. celtis changed with the seasons, with deutogynes being most abundant in summer and protogynes being most abundant in spring. The new species described herein are vagrants on their host plants.

Homoplastic evolution and host association of Eriophyoidea (Acari, Prostigmata) conflict with the morphological-based taxonomic system.

The superfamily Eriophyoidea is exceptionally diverse and its members are highly host-specific. Currently, the taxonomy of this group is based on morphology only. However, phylogenetic relationships in this group could be incorrect if the diagnostic morphological characters are homoplastic. Therefore, the phylogeny of 112 representative taxa of Eriophyoidea from China was determined using 18S, 28S D2-5 and D9-10 rRNA. Phylogenetic relationships were inferred through Bayesian, maximum likelihood and maximum parsimony methods, and then a number of clades or major clades were defined according to robust phylogenetic topologies combined with morphological comparison. Tests of monophyly showed that two of three families of Eriophyoidea as well as one subfamily and four tribes were not monophyletic. Ancestral character state reconstruction (ACSR) showed that five diagnostic morphological characters evolved several times, confounding the current taxonomy. Additionally, reconstruction of the history of host plant colonization suggested host switching occurred in a limited range of host plants. The host association data made it possible to determine taxonomic relationships more accurately. These results show that by integrating morphological and molecular information and host plant choice, it is possible to obtain a more accurate taxonomy and a deeper phylogenetic understanding of Eriophyoidea.

Cryptic diversity in host-associated populations of Tetra pinnatifidae (Acari: Eriophyoidea): what do morphometric, mitochondrial and nuclear data reveal and conceal?

Traditional morphology-based taxonomy of eriophyoid mites (Acari: Eriophyoidea) has been challenged by molecular-based technologies in the detection of cryptic species. However, the implications of such cryptic diversity appear to differ when methods based on different types of data are used. Here, samples of a host-associated eriophyoid mite species, Tetra pinnatifidae, collected from different host plants and localities are evaluated. The congruence of results based on morphometric (32 characters), mitochondrial (16S), and nuclear (28S) data were evaluated and showed a host-associated cryptic diversity dividing this morphospecies into several groups/clades that were morphometrically indistinguishable. In comparison, the 16S data confirmed cryptic speciation and intra-clade host-associated diversity, while 28S did not. In contrast, 28S data revealed potential gene flow between host-associated populations. High mitochondrial divergence, as well as low nuclear and morphological divergence indicated very recent stage of cryptic diversity of this eriophyoid mite.

Magnetic resonance imaging-based radiomics and deep learning models for predicting lymph node metastasis of squamous cell carcinoma of the tongue.

OBJECTIVE: This study aimed to establish a combined method of radiomics and deep learning (DL) in magnetic resonance imaging (MRI) to predict lymph node metastasis (LNM) preoperatively in patients with squamous cell carcinoma of the tongue. STUDY DESIGN: In total, MR images of 196 patients with lingual squamous cell carcinoma were divided into training (n = 156) and test (n = 40) cohorts. Radiomics and DL features were extracted from MR images and selected to construct machine learning models. A DL radiomics nomogram was established via multivariate logistic regression by incorporating the radiomics signature, the DL signature, and MRI-reported LN status. RESULTS: Nine radiomics and 3 DL features were selected. In the radiomics test cohort, the multilayer perceptron model performed best with an area under the receiver operating characteristic curve (AUC) of 0.747, but in the DL cohort, the best model (logistic regression) performed less well (AUC = 0.655). The DL radiomics nomogram showed good calibration and performance with an AUC of 0.934 (outstanding discrimination ability) in the training cohort and 0.757 (acceptable discrimination ability) in the test cohort. The decision curve analysis demonstrated that the nomogram could offer more net benefit than a single radiomics or DL signature. CONCLUSION: The DL radiomics nomogram exhibited promising performance in predicting LNM, which facilitates personalized treatment of tongue cancer.

Effect of Ephestia kuehniella Eggs on Development and Transcriptome of the Ladybird Beetle Propylea japonica.

The eggs of the Mediterranean flour moth, Ephestia kuehniella, are frequently utilized as alternative diets and have demonstrated promising outcomes when consumed by various insects. Nonetheless, the specific reasons for their effectiveness remain unclear. In our study, we assessed the developmental performance of the ladybird Propylea japonica when fed E. kuehniella eggs, alongside 12 factitious prey or artificial diets. Our findings revealed that ladybirds fed E. kuehniella eggs displayed a performance comparable to those fed the natural prey Megoura crassicauda. Transcriptome profiling of larvae raised on E. kuehniella eggs and M. crassicauda revealed that genes upregulated in the former group were enriched in metabolic pathways associated with carbohydrates, lipids, and other essential nutrients. This suggests that E. kuehniella eggs may have a higher nutrient content compared to natural prey. Furthermore, a notable downregulation in the expression of immune effector genes, such as Attacin and Coleoptericin, was observed, which might be attributed to the lower microbial content in E. kuehniella eggs compared to M. crassicauda. We suggest that the difference between E. kuehniella eggs and M. crassicauda as food sources for P. japonica lies in their nutrient and microbial contents. These findings provide valuable insights for the advancement of innovative artificial breeding systems for natural enemies.

Metabolism, digestion, and horizontal transfer: potential roles and interaction of symbiotic bacteria in the ladybird beetle Novius pumilus and their prey Icerya aegyptiaca.

In this study, we first time sequenced and analyzed the 16S rRNA gene data of predator ladybird beetles Novius pumilus and globally distributed invasive pest Icerya aegyptiaca at different stages, and combined data with bacterial genome sequences in N. pumilus to explored the taxonomic distribution, alpha and beta diversity, differentially abundant bacteria, co-occurrence network, and putative functions of their microbial community. Our finding revealed that Candidatus Walczuchella, which exhibited a higher abundance in I. aegyptiaca, possessed several genes in essential amino acid biosynthesis and seemed to perform roles in providing nutrients to the host, similar to other obligate symbionts in scale insects. Lactococcus, Serratia, and Pseudomonas, more abundant in N. pumilus, were predicted to have genes related to hydrocarbon, fatty acids, and chitin degradation, which may assist their hosts in digesting the wax shell covering the scale insects. Notably, our result showed that Lactococcus had relatively higher abundances in adults and eggs compared to other stages in N. pumilus, indicating potential vertical transmission. Additionally, we found that Arsenophonus, known to influence sex ratios in whitefly and wasp, may also function in I. aegyptiaca, probably by influencing nutrient metabolism as it similarly had many genes corresponding to vitamin B and essential amino acid biosynthesis. Also, we observed a potential horizontal transfer of Arsenophonus between the scale insect and its predator, with a relatively high abundance in the ladybirds compared to other bacteria from the scale insects.IMPORTANCEThe composition and dynamic changes of microbiome in different developmental stages of ladybird beetles Novius pumilus with its prey Icerya aegyptiaca were detected. We found that Candidatus Walczuchella, abundant in I. aegyptiaca, probably provide nutrients to their host based on their amino acid biosynthesis-related genes. Abundant symbionts in N. pumilus, including Lactococcus, Serratia, and Pseudophonus, may help the host digest the scale insects with their hydrocarbon, fatty acid, and chitin degrading-related genes. A key endosymbiont Arsenophonus may play potential roles in the nutrient metabolisms and sex determination in I. aegyptiaca, and is possibly transferred from the scale insect to the predator.

Effects of linalool on Botrytis cinerea growth and control of tomato gray mold.

We examined the antifungal characteristics of linalool against Botrytis cinerea using plate inhibition assay and spore germination assay, and assessed the capacity of linalool in controlling tomato gray mold disease via tomato pot inoculation assay. The results showed that linalool exhibited strong inhibitive effects on mycelial growth of B. cinerea, with an EC50 value of 0.581 mL·L-1. In the spore germination test, linalool treatment inhibited spore germination in a dose-dependent manner. The electric conductivity and the malondialdehyde (MDA) contents were significantly increased in linalool-treated B. cinerea than that of the control, indicating that linalool induced oxidative damage and destroyed the cell membrane integrity in B. cinerea. The activities of the superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in the linalool-treated B. cinerea were decreased significantly by 27.4%, 68.9% and 26.0%, respectively, suggesting that linalool inhibited the antioxidant activity of B. cinerea. In the pot experiment, the diameter of lesions in linalool-treated tomatoes was significantly smaller than that of the control. The activities of SOD, POD, CAT, polyphenol oxidase, and phenylalnine ammonialyase in the linalool-treated tomatoes increased, while the MDA content decreased, suggesting that linalool could alleviate the oxidative damage caused by B. cinerea and promote plant disease resistance. In summary, linalool had inhibitory effect on the growth of B. cinerea and could control gray mold disease in tomatoes. These findings could lay the foundation for developing bota-nical antifungal agents for management of tomato gray mold disease.