Cotesia Plutellae Research Articles

Viral imitation is the sincerest form of epigenetic flattery.

Viruses use multiple strategies to successfully generate progeny and overcome host defenses. In recent years, it has become increasingly evident that epigenetic mechanisms of host gene regulation are vulnerable to viral manipulation. In the form of histone mimicry, viral invasion of host chromatin is a striking example of how viruses have evolved to invade every aspect of cellular function for viral benefit. In this perspective, we will review how three viruses-influenza A, SARS-CoV-2, and Cotesia plutellae bracovirus-use histone mimicry to promote viral success through immune evasion. These examples highlight the importance of this burgeoning field and point toward the wealth of knowledge we have yet to uncover.

Characterization of larval gut microbiota of two endoparasitoid wasps associated with their common host, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae).

Insect gut microbes play important roles in digestion, metabolism, development, and environmental adaptation. Parasitoid wasps are one of the most important biological control agents in pest control, while the gut microbial species compositions and the associated functions have been poorly investigated. Two endoparasitoid wasps, Cotesia vestalis and Diadromus collaris, parasitize the larval stage and pupal stage of the diamondback moth, Plutella xylostella, respectively. Using whole-genome shotgun metagenomic sequencing, we characterized the gut microbial composition, diversity, and potential functional roles associated with the two parasitoid wasp larvae. The results reveal that Proteobacteria and Firmicutes are the dominant phyla in the gut of C. vestalis and D. collaris larvae, with Rhizobium and Enterococcus being the dominant genera. The putative microbial functions associated with the two parasitoid wasps might play a virtual role in assisting in consuming the host's nutritional composition. The enriched CAZymes family genes are primarily involved in the degradation and synthesis of chitin. Despite the richness of microbial species and communities, the microbes species and the microbial community structure exhibit significant similarity between the two parasitoid wasps and between the parasitoid wasp and the host P. xylostella. Notably, the prevalence of the genus Enterococcus shared among them suggests a possible link of gut microbes between the host and their associated parasitoids. Our study offers insights into the gut microbe-based interactions between the host and parasitoid wasps for the first time, potentially paving the way for the development of an ecologically friendly biocontrol strategy against the pest P. xylostella.IMPORTANCEEndoparasitoid wasps spend the majority of their lifespan within their host and heavily rely on the host's nutrition for survival. There is limited understanding regarding the composition and physiological impacts of gut microbial communities in parasitoid wasps, particularly during the larval stage, which is directly linked to the host. Based on a thorough characterization of the gut microbe and comprehensive comparative analysis, we found the microbial species of the larval parasitoid wasp Cotesia vestalis and the pupal parasitoid wasp Diadromus collaris were similar, sharing 159 genera and 277 species, as were the microbial community structure. Certain of the dominant microbial strains of the two parasitoid wasps were similar to that of their host Plutella xylostella larvae, revealing host insect may affect the microbial community of the parasitoid wasps. The putative microbial functions associated with the parasitoid wasp larvae play an important role in dietary consumption.

Influence of the parasitoid Cotesia vestalis on the distribution of diamondback moth larvae on cabbage plants

Influence of the parasitoid Cotesia vestalis on the distribution of diamondback moth larvae on cabbage plants

Reinforced colour preference of parasitoid wasps in the presence of floral scent: a case study of a cross-modal effect

We examined the possibility of a cross-modal effect in naïve Cotesia vestalis, a parasitoid wasp of diamondback moth larvae, by using artificial flower models of four colours (blue, green, yellow, and red) in the absence or presence of floral scent collected from Brassica rapa inflorescences. In a four-choice test, regardless of the floral scent, non-starved female wasps visited green and yellow models significantly more often than blue and red ones, although no significant difference was observed between visits to the green and yellow models. They seldom visited blue and red models. When starved, the wasps became even more particular, visiting yellow significantly more frequently than green models, irrespective of the presence of the floral scent, indicating that they preferred to use yellow visual cues in their food search. Furthermore, a factorial analysis of variance revealed a significant effect of the interaction between model colour and floral scent on the wasps’ visits to flower models. The floral scent induced starved and non-starved wasps to visit yellow and green models about twice as often as without the scent. A cross-modal effect of olfactory perception on the use of chromatic information by wasps may allow them to search efficiently for food sources.

Effect of faba bean nectar on longevity and fecundity of Plutella xylostella and its parasitoid Cotesia vestalis

Intercropping faba bean with vegetables provides a possibility to promote pest control and better nutrient cycling in sustainable agriculture. Faba bean produces extrafloral nectar which supports parasitoid wasps that play a role in the biological control of pest insects. However, adult lepidopteran pests also benefit from nectar, increasing their lifespan and the number of offspring they produce. Here, a laboratory-based study was conducted to assess the role of faba bean on the components of a Brassica-based host-parasitoid system. We measured how access to faba bean affected the longevity and fecundity of the brassica pest Plutella xylostella and its parasitoid Cotesia vestalis. It was also studied if odors of flowering faba bean disrupt host finding by C. vestalis in Y-tube bioassays and volatile organic compounds were analyzed to explain the olfaction-based choices made by the parasitoids. The longevity of C. vestalis was 6.6 times longer and the number of pupae produced almost 10 times greater when they had access to faba bean. Meanwhile, the longevity of P. xylostella was 3.6 times longer and it laid 4.6 times more eggs when provided access to faba bean. In Y-tube bioassays, C. vestalis females also oriented toward host-related odors of the damaged cabbage more than intact cabbage when odors of faba bean were mixed with both of them. In conclusion, faba bean provided sustenance to both pest insects and their natural enemies that prolonged their lifespans and their reproductive capacity.

An odorant receptor mediates the avoidance of Plutella xylostella against parasitoid

BackgroundEcosystems are brimming with myriad compounds, including some at very low concentrations that are indispensable for insect survival and reproduction. Screening strategies for identifying active compounds are typically based on bioassay-guided approaches.ResultsHere, we selected two candidate odorant receptors from a major pest of cruciferous plants—the diamondback moth Plutella xylostella—as targets to screen for active semiochemicals. One of these ORs, PxylOR16, exhibited a specific, sensitive response to heptanal, with both larvae and adult P. xylostella displaying heptanal avoidance behavior. Gene knockout studies based on CRISPR/Cas9 experimentally confirmed that PxylOR16 mediates this avoidance. Intriguingly, rather than being involved in P. xylostella–host plant interaction, we discovered that P. xylostella recognizes heptanal from the cuticular volatiles of the parasitoid wasp Cotesia vestalis, possibly to avoid parasitization.ConclusionsOur study thus showcases how the deorphanization of odorant receptors can drive discoveries about their complex functions in mediating insect survival. We also demonstrate that the use of odorant receptors as a screening platform could be efficient in identifying new behavioral regulators for application in pest management.

Front Cover Image

The cover image is based on the Research Article Identification of floral volatiles from Fagopyrum esculentum that attract Cotesia vestalis with potentially better biocontrol efficacy against Plutella xylostella by Shijun You et al., https://doi.org/10.1002/ps.7808.image

Identification of floral volatiles from Fagopyrum esculentum that attract Cotesia vestalis with potentially better biocontrol efficacy against Plutella xylostella.

Nectar plants provide extra nourishment for parasitoids, which can utilize floral volatiles to locate nectar-rich flowers. A promising strategy is to screen potential floral species based on the wasps' olfactory preferences for nectar sources, and to ensure their suitability for both natural enemies and targeted pests. Cotesia vestalis (Haliday) is a dominant parasitoid of the oligophagous pest Plutella xylostella, which poses a significant threat to cruciferous vegetables globally. However, the chemical cues in plant-parasitoid complexes mediating Cotesia vestalis to locate nectar food resources and the positive effect of nectar plants on the Cotesia vestalis population are poorly understood. The results showed that Fagopyrum esculentum was the most attractive plant that attracted Cotesia vestalis, not Plutella xylostella in 44 flowering plants from 19 families. 1,2-Diethyl benzene and 1,4-diethyl benzene, identified from the floral volatiles from F. esculentum in full bloom, were found to elicit dose-dependent electrophysiological responses and attract Cotesia vestalis adults, demonstrating their potential as semiochemicals. Moreover, the age-stage, two-sex life table revealed that feeding on nectar food increased the efficacy of Cotesia vestalis adults against Plutella xylostella. In summary, the findings provide insights into the chemical ecology of plant-parasitoid complexes and support the potential use of F. esculentum as insectary plants in habitat manipulation against Plutella xylostella by supplying natural nectar food for the Cotesia vestalis population. Our results suggest an attract and reward strategy based on an attractant for Cotesia vestalis to control Plutella xylostella, or the development of volatile-based artificial food for Cotesia vestalis. © 2023 Society of Chemical Industry.

The hymenopterous parasitoids of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), on cruciferous vegetables in Delhi, India

BackgroundThe diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a serious and economically important pest of crucifers in Delhi, India. Larvae and pupae of the pest were collected from the cabbage, cauliflower and broccoli crops grown in vegetable fields at the farm of ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi-110012, from December 2021 to June 2022. The larvae and pupae of the pest were transferred to the laboratory and reared for emergence of parasitoids’ adults at 25 ± 0.5 °C and RH 70 ± 5%.ResultsFour parasitoid species were emerged, viz. Apanteles mohandasi Sumodan & Narendran 1990, Cotesia vestalis (Haliday, 1834), Diadegma insulare (Cresson, 1865) and Diadromus collaris (Gravenhorst, 1829). Among them, A. mohandasi, C. vestalis and D. collaris were reported for the first time in Delhi, whereas D. insulare (Hymenoptera: Ichneumonidae) is recorded here for the first time in India. Additionally, the first record of parasitism by A. mohandasi on P. xylostella from Delhi was established. The highest parasitism percentage was that of C. vestalis and D. collaris. Moreover, higher parasitism rate was recorded during May 2022 in organically cultivated fields. The parasitism percentage by A. mohandasi, C. vestalis, D. insulare and D. collaris was 7.5, 22.5, 12.5 and 15%, respectively. Conversely, in conventionally farmed fields, the parasitism rates were 3.57, 16.67, 10 and 13.33%, respectively.ConclusionThe use of biological control agents particularly the parasitoids in the IPM program of P. xylostella should be considered, thereby reducing reliance on insecticides and increasing the efficacy of hymenopteran parasitoids.

Identification of immune‐related genes from the transcriptome of the venom gland in Cotesia plutellae

AbstractCotesia plutellae, an endoparasitoid wasp is the natural enemy against the diamondback moth, Plutella xylostella. Successful parasitization of C. plutellae requires maternal factors such as polydnavirus, venom proteins, and ovary proteins into the host, protecting their eggs from the host's immune system. To identify the immune‐related genes from the venom glands, we analyzed the transcriptome of venom glands via RNA‐seq. RNA‐seq analysis reveals that 39,207 transcripts were identified. Totally 106 immune‐related genes such as peptidoglycan‐recognition proteins, serpins, spätzles, phenoloxidase, defensin, and calreticulin, etc. were identified and classified into pathogen recognition, immune signal modulation, Toll pathway, IMD pathway, effectors, and other immune genes, depending on their biological functions. These results suggest that the transcriptome of the venom glands of C. plutellae can expand the understanding of insect immune response.

A new gene family (BAPs) of Cotesia bracovirus induces apoptosis of host hemocytes

ABSTRACT Polydnaviruses (PDVs), obligatory symbionts with parasitoid wasps, function as host immune suppressors and growth and development regulator. PDVs can induce host haemocyte apoptosis, but the underlying mechanism remains largely unknown. Here, we provided evidence that, during the early stages of parasitism, the activated Cotesia vestalis bracovirus (CvBV) reduced the overall number of host haemocytes by inducing apoptosis. We found that one haemocyte-highly expressed CvBV gene, CvBV-26-4, could induce haemocyte apoptosis. Further analyses showed that CvBV-26-4 has four homologs from other Cotesia bracoviruses and BV from wasps in the genus Glyptapanteles, and all four of them possessed a similar structure containing 3 copies of a well-conserved motif (Gly-Tyr-Pro-Tyr, GYPY). Mass spectrometry analysis revealed that CvBV-26-4 was secreted into plasma by haemocytes and then degraded into peptides that induced the apoptosis of haemocytes. Moreover, ectopic expression of CvBV-26-4 caused fly haemocyte apoptosis and increased the susceptibility of flies to bacteria. Based on this research, a new family of bracovirus genes, Bracovirus apoptosis-inducing proteins (BAPs), was proposed. Furthermore, it was discovered that the development of wasp larvae was affected when the function of CvBV BAP was obstructed in the parasitized hosts. The results of our study indicate that the BAP gene family from the bracoviruses group is crucial for immunosuppression during the early stages of parasitism.

Foliar Residual Toxicity of Insecticides to Brassica Pests and Their Natural Enemies.

Overuse of pesticides can result in the development of resistance, secondary pest outbreaks, and pest resurgence due to a reduction in natural enemies. The present study compares the residual toxicity of lambda-cyhalothrin, a relatively nonselective insecticide, with abamectin, indoxacarb, and spinosad, compounds which have been reported to be less harmful to arthropod natural enemies. Two key cosmopolitan pests of crucifer crops, (Plutella xylostella) and (Myzus persicae), and two of their respective hymenopteran parasitoids, (Cotesia vestalis) and (Aphidius colemani) were used as representative pests and natural enemies. The pyrethroid lambda-cyhalothrin was found to be the most persistent toxicant against both pest and both parasitoid species tested, while the lactones abamectin and spinosad were the least persistent toxicants. A leaf wax stripping technique was used to compare the contact toxicity of insecticide residues against adult C. vestalis and A. colemani in the epicuticular wax layer. For each compound, removal of epicuticular wax reduced the 24 h residual toxicity (LC50) of fresh deposits (day 0) by about an order of magnitude against C. vestalis. A second residual toxicity experiment showed that removal of epicuticular wax significantly reduced the residual toxicity of each compound against A. colemani at 0, 7, and 14 d after application, with little or no detectable residual activity for the oxadiazine indoxacarb or abamectin/spinosad respectively after 14 d. The present data supports the view that in addition to the intrinsic toxicity of insecticides to natural enemies, differences in their persistence as foliar residues should also be considered in IPM systems.

Orientation response of Cotesia plutellae Kurdjumov (Hymenoptera : Braconidae) towards nineteen straight-chain hydrocarbons ​​

The Cotesia plutellae (Kurdjumov) (Hymenoptera : Braconidae) is a larval endoparasitoid of the major crucifer pest, diamondback moth Plutella xylostella L. (Lepidoptera : Plutellidae). The oriental responses of C. plutellae towards 19 straight-chain hydrocarbons were scrutinized by Y tube choice bioassays. Stimulation for parasitoid elicited on application with 10 and 100 mg/l concentrations varied for each hydrocarbon. The study was conducted during the cole crop cultivation season in the winters of 2021-22 (January 2021-March 2022 at 28°32'7.8612'' N, 77°23'27.7044'' E). Out of all selected 19 hydrocarbons, Icosane emerged to be the best attractant with the highest percentage effectiveness of 1200%. The least attractancy was exhibited by Docosane. The possible behavioural manipulation of this specialist parasitoid using the desired concentration of hydrocarbon may be formulated and browbeaten for effective biological control of the diamondback moth.

Preliminary studies on the parasitism rate of larval parasitoids of the diamondback moth (Plutella xylostella) L. (Lepidoptera: Plutellidae) in the Ashanti region of Ghana

The diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) is the most important pest of the brassicas worldwide. Over the years, management of this pest has largely relied on conventional insecticides, with well-documented negative impacts. Biological control using indigenous natural enemies is a promising way to manage the pest while reducing the use of synthetic insecticides. However, due to the negative impact of synthetic insecticides on beneficial insects, the number of natural enemies in the agroecosystem is often below the levels that may have significant pest reduction. Here, we assessed the range and parasitism rates of the larval parasitoids of P. xylostella in the Ashanti Region of Ghana. On the whole, one hymenopteran endo-parasitoid species, Cotesia plutellae, was identified in the P. xylostella larval samples. In all, the percentage of field parasitism of P. xylostella larvae ranged between 11% and 23%. Given the percentage of parasitism in this preliminary study, we are of the view that there is potential in relying on endemic parasitoids to biologically manage P. xylostella if conditions in agroecology are improved to encourage the survival of these beneficial insects.

Changes in the Host Gut Microbiota during Parasitization by Parasitic Wasp Cotesia vestalis.

Simple SummaryCotesia vestalis is a larval endo-parasitoid of the diamondback moth (Plutella xylostella), which is a severe pest of cruciferous crops. The function of the gut microbiota of insects has been widely studied. However, it was unclear whether, and how, the gut microbiota of P. xylostella responds to its natural enemy, C. vestalis. In this study, a time-course experiment was performed to examine changes in the host–microbial community from the start of parasitization to the mature stage of the parasitoid larvae. Our results will provide a framework for studies of host-gut microbiota and parasitic wasp interactions.Parasites attack the host insects and possibly impact the host-gut microbiota, which leads to provision of a suitable host environment for parasites’ development. However, little is known about whether and how the parasitic wasp Cotesia vestalis alters the gut microbiota of the host Plutella xylostella. In this study, 16S rDNA microbial profiling, combined with a traditional isolation and culture method, were used to assess changes in the bacterial microbiome of parasitized and non-parasitized hosts at different developmental stages of C. vestalis larvae. Parasitization affected both the diversity and structure of the host-gut microbiota, with a significant reduction in richness on the sixth day post parasitization (6 DPP) and significant differences in bacterial structure between parasitized and non-parasitized hosts on the third day. The bacterial abundance of host-gut microbiota changed significantly as the parasitization progressed, resulting in alteration of potential functional contribution. Notably, the relative abundance of the predominant family Enterobacteriaceae was significantly decreased on the third day post-parasitization. In addition, the results of traditional isolation and culture of bacteria indicated differences in the bacterial composition between the three DPP and CK3 groups, as with 16S microbial profiling. These findings shed light on the interaction between a parasitic wasp and gut bacteria in the host insect during parasitization.

Multiple horizontal transfers of a Helitron transposon associated with a parasitoid wasp

In a previous study we described a Helitron transposon that apparently became one of the segments in the symbiotic Cotesia vestalis bracovirus (CvBV) from the parasitoid wasp C. vestalis. We presented evidence that this Helitron, named Hel_c35, invaded the C. vestalis genome through a horizontal transfer (HT) event from a dipteran and was later transferred horizontally from C. vestalis to a lepidopteran species. Based on the phylogeny of Hel_c35, we suggested that both HTs occurred in East Asia. We have also anticipated that, as more sequenced genomes from new species become available, more HTs involving Hel_c35 would be detected. Although the inclusion of Hel_c35 as a CvBV segment turned out to be a methodological artifact, the fact that Hel_c35 copies are present in the genomes of C. vestalis and other arthropods still remains. Here, we investigated the evolution of Hel_c35 in arthropods using an updated data set to reassess our previous findings. Most species (95%) included in the present work had their genomes sequenced after our initial study was published, thus representing new descriptions of taxa harboring Hel_c35. Our results expand considerably the number of putative HTs involving Hel_c35, with up to dozens of previously undescribed events, and suggest that the most recent HTs associated with C. vestalis took place in Europe. Considering the phylogenetic distribution of Hel_c35, and the evidence that its DNA sequences are present in the calyx fluid of C. vestalis and tissues from its parasitized host, we argue that many HT events were favored by the behavior of this wasp.

The effects of a naturalized weed, Lepidium virginicum, on the development and behaviors of the diamondback moth and its natural enemies in Hawaii

Weeds can play numerous important roles in pest suppression in agroecosystems. These include influencing the host searching behaviors of herbivorous pests and their natural enemies and providing shelter and alternative food sources for predators and parasitoids. Virginia pepperweed, Lepidium virginicum, is a widespread naturalized weed in Hawaii and can often be found in and around agricultural fields. It is a member of the Brassicaceae family and is a known host plant of the diamondback moth (DBM), Plutella xylostella. In this study, we found that DBM preferentially oviposit on L. virginicum (vegetative stage) when presented with a choice of cabbage. Using laboratory and semi-field trials, we investigated the responses of the natural enemies of DBM to the vegetative stage of L. virginicum and cabbage infested with DBM larvae. When DBM-infested plants were placed in the field for 48 h, more spiders and parasitized DBM larvae were recovered from the L. virginicum than from cabbage. In laboratory choice experiments, we demonstrated that the dominant DBM parasitoid species in Hawaii (Cotesia vestalis) oviposited in more host larvae on L. virginicum compared to cabbage, though this had no particular benefit for parasitoid development (adult size and sex ratio). Our findings suggest that the presence of L. virginicum in cabbage agroecosystems could be beneficial by serving to divert DBM oviposition away from cabbage and promoting predator and parasitoid populations.

Oviposition Preference and Performance of a Specialist Herbivore Is Modulated by Natural Enemies, Larval Odors, and Immune Status.

Insect herbivores frequently must balance host plant quality and the risk of attack by their natural enemies when making oviposition decisions. Yet, which factor is more important remains unresolved in plant-insect ecology. Here, we report the oviposition preference and larval performance of the brassicaceous specialist Plutella xylostella, in the context of plant quality (cabbage Brassica oleracea vs. mustard B. juncea) and associated natural enemies. Despite the greater larval weight and adult lifespan on cabbage, ovipositing females strongly preferred mustard. Both the egg parasitoid Trichogrammatoidea bactrae and the larval ectoparasitoid Bracon brevicornis are more likely to attack P. xylostella that feed on cabbage; thus, mustard represents enemy-reduced space from these two parasitoids. However, larval diet had no impact on the parasitism rate of specialist Cotesia vestalis. Feeding on mustard improved larval immune responses. The total hemocyte number, diversity, and phenoloxidase activity were higher in mustard-fed larvae which increased their survival against the entomopathogen, Bacillus thuringiensis. Interestingly, host plants altered the larval body odor profile. Mustard-fed larvae emitted allyl isothiocyanate (AITC) and butyl isothiocyanate (BITC) while cabbage-fed larvae emitted dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS) that served as short-range cues for larval parasitoids. For B. brevicornis, host body odor guided oviposition choice was crucial as their fitness was affected by the host larval diet. Although C. vestalis showed a clear preference towards volatiles emitted by mustard fed larvae, their fitness was unaltered. Taken together, our results illustrate that P. xylostella prefers to lay eggs on mustard plants providing enemy-reduced space from some, but not all, natural enemies.

The Dual Functions of a Bracovirus C-Type Lectin in Caterpillar Immune Response Manipulation.

Parasitoids are widespread in natural ecosystems and normally equipped with diverse viral factors to defeat host immune responses. On the other hand, parasitoids can enhance the antibacterial abilities and improve the hypoimmunity traits of parasitized hosts that may encounter pathogenic infections. These adaptive strategies guarantee the survival of parasitoid offspring, yet their underlying mechanisms are poorly understood. Here, we focused on Cotesia vestalis, an endoparasitoid of the diamondback moth Plutella xylostella, and found that C. vestalis parasitization decreases the number of host hemocytes, leading to disruption of the encapsulation reaction. We further found that one bracovirus C-type lectin gene, CvBV_28-1, is highly expressed in the hemocytes of parasitized hosts and participates in suppressing the proliferation rate of host hemocytes, which in turn reduces their population and represses the process of encapsulation. Moreover, CvBV_28-1 presents a classical bacterial clearance ability via the agglutination response in a Ca2+-dependent manner in response to gram-positive bacteria. Our study provides insights into the innovative strategy of a parasitoid-derived viral gene that has dual functions to manipulate host immunity for a successful parasitism.

A teratocyte-specific serpin from the endoparasitoid wasp Cotesia vestalis inhibits the prophenoloxidase-activating system of its host Plutella xylostella.

Many endoparasitoids adopt several parasitic factors, such as venom, polydnavirus and teratocytes, to suppress the immune response of their associated hosts including melanization for successful parasitism. A teratocyte‐specific expressed serpin gene, designated as CvT‐serpin6, was identified from the parasitoid Cotesia vestalis. The immunoblot result suggested that CvT‐serpin6 was secreted into extracellular space. qPCR results showed that CvT‐serpin6 was mainly transcribed at later stages of parasitism, and the transcriptional abundance of CvT‐serpin6 in teratocytes was significantly increased in response to the challenge of bacteria. Inhibitory assay indicated that recombinant CvT‐serpin6 (rCvT‐serpin6) could inhibit the activation of Plutella xylostella prophenoloxidase and ultimately resulted in the inhibition of melanization in P. xylostella haemolymph. Furthermore, we confirmed that rCvT‐serpin6 could form SDS‐stable complexes with activated PxPAP1 and PxPAP3 in a dose‐dependent manner. Altogether, our results further shed insight into the molecular mechanisms that teratocytes involved in controlling host immune response.