Exploiting integrative metabolomics to study host-parasite interactions in Plasmodium infections.

Despite years of research, malaria remains a significant global health burden, with poor diagnostic tests and increasing antimalarial drug resistance challenging diagnosis and treatment. While 'single-omics'-based approaches have been instrumental in gaining insight into the biology and pathogenicity of the Plasmodium parasite and its interaction with the human host, a more comprehensive understanding of malaria pathogenesis can be achieved through 'multi-omics' approaches. Integrative methods, which combine metabolomics, lipidomics, transcriptomics, and genomics datasets, offer a holistic systems biology approach to studying malaria. This review highlights recent advances, future directions, and challenges involved in using integrative metabolomics approaches to interrogate the interactions between Plasmodium and the human host, paving the way towards targeted antimalaria therapeutics and control intervention methods.

Herbal-based compounds: A review on treatments of cryptosporidiosis.

Cryptosporidium, a monoxenous apicomplexan coccidia, is a prevalent diarrhetic and an opportunistic agent, mainly in immunocompromised individuals. As there are few chemotherapeutic compounds that have limited efficacy, we need to identify new compounds or specific parasite targets for designing more potent drugs to treat cryptosporidiosis. Herbal products with low toxicity, environmental compatibility, wide therapeutic potential, and abundant resources can be considered alternatives for treatment. The current review tried to summarize the studies on plants or herbal bioactive constituents with anti-cryptosporidial activities. Based on constituents, plants act via different mechanisms, and further investigations are needed to clarify the exact mechanisms by which they act on the developmental stages of the parasite or host-parasite relationships.

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

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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.

Cuscuta campestris fine-tunes gene expression during haustoriogenesis as an adaptation to different hosts.

The Cuscuta genus comprises obligate parasitic plants that have an unusually wide host range. Whether Cuscuta uses different infection strategies for different hosts or whether the infection strategy is mechanistically and enzymatically conserved remains unknown. To address this, we investigated molecular events during the interaction between field dodder (Cuscuta campestris) and two host species of the Solanum genus that are known to react differently to parasitic infection. We found that host gene induction, particularly of cell wall fortifying genes, coincided with a differential induction of genes for cell wall degradation in the parasite in the cultivated tomato (Solanum lycopersicum) but not in a wild relative (Solanum pennellii). This indicates that the parasite can adjust its gene expression in response to its host. This idea was supported by the increased expression of C. campestris genes encoding an endo-ß-1,4-mannanase in response to exposure of the parasite to purified mono- and polysaccharides in a host-independent infection system. Our results suggest multiple key roles of the host cell wall in determining the outcome of an infection attempt.

Vascular implications of Dasineura sp. galls' establishment on Peumus boldus stems.

Some chewing larvae are capable of inducing galls in the host vascular cylinder, e.g. Dasineura sp. (Cecidomyiidae) on Peumus boldus stems. Due to the medicinal and economic importance of P. boldus, the anatomical and functional implications of establishment of Dasineura sp. on P. boldus stems were investigated. We asked if establishment of Dasineura sp. in P. boldus stems induces abnormalities at the cellular and organizational level of the vascular system that increase during gall development in favour of the hydric status of the gall. Anatomical alterations induced in the stems during gall development were determined. Cytohistometric analyses in mature galls were compared to non-galled stems, and water potential and leaf area of non-galled stems were compared with galled stems. Dasineura sp. establishes in the vascular cambium, leading to delignification and rupture of xylem cells, inhibiting formation of phloem and perivascular sclerenchyma. Gall diameter increases together with larval feeding activity, producing a large larval chamber and numerous layers of nutritive tissue, vascular parenchyma, and sclerenchyma. These anatomical alterations do not affect the leaf area of galled stems but favour increased water flow towards these stems. The anatomical alterations induced by Dasineura sp. in P. boldus stems guarantee water and nutrient supply to the gall and larva. After the inducer exits stems, some host branches no longer have vascular connections with the plant body.

Can species naming drive scientific attention? A perspective from plant-feeding arthropods.

How do researchers choose their study species? Some choices are based on ecological or economic importance, some on ease of study, some on tradition-but could the name of a species influence researcher decisions? We asked whether phytophagous arthropod species named after their host plants were more likely to be assayed for host-associated genetic differentiation (or 'HAD'; the evolution of cryptic, genetically isolated host specialists within an apparently more generalist lineage). We chose 30 arthropod species (from a Google Scholar search) for which a HAD hypothesis has been tested. We traced the etymologies of species names in the 30 corresponding genera, and asked whether HAD tests were more frequent among species whose etymologies were based on host-plant names (e.g. Eurosta solidaginis, which attacks Solidago) versus those with other etymologies (e.g. Eurosta fenestrata, from Latin fenestra, 'window'). Species with host-derived etymologies were more likely to feature in studies of HAD than those with other etymologies. We speculate that the etymology of a scientific name can draw a researcher's attention to aspects of life-history and thus influence the direction of our scientific gaze.

Chemical Cues From Honeydew and Cuticular Extracts of Trialeurodes Vaporariorum Serve as Kairomones for The Parasitoid Encarsia Formosa.

Kairomones are semiochemicals that are emitted by an organism and which mediate interspecific interaction that is of benefit to an organism of another species that receives these chemical substances. Parasitoids find and recognize their hosts through eavesdropping on the kairomones emitted from the by-products or the body of the host. Hemipteran insect pests feed on plant sap and excrete the digested plant materials as honeydew. Honeydew serves as a nutritional food source for parasitoids and a medium for micro-organisms whose activity induces the release of volatiles exploited by parasitoids for host location. The parasitoid Encarsia formosa preferentially parasitizes its host, the greenhouse whitefly, Trialeurodes vaporariorum, on tomato Solanum lycopersicum, but little is known about the chemicals that mediate these interactions. We investigated the olfactory responses of the parasitoid E. formosa to odours from honeydew and nymphs of T. vaporariorum in a Y-tube olfactometer. Arrestment behaviour of the parasitoid to honeydew and nymph extracts, as well as to synthetic hydrocarbons, was also observed in Petri-dish bioassays. We found that T. vaporariorum honeydew volatiles attracted the parasitoid E. formosa but odours from the whitefly nymphs did not. We also found that the parasitoid spent more time searching on areas treated with extracts of honeydew and nymphs than on untreated areas. Gas-chromatography-mass spectrometric analysis revealed that the honeydew volatiles contained compounds such as (Z)-3-hexenol, δ-3-carene, 3-octanone, α-phellandrene, methyl salicylate, ß-ocimene, ß-myrcene, and (E)-ß-caryophyllene which are known to be attractive to E. formosa. The cuticular extracts of the nymphs predominantly contained alkanes, alkenes, and esters. Among the alkanes, synthetic nonacosane arrested the parasitoid. Our findings are discussed in relation to how the parasitoid E. formosa uses these chemicals to locate its host, T. vaporariorum.

Dual activity of Meloidogyne incognita-regulated Musa acuminata Pathogenesis-related-10 (MaPR-10) gene.

Plant immunity to pathogen infections is a dynamic response that involves multiple organelles and defence signalling systems such as hypersensitive response (HR) and systemic acquired resistance (SAR). The latter requires the function of Pathogenesis-related (PR) proteins, a common plant protein family with diverse roles in plant innate immunity. Our previous proteomics study showed that a PR gene (ITC1587_Bchr9_P26466_MUSBA) was differentially regulated during a compatible banana-M. incognita interaction, substantiating the isolation of this gene in the current study. Here, we successfully isolated and characterised Pathogenesis-related-10 (PR10) gene with ß-1,3-glucanase and ribonuclease (RNase) activities from two Musa acuminata cultivars (denoted as MaPR10) namely Berangan and Grand Naine (ITC1256). We found that MaPR10 cloned sequences possess glycine-rich loop domain and shared conserved motifs specific to PR10 gene group, confirming its identity as a member of this group. Interestingly, we also found a catalytic domain sequence for glycoside hydrolase family 16 (EXDXXE), unique only to MaPR10 cloned sequences. Two peptide variants closely related to the reference sequence ITC1587_Bchr9_P26466_MUSBA namely MaPR10-BeB5 and MaPR10-GNA5 were overexpressed and purified to test for their functionality. Here, we confirmed that both protein variants possess ß-1,3-glucanase and ribonuclease (RNase) activities, and inhibit the growth of Aspergillus fumigatus, a human opportunistic pathogen. To our knowledge, this is the first PR10 plant proteins with such properties to be reported thus far.

Evaluating Volatile Plant Compounds of Psidium galapageium (Myrtales: Myrtaceae) as Repellents Against Invasive Parasitic Diptera in the Galapagos Islands.

Plant-based repellents represent a safe, economic, and viable alternative to managing invasive insects that threaten native fauna. Observations of self-medication in animals can provide important cues to the medicinal properties of plants. A recent study in the Galapagos Islands found that Darwin's finches apply the leaves of Psidium galapageium (Hooker 1847) to their feathers, extracts of which were repellent to mosquitoes and the parasitic fly Philornis downsi (Dodge & Aitkens 1968; Diptera: Muscidae). Introduced mosquitoes are suspected vectors of avian pathogens in the Galapagos Islands, whereas the larvae of P. downsi are blood-feeders, causing significant declines of the endemic avifauna. In this study, we investigated the volatile compounds found in P. galapageium, testing each against a model organism, the mosquito Anopheles arabiensis (Patton 1905; Diptera: Culicidae), with the aim of singling out the most effective compound for repelling dipterans. Examinations of an ethanolic extract of P. galapageium, its essential oil and each of their respective fractions, revealed a mixture of monoterpenes and sesquiterpenes, the latter consisting mainly of guaiol, trans-nerolidol, and ß-eudesmol. Of these, trans-nerolidol was identified as the most effective repellent to mosquitoes. This was subsequently tested at four different concentrations against P. downsi, but we did not find a repellence response. A tendency to avoid the compound was observed, albeit significance was not achieved in any case. The lack of repellence suggests that flies may respond to a combination of the volatile compounds found in P. galapageium, rather than to a single compound.

Defensive Mechanisms in Cucurbits against Melon Fly (Bactrocera cucurbitae) Infestation through Excessive Production of Defensive Enzymes and Antioxidants.

Melon fly (Bactrocera cucurbitae) is the most common pest of cucurbits, and it directly causes damage to cucurbit fruits in the early developmental stage. The infection of fruit tissues induces oxidative damage through increased generation of cellular reactive oxygen species. The effects of melon fly infestation on the production of defensive enzymes and antioxidant capabilities in five cucurbit species, namely, bottle gourd, chayote, cucumber, snake gourd, and bitter gourd, were investigated in this study. The total phenolic and flavonoid content was considerably higher in melon fly infestation tissues compared to healthy and apparently healthy tissues. The chayote and bottle gourd tissues expressed almost 1.5- to 2-fold higher phenolic and flavonoid contents compared to the tissues of bitter gourd, snake gourd, and cucumber upon infestation. Defensive enzymes, such as peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO), and catalase (CAT), were high in healthy and infected tissues of chayote and bottle gourd compared to bitter gourd, snake gourd, and cucumber. The activity of POD (60-80%), SOD (30-35%), PPO (70-75%), and CAT (40-50%) were high in infected chayote and bottle gourd tissue, representing resistance against infestation, while bitter gourd, snake gourd, and cucumber exhibited comparatively lower activity suggesting susceptibility to melon fly infection. The antioxidant properties were also high in the resistant cucurbits compared to the susceptible cucurbits. The current research has enlightened the importance of redox-regulatory pathways involving ROS neutralization through infection-induced antioxidative enzymes in host cucurbit resistance. The melon fly infestation depicts the possible induction of pathways that upregulate the production of defensive enzymes and antioxidants as a defensive strategy against melon fly infestation in resistant cucurbits.

Description of an Australian endemic species of Trioza (Hemiptera: Triozidae) pest of the endemic tea tree, Melaleuca alternifolia (Myrtaceae).

Psyllids, also known as jumping plant lice, are phloem feeding Hemiptera that often show a strict species-specific relationship with their host plants. When psyllid-plant associations involve economically important crops, this may lead to the recognition of a psyllid species as an agricultural or horticultural pest. The Australian endemic tea tree, Melaleuca alternifolia (Maiden & Betche) Cheel., has been used for more than a century to extract essential oils and, long before that, as a traditional medicine by Indigenous Australian people. Recently, a triozid species has been found to damage the new growth of tea trees both in Queensland and New South Wales, raising interest around this previously undocumented pest. Furthermore, adults of the same species were also collected from Citrus plantations, leading to potential false-positive records of the exotic pest Trioza erytreae (Del Guercio 1918), the African Citrus psyllid. Here we describe for the first time Trioza melaleucae Martoni sp. nov. providing information on its distribution, host plant associations and phylogenetic relationships to other Trioza species. This work enables both morphological and molecular identification of this new species, allowing it to be recognized and distinguished for the first time from exotic pests as well as other Australian native psyllids. Furthermore, the haplotype network analysis presented here suggests a close relationship between Trioza melaleucae and the other Myrtaceae-feeding Trioza spp. from Australia, New Zealand, and Taiwan.

The evolution of parasitism from mutualism in wasps pollinating the fig, Ficus microcarpa, in Yunnan Province, China.

Theory identifies factors that can undermine the evolutionary stability of mutualisms. However, theory's relevance to mutualism stability in nature is controversial. Detailed comparative studies of parasitic species that are embedded within otherwise mutualistic taxa (e.g., fig pollinator wasps) can identify factors that potentially promote or undermine mutualism stability. We describe results from behavioral, morphological, phylogenetic, and experimental studies of two functionally distinct, but closely related, Eupristina wasp species associated with the monoecious host fig, Ficus microcarpa, in Yunnan Province, China. One (Eupristina verticillata) is a competent pollinator exhibiting morphologies and behaviors consistent with observed seed production. The other (Eupristina sp.) lacks these traits, and dramatically reduces both female and male reproductive success of its host. Furthermore, observations and experiments indicate that individuals of this parasitic species exhibit greater relative fitness than the pollinators, in both indirect competition (individual wasps in separate fig inflorescences) and direct competition (wasps of both species within the same fig). Moreover, phylogenetic analyses suggest that these two Eupristina species are sister taxa. By the strictest definition, the nonpollinating species represents a "cheater" that has descended from a beneficial pollinating mutualist. In sharp contrast to all 15 existing studies of actively pollinated figs and their wasps, the local F. microcarpa exhibit no evidence for host sanctions that effectively reduce the relative fitness of wasps that do not pollinate. We suggest that the lack of sanctions in the local hosts promotes the loss of specialized morphologies and behaviors crucial for pollination and, thereby, the evolution of cheating.

Does phosphorus influence performance of a native hemiparasite and its impact on a native legume?

Phosphorus (P) is an essential plant nutrient and can become limiting in terrestrial ecosystems where parasitic plant:host associations occur. Yet little is known on how P availability influences parasite performance and its impact on hosts. We investigated the performance of the Australian native stem hemiparasite Cassytha pubescens and its impact on the native leguminous shrub Acacia paradoxa in high or low P conditions in a glasshouse experiment. Infected plants had significantly lower total, shoot, root and nodule biomass and shoot:root ratio than uninfected plants, regardless of P supply. The significant negative effect of infection on arbuscular mycorrhizal colonisation of host roots was more severe in the high P treatment. Infection significantly decreased predawn quantum yield of A. paradoxa in low P but not high P conditions. This finding may be due to the parasite-induced significant enrichment of aluminium in host foliage in low P but not high P treatments. A. paradoxa had significantly lower foliar phosphorus concentration [P] and nitrogen concentration in low P than high P conditions. Parasite biomass and photosynthetic performance were unaffected by P, whereas C. pubescens had significantly lower stem [P] in the low P than high P treatment. Parasite carbon isotope composition was significantly higher than that of the host, especially in low P conditions. Our results show that: (a) native parasite growth and its negative impact on growth of this native shrub was unaffected by P supply and (b) soil P conditions may have no influence on stem hemiparasite:host associations in nature.

Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities.

Toxoplasma gondii is an apicomplexan parasite causing toxoplasmosis, a common disease, which is most typically asymptomatic. However, toxoplasmosis can be severe and even fatal in immunocompromised patients and fetuses. Available treatment options are limited, so there is a strong impetus to develop novel therapeutics. This review focuses on the role of oxidative stress in the pathophysiology and treatment of T. gondii infection. Chemical compounds that modify redox status can reduce the parasite viability and thus be potential anti-Toxoplasma drugs. On the other hand, oxidative stress caused by the activation of the inflammatory response may have some deleterious consequences in host cells. In this respect, the potential use of natural antioxidants is worth considering, including melatonin and some vitamins, as possible novel anti-Toxoplasma therapeutics. Results of in vitro and animal studies are promising. However, supplementation with some antioxidants was found to promote the increase in parasitemia, and the disease was then characterized by a milder course. Undoubtedly, research in this area may have a significant impact on the future prospects of toxoplasmosis therapy.

High-content approaches to anthelmintic drug screening.

Most anthelmintics were discovered through in vivo screens using animal models of infection. Developing in vitro assays for parasitic worms presents several challenges. The lack of in vitro life cycle culture protocols requires harvesting worms from vertebrate hosts or vectors, limiting assay throughput. Once worms are removed from the host environment, established anthelmintics often show no obvious phenotype - raising concerns about the predictive value of many in vitro assays. However, with recent progress in understanding how anthelmintics subvert host-parasite interactions, and breakthroughs in high-content imaging and machine learning, in vitro assays have the potential to discern subtle cryptic parasite phenotypes. These may prove better endpoints than conventional in vitro viability assays.

Targeting of anti-microbial proteins to the hyphal surface amplifies protection of crop plants against Phytophthora pathogens.

Phytophthora pathogens are a persistent threat to the world's commercially important agricultural crops, including potato and soybean. Current strategies aim at reducing crop losses rely mostly on disease-resistance breeding and chemical pesticides, which can be frequently overcome by the rapid adaptive evolution of pathogens. Transgenic crops with intrinsic disease resistance offer a promising alternative and continue to be developed. Here, we explored Phytophthora-derived PI3P (phosphatidylinositol 3-phosphate) as a novel control target, using proteins that bind this lipid to direct secreted anti-microbial peptides and proteins (AMPs) to the surface of Phytophthora pathogens. In transgenic Nicotiana benthamiana, soybean, and potato plants, significantly enhanced resistance to different pathogen isolates was achieved by expression of two AMPs (GAFP1 or GAFP3 from the Chinese medicinal herb Gastrodia elata) fused with a PI3P-specific binding domain (FYVE). Using the soybean pathogen P. sojae as an example, we demonstrated that the FYVE domain could boost the activities of GAFPs in multiple independent assays, including those performed in vitro, in vivo, and in planta. Mutational analysis of P. sojae PI3K1 and PI3K2 genes of this pathogen confirmed that the enhanced activities of the targeted GAFPs were correlated with PI3P levels in the pathogen. Collectively, our study provides a new strategy that could be used to confer resistance not only to Phytophthora pathogens in many plants but also potentially to many other kinds of plant pathogens with unique targets.

Plant silicon application alters leaf alkaloid concentrations and impacts parasitoids more adversely than their aphid hosts.

Grasses accumulate large amounts of silicon (Si) which acts as a highly effective physical defence against insect herbivory, however recent evidence shows that Si supplementation also modifies plant secondary metabolite concetrations. Changes in plant secondary metabolites concentrations can have cascading effects on higher trophic levels, such as parasitoids, as they are dependent on the host herbivore for growth and development. However, relatively little is known about how Si application affects higher trophic levels. We examined the effects of Si addition on alkaloid content in leaves of Phalaris aquatica (Poaceae) and the effect on interactions between an aphid (Rhopalosiphum padi) and its parasitoid (Aphidius colemani). Si supplementation had no effect on aphid abundance or parasitism rate. Adult aphids, aphid mummies (parasitised aphids) and the emergent parasitoids were, however, significantly smaller on Si+ plants. Parasitoid traits (size and emergence) were correlated with aphid mummy size. Si addition reduced parasitoid emergence rate and size due to reduced host mummy size, in addition, significantly fewer females emerged from mummies on Si+ plants. Aphid infestation significantly altered alkaloids concentrations, reducing gramine by 80% while increasing tryptamine by 91% in Si- plants. Si addition reduced aphid-induced tryptamine concentrations by 64% and increased 5-MeO-tryptamine by over 800% in control and 142% in aphid infested plants. Our results show that while Si addition has modest impacts on the herbivore, it significantly alters secondary metabolites and has stronger effects on the higher trophic level through changes in the quality of the parasitised host.

Sarracenia alata (Alph.Wood) Alph.Wood Microcuttings as a Source of Volatiles Potentially Responsible for Insects' Respond.

Rare carnivorous plants representing the genus Sarracenia are perceived as very interesting to scientists involved in various fields of botany, ethnobotany, entomology, phytochemistry and others. Such high interest is caused mainly by the unique capacity of Sarracenia spp. to attract insects. Therefore, an attempt to develop a protocol for micropropagation of the Sarracenia alata (Alph.Wood) Alph.Wood, commonly named yellow trumpets, and to identify the specific chemical composition of volatile compounds of this plant in vitro and ex vivo was undertaken. Thus, the chemical volatile compounds excreted by the studied plant to attract insects were recognized with the application of the headspace solid-phase microextraction (HS-SPME) coupled with the GC-MS technique. As the major volatile compounds (Z)-3-hexen-1-ol (16.48% ± 0.31), (E)-3-hexen-1-ol acetate (19.99% ± 0.01) and ß-caryophyllene (11.30% ± 0.27) were identified. Further, both the chemical assumed to be responsible for attracting insects, i.e., pyridine (3.10% ± 0.07), and whole plants were used in in vivo bioassays with two insect species, namely Drosophila hydei and Acyrthosiphon pisum. The obtained results bring a new perspective on the possibilities of cultivating rare carnivorous plants in vitro since they are regarded as a valuable source of bioactive volatile compounds, as including ones with repellent or attractant activity.

Potato cyst nematodes Globodera rostochiensis and G. pallida.

TAXONOMY: Phylum Nematoda; class Chromadorea; order Rhabditida; suborder Tylenchina; infraorder Tylenchomorpha; superfamily Tylenchoidea; family Heteroderidae; subfamily Heteroderinae; Genus Globodera. BIOLOGY: Potato cyst nematodes (PCN) are biotrophic, sedentary endoparasitic nematodes. Invasive (second) stage juveniles (J2) hatch from eggs in response to the presence of host root exudates and subsequently locate and invade the host. The nematodes induce the formation of a large, multinucleate syncytium in host roots, formed by fusion of up to 300 root cell protoplasts. The nematodes rely on this single syncytium for the nutrients required to develop through a further three moults to the adult male or female stage. This extended period of biotrophy-between 4 and 6 weeks in total-is almost unparalleled in plant-pathogen interactions. Females remain at the root while adult males revert to the vermiform body plan of the J2 and leave the root to locate and fertilize the female nematodes. The female body forms a cyst that contains the next generation of eggs. HOST RANGE: The host range of PCN is limited to plants of the Solanaceae family. While the most economically important hosts are potato (Solanum tuberosum), tomato (Solanum lycopersicum), and aubergine (Solanum melongena), over 170 species of Solanaceae are thought to be potential hosts for PCN (Sullivan et al., 2007). DISEASE SYMPTOMS: Symptoms are similar to those associated with nutrient deficiency, such as stunted growth, yellowing of leaves and reduced yields. This absence of specific symptoms reduces awareness of the disease among growers. DISEASE CONTROL: Resistance genes (where available in suitable cultivars), application of nematicides, crop rotation. Great effort is put into reducing the spread of PCN through quarantine measures and use of certified seed stocks. USEFUL WEBSITES: Genomic information for PCN is accessible through WormBase ParaSite.

Deletion of a Golgi protein in Trypanosoma cruzi reveals a critical role for Mn2+ in protein glycosylation needed for host cell invasion and intracellular replication.

Trypanosoma cruzi is a protist parasite and the causative agent of American trypanosomiasis or Chagas disease. The parasite life cycle in its mammalian host includes an intracellular stage, and glycosylated proteins play a key role in host-parasite interaction facilitating adhesion, invasion and immune evasion. Here, we report that a Golgi-localized Mn2+-Ca2+/H+ exchanger of T. cruzi (TcGDT1) is required for efficient protein glycosylation, host cell invasion, and intracellular replication. The Golgi localization was determined by immunofluorescence and electron microscopy assays. TcGDT1 was able to complement the growth defect of Saccharomyces cerevisiae null mutants of its ortholog ScGDT1 but ablation of TcGDT1 by CRISPR/Cas9 did not affect the growth of the insect stage of the parasite. The defect in protein glycosylation was rescued by Mn2+ supplementation to the growth medium, underscoring the importance of this transition metal for Golgi glycosylation of proteins.