ABSTRACT
Plant defenses are conserved among closely related species, but domestication can alter host genotypes through artificial selection with potential losses in host defenses. Therefore, both domestication and host phylogenetic structure may influence plant virus infection outcomes. Here, we examined the association of phylogeny and domestication with the fitness of infected plants. We inoculated three pairs of domesticated and wild/non-cultivated squash (Cucurbita spp.) with a combination of two viruses commonly found to co-infect cucurbits, zucchini yellow mosaic virus (ZYMV) and squash mosaic virus (SqMV), and recorded fitness traits related to flowers, pollination, fruit and seed viability in the field over two separate years. In an additional field experiment, we recorded the relative abundance of both viruses via RT-qPCR. We found a gradient of susceptibility across the 6 tested lineages and phylogenetic structure, but not domestication, contributed to differences in infection outcomes and impacts on several fitness traits including fruit number, fruit weight, and germination. Plant virus infection also impacted the quantity and quality of floral rewards and visitation rates of specialist bee pollinators. There were no detectable differences in viral load between the 6 host taxa for either virus individually or the ratio of ZYMV:SqMV. Our results highlight the importance of phylogenetic structure in predicting host susceptibility to disease across wild and domesticated plants and the ability of several hosts to maintain fitness in the field despite infection. Broader consequences of plant pathogens for beneficial insects, such as pollinators, should also be considered in future research.
ABSTRACT
Antimicrobial resistance in agriculture is a global concern and carries huge financial consequences. Despite that, practical solutions for growers that are sustainable, low cost and environmentally friendly have been sparse. This has created opportunities for the agrochemical industry to develop pesticides with novel modes of action. Recently the use of photodynamic inactivation (PDI), classically used in cancer treatments, has been explored in agriculture as an alternative to traditional chemistries, mainly as a promising new approach for the eradication of pesticide resistant strains. However, applications in the field pose unique challenges and call for new methods of evaluation to adequately address issues specific to PDI applications in plants and challenges faced in the field. The aim of this review is to summarize in vitro, ex vivo, and in vivo/in planta experimental strategies and methods used to test and evaluate photodynamic agents as photo-responsive pesticides for applications in agriculture. The review highlights some of the strategies that have been explored to overcome challenges in the field.
Subject(s)
Pesticides , Photosensitizing Agents , Photosensitizing Agents/chemistry , Agriculture/methods , Pesticides/chemistry , Pesticides/pharmacology , PlantsABSTRACT
ABSTRACT: Co-facilitation (combining presence and expertise of clinical faculty and simulationists during all stages of simulation) presents an opportunity to improve student perceptions of effectiveness. Using a retrospective before and after comparison, data on students' perceptions were collected from baccalaureate nursing students in clinical courses after each simulation experience. Mean differences in Simulation Effectiveness Tool-Modified scores for pre- and post-implementation were compared, as well as scores between levels of students. Statistically significant improvements in student-rated simulation effectiveness were found with co-facilitation. The authors recommend future studies expanding this methodology and considering co-facilitation where feasible.
Subject(s)
Education, Nursing, Baccalaureate , Simulation Training , Students, Nursing , Humans , Retrospective Studies , Education, Nursing, Baccalaureate/methods , Clinical Competence , Computer Simulation , Simulation Training/methodsABSTRACT
Control of plant pathogens using chemical and synthetic pesticides raises a major safety concern for humans and the environment. Despite the ongoing exploration of sustainable alternative methods, management practices for pathogens, especially bacteria, have remained almost unchanged over decades, whereby long-term uses of copper and antibiotics has led to widespread bacterial resistance in the field. Antimicrobial photodynamic inactivation (aPDI) of bacteria is emerging as an alternative strategy to combat resistant plant pathogens. aPDI utilizes light-sensitive molecules (photosensitizers) that upon illumination produce reactive oxygen species able to kill pathogens. Here we explore the potential of an anionic semisynthetic water-soluble derivative of chlorophyl (Sodium Magnesium Chlorophyllin: Mg-chl), as an antibacterial agent in planta, by simulating processes naturally occurring in the field. Mg-chl in combination with Na2EDTA (cell wall permeabilizing agent) was able to effectively inhibit Pseudomonas syringae pv. tomato DC3000 in vitro and in planta in both tomato and N. benthamiana. Notably, Mg-chl in combination with Na2EDTA and the common surfactant Morwet D-400 significantly reduced Xanthomonas hortorum pv. gardneri and Xanthomonas fragarie, respectively, in a commercial greenhouse trial against bacterial spot disease in tomato and in field experiments against angular leaf spot disease in strawberries.
ABSTRACT
OBJECTIVES: To determine sociodemographics and caregiver burdens associated with overnight hospitalization, hospice utilization, and hospitalization frequency among persons with dementia (PWD). METHODS: Cross-sectional analysis of PWD (n = 899) of the National Health and Aging Trends Study linked to the National Study of Caregiving. Logistic and proportional odds regression determined the effects of caregiver burdens on overnight hospitalization, hospice use, and hospitalization frequency. Differences between PWD alive not-alive groups were compared on overnight hospitalization and frequency. RESULTS: Alive PWD (n = 804) were 2.36 times more likely to have an overnight hospital stay (p = 0.004) and 1.96 times more likely to have multiple hospitalizations when caregivers found it physically difficult to provide care (p = 0.011). Decedents aged 65-74 (n = 95) were 4.55 times more likely to experience overnight hospitalizations than 85+, hospitalizations were more frequent (odds ratio [OR] = 4.84), and there was a significant difference between PWD alive/not alive groups (p = 0.035). Decedents were 5.60 times more likely to experience an overnight hospitalization when their caregivers had financial difficulty, hospitalizations were more frequent when caregivers had too much to handle (OR = 8.44) and/or no time for themselves (OR = 10.67). When caregivers had no time for themselves, a significant difference between alive/not alive groups (p = 0.018) was detected in hospitalization frequency. PWD whose caregivers had emotional difficulty helping were 5.89 times more likely to utilize hospice than caregivers who did not report emotional difficulty. SIGNIFICANCE OF RESULTS: Care transitions among PWD at the end of life are impacted by the circumstances and experiences of their caregivers. Subjective caregiver burdens represent potentially modifiable risks for undesired care transitions and opportunities for promoting hospice use. Future work is warranted to identify and address these issues as they occur.
ABSTRACT
Obligate symbioses occur when organisms require symbiotic relationships to survive. Some parasitic wasps of caterpillars possess obligate mutualistic viruses called "polydnaviruses." Along with eggs, wasps inject polydnavirus inside their caterpillar hosts where the hatching larvae develop inside the caterpillar. Polydnaviruses suppress the immune systems of their caterpillar hosts, which enables egg hatch and wasp larval development. It is unknown whether polydnaviruses also manipulate the salivary proteins of the caterpillar, which may affect the elicitation of plant defenses during feeding by the caterpillar. Here, we show that a polydnavirus of the parasitoid Microplitis croceipes, and not the parasitoid larva itself, drives the regulation of salivary enzymes of the caterpillar Helicoverpa zea that are known to elicit tomato plant-defense responses to herbivores. The polydnavirus suppresses glucose oxidase, which is a primary plant-defense elicitor in the saliva of the H. zea caterpillar. By suppressing plant defenses, the polydnavirus allows the caterpillar to grow at a faster rate, thus improving the host suitability for the parasitoid. Remarkably, polydnaviruses manipulate the phenotypes of the wasp, caterpillar, and host plant, demonstrating that polydnaviruses play far more prominent roles in shaping plant-herbivore interactions than ever considered.
Subject(s)
Host-Parasite Interactions/immunology , Larva/immunology , Lepidoptera/immunology , Plant Immunity/immunology , Polydnaviridae/physiology , Solanum lycopersicum/immunology , Wasps/physiology , Animals , Glucose Oxidase/metabolism , Herbivory , Larva/parasitology , Larva/virology , Lepidoptera/parasitology , Lepidoptera/virology , Predatory Behavior , Symbiosis , Virus Integration , Virus ReplicationABSTRACT
The Gram-negative enterobacterium Erwinia amylovora causes fire blight disease in apple and pear trees. Lipopolysaccharides and the exopolysaccharide amylovoran are essential E. amylovora virulence factors. We found that mutations in rfbX disrupted amylovoran production and virulence in apple fruits and tree shoots and that the deletion of yibD suppressed the rfbX mutant phenotype. The level of expression of yibD was about 10-fold higher in the ΔrfbX mutant than the wild type. A forward genetic suppressor screen in the ΔrfbX mutant uncovered multiple mutations in yibD and supported the conclusion that the virulence defect of rfbX mutants is due to reduced amylovoran production. The yibD and rfbX genes are expressed as a two-gene operon, yibD rfbX The rfbX gene encodes a previously uncharacterized putative polysaccharide subunit transporter, while yibD encodes a predicted glycosyltransferase. Mutation of rfbX did not have a detectable effect on lipopolysaccharide patterns; however, the overexpression of yibD in both the wild-type and ΔyibD ΔrfbX genetic backgrounds disrupted both amylovoran and lipopolysaccharide production. Additionally, the overexpression of yibD in the ΔyibD ΔrfbX mutant inhibited bacterial growth in amylovoran-inducing medium. This growth inhibition phenotype was used in a forward genetic suppressor screen and reverse-genetics tests to identify several genes involved in lipopolysaccharide production, which, when mutated, restored the ability of the ΔyibD ΔrfbX mutant overexpressing yibD to grow in amylovoran-inducing medium. Remarkably, all the lipopolysaccharide gene mutants tested were defective in lipopolysaccharide and amylovoran production. These results reveal a genetic connection between amylovoran and lipopolysaccharide production in E. amylovoraIMPORTANCE This study discovered previously unknown genetic connections between exopolysaccharide and lipopolysaccharide production in the fire blight pathogen Erwinia amylovora This represents a step forward in our understanding of the biology underlying the production of these two macromolecules. Fire blight is an economically important disease that impacts the production of apples and pears worldwide. Few fire blight control measures are available, and growers rely heavily on antibiotic applications at bloom time. Both exopolysaccharide and lipopolysaccharide are E. amylovora virulence factors. Our results indicate that the overexpression of the yibD gene in E. amylovora disrupts both lipopolysaccharide production and exopolysaccharide production. This effect could potentially be used as the basis for the development of an antivirulence treatment for the prevention of fire blight disease.
Subject(s)
Bacterial Proteins/metabolism , Erwinia amylovora/genetics , Membrane Transport Proteins/metabolism , Plant Diseases/microbiology , Polysaccharides, Bacterial/biosynthesis , Bacterial Proteins/genetics , Erwinia amylovora/metabolism , Erwinia amylovora/pathogenicity , Gene Expression Regulation, Bacterial , Genes, Bacterial , Malus/microbiology , Membrane Transport Proteins/genetics , Mutation/genetics , Operon , Pyrus/microbiology , Virulence/geneticsABSTRACT
Microplitis croceipes is a solitary parasitoid that specializes on noctuid larvae of Helicoverpa zea and Heliothis virescens. Both the parasitoid and its hosts are naturally distributed across a large part of North America. When parasitoids deposit their eggs into hosts, venom and polydnaviruses (PDVs) are also injected into the caterpillars, which can suppress host immune responses, thus allowing parasitoid larvae to develop. In addition, PDVs can regulate host oral cues, such as glucose oxidase (GOX). The purpose of this study was to determine if parasitized caterpillars differentially induce plant defenses compared to non-parasitized caterpillars using two different caterpillar host/plant systems. Heliothis virescens caterpillars parasitized by M. croceipes had significantly lower salivary GOX activity than non-parasitized caterpillars, resulting in lower levels of tomato defense responses, which benefited parasitoid performance by increasing the growth rate of parasitized caterpillars. In tobacco plants, parasitized Helicoverpa zea caterpillars had lower GOX activity but induced higher plant defense responses. The higher tobacco defense responses negatively affected parasitoid performance by reducing the growth rate of parasitized caterpillars, causing longer developmental periods, and reduced cocoon mass and survival of parasitoids. These studies demonstrate a species-specific effect in different plant-insect systems. Based on these results, plant perception of insect herbivores can be affected by parasitoids and lead to positive or negative consequences to higher trophic levels depending upon the particular host-plant system.
Subject(s)
Moths/physiology , Nicotiana/parasitology , Solanum lycopersicum/parasitology , Wasps/physiology , Animals , Female , Glucose Dehydrogenases/metabolism , Glucose Oxidase/metabolism , Host-Parasite Interactions , Larva/metabolism , Solanum lycopersicum/metabolism , Oviposition/physiology , Parasites , Plant Diseases/parasitology , Plant Extracts/chemistry , Plant Extracts/metabolism , Plant Leaves/chemistry , Plant Leaves/metabolism , Species Specificity , Nicotiana/metabolismABSTRACT
ESCULAPIO Project, funded by the Centre for Disease Prevention and Control (CCM) of the Italian Ministry of Health, for the program 2013, aims at increasing awareness on vaccine preventable infectious diseases (VPID) and vaccination in different targets of population and at spreading the culture of prevention by the development of information/training interventions on VPID. In Tuscany Region (Central Italy), educational courses on VPID in high schools were organized and students were stimulated to prepare informative materials on VPID for lower grade school pupils. Educational games for school pupils were realized in Liguria Region (Northern Italy) with the aim to increase awareness and knowledge of vaccination among primary school children, their families, and teachers. The Sicilian Operative Unit (OU) developed and validated a questionnaire to collect data on the main factors influencing vaccine uptake in a population from Southern Italy and spreading information on vaccines to the general population. Aim of the activities performed in Apulia Region (Southern Italy) was to collect, directly from the public, a set of issues to which people were more "sensitive," in order to perceive the dimension of informative needs and the misinformation in the field of vaccinations. A toll-free telephone line to answer questions on VPID was also the aim of the Apulian activities. The objective of the OU of Sardinia (Southern Italy) was to increase knowledge on VPID and adherence to immunization campaigns in health care workers (HCW) by realizing traditional and e-learning training courses and initiatives of health promotion in healthcare and hospital setting. Interventions to promote vaccinations in maternal and child health services and outreach interventions in case of parental non-compliance with vaccination schedules were performed in the Veneto Region (Northern Italy), with the aim to reach a particular subgroup of the general population: new or future parents. The activities of Veneto Region aimed also at realizing individual interviews with parents and/or home visit, if considered useful, for families not respondents to the active ordinary call.
Subject(s)
Communicable Disease Control/methods , Health Communication , Vaccination Coverage , Government Programs , Humans , ItalyABSTRACT
A family of novel thienylbenzoxazol-5-yl-L-alanines, consisting of an alanine core bearing a benzoxazole at the side chain with a thiophene ring at position 2, substituted with different (hetero)aryl substituents, was synthesised to study the tuning of the photophysical and chemosensory properties of the resulting compounds. These novel heterocyclic alanines 3a-f and a series of structurally related bis-thienylbenzoxazolyl-alanines 3g-j were evaluated for the first time in the recognition of selected metal cations with environmental, medicinal and analytical interest such as Co2+, Cu2+, Zn2+ and Ni2+, in acetonitrile solution, with the heterocycles at the side chain acting simultaneously as the coordinating and reporting units, via fluorescence changes. This behaviour can be explained by the involvement of the electron donor heteroatoms in the recognition event, through complexation of the metal cations. The spectrofluorimetric titrations showed that thienylbenzoxazolyl-alanines 3a-j and 4a,b were non-selective fluorimetric chemosensors for the above-mentioned cations, with the best results being obtained for the interaction of Cu2+ with bis-alanine 3j and deprotected alanines 4a,b. The encouraging photophysical and metal ion sensing properties of these thienylbenzoxazolyl-alanines suggest that they can be used to obtain bioinspired fluorescent reporters for metal ion such as peptides/proteins with chemosensory/probing ability.
Subject(s)
Alanine/analogs & derivatives , Fluorescence , Metals/analysisABSTRACT
The physicochemical composition and the technological and sensory properties of hamburgers made with meat from Ile de France lambs fed on different levels (0, 10, 20, 30 and 40%) of whole cottonseed were studied. The addition of whole cottonseed to the lambs' diets decreased the thiobarbituric acid reactive substances in the lamb meat and altered the physicochemical characteristics of the hamburgers, which were characterised by low lipid ( y^=4.27 ), cholesterol ( y^=75.15 ) and caloric content ( y^=122.04 ). The results regarding cooking characteristics were directly related to the microscopic observations regarding the hamburgers; the more cohesive structures exhibited better performance after cooking, with increased cooking yield and moisture retention, and decreased cooking loss. The levels of whole cottonseed did not influence the texture profile, but they negatively affected the acceptability of the hamburgers, since as the levels of cotton seedlings increased, the scores for the sensorial attributes decreased. Thus, a maximum inclusion of 16.7% of whole cottonseed in the dry matter of the diet of lambs is recommended.
ABSTRACT
Mechanical damage caused by insect feeding along with components present in insect saliva and oral secretions are known to induce jasmonic acid-mediated defense responses in plants. This study investigated the effects of bacteria from oral secretions of the fall armyworm Spodoptera frugiperda on herbivore-induced defenses in tomato and maize plants. Using culture-dependent methods, we identified seven different bacterial isolates belonging to the family Enterobacteriacea from the oral secretions of field-collected caterpillars. Two isolates, Pantoea ananatis and Enterobacteriaceae-1, downregulated the activity of the plant defensive proteins polyphenol oxidase and trypsin proteinase inhibitors (trypsin PI) but upregulated peroxidase (POX) activity in tomato. A Raoultella sp. and a Klebsiella sp. downregulated POX but upregulated trypsin PI in this plant species. Conversely, all of these bacterial isolates upregulated the expression of the herbivore-induced maize proteinase inhibitor (mpi) gene in maize. Plant treatment with P. ananatis and Enterobacteriaceae-1 enhanced caterpillar growth on tomato but diminished their growth on maize plants. Our results highlight the importance of herbivore-associated microbes and their ability to mediate insect plant interactions differently in host plants fed on by the same herbivore.
Subject(s)
Gastrointestinal Microbiome , Solanum lycopersicum/immunology , Spodoptera/microbiology , Zea mays/immunology , Animals , Bacteria/isolation & purification , Herbivory , Insect Proteins/metabolism , Larva/growth & development , Solanum lycopersicum/parasitology , Saliva/enzymology , Salivary Proteins and Peptides/metabolism , Weight Gain , Zea mays/parasitologyABSTRACT
Members of the plant virus genus Ourmiavirus are characterized by having non-enveloped bacilliform virions with a series of discrete lengths from 30 to 62 nm composed of a single coat protein (CP). The genome consists of three positive-sense single-stranded RNAs, each encoding a single protein. The RNA-dependent RNA polymerase (RdRp) has closest similarity to that of viruses from the family Narnaviridae; the movement protein (MP) is similar to the MPs of tombusviruses; the CP shows limited similarity to the CPs of several plant and animal viruses. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the genus Ourmiavirus, which is available at www.ictv.global/report/ourmiavirus.
Subject(s)
Plant Viruses/classification , RNA Viruses/classification , Capsid Proteins/chemistry , Capsid Proteins/genetics , Classification , Genome, Viral , Plant Viruses/genetics , Plant Viruses/physiology , Plant Viruses/ultrastructure , RNA Viruses/genetics , RNA Viruses/physiology , RNA Viruses/ultrastructure , RNA, Viral/chemistry , RNA, Viral/genetics , RNA-Dependent RNA Polymerase/chemistry , Virion/chemistry , Virion/ultrastructure , Virus ReplicationABSTRACT
Insect gut-associated microbes modulating plant defenses have been observed in beetles and piercing-sucking insects, but the role of caterpillar-associated bacteria in regulating plant induced defenses has not been adequately examined. We identified bacteria from the regurgitant of field-collected Helicoverpa zea larvae using 16S ribosomal RNA (rRNA) gene sequencing and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. A combination of biochemical, molecular, and confocal electron microscopy methods were used to determine the role of caterpillar-associated bacteria in mediating defenses in Solanum lycopersicum (tomato). Laboratory-reared H. zea inoculated with one of the bacteria identified in field-collected H. zea, Enterobacter ludwigii, induced expression of the tomato defense-related enzyme polyphenol oxidase and genes regulated by jasmonic acid (JA), whereas the salicylic acid (SA)-responsive pathogenesis-related gene was suppressed. Additionally, saliva and its main component glucose oxidase from inoculated caterpillars played an important role in elevating tomato anti-herbivore defenses. However, there were only low detectable amounts of regurgitant or bacteria on H. zea-damaged tomato leaves. Our results suggest that H. zea gut-associated bacteria indirectly mediate plant-insect interactions by triggering salivary elicitors. These findings provide a proof of concept that introducing gut bacteria to a herbivore may provide a novel approach to pest management through indirect induction of plant resistance.
Subject(s)
Digestive System/microbiology , Enterobacter/physiology , Lepidoptera/microbiology , Saliva/metabolism , Solanum lycopersicum/immunology , Animals , Catechol Oxidase/metabolism , Cyclopentanes , Glucose Oxidase/metabolism , Herbivory , Larva/microbiology , Solanum lycopersicum/enzymology , OxylipinsABSTRACT
Polygonum ringspot virus (PolRSV) is a recently characterized Tospovirus reported in Italy. Northern blot analyses of PolRSV infections in Nicotiana benthamiana and tomato plants showed that a viral RNA species with nearly twice the length of the Small genomic RNA (S-RNA) accumulated abundantly in the former host, but was not detected in the latter. Additional assays confirmed that biogenesis of this novel RNA species was common to all PolRSV isolates tested and also to an isolate of Tomato spotted wilt virus (TSWV). Given its size, we hypothesized that the novel RNA species was a dimer molecule and we confirmed this hypothesis by RNA sequencing (RNAseq) analysis and reverse transcription (RT)-PCR of putative predicted dimer junction sites in RNA extracts of N. benthamiana challenged with PolRSV isolates Plg6 and Plg13/2. We also confirmed that these molecules are derived from head-to-tail dimers and often contain deletions at their junction sites. We named these novel molecules imperfect dimer RNAs (IMPD-RNAs). PolRSV IMPD-RNAs systemic accumulation in a range of host plants was restricted to N. benthamiana and Nicotiana occidentalis. Notably, IMPD-RNAs accumulation was modulated by temperature and their generation was restricted to late stages of systemic infection (12 days post-inoculation) in N. benthamiana. Differently from all other PolRSV isolates used in this study, Plg13/2 generated more IMPD-RNAs coupled with low amounts of genomic S-RNA and maintained them even at 18 °C, besides having lost the ability to infect tomato plants. This is the first characterization of S-RNA dimers for Tospovirus, and of occurrence of dimers of genomic segments at the whole organism level for Bunyaviridae.
Subject(s)
Host Specificity , Plant Diseases/virology , RNA, Viral/chemistry , RNA, Viral/metabolism , Solanum lycopersicum/virology , Tospovirus/physiology , Dimerization , Italy , RNA, Viral/genetics , Temperature , Nicotiana/virology , Tospovirus/chemistry , Tospovirus/geneticsABSTRACT
Insect symbiotic bacteria affect host physiology and mediate plant-insect interactions, yet there are few clear examples of symbiotic bacteria regulating defense responses in different host plants. We hypothesized that plants would induce distinct defense responses to herbivore- associated bacteria. We evaluated whether preferred hosts (horsenettle) or non-preferred hosts (tomato) respond similarly to oral secretions (OS) from the false potato beetle (FPB, Leptinotarsa juncta), and whether the induced defense triggered by OS was due to the presence of symbiotic bacteria in OS. Both horsenettle and tomato damaged by antibiotic (AB) treated larvae showed higher polyphenol oxidase (PPO) activity than those damaged by non-AB treated larvae. In addition, application of OS from AB treated larvae induced higher PPO activity compared with OS from non-AB treated larvae or water treatment. False potato beetles harbor bacteria that may provide abundant cues that can be recognized by plants and thus mediate corresponding defense responses. Among all tested bacterial isolates, the genera Pantoea, Acinetobacter, Enterobacter, and Serratia were found to suppress PPO activity in tomato, while only Pantoea sp. among these four isolates was observed to suppress PPO activity in horsenettle. The distinct PPO suppression caused by symbiotic bacteria in different plants was similar to the pattern of induced defense-related gene expression. Pantoea inoculated FPB suppressed JA-responsive genes and triggered a SA-responsive gene in both tomato and horsenettle. However, Enterobacter inoculated FPB eliminated JA-regulated gene expression and elevated SA-regulated gene expression in tomato, but did not show evident effects on the expression levels of horsenettle defense-related genes. These results indicate that suppression of plant defenses by the bacteria found in the oral secretions of herbivores may be a more widespread phenomenon than previously indicated.
Subject(s)
Bacteria , Coleoptera/microbiology , Herbivory , Solanum lycopersicum/microbiology , Solanum lycopersicum/physiology , Symbiosis , Animals , Catechol Oxidase/metabolism , Cyclopentanes/metabolism , Eating , Larva/microbiology , Solanum lycopersicum/cytology , Solanum lycopersicum/metabolism , Oxylipins/metabolism , Salicylic Acid/metabolism , Signal TransductionABSTRACT
Induced plant defenses in response to herbivore attack are modulated by cross-talk between jasmonic acid (JA)- and salicylic acid (SA)-signaling pathways. Oral secretions from some insect herbivores contain effectors that overcome these antiherbivore defenses. Herbivores possess diverse microbes in their digestive systems and these microbial symbionts can modify plant-insect interactions; however, the specific role of herbivore-associated microbes in manipulating plant defenses remains unclear. Here, we demonstrate that Colorado potato beetle (Leptinotarsa decemlineata) larvae exploit bacteria in their oral secretions to suppress antiherbivore defenses in tomato (Solanum lycopersicum). We found that antibiotic-untreated larvae decreased production of JA and JA-responsive antiherbivore defenses, but increased SA accumulation and SA-responsive gene expression. Beetles benefit from down-regulating plant defenses by exhibiting enhanced larval growth. In SA-deficient plants, suppression was not observed, indicating that suppression of JA-regulated defenses depends on the SA-signaling pathway. Applying bacteria isolated from larval oral secretions to wounded plants confirmed that three microbial symbionts belonging to the genera Stenotrophomonas, Pseudomonas, and Enterobacter are responsible for defense suppression. Additionally, reinoculation of these bacteria to antibiotic-treated larvae restored their ability to suppress defenses. Flagellin isolated from Pseudomonas sp. was associated with defense suppression. Our findings show that the herbivore exploits symbiotic bacteria as a decoy to deceive plants into incorrectly perceiving the threat as microbial. By interfering with the normal perception of herbivory, beetles can evade antiherbivore defenses of its host.
Subject(s)
Bacteria/immunology , Coleoptera/microbiology , Herbivory/physiology , Mouth/microbiology , Plant Immunity , Solanum lycopersicum/immunology , Solanum lycopersicum/microbiology , Animals , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Bacteria/ultrastructure , Catechol Oxidase/metabolism , Coleoptera/drug effects , Cyclopentanes/metabolism , Flagellin/pharmacology , Gene Expression Regulation, Plant/drug effects , Herbivory/drug effects , Larva/drug effects , Larva/growth & development , Larva/physiology , Solanum lycopersicum/genetics , Molecular Sequence Data , Oxylipins/metabolism , Plant Immunity/drug effects , Plant Immunity/genetics , Plant Leaves/microbiology , Plant Leaves/ultrastructure , Salicylic Acid/metabolism , Signal Transduction/drug effects , Signal Transduction/genetics , Symbiosis/drug effects , Symbiosis/geneticsABSTRACT
We report the first complete nucleotide sequence of a tomato spotted wilt virus (genus Tospovirus, family Bunyaviridae) isolate from the United States. The tripartite genome of PA01 consisted of L, M and S RNAs of 8914, 4765 and 2984 nt, respectively. Similarity percentages in nucleotide and amino acid sequence among PA01 and previously characterized TSWV isolates are provided here. Phylogenetic analysis on the RNA-dependent RNA polymerase (RdRp) gene placed PA01 in a different clade from an isolate from Hawaii that was partially characterized previously. Evidence of two putative reassortment events in the M segment, among PA01 and isolates from South Korea, Italy and Brazil, was found by phylogenetic and recombination analysis, further supporting a role for genetic exchange among isolates of different geographic origin in TSWV evolution.
Subject(s)
Genome, Viral , Plant Diseases/virology , Solanum lycopersicum/virology , Tospovirus/genetics , Tospovirus/isolation & purification , Base Sequence , Brazil , Hawaii , Italy , Molecular Sequence Data , Phylogeny , Republic of Korea , Tospovirus/classification , United StatesABSTRACT
Plant virus detection and identification in crops is a pillar for disease management, import of crop material, production of clean stock plants and basic plant virology studies. In this report, we present a platform for the enrichment and isolation of known or unknown viruses. This platform is based on carbon nanotube arrays inside a microfluidic device that can be a solution for the identification of low titer viruses from plants. Using our microfluidic devices, we achieved enrichment of two economically important viruses, the orthotospovirus, tomato spotted wilt orthotospovirus (TSWV) and the potyvirus, zucchini yellow mosaic virus (ZYMV). The carbon nanotube arrays integrated in these microfluidic devices are capable of trapping viruses discriminated by their size; the virus rich arrays can be then analyzed by common downstream techniques including immunoassays, PCR, HTS and electron microscopy. This procedure offers a simple to operate and portable sample preparation device capable of trapping viruses from raw plant extracts while reducing the host contamination.
Subject(s)
Nanotubes, Carbon , Plant Viruses , Microfluidics , Plant DiseasesABSTRACT
Breast cancer is a leading cause of death in women, and its management highly depends on early disease diagnosis and monitoring. This remains challenging due to breast cancer's heterogeneity and a scarcity of specific biomarkers that could predict responses to therapy and enable personalized treatment. This Perspective describes the diagnostic landscape for breast cancer management, molecular strategies targeting receptors overexpressed in tumors, the theranostic potential of the oxytocin receptor (OTR) as an emerging breast cancer target, and the development of OTR-specific optical and nuclear tracers to study, visualize, and treat tumors. A special focus is on the chemistry and pharmacology underpinning OTR tracer development, preclinical in vitro and in vivo studies, challenges, and future directions. The use of peptide-based tracers targeting upregulated receptors in cancer is a highly promising strategy complementing current diagnostics and therapies and providing new opportunities to improve cancer management and patient survival.