High Pathogen Pressure Research Articles

Comparison of plant microbiota in diseased and healthy rice reveals methylobacteria as health signatures with biocontrol capabilities

IntroductionRice (Oryza sativa) is a staple food worldwide, but its production is under constant pressure from both abiotic and biotic stresses, resulting in high use of agrochemicals. The plant microbiome harbours microorganisms that can benefit plant health and provide alternatives to the use of agrochemicals. The composition of plant microbiomes depends on many factors (soil composition, age, and health) and is considered a primary driver of future plant health. To identify plant microbiomes that protect against disease, we hypothesised that asymptomatic rice plants in fields under high pathogen pressure (i.e., healthy islands of plants among predominantly diseased plants) might harbour a microbiota that protects them from disease.Material and MethodsWe sampled healthy and leaf-diseased plants in rice fields with high disease incidence in Cambodia and profiled their microbiota at leaf, root, and rhizosphere levels using 16S V3V4 and 18S V4 amplicon barcoding sequencing.ResultsComparison of amplicon sequence variants (ASV) of the microbiota of healthy and diseased samples revealed both disease and healthy signatures (significant enrichment or depletion at ASV/species/genus level) in both fields. The genera Methylobacterium and Methylorubrum were identified health taxa signatures with several species significantly enriched in healthy leaf samples (Methylobacterium indicum, Methylobacterium komagatae, Methylobacterium aerolatum, and Methylorubrum rhodinum). A cultivation approach on rice samples led to the isolation of bacterial strains of these two genera, which were further tested as bioinoculants on rice leaves under controlled conditions, showing for some of them a significant reduction (up to 77%) in symptoms induced by Xanthomonas oryzae pv. oryzae infection.DiscussionWe validated the hypothesis that healthy plants in fields under high disease occurrence can host specific microbiota with biocontrol capacities. This strategy could help identify new microbes with biocontrol potential for sustainable rice production.

Symbiotic bacteria and fungi proliferate in diapause and may enhance overwintering survival in a solitary bee.

Host-microbe interactions underlie the development and fitness of many macroorganisms, including bees. Whereas many social bees benefit from vertically transmitted gut bacteria, current data suggests that solitary bees, which comprise the vast majority of species diversity within bees, lack a highly specialized gut microbiome. Here, we examine the composition and abundance of bacteria and fungi throughout the complete life cycle of the ground-nesting solitary bee Anthophora bomboides standfordiana. In contrast to expectations, immature bee stages maintain a distinct core microbiome consisting of Actinobacterial genera (Streptomyces, Nocardiodes) and the fungus Moniliella spathulata. Dormant (diapausing) larval bees hosted the most abundant and distinctive bacteria and fungi, attaining 33 and 52 times their initial copy number, respectively. We tested two adaptive hypotheses regarding microbial functions for diapausing bees. First, using isolated bacteria and fungi, we found that Streptomyces from brood cells inhibited the growth of multiple pathogenic filamentous fungi, suggesting a role in pathogen protection during overwintering, when bees face high pathogen pressure. Second, sugar alcohol composition changed in tandem with major changes in fungal abundance, suggesting links with bee cold tolerance or overwintering biology. We find that A. bomboides hosts a conserved core microbiome that may provide key fitness advantages through larval development and diapause, which raises the question of how this microbiome is maintained and faithfully transmitted between generations. Our results suggest that focus on microbiomes of mature or active insect developmental stages may overlook stage-specific symbionts and microbial fitness contributions during host dormancy.

Conventional and Biopesticide Fungicides for Cucurbit Downy Mildew Control on Cucumber in Michigan

Michigan ranks first in the nation in cucumber production for processing (pickling), contributing over $45 million to the state's economy in 2019. Cucurbit downy mildew, caused by the oomycete Pseudoperonospora cubensis, is the most important disease of cucumber and an annual threat to yields. Fungicides are the most important means to control P. cubensis. Our goal was to monitor currently labelled conventional fungicides and biopesticides for efficacy over the course of an entire cropping period under high pathogen pressure. Field trials were conducted at the Michigan State University Plant Pathology Research Farm in 2021 and 2022. Fungicides were applied weekly, and disease severity was evaluated by visually assessing the percentage of foliar area showing downy mildew symptoms. At the end of the season, the relative area under the disease progress curve (rAUDPC) was calculated using the disease severity data. Based on rAUDPC results, oxathiapiprolin premixed with chlorothalonil was the most effective fungicide at controlling P. cubensis and was significantly better than all other conventional fungicides in both years tested. In both years, all conventional treatments had a significantly lower rAUDPC than the untreated control except pyraclostrobin, dimethomorph, and fluopicolide. No biopesticide fungicide reduced the rAUDPC compared with the untreated control in either year evaluated.

Augmented screening of sunflower inbreds for Alternariaster leaf blight diseaseunder polyhouse conditions

A total of 206 sunflower inbreds were screened for Alternariaster leaf blight resistance under poly house conditions. The results showed that eight sunflower inbreds including maintainer line, prebred lines and restorer linesviz., HA24B, PB-898, PB-904, PB-205, PB-905, ID-32, PB-889, RGP-278-2 showed tolerant reaction to Alternariaster leaf blight and able to set good seeds under high pathogen pressure.

A Bayesian model for control strategy selection against Plasmopara viticola infections.

Plant pathogens pose a persistent threat to grape production, causing significant economic losses if disease management strategies are not carefully planned and implemented. Simulation models are one approach to address this challenge because they provide short-term and field-scale disease prediction by incorporating the biological mechanisms of the disease process and the different phenological stages of the vines. In this study, we developed a Bayesian model to predict the probability of Plasmopara viticola infection in grapevines, considering various disease management approaches. To aid decision-making, we introduced a multi-attribute utility function that incorporated a sustainability index for each strategy. The data used in this study were derived from trials conducted during the production years 2018-2020, involving the application of five disease management strategies: conventional Integrated Pest Management (IPM), conventional organic, IPM with substantial fungicide reduction combined with host-defense inducing biostimulants, organic management with biostimulants, and the use of biostimulants only. Two scenarios were considered, one with medium pathogen pressure (Average) and another with high pathogen pressure (Severe). The results indicated that when sustainability indexes were not considered, the conventional IPM strategy provided the most effective disease management in the Average scenario. However, when sustainability indexes were included, the utility values of conventional strategies approached those of reduced fungicide strategies due to their lower environmental impact. In the Severe scenario, the application of biostimulants alone emerged as the most effective strategy. These results suggest that in situations of high disease pressure, the use of conventional strategies effectively combats the disease but at the expense of a greater environmental impact. In contrast to mechanistic-deterministic approaches recently published in the literature, the proposed Bayesian model takes into account the main sources of heterogeneity through the two group-level effects, providing accurate predictions, although precise estimates of random effects may require larger samples than usual. Moreover, the proposed Bayesian model assists the agronomist in selecting the most effective crop protection strategy while accounting for induced environmental side effects through customizable utility functions.

Elevated nutrient supply can exert worse effects on Norway spruce than drought, viewed through chemical defence against needle rust.

Abiotic factors such as water and nutrient availability can exert a dominant influence on the susceptibility of plants to various pathogens. Effects of abiotic environmental factors on phenolic compound concentrations in the plant tissue may represent one of the major underlying mechanisms, as these compounds are known to play a substantial role in plant resistance to pests. In particular, this applies to conifer trees, in which a large range of phenolic compounds are produced constitutively and/or induced by pathogen attack. We subjected Norway spruce saplings to water limitation and elevated nutrient supply over two years and subsequently controlled infection with the needle rust Chrysomyxa rhododendri and analysed both constitutive and inducible phenolic compound concentrations in the needles as well as the degree of infection. Compared to the control group, both drought and fertilization profoundly modified the constitutive and pathogen induced profiles of phenolic compounds, but had little impact on the total phenolic content. Fertilization predominantly affected the inducible phenolic response and led to higher infection rates by C. rhododendri. Drought stress, in contrast, mainly shaped the phenolic profiles in healthy plant parts and had no consequences on the plant susceptibility. The results show that specific abiotic effects on individual compounds seem to be decisive for the infection success of C. rhododendri, whereby the impaired induced response in saplings subjected to nutrient supplementation was most critical. Although drought effects were minor, they varied depending on the time and length of water limitation. The results indicate that prolonged drought periods in the future may not significantly alter the foliar defence of Norway spruce against C. rhododendri, but fertilization, often propagated to increase tree growth and forest productivity, can be counterproductive in areas with high pathogen pressure.

Complete Genome Sequences of Five Gram-Negative Bacterial Strains Comprising Synthetic Bacterial Consortium "The Great Five" with Antagonistic Activity Against Plant-Pathogenic Pectobacterium spp. and Dickeya spp.

Complete Genome Sequences of Five Gram-Negative Bacterial Strains Comprising Synthetic Bacterial Consortium "The Great Five" with Antagonistic Activity Against Plant-Pathogenic Pectobacterium spp. and Dickeya spp.

The relative susceptibility of grapevine rootstocks to black foot disease is dependent on inoculum pressure

Black foot disease of grapevines is a major economic issue for the viticulture industry worldwide. The disease is mainly associated with a complex of pathogen species within the genera Dactylonectria and Ilyonectria. The susceptibility of six grapevine rootstock cultivars to black foot disease under field conditions was assessed. Callused rootstocks of 101-14, 5C, 420A, Riparia Gloire, Schwarzmann and 3309C were planted into soil containing low natural pathogen populations or inoculated with isolates representing the species diversity in New Zealand. Disease incidence, disease severity and dry weight accumulation were assessed after 8 months of growth. Root and shoot dry weights were not significantly affected by inoculation treatment, but differed among rootstock cultivars, with cultivar 420A having the lowest root and shoot dry weight, cultivar 3309C having the largest shoot dry weight and cultivar 5C the largest root dry weight. The relative susceptibility of rootstocks differed significantly depending on whether they were grown under low natural inoculum pressure or a higher pressure in artificially inoculated soil. Schwarzmann and Riparia Gloire rootstock cultivars were the least susceptible under natural low inoculum pressure, but were the most susceptible in inoculated soil. In contrast, 5C was one of the most susceptible under low inoculum levels but was the least susceptible under high pathogen pressure. The result of the study indicate that black foot pathogen inoculum levels in soil affect the relative susceptibility of grapevine rootstocks to infection, and may have implications for the selection of rootstocks for planting.

Silica Nanoparticle Dissolution Rate Controls the Suppression of Fusarium Wilt of Watermelon (Citrullus lanatus).

Projected population increases over the next 30 years have elevated the need to develop novel agricultural technologies to dramatically increase crop yield, particularly under conditions of high pathogen pressure. In this study, silica nanoparticles (NPs) with tunable dissolution rates were synthesized and applied to watermelon (Citrullus lanatus) to enhance plant growth while mitigating development of the Fusarium wilt disease caused by Fusarium oxysporum f. sp. niveum. The hydrolysis rates of the silica particles were controlled by the degree of condensation or the catalytic activity of aminosilane. The results demonstrate that the plants treated with fast dissolving NPs maintained or increased biomass whereas the particle-free plants had a 34% decrease in biomass. Further, higher silicon concentrations were measured in root parts when the plants were treated with fast dissolving NPs, indicating effective silicic acid delivery. In a follow-up field study over 2.5 months, the fast dissolving NP treatment enhanced fruit yield by 81.5% in comparison to untreated plants. These findings indicate that the colloidal behavior of designed nanoparticles can be critical to nanoparticle-plant interactions, leading to disease suppression and plant health as part of a novel strategy for nanoenabled agriculture.

Further In Vitro Assessment and Mid-Term Evaluation of Control Strategy of Xylella fastidiosa subsp. pauca in Olive Groves of Salento (Apulia, Italy).

During recent years; Xylella fastidiosa subsp. pauca (Xfp) has spread in Salento causing relevant damage to the olive groves. Measures to contain the spreading of the pathogen include the monitoring of the areas bordering the so-called “infected” zone and the tree eradication in case of positive detection. In order to provide a control strategy aimed to maintain the tree productivity in the infected areas, we further evaluated the in vitro and in planta mid-term effectiveness of a zinc-copper-citric acid biocomplex. The compound showed an in vitro bactericidal activity and inhibited the biofilm formation in representative strains of X. fastidiosa subspecies, including Xfp isolated in Apulia from olive trees. The field mid-term evaluation of the control strategy assessed by quantitative real-time PCR in 41 trees of two olive groves of the “infected” area revealed a low concentration of Xfp over the seasons upon the regular spraying of the biocomplex over 3 or 4 consecutive years. In particular, the bacterial concentration lowered in July and October with respect to March, after six consecutive treatments. The trend was not affected by the cultivar and it was similar either in the Xfp-sensitive cultivars Ogliarola salentina and Cellina di Nardò or in the Xfp-resistant Leccino. Moreover, the scoring of the number of wilted twigs over the seasons confirmed the trend. The efficacy of the treatment in the management of olive groves subjected to a high pathogen pressure is highlighted by the yielded a good oil production

Identification of Field Tolerance and Resistance to Mal Secco Disease in a Citrus Germplasm Collection in Sicily

Mal secco is a tracheomycotic disease caused by the fungus Plenodomus tracheiphilus (Petri) Gruyter, Aveskamp, and Verkley that has caused severe damage and loss of yield in the citrus industry in the Mediterranean area, for 100 years. While the disease can affect different cultivated citrus species, lemon (C. × limon var. limon (L.) Burm. f.) and citron are the most susceptible. The identification of resistant or field-tolerant clones and hybrids is a major goal for lemon growers and breeders. To identify sources of resistance or tolerance to the disease, we performed a phenotypic survey on a lemon and lemon-like open-field germplasm planted at CREA (Research Centre for Olive, Fruit and Citrus Crops), Italy, in an area with high pathogen pressure. Phenotyping was performed visually, four times, for three consecutive years, on a total of 50 accessions, with two or three replicate trees per accession. Moreover, molecular screening based on real-time PCR was performed, for two consecutive years, on twigs, young leaves, and mature leaves of all plants, to detect the pathogen in the absence of clear symptoms. The accessions were categorized into seven groups based on the presence of visual symptoms, real-time PCR pathogen detection, and canopy volume. The results revealed sources of tolerance in lemon and citron hybrids. The molecular screening identified P. tracheiphilus in all lemon clones, with mean Ct values ranging from 17 to 39. The screening also identified P. tracheiphilus in clones without clear symptoms, indicating their ability to tolerate the disease. Moreover, a strong negative correlation was found between the Ct values in twigs and symptom severity (r = −0.72). This indicates that the DNA from twigs is the most appropriate for use in performing reliable phenotyping of mal secco susceptibility in adult plants. An autotetraploid lemon (Doppio Lentini) seems to be immune to the disease, under natural pressure, since P. tracheiphilus was not detected by real-time PCR and visual screening. Overall, the data obtained are a valuable resource for identifying both the most tolerant lemon varieties suitable for areas with high pathogen pressure and the best breeding parents for the introgression of resistance genes into lemon genotypes.

Microbiome-guided evaluation of Bacillus subtilis BIOUFLA2 application to reduce mycotoxins in maize kernels

Fungal diseases are aggravating globally in crop cultivation despite of growing inputs of chemical fungicides. Ear rot and fumonisin contamination of kernels caused by Fusarium verticillioides lead to qualitative and quantitative reductions in maize production. In tropical agriculture, high yielding maize currently can only be assured through foliar protection using fungicides due to the high pathogen pressure. However, the use of chemical fungicides alone does not guarantee the protection of kernels. Recently, a tandem application of fungicides with the Bacillus subtilis strain BIOUFLA2 was identified as a promising strategy to control F. verticillioides-caused diseases. We have employed an integrative approach to assess changes in the microbiome of maize subjected to a combination of chemical and biological fungicides and contrasted it to conventional treatments. This was complemented with molecular and analytical monitoring of the pathogen and mycotoxin levels. Two sampling times were included (10 days after application of treatments and upon harvesting) and two maize fields to account for regional differences. A comparative analysis indicated a treatment-specific enrichment of bacterial and fungal OTUs (Operational Taxonomic Units) that were not detectable in the maize microbiome of untreated plants. Both, the chemical and the tandem application of a chemical and biological pesticide resulted in the occurrence of unique OTUs. Samples subjected to these treatments harbored up to 22 additional OTUs. The lowest fumonisin concentration was observed in the treatment that encompassed BIOUFLA2 (field 1 = 0.29 ppm and field 2 = 0.77 ppm), while the conventional fungicide application resulted in the highest mycotoxin concentrations (field 1 = 3.84 ppm and field 2 = 10.02 ppm). Our study provided strong evidence that conventional treatments of maize with fungicides can promote mycotoxin levels in grains and that partial replacement with biologicals can increase the treatment efficiency.

Inheritance pattern of resistance to Fusarium wilt (Fusarium oxysporum f. sp sesame) in sesame

Fusarium wilts (Fusarium oxysporum f.sp. sesame) is among of the most destructive soil-borne disease of sesame in Uganda. The disease may cause yield loss of up to 100% if not controlled. Breeding and use of resistant varieties is the most economic and eco-friendly solution to the disease since majority of sesame growers are resource constrained. Some genotypes were reported to be moderately resistant to the disease in Uganda. However its nature of inheritance was not studied. Successful breeding requires selection of suitable parents and whose pattern of inheritance of disease resistance is known. In this study, eight parental genotypes of sesame with different levels of resistance to Fusarium wilt pathogen were used in a full diallel to produce F1 progenies. The eight parents and F1 progenies were evaluated in the screen house under high pathogen pressure through artificial infection in an Alpha Lattice Design of three replicates. The results revealed that additive and non-additive gene actions contributed to controlling resistance to Fusarium wilt. However non-additive were more predominant which were signposted by moderate Baker’s ratio (53.9%) and low Coefficient of Genetic Determination narrow sense (h2 = 45.1%). Moreover, the study indicated that maternal effects have influence toward resistance to Fusarium wilt in sesame. Among eight parents used parent Sesim 2 (with EM% GCA effect 7.32, and DI% GCA effect -4.02) and EM15-1-5 (with EM% GCA effect 3.07%, and DI% GCA effect -11.58%) were good combiner parents for transmitting resistance and are recommended for use in breeding for Fusarium wilt resistance. Key words: Fusarium wilt, inheritance, incidence, resistance, sesame,

English

Fusarium wilt is one of the most devastating diseases in sesame production in Uganda, caused by a fungus called Fusarium oxysporum f.sp. sesami. Its incidence ranges from 17.1 to 73.3%. Some sesame genotypes have been reported to resist Fusarium wilt; however, have not been precisely determined. In this study, 30 sesame genotypes that included released varieties, improved elite breeding lines and introductions were screened in the screenhouse under high pathogen pressure following artificial infection using five isolates of F. oxysporum f.sp sesami. The results revealed that sesame genotypes showed different response to the pathogen and thus disease development among the genotypes. The genotype effect was significant (P≤0.001) for disease incidence. Two genotypes (EM15-1-5 and Sesim 2) were identified and rated moderately resistant to Fusarium wilt (37.3 and 33.8%), respectively. Whereas, seven genotypes showed moderate susceptibility and 21 genotypes were susceptible for Fusarium wilt infection. No genotype was identified as being immune to the disease. It is noteworthy for sesame breeding programme in Uganda to continue evaluating other genotypes from existing germplasm which were not tested for resistance to Fusarium wilt in this study. Also more germplasm should be assembled and screened for resistance to the disease and other agronomic traits. Key words: Fusarium oxysporum f. sp. sesame, incidence, resistance. &nbsp

Hosts do not simply outsource pathogen resistance to protective symbionts.

Microbial symbionts commonly protect their hosts from natural enemies, but it is unclear how protective symbionts influence the evolution of host immunity to pathogens. One possibility is that 'extrinsic' protection provided by symbionts allows hosts to reduce investment in 'intrinsic' immunological resistance mechanisms. We tested this idea using pea aphids (Acyrthosiphon pisum) and their facultative bacterial symbionts that increase host resistance to the fungal pathogen Pandora neoaphidis. The pea aphid taxon is composed of multiple host plant associated populations called biotypes, which harbor characteristic communities of symbionts. We found that biotypes that more frequently carry protective symbionts have higher, rather than lower, levels of intrinsic resistance. Within a biotype there was no difference in intrinsic resistance between clones that did and did not carry a protective symbiont. The host plant on which an aphid feeds did not strongly influence intrinsic resistance. We describe a simple conceptual model of the interaction between intrinsic and extrinsic resistance and suggest that our results may be explained by selection favoring both the acquisition of protective symbionts and enhanced intrinsic resistance in habitats with high pathogen pressure. Such combined protection is potentially more robust than intrinsic resistance alone.

Effects of initial nematode population density and water regime on resistance and tolerance to the rice root-knot nematode Meloidogyne graminicola in African and Asian rice genotypes

ABSTRACTThe rice root-knot nematode (RKN), Meloidogyne graminicola, is an important pathogen affecting rice production in South and Southeast Asia. Efficacy of resistance and tolerance in selected M. graminicola-resistant African rice genotypes TOG5674, TOG5675 and CG14 and -susceptible Asian rice genotypes IR64 and UPLRi-5 were examined under a range of initial population densities (Pi) and water regimes. Resistance to M. graminicola in resistant rice genotypes was not broken with increasing pathogen pressure (Pi = 15,000 to 60,000 J2/plant). Resistant rice genotypes were even tolerant to the damage and yield loss caused by high pathogen pressure. On the other hand, increasing Pi levels caused more damage on susceptible rice genotypes. Final nematode population densities in the root systems of resistant and susceptible rice genotypes were significantly lower under flooded conditions than under upland and drought conditions. TOG5674, TOG5675 and CG14 were more tolerant to M. graminicola infection even when grown under upland and drought conditions while IR64 and UPLRi-5 were highly sensitive.

A Metatranscriptomic Approach to the Identification of Microbiota Associated with the Ant Formica exsecta

Social insects live in cooperative colonies, often in high densities and with closely related individuals, and interact using social contact behaviours. Compared to solitary insects, social insects have evolved multi-level immunity that includes immune responses common to holometabolous insects, and social immunity, which is exclusive to social taxa. This suggests that social insects may be subject to high pathogen pressure, yet relatively little is known about the range of symbiotic and pathogenic microbial communities that associate with social insects. In this study we examined transcriptome data generated from the ant Formica exsecta for sequences identifying as microbes (or other organisms potentially of non-ant origin). Sequences showing homology to two viruses and several other potentially or obligate intracellular organisms, such as Wolbachia, Arsenophonus, Entomoplasmatales and Microsporidia, were present in the transcriptome data. These homologous sequence matches correspond to genera/species that have previously been associated with a variety of insects, including social insects. There were also sequences with identity to several other microbes such as common moulds and soil bacteria. We conclude that this sequence data provides a starting point for a deeper understanding of the biological interactions between a species of ant and the micro- and macrobiotic communities that it potentially encounters.

Costs of resistance to fungal pathogens in genetically modified wheat

Aims Many resistance genes against fungal pathogens show costs of resistance. Genetically modified (GM) plants that differ in only one or a few resistance genes from control plants present ideal systems for measuring these costs in the absence of pathogens. Methods To assess the ecological relevance of costs of pathogen resistance, we grew individual plants of four transgenic spring wheat lines in a field trial with three pathogen levels and varied the genetic diversity of the crop. Important Findings We found that two lines with a Pm3b transgene were more resistant to powdery mildew than their sister lines of the variety Bobwhite, whereas lines with chitinase (A9) or chitinase and glucanase (A13) transgenes were not more resistant than their mother variety Frisal. Nevertheless, in the absence of the pathogen, both the GM lines of Bobwhite as well as those of Frisal performed significantly worse than their controls, i.e. Pm3b#1 and Pm3b#2 had 39% or 53% and A9 and A13 had 14% or 23% lower yields. In the presence of the pathogen, all GM lines except Pm3b#2 could increase their yields and other fitness-related traits, reaching the performance levels of the control lines. Line Pm3b#2 seemed to have lost its phenotypic plasticity and had low performance in all environments. This may have been caused by very high transgene expression. No synergistic effects of mixing different GM lines with each other were detected. This might have been due to high transgene expression or the similarity between the lines regarding their resistance genes. We conclude that costs of resistance can be high for transgenic plants with constitutive transgene expression and that this can occur even in cases where the non-transgenic control lines are already relatively resistant, such as in our variety Frisal. Transgenic plants could only compete with conventional varieties in environments with high pathogen pressure. Furthermore, the large variability among the GM lines, which may be due to unpredictable transgene expression, suggests that case-by-case assessments are necessary to evaluate costs of resistance.

Disgust as an adaptive system for disease avoidance behaviour

You have accessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Curtis Valerie, de Barra Mícheál and Aunger Robert 2011Disgust as an adaptive system for disease avoidance behaviourPhil. Trans. R. Soc. B3661320http://doi.org/10.1098/rstb.2011.0002SectionYou have accessCorrectionsDisgust as an adaptive system for disease avoidance behaviour Valerie Curtis Valerie Curtis Google Scholar Find this author on PubMed Search for more papers by this author , Mícheál de Barra Mícheál de Barra Google Scholar Find this author on PubMed Search for more papers by this author and Robert Aunger Robert Aunger Google Scholar Find this author on PubMed Search for more papers by this author Valerie Curtis Valerie Curtis Google Scholar Find this author on PubMed Search for more papers by this author , Mícheál de Barra Mícheál de Barra Google Scholar Find this author on PubMed Search for more papers by this author and Robert Aunger Robert Aunger Google Scholar Find this author on PubMed Search for more papers by this author Published:27 April 2011https://doi.org/10.1098/rstb.2011.0002This article corrects the followingResearch ArticleDisgust as an adaptive system for disease avoidance behaviourhttps://doi.org/10.1098/rstb.2010.0117 Valerie Curtis, Mícheál de Barra and Robert Aunger volume 366issue 1563Philosophical Transactions of the Royal Society B: Biological Sciences12 February 2011Phil. Trans. R. Soc. B366, 389–401 (12 February 2011) (doi:10.1098/rstb.2010.0117)In figure 1, ‘Middle East and North America’ should read ‘Middle East and North Africa’.In the second paragraph of §8 the word ‘higher’ should be replaced by ‘lower’ to read‘While we have set out evidence from many types of source about the individual links, is there any evidence of it acting as a complete system? Some intriguing new studies provide evidence that this is the case. It has been shown that societies faced with high pathogen pressure have lower average scores on personality traits such as extraversion and openness to experience …’. Previous Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Eyal T, Dar R and Liberman N (2021) Is disgust in obsessive-compulsive disorder mediated by fear of pathogens?, Journal of Anxiety Disorders, 10.1016/j.janxdis.2020.102340, 77, (102340), Online publication date: 1-Jan-2021. Hinzmann J, Borg C, Verwoerd J and de Jong P (2019) The Reciprocal Relationship Between Sexual Arousal and Disgust as Evidenced in Automatic Approach-Avoidance Behavior, The Journal of Sex Research, 10.1080/00224499.2019.1658064, 57:3, (384-396), Online publication date: 23-Mar-2020. Parmentier F, Fraga I, Leiva A and Ferré P (2019) Distraction by deviant sounds: disgusting and neutral words capture attention to the same extent, Psychological Research, 10.1007/s00426-019-01192-4, 84:7, (1801-1814), Online publication date: 1-Oct-2020. Pellegrino R, Crandall P and Seo H (2015) Hand washing and disgust response to handling different food stimuli between two different cultures, Food Research International, 10.1016/j.foodres.2014.12.027, 76, (301-308), Online publication date: 1-Oct-2015. Pellegrino R, Crandall P, O'Bryan C and Seo H (2015) A review of motivational models for improving hand hygiene among an increasingly diverse food service workforce, Food Control, 10.1016/j.foodcont.2014.09.015, 50, (446-456), Online publication date: 1-Apr-2015. Curtis V (2011) Why disgust matters, Philosophical Transactions of the Royal Society B: Biological Sciences, 366:1583, (3478-3490), Online publication date: 12-Dec-2011. Melis C, Falcicchio G, Wold P and Billing A (2021) Species identification skills in teacher education students: the role of attitude, context and experience, International Journal of Science Education, 10.1080/09500693.2021.1928326, (1-17) Related articlesDisgust as an adaptive system for disease avoidance behaviour12 February 2011Philosophical Transactions of the Royal Society B: Biological Sciences This Issue27 April 2011Volume 366Issue 1568Theme issue 'The ocular lens: a classic model for development, physiology and disease' compiled and edited by Michael A. Wride and I. Michael Wormstone Article InformationDOI:https://doi.org/10.1098/rstb.2011.0002Published by:Royal SocietyPrint ISSN:0962-8436Online ISSN:1471-2970History: Published online27/04/2011Published in print27/04/2011 License:This journal is © 2011 The Royal Society Citations and impact Subjectsbehaviourevolutionhealth and disease and epidemiology

Rapid Evolution of Immune Proteins in Social Insects

The existence of behavioral traits connected to defense against pathogens manifests the importance of pathogens in the evolution of social insects. However, very little is known about how pathogen pressure has affected the molecular evolution of genes involved in their innate immune system. We have studied the sequence evolution of several immune genes in ants and honeybees. The results show high rates of evolution in both ants and honeybees as measured by the ratio of amino acid changes to silent nucleotide changes, the ratio being clearly higher than in Drosophila immune genes or in nonimmunity genes of bees. This conforms to our expectations based on high pathogen pressure in social insects. The codon-based likelihood method found clear evidence of positive selection only in one ant gene, even though positive selection has earlier been found in both ant and termite immune genes. There is now indication that selection on the amino acid composition of the immune-related genes has been an important part in the fight against pathogens by social insects. However, we cannot distinguish in all the cases whether the high observed d(N)/d(S) ratio results from positive selection within a restricted part of the studied genes or from relaxation of purifying selection associated with effective measures of behaviorally based colony-level defenses.