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Phytophthora palmivora, a hemibiotrophic oomycete, causes diseases in several economically important tropical crops, such as oil palm, which it is responsible for a devastating disease called bud rot (BR). Despite recent progress in understanding host resistance and virulence mechanisms, many aspects remain unknown in P. palmivora isolates from oil palm. Model pathosystems are useful for understanding the molecular interactions between pathogens and hosts. In this study, we utilized detached leaves and whole seedlings of Arabidopsis thaliana Col-0 to describe and evaluate the infection process of three P. palmivora isolates (CPPhZC-05, CPPhZC-04, CPPhZOC-01) that cause BR in oil palm. Two compatible isolates (CPPhZC-05 and CPPhZOC-01) induced aqueous lesions at 72 h post-inoculation (hpi), with microscopic visualization revealing zoospore encysting and appressorium penetration at 3 hpi, followed by sporangia generation at 72 hpi. In contrast, an incompatible isolate (CPPhZC-04) exhibited cysts that could not penetrate tissue, resulting in low leaf colonization. Gene expression of ten P. palmivora infection-related genes was quantified by RT-qPCR, revealing overexpression in compatible isolates, but not in the incompatible isolate. Additionally, key genes associated with salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Arabidopsis exhibited regulation during interaction with the three isolates. These findings demonstrate that P. palmivora can infect Arabidopsis Col-0, and variability is observed in the interaction between Arabidopsis-Col-0 and P. palmivora isolates. Establishing this pathosystem is expected to enhance our understanding of P. palmivora's pathology and physiology. [ABSTRACT FROM AUTHOR]

Climate change (CC) is a complex phenomenon that has the potential to significantly alter marine, terrestrial, and freshwater ecosystems worldwide. Global warming of 2°C is expected to be exceeded during the 21st century, and the frequency of extreme weather events, including floods, storms, droughts, extreme temperatures, and wildfires, has intensified globally over recent decades, differently affecting areas of the world. How CC may impact multiple food safety hazards is increasingly evident, with mycotoxin contamination in particular gaining in prominence. Research focusing on CC effects on mycotoxin contamination in edible crops has developed considerably throughout the years. Therefore, we conducted a comprehensive literature search to collect available studies in the scientific literature published between 2000 and 2023. The selected papers highlighted how warmer temperatures are enabling the migration, introduction, and mounting abundance of thermophilic and thermotolerant fungal species, including those producing mycotoxins. Certain mycotoxigenic fungal species, such as Aspergillus flavus and Fusarium graminearum, are expected to readily acclimatize to new conditions and could become more aggressive pathogens. Furthermore, abiotic stress factors resulting from CC are expected to weaken the resistance of host crops, rendering them more vulnerable to fungal disease outbreaks. Changed interactions of mycotoxigenic fungi are likewise expected, with the effect of influencing the prevalence and co‐occurrence of mycotoxins in the future. Looking ahead, future research should focus on improving predictive modeling, expanding research into different pathosystems, and facilitating the application of effective strategies to mitigate the impact of CC. [ABSTRACT FROM AUTHOR]

Plant viruses can modulate insect vector behaviour directly and/or indirectly by altering plant biochemistry. In many instances, such behavioural alterations increase the frequency of encounters between host and vector, leading to enhanced virus dispersal in ecosystems. In the current study using Cucumber mosaic virus (CMV), Capsicum annuum L. (Solanaceae), and Myzus persicae (Sulzer) (Hemiptera: Aphididae) as a pathosystem, we evaluated the direct and indirect effects of CMV on M. persicae biology and behavioural responses. Data showed that CMV indirectly modulates the aphid vector by providing fitness benefits to aphids, leading to enhanced aphid reproduction on CMV‐infected pepper plants in comparison with non‐infected C. annuum plants. Furthermore, CMV can also alter aphid behaviour directly by modulating the behavioural response of viruliferous aphids towards non‐infected plants. We demonstrate that CMV directly and indirectly modulates the insect vector thereby enhancing its transmission in agroecosystems. [ABSTRACT FROM AUTHOR]

Copyright of Ethos (0860-8024) is the property of John Paul II Institute, Faculty of Philosophy, John Paul II Catholic University of Lublin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The biotrophic fungus Hemileia vastatrix is the pathogen responsible for coffee leaf rust, a devastating disease in several coffee-producing countries. Despite the importance of studying the interaction between Coffea and H. vastatrix, a more comprehensive understanding of the mechanisms involved in this pathosystem is necessary. The role of eight candidate genes was analyzed aiming at identifying and validating new important coffee resistance genes and understanding their interaction with H. vastatrix. These genes were identified in the most important sources of coffee resistance, the Híbrido de Timor CIFC 832/2 and CIFC 832/1. Previous works found six resistance genes and, in our research, other two new genes were identified in BAC clones and validated by RT-qPCR during compatible and incompatible interactions between Coffea and H. vastatrix. An interactome approach was performed using Coffea-H. vastatrix and Coffea-Coffea proteins to better understand the biological process and the interaction of the host-pathogen. Two networks of interactions from the compiled data were built focused on candidate genes associated with pre-haustorial resistance (12 and 24 h.a.i) in coffee plants against the pathogen. The results showed, for the first time, differentially expressed proteins (DEPs) positively regulated in the incompatible interaction Coffea-H. vastatrix. These coffee proteins interact with each other and with secreted and/or transmembrane pathogen proteins. The obtained results also show that DEPs found are involved in important plant defense pathways such as pathways associated with the response to wounds, signaling, regulation of the innate immune response and the transmembrane receptor protein serine/threonine kinase pathway. The present work shows the involvement of genes in both pathogen recognition and signaling cascades, which act in pre-haustorial defense mechanisms of HdT coffee. Therefore, the candidate genes analyzed, together with the biological processes elucidated, have the potential to contribute to the development of new control strategies against the fungus H. vastatrix within coffee breeding programs aiming to develop cultivars with durable resistance.

Phytophthora palmivora, a hemibiotrophic oomycete, causes diseases in several economically important tropical crops, such as oil palm, which it is responsible for a devastating disease called bud rot (BR). Despite recent progress in understanding host resistance and virulence mechanisms, many aspects remain unknown in P. palmivora isolates from oil palm. Model pathosystems are useful for understanding the molecular interactions between pathogens and hosts. In this study, we utilized detached leaves and whole seedlings of Arabidopsis thaliana Col-0 to describe and evaluate the infection process of three P. palmivora isolates (CPPhZC-05, CPPhZC-04, CPPhZOC-01) that cause BR in oil palm. Two compatible isolates (CPPhZC-05 and CPPhZOC-01) induced aqueous lesions at 72 h post-inoculation (hpi), with microscopic visualization revealing zoospore encysting and appressorium penetration at 3 hpi, followed by sporangia generation at 72 hpi. In contrast, an incompatible isolate (CPPhZC-04) exhibited cysts that could not penetrate tissue, resulting in low leaf colonization. Gene expression of ten P. palmivora infection-related genes was quantified by RT-qPCR, revealing overexpression in compatible isolates, but not in the incompatible isolate. Additionally, key genes associated with salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Arabidopsis exhibited regulation during interaction with the three isolates. These findings demonstrate that P. palmivora can infect Arabidopsis Col-0, and variability is observed in the interaction between Arabidopsis-Col-0 and P. palmivora isolates. Establishing this pathosystem is expected to enhance our understanding of P. palmivora’s pathology and physiology.

This article presents an analysis of the ways in which illness experience is represented in literary work as a process in defective (a term coined by Iwona Boruszkowska) time and space. Aneta Żukowska’s autopathography Mięcho [Meat] is presented as a case study. In illness narratives hierarchically structured space of the clinic plays an important role, while time is reorganized by the rules imposed within the pathosystem (a term coined by Agnieszka Dauksza). The analysis of the ways of representing time and space in illness narratives allows for illness to be depicted as both embodied and idiosyncratic experience, and a process that is situated within and influenced by the external conditions of medical system. It is a valuable perspective for the literary studies of illness narratives as well as an important context for the medical humanities, a discipline which aims to elevate patients’ voices within the healthcare system. [ABSTRACT FROM AUTHOR]

In plant-pathogen relations, disease symptoms arise from the interaction of the host and pathogen genomes. Host-pathogen functional gene interactions are well described, whereas little is known about how the pathogen genetic variation modulates both organisms' transcriptomes. To model and generate hypotheses on a generalist pathogen control of gene expression regulation, we used the Arabidopsis thaliana-Botrytis cinerea pathosystem and the genetic diversity of a collection of 96 B. cinerea isolates. We performed expression-based genome-wide association (eGWA) for each of 23,947 measurable transcripts in Arabidopsis (host), and 9267 measurable transcripts in B. cinerea (pathogen). Unlike other eGWA studies, we detected a relative absence of locally acting expression quantitative trait loci (cis-eQTL), partly caused by structural variants and allelic heterogeneity hindering their identification. This study identified several distantly acting trans-eQTL linked to eQTL hotspots dispersed across Botrytis genome that altered only Botrytis transcripts, only Arabidopsis transcripts, or transcripts from both species. Gene membership in the trans-eQTL hotspots suggests links between gene expression regulation and both known and novel virulence mechanisms in this pathosystem. Genes annotated to these hotspots provide potential targets for blocking manipulation of the host response by this ubiquitous generalist necrotrophic pathogen.

Over the last 20 years, begomoviruses have emerged as devastating pathogens, limiting the production of different crops worldwide. Weather conditions increase vector populations, with negative effects on crop production. In this work we evaluate the relationship between the incidence of begomovirus and weather before and during the crop cycle. Soybean and bean fields from north-western (NW) Argentina were monitored between 2001 and 2018 and classified as moderate (≤50%) or severe (>50%) according to the begomovirus incidence. Bean golden mosaic virus (BGMV) and soybean blistering mosaic virus (SbBMV) were the predominant begomovirus in bean and soybean crops, respectively. Nearly 200 bio-meteorological variables were constructed by summarizing climatic variables in 10-day periods from July to November of each crop year. The studied variables included temperature, precipitation, relative humidity, wind (speed and direction), pressure, cloudiness, and visibility. For bean, high maximum winter temperatures, low spring humidity, and precipitation 10 days before planting correlated with severe incidence. In soybeans, high temperatures in late winter and in the pre-sowing period, and low spring precipitations were found to be good predictors of high incidence of begomovirus. The results suggest that temperature and pre-sowing precipitations can be used to predict the incidence status [predictive accuracy: 80% (bean) and 75% (soybean)]. Thus, these variables can be incorporated in early warning systems for crop management decision-making to reduce the virus impact on bean and soybean crops. [ABSTRACT FROM AUTHOR]

A central goal of studying host-pathogen interaction is to understand how host and pathogen manipulate each other to promote their own fitness in a pathosystem. Co-transcriptomic approaches can simultaneously analyze dual transcriptomes during infection and provide a systematic map of the cross-kingdom communication between two species. Here we used the Arabidopsis-B. cinerea pathosystem to test how plant host and fungal pathogen interact at the transcriptomic level. We assessed the impact of genetic diversity in pathogen and host by utilization of a collection of 96 isolates infection on Arabidopsis wild-type and two mutants with jasmonate or salicylic acid compromised immunities. We identified ten B. cinereagene co-expression networks (GCNs) that encode known or novel virulence mechanisms. Construction of a dual interaction network by combining four host- and ten pathogen-GCNs revealed potential connections between the fungal and plant GCNs. These co-transcriptome data shed lights on the potential mechanisms underlying host-pathogen interaction.

The present research is focused on bioinformatics and genes expression analysis aiming to elucidate new aspects of resistance mechanisms in the experimental model of the sunflower-broomrape interaction. The qPCR analysis of WHY1, TGA2 and TGA5 transcription factors revealed transient, oscillating changes in the accumulation of mRNA in plants cultivated in the absence and presence of pathogen in dynamics. The highest level of relative expression of WHY1 factor was attested in the roots of host plant during the stage of aerial shoots development (67 days), contrary to factors belonging to TGA family, which showed minimal values of the relative expression at the same stage of development. In the most of cases WHY1, TGA2 and TGA5 genes were found to be suppressed in the roots of sunflower-resistant genotypes under biotic stress. The higher number of gene interactions is due to co-expression in the case of WHY1 (93.68 %) and the presence of common protein domains in the case of TGA family factors (70 %). Associations between the NPR1 gene with TGA2 (46 connections) and TGA5 (33 interactions) have also been identified. The highest fluctuations in the level of relative expression of the NPR1 gene (key element in the manifestation of plant resistance) are found in the sensitive genotype Performer, in the case of noninfested plants and in resistant hybrid PR64LE20 under biotic stress.

Additionally, quantitative disease loci (QDL) appears to be independent from the presence of qualitative resistance; thus, it is possible that breeding for QDR may not necessarily include genes for qualitative resistance. Genome-wide association, quantitative disease resistance, plant breeding, quantitative trait loci (QTL) analysis, pathosystem, fine mapping, pre-breeding, genomic selection (GS) Keywords: quantitative disease resistance; plant breeding; genome-wide association; quantitative trait loci (QTL) analysis; pathosystem; fine mapping; pre-breeding; genomic selection (GS) EN quantitative disease resistance plant breeding genome-wide association quantitative trait loci (QTL) analysis pathosystem fine mapping pre-breeding genomic selection (GS) 1 5 5 04/18/22 20220413 NES 220413 In plant breeding and genetics, traits are frequently classified into qualitative and quantitative. It is widely recognized that QDR provides long term host defense toward the disease, probably due to multiple genes requiring mutation for resistance breakdown as opposed to single genes as in the case of gene-for-gene resistance. [Extracted from the article]

Over the last 20 years, begomoviruses have emerged as devastating pathogens, limiting the production of different crops worldwide. Weather conditions increase vector populations, with negative effects on crop production. In this work we evaluate the relationship between the incidence of begomovirus and weather before and during the crop cycle. Soybean and bean fields from north-western (NW) Argentina were monitored between 2001 and 2018 and classified as moderate (≤50%) or severe (>50%) according to the begomovirus incidence. Bean golden mosaic virus (BGMV) and soybean blistering mosaic virus (SbBMV) were the predominant begomovirus in bean and soybean crops, respectively. Nearly 200 bio-meteorological variables were constructed by summarizing climatic variables in 10-day periods from July to November of each crop year. The studied variables included temperature, precipitation, relative humidity, wind (speed and direction), pressure, cloudiness, and visibility. For bean, high maximum winter temperatures, low spring humidity, and precipitation 10 days before planting correlated with severe incidence. In soybeans, high temperatures in late winter and in the pre-sowing period, and low spring precipitations were found to be good predictors of high incidence of begomovirus. The results suggest that temperature and pre-sowing precipitations can be used to predict the incidence status [predictive accuracy: 80% (bean) and 75% (soybean)]. Thus, these variables can be incorporated in early warning systems for crop management decision-making to reduce the virus impact on bean and soybean crops.

The chrysanthemum is the second most important cut flower in the world, however, its quality and commercial value is affected by the leaf blight produced by Alternaria spp. The objective of this work was to evaluate the causal agent of leaf blight in Chrysanthemum, and its control with aqueous extracts of Acalypha gaumeri and Bonellia flammea. The fungus was collected and identified from leaves and stems of chrysanthemum plants. Subsequently, molecular identification and pathogenicity tests were performed on chrysanthemum plants. In the field, treatments were evaluated with weekly applications of: T1: B. flammea bark extract, T2: A. gaumeri root extract, T3: negative control (water) and T4: Captan® fungicide. Prior to the application of the treatments, plants were inoculated with the isolated fungus (2.5 × 106 spores mL-1) and severity was evaluated. Alternaria chrysanthemi was identified as the causal agent. Based on the severity percentage, the lowest averages of the area under the disease progress curve, the lowest rates of apparent infection, the lowest intensity of the disease and the greater effectiveness in controlling the disease were observed for T2 (165, 0.017, 8 and 67%, respectively) followed by T1 (186, 0.022, 13 y 50 %, respectively) and T4 (179, 0.023, 14 y 45%, respectively), observing a significantly different than negative control T3 (369, 0.025, 25 and 0%, respectively). Plant extracts have potential to be used as an alternative in the management of Alternaria leaf blight in chrysanthemum. [ABSTRACT FROM AUTHOR]

Introduction: Protists of the genus Labyrinthula cause the so-called “Wasting Disease” in seagrass, Thalassia testudinum. Monitoring in the Colombian Caribbean since 2008 has shown spatial and temporal variation in the disease’s incidence, but without the high mortality observed in other regions of the world. Objective: To analyze some epidemiological parameters in T. testudinum and to compare metabolites between healthy and infected plants. Methods: We recorded severity, incidence and prevalence of this disease in Tayrona National Natural Park and Providencia Island, and we analyze water and sediment samples. Additionally, we applied gas and liquid chromatography, coupled with mass spectrometry, to methanolic extracts from leaf and rhizome samples of healthy and infected shoots. Results: The meadows were in good condition, despite the scarce seagrass shoots in Tayrona and a high incidence (15 %) and severity (35.5 %) of the disease in Providencia. Infected plants had lower levels of phenols, flavonoids and sugars. Sulphated flavones with aglycone luteolin and diosmetin, sterols (sitosterol and stigmasterol) and volatile oxylipins are accumulated in leaves (3-hydroxy-2-isopentanone) and isopentaenoic and octadecatrienoic acids in rhizomes. Conclusions: These Colombian seagrasses have differential production of metabolites. Probably as a successful defense, even at low levels of severity (0.1 %) and incidence (1 %) of the disease. [ABSTRACT FROM AUTHOR]

Key message: Overstory shade enhances photochemical performance of feral citrus trees and reduces transmission of an invasive vectored pathogen. Feral citrus trees growing under forest overstory appeared healthy and showed no symptoms of huanglongbing (HLB; citrus greening disease), despite high infection rates and obvious symptoms in open plantings. We undertook a survey in a natural ecosystem area with abundant understory feral citrus (Citrus × paradisi Macfad.) trees to understand how natural understory conditions affect distribution of the HLB causal bacterium, Candidatus Liberibacter asiaticus, and its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). Citrus also undergoes high irradiance-induced photoinhibition which is exacerbated by HLB. We hypothesized that the understory environment would minimize photodamage and improve photochemical functions. We examined sixty citrus trees, across a high-low overstory density (gap fraction, GF) gradient, for photochemical performances and other key leaf traits associated with disease symptoms or shade acclimation. We did not detect any psyllids in the understory during early summer when peak outbreak of the vector population was expected, and only a few trees were infected with Ca. L. asiaticus. Leaf pigment stoichiometry and photosystem-II functions showed strong acclimation to overstory GF. Photochemical performance improved with decreasing overstory GF due to increased electron transport efficiencies from donor to acceptor sites. No difference in measured leaf biochemical traits and photosystem-II performances was observed between infected and uninfected understory trees, though the number of infected trees was small. We conclude that the naturally shaded understory environment greatly inhibits the HLB pathosystem by deterring the arrival of the vector and significantly improves the photosystem-II performance of citrus, making the shaded environment advantageous for the feral citrus population. [ABSTRACT FROM AUTHOR]

Beneficial plant‐associated soil microbes can promote plant tolerance to stress and promote nutrient uptake. Yet, the benefits of microbes for plant health can be altered by above‐ground stressors like herbivores and pathogens. However, few studies have assessed reciprocal plant‐mediated interactions between beneficial soil microbes and multiple above‐ground stressors.We assessed if soil rhizobia influenced complex interactions among pea host plants, a vector herbivore (aphids) and a plant virus (Pea enation mosaic virus, PEMV). We also examined how aphids and PEMV affected the function of soil rhizobia.We show that plants attacked by PEMV produced fewer root nodules and had lower fresh root nodule biomass per g of fresh plant root biomass, and decreased expression of genes associated with nodulation, suggesting PEMV inhibited nitrogen fixation by rhizobia. However, soil rhizobia decreased aphid abundance and PEMV titre on host plants, such that rhizobia decreased the susceptibility of plants to herbivores and pathogens.Assays of amino acids, and gene expression related to hormone signalling, show interactions among rhizobia, plants, aphids and PEMV were mediated by plant defence and nutrients. Viruliferous aphids induced salicylic acid in plants, and salicylic acid suppressed the function of rhizobia. Aphids feeding on plants grown in rhizobia‐inoculated soil also obtained fewer essential amino acids than those feeding on plants grown in un‐inoculated sterilized soil.Mutually antagonistic plant‐mediated interactions between soil microbes and above‐ground stressors affected plant susceptibility and herbivore nutrient uptake. This suggests ecological effects of soil microbes and above‐ground stressors for plant health will likely vary based on multi‐trophic plant‐mediated interactions among herbivores, pathogens and soil microbes. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

The interaction between plants and pathogens is a very dynamic and complex relationship that also includes a high degree of specificity, and it is precisely this last characteristic which triggers such important responses in the survival of one or the other. The pathosystem formed by tomato (Solanum lycopersicum L.) and Fusarium oxysporum f. sp. lycopersici (Fol) has been the subject of multiple studies due to the importance of the vegetable worldwide and for the economic and ecological impact of the fungus responsible for the vascular wilt disease in tomato, causing losses that go up to 100%. One way to find alternatives for the management of any pathosystem is to know the actors involved and the mechanisms that govern the interaction through technological and scientific advances that clearly show how the interaction develops on a genetic level. This review collects the information from different scientific sources with focus on the knowledge of the fungus, tomato cultivation and plant defense applied to this pathosystem, as well as the molecular mechanisms.

ABSTRACT Cashew gummosis is one of the main diseases of the cashew in the semi-arid region of the northeast and is characterised by a decline in the plants and a reduction in stand. Lasiodiplodia theobromae, the causal agent, is an endophytic fungus that eventually takes on pathogenic characteristics; however, the environmental conditions that cause this change in behaviour are still unknown. It is assumed that stress in the host caused by environmental changes stimulate pathogenicity. The aim of this study was to define the relationship between climate and geographical factors and the occurrence of gummosis. Rainfall data, maximum and minimum temperature, thermal amplitude, and the altitude of 14 micro-regions in the northeast were compared and classified into five frequencies of disease occurrence: 0 (no occurrence), 1 (rare occurrence), 2 (frequent occurrence), 3 ( generalised occurrence) and 4 (generalised high-severity occurrence). The data were submitted to the Doornik-Hansen test for multivariate normality, and principal component analysis was carried out using the correlation matrix between the climate and geographical variables and occurrence of the disease. Areas of disease severity were correlated (Pearson’s correlation). Only thermal amplitude, altitude and latitude were associated with the different areas of gummosis occurrence. The districts of Buíque, in the state of Pernambuco, and São Raimundo Nonato, Canto do Buriti and Pio IX, in Piauí, with the highest incidence of the disease, had the highest values for thermal amplitude, altitude and latitude. Whereas the districts of Pacajus and Beberibe had a lower occurrence of gummosis, with lower values for thermal amplitude, altitude and latitude.

SUMMARY: The fungal genus Cochliobolus describes necrotrophic pathogens that give rise to significant losses on rice, wheat, and maize. Revealing plant mechanisms of non‐host resistance (NHR) against Cochliobolus will help to uncover strategies that can be exploited in engineered cereals. Therefore, we developed a heterogeneous pathosystem and studied the ability of Cochliobolus to infect dicotyledons. We report here that C. miyabeanus and C. heterostrophus infect Arabidopsis accessions and produce functional conidia, thereby demonstrating the ability to accept Brassica spp. as host plants. Some ecotypes exhibited a high susceptibility, whereas others hindered the necrotrophic disease progression of the Cochliobolus strains. Natural variation in NHR among the tested Arabidopsis accessions can advance the identification of genetic loci that prime the plant's defence repertoire. We found that applied phytotoxin‐containing conidial fluid extracts of C. miyabeanus caused necrotic lesions on rice leaves but provoked only minor irritations on Arabidopsis. This result implies that C. miyabeanus phytotoxins are insufficiently adapted to promote dicot colonization, which corresponds to a retarded infection progression. Previous studies on rice demonstrated that ethylene (ET) promotes C. miyabeanus infection, whereas salicylic acid (SA) and jasmonic acid (JA) exert a minor function. However, in Arabidopsis, we revealed that the genetic disruption of the ET and JA signalling pathways compromises basal resistance against Cochliobolus, whereas SA biosynthesis mutants showed a reduced susceptibility. Our results refer to the synergistic action of ET/JA and indicate distinct defence systems between Arabidopsis and rice to confine Cochliobolus propagation. Moreover, this heterogeneous pathosystem may help to reveal mechanisms of NHR and associated defensive genes against Cochliobolus infection. Significance Statement: Revealing plant mechanisms of non‐host resistance (NHR) against Cochliobolus will help to uncover strategies that can be exploited in engineered cereals. Thus, we developed a heterogeneous pathosystem and studied the ability of Cochliobolus to infect various Arabidopsis accessions. Our results indicate distinct defence systems between Arabidopsis and rice to confine Cochliobolus propagation. Moreover, this pathosystem may help to reveal mechanisms of NHR and associated defensive genes against Cochliobolus infection. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A central goal of studying host-pathogen interaction is to understand how host and pathogen manipulate each other to promote their own fitness in a pathosystem. Co-transcriptomic approaches can simultaneously analyze dual transcriptomes during infection and provide a systematic map of the cross-kingdom communication between two species. Here we used the Arabidopsis-B. cinerea pathosystem to test how plant host and fungal pathogen interact at the transcriptomic level. We assessed the impact of genetic diversity in pathogen and host by utilization of a collection of 96 isolates infection on Arabidopsis wild-type and two mutants with jasmonate or salicylic acid compromised immunities. We identified ten B. cinereagene co-expression networks (GCNs) that encode known or novel virulence mechanisms. Construction of a dual interaction network by combining four host- and ten pathogen-GCNs revealed potential connections between the fungal and plant GCNs. These co-transcriptome data shed lights on the potential mechanisms underlying host-pathogen interaction.

The charcoal disease agents, Biscogniauxia mediterranea and Obolarina persica are two latent, ascomycetous oak pathogens in the Middle Eastern Zagros forests, where they have devastating effects, particularly during drought. Under greenhouse conditions, we investigated the effects of the two charcoal disease agents individually and in combination with drought on survival, growth, foliar gas-exchange, pigment content, oxidative stress and the antioxidant response of Quercus infectoria and Q. libani, two of the dominant tree species in this region. Commonly, the strongest negative effects emerged in the drought–pathogen interaction treatments. Q. infectoria showed less severe lesions, higher survival, more growth, and less leaf loss than Q. libani under combined biotic and abiotic stress. In both oak species, the combination of pathogen infection and drought resulted in more than 50% reduction in foliar gas-exchange parameters with partial recovery over time in Q. infectoria suggesting a superior defense system. Indeed, enhanced foliar anthocyanin, total soluble protein and glutathione concentrations imply an upregulation of the antioxidant defense system in Q. infectoria under stress while none of these parameters showed a significant treatment response in Q. libani. Consequently, Q. infectoria foliage showed no significant increase in superoxide, lower lipoxygenase activity, and less electrolyte leakage compared to the highly elevated levels seen in Q. libani indicating oxidative damage. Our findings indicate greater drought tolerance and pathogen resilience in Q. infectoria compared to Q. libani. Under future climate scenarios, we therefore expect changes in forest community structure driven by a decline in Q. libani and closely associated organisms.

Abstract Trees are large organisms that structure forest ecosystems by providing an environment for an enormous diversity of animal, microbial and plant species. As these species use trees as their common hosts, many are likely to interact with each other directly or indirectly. From studies on herbaceous plant species we know that microbes can affect the interaction of plants with herbivorous insects, for example via changes in plant metabolite profiles. The consequences of fungal colonization for tree-insect interactions are, however, barely known, despite the importance of these ecological communities. In this review we explore the interaction of leaf-inhabiting pathogenic and endophytic fungi with trees and the consequences for tree-living insect herbivores. We discuss molecular, physiological, chemical, biochemical and ecological aspects of tree-fungus interactions and summarize the current knowledge on the direct and indirect effects of tree-inhabiting fungi on insect herbivores. Our mechanistic understanding of the tripartite interaction of trees with leaf-inhabiting fungi and insect herbivores is still in its infancy. We are currently facing substantial drawbacks in experimental methodology that prevent us from revealing the effect of one single fungal species on a particular insect herbivore species and vice versa. Future studies applying a versatile toolbox of modern molecular, chemical analytical and ecological techniques in combined laboratory and field experiments will unequivocally lead to a better understanding of fungus-tree-insect interactions. [ABSTRACT FROM AUTHOR]

The spot blotch disease of wheat is caused by Bipolaris sorokiniana, which is an anamorph (teleomorph Cochliobolus sativus). The disease mainly occurs in warm, humid wheat‐growing regions, and the Eastern Gangetic Plains (EGP) of South Asia is a hotspot. Significant progress has been made in recent years in characterizing the host–pathogen interaction. The study of the pathogen's life cycle and diversity have been an active area of research. A number of resistance sources have also been identified, characterized and used for breeding. Although immunity has not been observed in any genotype, cultivars displaying a relatively high level of resistance have been developed and made available to farmers. Further progress will require regular use of marker‐assisted breeding, genomic selection, gene editing and transgenic interventions. This review summarizes the current state of knowledge about genetic and breeding efforts on the wheat–B. sorokiniana pathosystem and discusses ways in which emerging tools can be used for future research to understand the mechanism involved in infection and for developing cultivars exhibiting a high level of resistance. [ABSTRACT FROM AUTHOR]