Search

The article emphasizes the need for expanding the differential sets used in race typing experiments for plant pathologists to provide valuable information to plant breeders. Specifically focusing on stripe rust, a fungal disease that affects wheat crops, the article explains how the pathogen evolves and gains virulence over time, necessitating the continuous introgression of resistance from different sources. The article also highlights the importance of including relevant differential genotypes in race typing experiments to support the development of resistant cultivars. Additionally, the document provides a list of wheat cultivars and their corresponding resistance genes to stripe rust, along with discussing the significance of standardizing race typing conditions for more accurate and comparable results in studying the population dynamics of the stripe rust pathogen in North America. [Extracted from the article]

Brome mosaic virus (BMV) is a member of the Bromovirus genus in the Bromoviridae family. Due to its genetic and biochemical features, BMV is considered as one of the most important plant viruses in molecular plant pathology. Although BMV is widely used in many laboratories as a convenient model for molecular studies, knowledge regarding its biology, pathogenicity, virulence and genetic differentiation within natural populations is rather limited. In this study, the complete genome sequence of 16 BMV isolates originating from different hosts was obtained. Recombination, selection pressure and phylogenetic analyses were carried out using newly obtained BMV sequences and 10 others described to date. The nucleotide and amino acid sequence identities of the 26 BMV sequences were relatively high and ranged from 96.4% to 99.4% for nucleotide sequences and from 95.7% to 99.6% for amino acid sequences. Further analysis revealed that both selection and recombination are shaping the population structure of BMV. The presence of six possible recombination sites within open reading frames and one within the 3′ untranslated region of RNA2 was identified. Selection pressure analysis indicated that most codons were subjected to purifying selection; however, 14 codons were found to be under positive selection pressure. The results presented here expand the current knowledge regarding BMV diversity and the evolutionary forces shaping BMV population structure. [ABSTRACT FROM AUTHOR]

T1 and T2 were cultured in a multiplication medium (MM) for cassava shoot tips (Medina et al., [19]), whereas T3 was cultured in a plant regeneration medium specific for cassava shoot apical meristems (Collavino et al., [6]). To our knowledge, this is the first report of CsCMV infecting meristematic cells of cassava plants and shows that in vitro culture of meristems does not always lead to complete virus eradication. 10 Faccioli, G. & Colombarini, A. (1996) Correlation of potato virus S and virus M contents of potato meristem tips with the percentage of virus-free plantlets produced in vitro. (2010) Tobacco ringspot virus persists in the shoot apical meristem but not in the root apical meristem of infected tobacco. [Extracted from the article]

Soybean root rot disease caused by I Phytophthora sojae i seriously constrains soybean yield. Soybean root rot disease, one of the most destructive soybean diseases, occurs throughout the growth period, resulting in considerable yield losses ([3]). CRISPR/Cas9-mediated editing of GmTAP1 confers enhanced resistance to Phytophthora sojae in soybean Knocking out the susceptibility gene GmTAP1 in soybean created new soybean lines resistant to several I P. sojae i strains and these lines showed no agronomic penalties in the field. [Extracted from the article]

In this Special Issue, Blandenet et al. [[22]] generated the membrane protein glycosyl-transferase BcCps1 deletion mutant in I B. cinerea i and elucidated the functions of BcCps1. In this Special Issue, 156 genome assemblies were used to construct a pan-genome of I P. oryzae i ; then, the mechanisms of genetic divergence and virulence variation of different sub-populations were elucidated. The pan-genome contained a total of 24,100 genes - twice that of the reference genome 70-15 strain, including 70% of core genes and 5% of strain-specific genes. Moreover, the genome sequence data of six other fungal plant pathogens were performed, and their genome sizes ranged from 38.25 Mb to 66 Mb (Table 1). [Extracted from the article]

These papers cover established and emerging viral tools for functional genomics in maize, a genomic study of maize resistance genes, and the identification and detailed characterization of maize genes involved in pathogen resistance and microbial genes involved in pathogenicity. The first identification of a plant disease resistance gene, I Hm1 i (Johal & Briggs, [12]), and of a plant disease susceptibility gene, I T-urf13 i (Dewey et al., [7]), occurred in maize. Thatcher, Jung et al. ([35], this issue) took advantage of the recent availability of a set of diverse maize genome sequences to characterize the diversity of NLR genes in maize as well as the maize relative I Zea luxurians i . Maize ( I Zea mays i ) is an annual grass belonging to the tribe Andropogoneae of the family Gramineae. [Extracted from the article]

Since high-level expression of I SAE1 i also caused accelerated senescence in I Arabidopsis thaliana i leaves, the extensin-related senescence mechanism uncovered by [8] may play a critical role in senescence initiation in all dicots. For example, although leaf senescence follows a genetically predisposed timeline, entry into the senescence program can be altered by environmental inputs, which is best illustrated by the accelerated leaf senescence of plants that grow under stress conditions. Keywords: Arabidopsis; cell wall; extensin; leaf senescence; tomato; ubiquitin ligase EN Arabidopsis cell wall extensin leaf senescence tomato ubiquitin ligase 5419 5421 3 10/04/23 20230929 NES 230929 B Extensins are a family of cell wall proteins that play important roles in plant development and environmental responses. (A) Hypothesis 1: cell wall-localized SAE1 interacts with senescence signaling protein A. The senescence program is triggered when the senescence signaling protein is activated beyond a critical threshold. [Extracted from the article]

APPENDIX Protocol for mechanical inoculation of test plants Buffers and chemicals Standard phosphate buffers can be used for inoculation of most viruses and plant species. B Specific scope: b This Standard describes how to perform mechanical inoculation of test plants for detection, propagation and characterisation of plant viruses and viroids. In the past, mechanical inoculation was also used for virus identification, by selecting test plants that could produce a characteristic/specific symptom profile for the virus isolate. [Extracted from the article]

Journal of Plant Pathology 87, 45 - 51. 25 Felix MR & Clara MIE (2002) Two necrovirus isolates with properties of olive latent virus 1 and tobacco necrosis virus from olive in Portugal. Scientific opinion on the risk to plant health posed by Arabis mosaic virus, Raspberry ringspot virus, Strawberry latent ringspot virus and Tomato black ring virus to the EU territory with the identification and evaluation of risk reduction options. B Specific scope: b This Standard describes the production of certified pathogen-tested olive trees and rootstocks. 42 Mathioudakis MM, Saponari M, Hasiowjaroszewska B, Elbeaino T & Koubouris G (2020) Detection of viruses in olive cultivars in Greece, using a rapid and effective RNA extraction method, for certification of virus-tested propagation material. [Extracted from the article]

The article discusses the career and achievements of Gary D. Foster, who has been named an honorary member of the British Society for Plant Pathology (BSPP). Foster grew up in Northern Ireland and initially had interests in motorbikes and rugby, but a broken ankle led him to pursue studying. He eventually developed a passion for plant virology and went on to conduct research on potato viruses and plant transformation. Foster has made significant contributions to the field and has been involved in various projects and collaborations. He is particularly proud of his work with the Community Network for African Vector-Borne Plant Viruses and his role as Editor-in-Chief of the BSPP journal Molecular Plant Pathology. Foster expresses gratitude for being named an honorary member of the BSPP. [Extracted from the article]

Assessing immune responses and cell death in Nicotiana benthamiana leaf agro‐infiltration assays is a powerful and widely used experimental approach in molecular plant pathology. Here, we describe a reliable high‐throughput protocol to quantify strong, macroscopically visible cell death responses in N. benthamiana agro‐infiltration assays. The method relies on measuring the reduction of leaf autofluorescence in the red spectrum upon cell death induction and provides quantitative data suitable for straightforward statistical analysis. Two different well‐established model nucleotide‐binding and leucine‐rich repeat domain proteins (NLRs) were used to ensure the genericity of the approach. Its accuracy and versatility were compared to visual scoring of the cell death response and standard methods commonly used to characterize NLR activities in N. benthamiana. A discussion of the advantages and limitations of our method compared to other protocols demonstrates its robustness and versatility and provides an effective means to select the best‐suited protocol for a defined experiment. [ABSTRACT FROM AUTHOR]

Uncovering the mysterious route of sterols in oomycetes should reveal how the various components interact and how sterol auxotroph oomycetes manage to recruit and exploit sterols for survival in their natural habitat. The fact that sterol-binding activity of PR-1 is pivotal for inhibiting the development of I Phytophthora brassicae i [[18]], presumably by acting as competitor of sterol sensors or sterol transport proteins or by sequestering sterols from the membrane, could explain its anti-oomycete activity observed in many previous studies [[19]]. This, in turn, relies on a balanced system of intracellular sterol transport and distribution, sterol storage and release, and also sterol sensing, a system that is likely supported by sterol-binding and sterol-sensing proteins and enzymes for sterol biosynthesis or transforming free sterols into sterol conjugates. Another defense-related enzyme is PSAT1, a phospholipid:sterol acyltransferase catalyzing formation of sterol esters (i.e., conjugates of sterols and fatty acids) and affecting sterol homeostasis [[25]]. [Extracted from the article]

Phytoplasmas are obligate phytopathogenic bacteria associated with devastating diseases in hundreds of crops across the world. They have been responsible for huge economic losses in many crop plants for decades now. Isolation and establishment of axenic culture of phytoplasma in complex media is a recent progress in phytoplasma research. Earlier methods for phytoplasma disease detection included symptom profiling, microscopy, serology and dodder transmission studies. With advancement in the field of molecular biology, phytoplasma diagnostics and characterisation witnessed radical improvement. Starting from PCR amplification which often necessities a nested PCR on account of low titre of phytoplasmas, to the closed tube quantitative PCR assays and then the ddPCR, an array of diagnostics have been developed for phytoplasma. The isothermal diagnostic platforms are the latest addition to this and the Loop Mediated Isothermal Amplification (LAMP) assay has been applied for the detection of phytoplasma from several hosts. The futuristic approach in phytoplasma detection will be very likely provided by an integration of nanotechnology and molecular diagnostics. Phytoplasma disease management majorly relies on early detection, vector control, use of disease free planting materials and cultivation of resistant varieties. Hence understanding the molecular mechanism of phytoplasma—host interaction is as important as timely and accurate detection, in the management of phytoplasma diseases. Further, the changing climatic scenario and global warming may lead to an upsurge in the phytoplasma diseases spread and severity across the world, making disease management even more challenging. [ABSTRACT FROM AUTHOR]

Classical assessments of soil nematode communities typically consider morphological identification of 100-200 nematodes, extrapolating to total live, active nematodes extracted from a 100 g soil sample, that frequently pools bulk soil, small root fragments, and adhering rhizosphere soil. Measuring soil nematode abundance and diversity Nematologists have historically focused on plant parasitic nematodes in a plant protection perspective, with free-living nematodes frequently being discarded or omitted altogether from plant and soil studies. It is also possible to produce chemical baits that could be dispersed into the soil in capsules to manipulate the behaviour of soil-dwelling nematodes; this would have to be specific enough to attract parasitic nematodes while avoiding removal of beneficial nematodes from the soil. [Extracted from the article]

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH or Gap) is a ubiquitously distributed enzyme that plays an essential role in the glycolytic and gluconeogenic pathways. However, additional roles have been described unrelated to its enzymatic function in diverse organisms, often linked to its presence in the cell surface or as a secreted protein. Despite being a paradigm among multifunctional/moonlighting proteins, little is known about its possible roles in phytopathogenic bacteria. In the present work we have studied three putative gap paralogous genes identified in the genome of Pseudomonas syringae pv. tomato (Pto) DC3000, an important model in molecular plant pathology, with the aim of determining their physiological and possible non-canonical roles in this bacterium and in the plant infection process. We have established that the Gap1 protein has a predominantly glycolytic activity, whereas the NADPH-dependent Gap2 main activity is gluconeogenic. The third paralogue lacks GAPDH activity in Pto but is indispensable for vitamin B6 metabolism and displays erythrose-4-phosphate dehydrogenase activity, thus referred as epd. Both Gap enzymes exhibit distinct functional characteristics depending on the bacterium physiological state, with Gap1 presenting a substantial role in motility, biosurfactant production and biofilm formation. On the other hand, solely Gap2 appears to be essential for growth on tomato plant. Furthermore, Gap1 and Gap2 present a distinctive transcriptional regulation and both have been identified exported outside the cells with different definite media compositions. This serves as compelling evidence of additional roles beyond their central metabolic functions. [Display omitted] [ABSTRACT FROM AUTHOR]

Leafy gall is a bacterial disease, caused by “Rhodococcus fascians”, a gram-positive bacterial pathogen. The bibliometric analysis had been conducted to understand the active authors, organizations, journals, and countries involved in the research domain of “Leafy gall”. All published articles related to “Leafy gall” from “Scopus”, were analyzed using the VOS viewer to develop analysis tables and visualization maps. This article had set the objective to consolidate the scientific literature regarding the “Leafy gall” and also to find out the trends related to the same. The most active journals in this research domain were identified as Molecular Plant-Microbe Interactions, Planta, and Embo Journal. The most active countries was Belgium. The leading organizations engaged in the research regarding Leafy gall were Ghent University and Université libre de Bruxelles of Belgium. The most active authors who had made valuable contributions related to Leafy gall disease were Vereecke D. and Van Montagu M. [ABSTRACT FROM AUTHOR]

Seed transmission is a key point of the CBB disease cycle, favouring both vertical transmission of the pathogen and worldwide distribution of the disease through global seed trade. European Cooperation in Science and Technology (COST) is a funding organization for the creation of research networks, called COST Actions, that provide networking opportunities for researchers and innovators to strengthen Europe's capacity to address scientific, technological, and societal challenges. In addition, we complement this set of pathogens with a Pathogen Profile about cassava-infecting xanthomonads because of their important socioeconomic impact worldwide. [Extracted from the article]

Keywords: effectors; fungal plant pathogen; qualitative resistance; quantitative resistance; resistance genes EN effectors fungal plant pathogen qualitative resistance quantitative resistance resistance genes 1301 1303 3 07/19/21 20210815 NES 210815 Disease resistance is one of the most desired traits for plant breeders. These phases are associated with the expression of fungal effector genes in "waves", with "early" and "late" effector genes (Gervais I et al i ., 2017) - the latter being expressed during endophytic stem colonization (also known as "LmSTEEs" for ' I L i . An effector that is recognized by a plant immune receptor is encoded by the "corresponding" avirulence gene in the pathogen. Candidate effector genes of the late "wave" were placed under the control of an early effector gene promoter, making it possible to screen a collection of I B i . [Extracted from the article]

The molecular interactions between tomato and Cladosporium fulvum have been an important model for molecular plant pathology. Complex genetic loci on tomato chromosomes 1 and 6 harbor genes for resistance to Cladosporium fulvum, encoding receptor like-proteins that perceive distinct Cladosporium fulvum effectors and trigger plant defenses. Here, we report classical mapping strategies for loci in tomato accessions that respond to Cladosporium fulvum effector Ecp5, which is very sequence-monomorphic. We screened 139 wild tomato accessions for an Ecp5-induced hypersensitive response, and in five accessions, the Ecp5-induced hypersensitive response segregated as a monogenic trait, mapping to distinct loci in the tomato genome. We identified at least three loci on chromosomes 1, 7 and 12 that harbor distinct Cf-Ecp5 genes in four different accessions. Our mapping showed that the Cf-Ecp5 in Solanum pimpinellifolium G1.1161 is located at the Milky Way locus. The Cf-Ecp5 in Solanum pimpinellifolium LA0722 was mapped to the bottom arm of chromosome 7, while the Cf-Ecp5 genes in Solanum lycopersicum Ontario 7522 and Solanum pimpinellifolium LA2852 were mapped to the same locus on the top arm of chromosome 12. Bi-parental crosses between accessions carrying distinct Cf-Ecp5 genes revealed putative genetically unlinked suppressors of the Ecp5-induced hypersensitive response. Our mapping also showed that Cf-11 is located on chromosome 11, close to the Cf-3 locus. The Ecp5-induced hypersensitive response is widely distributed within tomato species and is variable in strength. This novel example of convergent evolution could be used for choosing different functional Cf-Ecp5 genes according to individual plant breeding needs. [ABSTRACT FROM AUTHOR]

The use of advanced molecular methods in plant pathology and applied microbiology has necessitated for more accurate, rapid detection and identification of plant pathogens. This is particularly significant given accelerated emergence of virulence that leads to increased prevalence of plant pathogens. Thus, the capacity to contain plant pathogens and ultimately disease progression is key to ensuring crop biosecurity and overall food security. Of recent, research on pathogens utilizes a holistic approach focusing on elucidating growth dynamics within the entire biome rather than studying individual or closely related isolates in unison. This has advanced knowledge and information of microbial ecosystem within natural environments in the twenty first century. Applied technological platforms used for rapid detection and profiling microbial biomes in this regard include digital PCR, pyrosequencing, Illumina, DNA microarray and barcoding, Ion torrent, and nanopore. These technologies have been applied in various fields including human health and medicine, marine and animal biology, crop production and water quality research, to mention but a few. Although much has been done and achieved through the development of several technologies, more accuracy is required to circumvent the shortfalls still experienced. This includes integrating existing methods with new applications such as viability PCRs and microbial viability testing. Hence, this review provides critical analysis of some widely used latest technologies in rapid detection and identification of plant pathogens, and profiling plant associated microbiomes that reveal growth dynamics and population diversity. The advantages and limitations of the technologies are also discussed. [ABSTRACT FROM AUTHOR]

The effects of the I Bacillus i cell-free filtrates on the motility of I M. incognita i J2 were evaluated by exposing 25 J2 to a 100% filtrate concentration of each I Bacillus i spp., with a non-inoculated LB broth serving as the control for both Trial 1 and Trial 2. Only the 100% filtrate concentrations were used for each I Bacillus i spp. since it has been shown in earlier studies for I B. cereus i , I B. firmus i , I B. pumilus i and I B. subtilis i that this concentration inhibits the motility of I Meloidogyne i spp. When cultivated in LB broth each of the I Bacillus i spp. reached their stationary growth phase between 48 h ( I B. cereus i and I B. soli i ) and 72 h ( I B. firmus i , I B. pumilus i and I B. subtilis i ) (Fig. [Extracted from the article]

The specific recognition of pathogen effectors by intracellular nucleotide-binding and leucine-rich repeat domain receptors (NLRs) is an important component of plant immunity. Creating NLRs with new bespoke recognition specificities is a major goal in molecular plant pathology as it promises to provide unlimited resources for the resistance of crops against diseases. Recent breakthrough discoveries on the structure and molecular activity of NLRs begin to enable their knowledge-guided molecular engineering. First, studies succeeded to extend or change effector recognition specificities by modifying, in a structure-guided manner, the NLR domains that directly bind effectors. By modifying the LRR domain of the singleton NLR Sr35 or the unconventional decoy domains of the helper NLRs RGA5 or Pik-1, receptors that detected other or additional effectors were created. [Display omitted] [ABSTRACT FROM AUTHOR]

Because the pipeline they developed is low-cost and requires minimal manual labor, Delp and Iyer-Pascuzzi are now using these methods to phenotype water-stressed plants, and hope to subsequently use the pipeline for QTL analysis of drought tolerance. In susceptible plants, seven of the 10 descriptors were significantly reduced after 6 days of disease progression; the other three descriptors (plant height, Y mass and convex perimeter) also decreased, although the differences were not statistically significant. Bacterial wilt is caused by the I Ralstonia solanacearum i species complex, which is considered one of the 10 most damaging plant pathogens in the world (Mansfield et al., [2]). [Extracted from the article]

Summary: Dothistroma needle blight is one of the most devastating pine tree diseases worldwide. New and emerging epidemics have been frequent over the last 25 years, particularly in the Northern Hemisphere, where they are in part associated with changing weather patterns. One of the main Dothistroma needle blight pathogens, Dothistroma septosporum, has a global distribution but most molecular plant pathology research has been confined to Southern Hemisphere populations that have limited genetic diversity. Extensive genomic and transcriptomic data are available for a D. septosporum reference strain from New Zealand, where an introduced clonal population of the pathogen predominates. Due to the global importance of this pathogen, we determined whether the genome of this reference strain is representative of the species worldwide by sequencing the genomes of 18 strains sampled globally from different pine hosts. Genomic polymorphism shows substantial variation within the species, clustered into two distinct groups of strains with centres of diversity in Central and South America. A reciprocal chromosome translocation uniquely identifies the New Zealand strains. Globally, strains differ in their production of the virulence factor dothistromin, with extremely high production levels in strain ALP3 from Germany. Comparisons with the New Zealand reference revealed that several strains are aneuploids; for example, ALP3 has duplications of three chromosomes. Increased gene copy numbers therefore appear to contribute to increased production of dothistromin, emphasizing that studies of population structure are a necessary adjunct to functional analyses of genetic polymorphisms to identify the molecular basis of virulence in this important forest pathogen. [ABSTRACT FROM AUTHOR]

Choy sum (Brassica rapa var. parachinensis), leafy mustard (Brassica juncea) and pak choi (B. rapa var. chinensis) are highly nutritious components of diets in Taiwan and other Asian countries, and bacterial black rot caused by Xanthomonas campestris pv. campestris (Xcc) is a major biotic constraint in these crops. As very little was known about the Xcc strains from these crops in these regions, including their cross‐pathogenicity and aggressiveness on different hosts, Xcc strains were obtained from cabbage (Brassica oleracea var. capitata), choy sum, leafy mustard and pak choi crops in Taiwan. Two previously published PCR‐based assays reliably distinguished the Xcc strains from other Xanthomonas species and subspecies. Phylogenetic analysis based on repetitive sequence‐based PCR assays placed the Xcc strains in a clade distinct from other Xanthomonas species, and also showed host specificity. Although all of the Xcc strains from the different host species were pathogenic on all five Brassica test species in both a detached leaf assay and an intact plant assay, in the intact plant assay they showed differences in virulence or aggression on the different test hosts. The Xcc strains from leafy mustard and pak choi were consistently highly aggressive on all the test host genotypes, but the strains from choy sum and cabbage were less aggressive on leafy mustard and choy sum. The intact plant assay proved more discriminating and reliable than the detached leaf assay for comparing the aggressiveness of Xcc strains on different host genotypes, and so, with the new Xcc strains isolated in this study, will be useful for screening leafy brassica germplasm accessions for resistance to black rot. [ABSTRACT FROM AUTHOR]

Identifying traits involved in plant–pathogen interactions is one of the major objectives in molecular plant pathology. Evolutionary analyses may assist in the identification of genes encoding traits that are involved in virulence and local adaptation, including adaptation to agricultural intervention strategies. In the past decades, the number of available genome sequences of fungal plant pathogens has rapidly increased, providing a rich source for the discovery of functionally important genes as well as inference of species histories. Positive selection in the form of diversifying or directional selection leaves particular signatures in genome alignments and can be identified with statistical genetics methods. This review summarises the concepts and approaches used in evolutionary genomics and lists major discoveries related to plant–pathogen adaptative evolution. We underline the significant contribution of evolutionary genomics in discovering virulence-related traits and the study of plant–pathogen ecology and adaptive evolution. • Plant pathogens specialise to the infection of distinct hosts. Host specialisation involves changes in sequence composition and gene regulation that allow the pathogen to overcome host defences. • Genome data provides a rich resource to identify rapidly evolving genes or regulatory sequences with a role in host infection. These may be identified as regions exhibiting signatures of positive (arms race) or balancing (trench-warfare) selection. • Evolutionary analyses that include both polymorphism and divergence data can be used to disentangle the type of selection acting along the genome. • Plant pathogens can have complex life cycles and theoretical developments are necessary to improve our power to detect selection and understand pathogen evolution. [ABSTRACT FROM AUTHOR]

Pyramiding the AIN and AKR aphid resistance genes results in a Mosaic virus in soybean; reviewed in (Joshi and Nayak, 2010)], and resistance to herbivores [Soybean aphid in soybean Aphids, gene pyramid, host-plant resistance, Medicago truncatula, phytohormone crosstalk, R gene. [Extracted from the article]

The approximately 2-Mb MoT mini-chromosome lacks house-keeping genes, and 52.8% of its sequences are transposons, a significant enrichment similar to what has been reported in lineage-specific chromosomes in the I Fusarium oxysporum i species complex [[5]]. Interestingly, though these two effectors are located on separate chromosomes in MoO, I PWL2 i and I BAS1 i are physically linked in the mini-chromosome of MoT, indicating the shuffling of effector genes. The enrichment and shuffling of effector genes on mini-chromosomes might have provided a reservoir of retained effector genes at the pathogen population level and promoted documented effector gene mobility through movement to new locations in core chromosome ends [[8]]. [Extracted from the article]

Phytophthora capsic i, a highly dynamic and destructive oomycete pathogen, causes devastating diseases on a wide range of plants worldwide. However, the detailed molecular mechanisms of pathogenicity is still largely unclear. In this study, three different mRNA pool libraries were constructed from its developmental stage, early or late infection stage of the model plant Arabidopsis thaliana , and then were investigated by the RNA-Seq approach. The results demonstrated that 1456 novel transcripts that had not linked to any annotated gene were identified, and 296 genes were found to undergo alternative splicing. Comparative analysis of three different libraries further showed that distinct transcriptional changes of pathogenicity genes were found. A large number of genes containing cell wall degrading enzymes, major facilitator superfamily genes and cytochrome P450 genes were highly induced during infection. In addition, several types of well-known effectors including RxLR, CRN, Elicitin and NLP proteins also showed high transcript abundances during infection. The transcriptional levels of six effector genes during the infection process were further validated by qRT-PCR. Collectively, this study provides a basic understanding of pathogenic mechanisms of P. capsici during the interaction with plants. [ABSTRACT FROM AUTHOR]

Nicotiana benthamiana is a valuable model organism in plant biology research. This report describes its extended applicability in the field of molecular plant pathology by introducing a nonbiotrophic fungal pathogen Cercospora nicotianae that can be conveniently used under laboratory conditions, consistently induces a necrotic leaf spot disease on Nicotiana benthamiana, and is specialized on solanaceous plants. Our inoculation studies showed that C. nicotianae more effectively colonizes N. benthamiana than its conventional host, N. tabacum. The functions of two critical regulators of host immunity, coronatine-insensitive 1 (COI1) and ethylene-insensitive 2 (EEM2), were studied in N. benthamiana using Tobacco rattle virus-based virus-induced gene silencing (VIGS). Perturbation of jasmonic acid or ethylene signaling by VIGS of either COH or EIN2, respectively, resulted in markedly increased Cercospora leaf spot symptoms on N. benthamiana plants. These results suggest that the N. benthamiana- C. nicotianae host-pathogen interaction is a prospective but hitherto unutilized pathosystem for studying gene functions in diseased plants. [ABSTRACT FROM AUTHOR]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief of Physiological and Molecular Plant Pathology. The article is a duplicate of a paper that has already been published in the Egyptian Journal of Phytopathology (2009, 37: 59–77; https://doi.org/10.21608/EJP.2009.235030). As per the author guidelines, PMPP does not permit the publication of previously published studies and doing so contributes to diminishing the importance of published findings and distorts the academic record of the authors. One of the conditions of submission of a paper for publication is therefore that authors declare explicitly that the paper has not been previously published and is not under consideration for publication elsewhere. As such this article represents a misuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process, which occurred in 2011. [ABSTRACT FROM AUTHOR]

Severe root rot was observed in fields of cabbages (Brassica oleracea L.) in 2015 in China. Cardinal symptoms of this disease included root rot and wilting leaves. A fungus was isolated from diseased tissues consistently. Based on the morphological features and molecular analysis of the ITS-5.8S rDNA and D1/D2 domain of the 28S rRNA gene, it was identified as Plectosphaerella cucumerina. This is the first report of P. cucumerina causing cabbage root rot in China and the world. [ABSTRACT FROM AUTHOR]

Molecular plant pathology has focused on studying large-effect qualitative resistance loci that predominantly function in detecting pathogens and/or transmitting signals resulting from pathogen detection. By contrast, less is known about quantitative resistance loci, particularly the molecular mechanisms controlling variation in quantitative resistance. Recent studies have provided insight into these mechanisms, showing that genetic variation at hundreds of causal genes may underpin quantitative resistance. Loci controlling quantitative resistance contain some of the same causal genes that mediate qualitative resistance, but the predominant mechanisms of quantitative resistance extend beyond pathogen recognition. Indeed, most causal genes for quantitative resistance encode specific defense-related outputs such as strengthening of the cell wall or defense compound biosynthesis. Extending previous work on qualitative resistance to focus on the mechanisms of quantitative resistance, such as the link between perception of microbe-associated molecular patterns and growth, has shown that the mechanisms underlying these defense outputs are also highly polygenic. Studies that include genetic variation in the pathogen have begun to highlight a potential need to rethink how the field considers broad-spectrum resistance and how it is affected by genetic variation within pathogen species and between pathogen species. These studies are broadening our understanding of quantitative resistance and highlighting the potentially vast scale of the genetic basis of quantitative resistance. [ABSTRACT FROM AUTHOR]

In September 2014, Phytophthora rot on wasabi plants [ Wasabia japonica (Miq.) Matsum.] was found for the first time in the city of Okutama, Tokyo, Japan. A Phytophthora sp. strain was constantly isolated from brown stem bases and rhizomes of infected plants. The same symptoms as those observed in the field were produced in vitro through inoculation of test plants with the isolated Phytophthora sp. The fungus was identified as Phytophthora drechsleri based on morphological and DNA sequence comparison. Phytophthora rot, 'eki-byo' in Japanese, is proposed for this disease common name. [ABSTRACT FROM AUTHOR]

Future Challenges in Plant Pathology Plant infection is a complicated process. On encountering a plant, pathogenic microorganisms must first adapt to life on the epiphytic surface, and survive long enough to initiate an infection. Responsiveness to the environment is critical throughout infection, with intracellular and community-level signal transduction pathways integrating environmental signals and triggering appropriate responses in the bacterial population. Ultimately, phytopathogens must migrate from the epiphytic surface into the plant tissue using motility and chemotaxis pathways. This migration is coupled with overcoming the physical and chemical barriers to entry into the plant apoplast. Once inside the plant, bacteria use an array of secretion systems to release phytotoxins and protein effectors that fulfil diverse pathogenic functions (Fig. [ABSTRACT FROM AUTHOR]

Aims To determine the molecular variability and develop specific Sequence Characterized Amplified Region ( SCAR) marker for the detection of Magnaporthe grisea causing blast disease in finger millet. Methods and Results Random amplified polymorphic DNA ( RAPD) was performed with 14 isolates of M. grisea using 20 random primers. SCAR marker was developed for accurate and specific detection of M. grisea infecting only finger millets. The genetic similarity coefficient within each group and variation between the groups was observed. Among the primers, OPF-08 generated a RAPD polymorphic profile that showed common fragment of 478 bp in all the isolates. This fragment was cloned and sequenced. SCAR primers, Mg- SCAR- FP and Mg- SCAR- RP, were designed using sequence of the cloned product. The specificity of the SCAR primers was evaluated using purified DNA from M. grisea isolates from finger millets and other pathogens viz., Pyricularia oryzae, Colletotrichum gloeosporioides, Colletotrichum falcatum and Colletotrichum capcisi infecting different crops. The SCAR primers amplified only specific 460 bp fragment from DNA of M. grisea isolates and this fragment was not amplified in other pathogens tested. Conclusion SCAR primers distinguish blast disease of finger millet from rice as there is no amplification in the rice blast pathogen. PCR-based SCAR marker is a convenient tool for specific and rapid detection of M. grisea in finger millets. Significance and Impact of the Study Genetic diversity in fungal population helps in developing a suitable SCAR marker to identify the blast pathogen at the early stage of infection. [ABSTRACT FROM AUTHOR]

The authors convey their response to a feedback about their report on the selective transport and role of silicon in plants. Topics mentioned include the role of silicic acid as an intracellular signaling agent, the differences between the mechanical barrier hypothesis and the apoplastic obstruction hypothesis, and the existence of a synergistic mechanical protection by callose and silica against pathogens in horsetail.

The sequences of the 3′-terminal region of four Czech Potato virus M isolates VIRUBRA 4/007, VIRUBRA 4/009, VIRUBRA 4/016 and VIRUBRA 4/035 were determined and compared with sequences of PVM isolates available in GenBank. Among the Czech isolates, VIRUBRA 4/007 and 4/016 as well as VIRUBRA 4/016 and 4/035 showed the highest nucleotide identity (93%). Isolates VIRUBRA 4/007, 4/016 and 4/035 were most similar to the PV0273 isolate from Germany and to the wild isolate from Russia. Interestingly, isolate VIRUBRA 4/009 significantly differed from the other three Czech isolates and was the only European isolate that showed the highest nucleotide identity with American isolates. Moreover, the PVM isolates from the Czech Republic and Germany differed in their host range. Phylogenetic analysis based on ORF5 coding for coat protein showed that the Czech isolates could be classified in two of the three groupings of the phylogenetic tree obtained. This is the first report on molecular and biological analysis of the genome sequences of PVM isolates from the Czech Republic. [ABSTRACT FROM AUTHOR]

The objective of this research was to assess the relative expression of candidate genes associated to plant disease resistance in Pinus radiata inoculated with Fusarium circinatum by using two different inoculation methods. Microdroplet inoculation allowed an earlier and reliable selection of contrasting genotypes, however, spray inoculation method was more informative for gene expression analysis. Thaumatin-like protein, peroxidase, phenylalanine ammonia lyase, pinosylvin synthase and phenylcoumaran benzylic ether reductase genes increased significantly their transcription levels after inoculation with the pathogen in the resistant genotype, while in the susceptible genotype these genes showed lower relative expression. [ABSTRACT FROM AUTHOR]

A pathogenicity island within the genome of a multi-host plant bacterium, Pseudomonas cichorii strain SPC9018, comprises the hrp genes encoding a type III secretion system and the pat gene encoding an N -acetyltransferase proposed to play a role in virulence. However, the function of the N -acetyltransferase remains poorly characterized. Interestingly, limiting the iron condition using a phytosiderophore, mugineic acid, resulted in reduced virulence of strain SPC9018 on respective host plants, including eggplant, similar to the reduced virulence observed with a pat gene-deletion mutant. Spectroscopic analyses showed that the pat deletion reduced the concentration of pyoverdine, which is the main siderophore produced by strain SPC9018, leading to a reduction in pyoverdine-mediated iron acquisition. Furthermore, the pat gene deletion mutant showed enhanced expression of the fecA , pvdL, and pvdR genes, whose expression is induced under deficient siderophore-mediated iron uptake. The pat -deletion mutant showed a hyper-swarming phenotype, and the addition of iron decreased this swarming motility. The pat deletion also reduced the adhesion ability of the bacteria, similar to the effect of iron-limited conditions. Furthermore, deletion of the pat gene enhanced expression of the hrp genes. These findings suggested that the pat gene encoding the N -acetyltransferase may be implicated in iron acquisition, contributing to host specificity of P. cichorii strain SPC9018 and its virulence. [ABSTRACT FROM AUTHOR]