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Impact of Xylella fastidiosa Subspecies pauca in European Olives
Xylella fastidiosa is the causal agent of plant diseases that cause massive economic damage. In 2013, a strain of the bacterium was, for the first time, detected in the European territory (Italy), causing the Olive Quick Decline Syndrome. We simulate future spread of the disease based on climatic-suitability modeling and radial expansion of the invaded territory. An economic model is developed to compute impact based on discounted foregone profits and losses in investment. The model projects impact for Italy, Greece, and Spain, as these countries account for around 95% of the European olive oil production. Climatic suitability modeling indicates that, depending on the suitability threshold, 95.5 to 98.9%, 99.2 to 99.8%, and 84.6 to 99.1% of the national areas of production fall into suitable territory in Italy, Greece, and Spain, respectively. For Italy, across the considered rates of radial range expansion the potential economic impact over 50 y ranges from 1.9 billion to 5.2 billion Euros for the economic worst-case scenario, in which production ceases after orchards die off. If replanting with resistant varieties is feasible, the impact ranges from 0.6 billion to 1.6 billion Euros. Depending on whether replanting is feasible, between 0.5 billion and 1.3 billion Euros can be saved over the course of 50 y if disease spread is reduced from 5.18 to 1.1 km per year. The analysis stresses the necessity to strengthen the ongoing research on cultivar resistance traits and application of phytosanitary measures, including vector control and inoculum suppression, by removing host plants.
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"Plants | Free Full-Text | Two New Putative Plant Viruses from Wood Metagenomics Analysis of an Esca Diseased Vineyard | HTML
The concept of plant as a holobiont is now spreading among the scientific community and the importance to study plant-associated microorganisms is becoming more and more necessary. Along with bacteria and fungi, also viruses can play important roles during the holobiont-environment interactions. In grapevine, viruses are studied mainly as pathological agents, and many species (more than 80) are known to be able to replicate inside its tissues. In this study two new viral species associated with grape wood tissues are presented, one belongs to the Potyviridae family and one to the Bunyavirales order. Due to the ability of potyviruses to enhance heterologous virus replication, it will be important to assess the presence of such a virus in the grapevine population to understand its ecological role. Furthermore, the association of the cogu-like virus with esca symptomatic samples opens new questions and the necessity of a more detailed characterization of this virus.
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"Costa Rica decrees emergency in fight against TR4
New government decree will streamline the release of resources from a state phytosanitary service fund
Costa Rica declared a state of phytosanitary emergency on Wednesday in a clear escalation of its struggle to protect its banana industry from Fusarium Wilt TR4.President Carlos Alvarado, and the Minister of Agriculture and Livestock, Renato Alvarado, signed the decree that enables resources from the State Phytosanitary Service to combat new or existing pests that may cause damage to national agriculture, as well as the execution of preventive actions that protect productive activity.In a statement, the president said the aim was “to reduce a risk that could be a threat to banana producers…and protect our agri-food sector and the thousands of people who work in this activity”.The first Latin American cases of Fusarium Wilt TR4 – also known as Panama disease – were detected last year in Colombia. The pathogen is not yet present in Costa Rica, and to prevent this the funds will be allocated to investment, training and outreach to technicians, producers and the general public and to intensify continuous surveillance activities in the plantations of musaceae (banana and plantain).“A country-wide effort is required, but it goes much further than this. We also need international support; it is about maintaining an articulated job for the benefit of the banana industry and its workers, ”said Jorge Sauma, manager of the National Banana Corporation (Corbana).According to Corbana, the industry generates 40,000 direct jobs and 100,000 indirect jobs, which represents 76 per cent of the workforce in the Caribbean area. Costa Rica exports around US$1bn of bananas every year.TR4 is a fungus that colonises, infects and destroys Cavendish plants, which account for the overwhelming majority of bananas traded and sold around the world. It has already caused major damage to banana plantations in parts of Asia, with other cases reported more recently in Australia, Jordan, Mozambique and Pakistan.With four of the world's top five banana exporters in Latin America, the potential impact of TR4 on the region’s banana business is considerable.The pathogen that is spread, mainly, by the movement of planting material in the soil particles that adhere to people’s footwear, tools and vehicles, and through runoff water or irrigation that drags the fungus from one place to another.The only preventive measure currently available is quarantine, preventing the transfer of affected soil or plant material from infected areas to Fusarium TR4-free areas."
"First Report of Duranta leaf curl virus Infecting Ficus virens Showing Leaf Curl Symptoms in Pakistan | Plant Disease
Ficus virens (family: Moraceae) is a deciduous tree found in the Indian subcontinent, some other Southeast Asian countries, and northern Australia. It is valued for its latex, wood, and medicinal and edible products. In December 2018, during a routine survey to record begomoviruses other than cotton infecting viruses in Pakistan, curling of young leaves, which is a typical symptom of infection by viruses of the genus Begomovirus, was observed in F. virens trees in a park in Lahore, central Punjab, Pakistan. The total DNA of three trees was extracted using the Viral Gene-spin Viral DNA/RNA Extraction Kit (iNtRON Biotechnology, Seongnam, Korea) and used as a template in PCR amplification with begomovirus-specific primers: Beg-F (5′-CCGTGCTGCTGCCCCCATTGTCCGCGTCAC-3′) and Beg-R (5′- CTGCCACAACCATGGATTCACGCACAGGG-3′). The amplified 1-kb DNA was cloned into the pGEM-3Zf (+) vector (Promega, Madison, WI) and sequenced by a commercial sequencing service (Macrogen, Seoul, Korea). NCBI BLAST results revealed a nucleotide (nt) sequence identity of 95, 93, and 92% with chilli leaf curl India virus, rose leaf curl virus, and papaya leaf crumple virus, respectively. Based on the sequence obtained, new primers, DCP-F (5′-AGCACATTGGTAAAGTCATGTGTG-3′) and DCP-R (5′-GGATATCATGTCTGGACTCAAATG-3′), were designed to obtain full-length DNA-A of the begomovirus. An approximately 2.8-kb product was amplified and cloned. The resulting sequence (GenBank accession no. MN537564) showed 97.43% nt identity with duranta leaf curl virus (DLCV; KT948069), a Begomovirus species reported in the ornamental shrub Duranta erecta in Pakistan by Iram et al. (2005) and by Anwar et al. (2017). In the former case, only DNA-A of DLCV was found without any associated molecules such as DNA-B or DNA β, whereas, in the latter case, tomato leaf curl New Delhi virus DNA-B was found in association with the DNA-A of DLCV, like in many other Old World begomoviruses. The attempt to amplify DNA-B through PCR using newly designed primers NDB-F (5′-AAACACAGGAGGGATCGGAG-3′) and NDB-R (5′-CACAGATTTCCTTACGCGTATATT-3′) based on the sequence KT948071 was unsuccessful. Similarly, efforts to detect alphasatellite and betasatellite molecules in infected F. virens using universal primers (Bull et al. 2003; Briddon et al. 2002) were unsuccessful. Furthermore, Southern blot hybridization was carried out using [32P]-radiolabeled PCR product of 1 kb obtained with Beg-F/R primers as a probe. This produced dsDNA bands of different conformations as well as a ssDNA band, which confirms the presence of DLCV in F. virens. Members of the family Geminiviridae, to which begomoviruses belong, mainly infect herbaceous hosts, but they have also been reported in a few woody hosts, such as citrus chlorotic dwarf associated virus in citrus (Loconsole et al. 2012), grapevine red blotch virus in grape (Al Rwahnih et al. 2013), jatropha mosaic virus in Jatropha multifida (Polston et al. 2014), and apple geminivirus 1 in apple tree (Liang et al. 2015). To our knowledge, this is the first report of DLCV infecting F. virens in Pakistan. The results obtained here indicate that F. virens may serve as an alternative host of DLCV and a possible source of infection to the commonly grown D. erecta ornamental garden hedge.The author(s) declare no conflict of interest.References:Al Rwahnih, M., et al. 2013. Plant Dis. 103:1069. https://doi.org/10.1094/PHYTO-10-12-0253-R Google ScholarAnwar, S., et al. 2017. Arch. Virol. 163:809. https://doi.org/10.1007/s00705-017-3672-y Crossref, ISI, Google ScholarBriddon, R. W., et al. 2002. Mol. Biotechnol. 20:315. https://doi.org/10.1385/MB:20:3:315 Crossref, ISI, Google ScholarBull, S. E., et al. 2003. Mol. Biotechnol. 23:83. https://doi.org/10.1385/MB:23:1:83 Crossref, ISI, Google ScholarIram, S., et al. 2005. J. Plant Pathol. 54:260. https://doi.org/10.1111/j.1365-3059.2005.01129.x Crossref, Google ScholarLiang, P., et al. 2015. J. Gen. Virol. 96:2411. https://doi.org/10.1099/vir.0.000173 Crossref, ISI, Google ScholarLoconsole, G., et al. 2012. Virology 432:162. https://doi.org/10.1016/j.virol.2012.06.005 Crossref, ISI, Google ScholarPolston, J. E., et al. 2014. Arch. Virol. 159:3131. https://doi.org/10.1007/s00705-014-2132-1 Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by Animal and Plant Quarantine Agency (Z-1543086-2017-21-01)."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
According to a news article released by the University of California Riverside (UCR), scientists there have found a substance which may be capable of controlling Citrus Greening Disease. The disease, also known as Huanglongbing or HLB, has devastated citrus in Florida and in other regions worldwide. It also threatens California crops."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
The article says the new treatment effectively kills the bacterium causing the disease with a naturally occurring molecule found in wild citrus relatives. This molecule, an antimicrobial peptide, offers numerous advantages over the antibiotics currently used to treat the disease."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
UCR geneticist Hailing Jin, who discovered the potential cure after a five-year search, explained that unlike antibiotic sprays, the peptide is stable even when used outdoors in high heat, easy to manufacture and safe for humans."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
“This peptide is found in the fruit of greening-tolerant Australian finger limes, which has been consumed for hundreds of years,” Jin said. “It is much safer to use this natural plant product on agricultural crops than other synthetic chemicals.”"
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
Currently, some growers in Florida are spraying antibiotics and pesticides in an attempt to save trees from the CLas bacterium that causes citrus greening, also known as Huanglongbing or HLB."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
“Most antibiotics are temperature sensitive, so their effects are largely reduced when applied in the hot weather,” Jin said. “By contrast, this peptide is stable even when used in 130-degree heat.”"
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
Jin found the peptide by examining plants such as the Australian finger lime known to possess natural tolerance for the bacteria that causes Citrus Greening Disease, and she isolated the genes that contribute to this innate immunity. One of these genes produces the peptide, which she then tested over the course of two years. Improvement was soon visible."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
“You can see the bacteria drastically reduced, and the leaves appear healthy again only a few months after treatment,” Jin said."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
Because the peptide only needs to be re-applied a few times per year, it is highly cost effective for growers. This peptide can also be developed into a vaccine-like solution to protect young healthy plants from infection, as it is able to induce the plant’s innate immunity to the bacteria."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
Jin’s peptide can be applied by injection or foliage spray, and it moves systemically through plants and remains stable, which makes the effect of the treatment stronger."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
The treatment will be further enhanced with proprietary injection technology made by Invaio Sciences. UC Riverside has entered into an exclusive, worldwide license agreement with Invaio, ensuring this new treatment goes exactly where it’s needed in plants."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
“Invaio is enthusiastic to partner with UC Riverside and advance this innovative technology for combating the disease known as Citrus Greening or Huanglongbing,” said Invaio Chief Science Officer Gerardo Ramos. “The prospect of addressing this previously incurable and devastating crop disease, helping agricultural communities and improving the environmental impact of production is exciting and rewarding. This is crop protection in harmony with nature.”"
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
The need for an HLB cure is a global problem, but hits especially close to home as California produces 80% of all the fresh citrus in the United States, said Brian Suh, director of technology commercialization in UCR’s Office of Technology Partnerships, which helps bring university technology to market for the benefit of society through licenses, partnerships, and startup companies."
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
“This license to Invaio opens up the opportunity for a product to get to market faster,” Suh said. “Cutting edge research from UCR, like the peptide identified by Dr. Jin, has a tremendous amount of commercial potential and can transform the trajectory of real-world problems with these innovative solutions.”"
"UCR Scientists Say New Peptide Could Control HLB - Citrus Industry Magazine
Source: UC Riverside Newsroom"
"Pest survey card on Spodoptera frugiperda | European Food Safety
This pest survey card was prepared in the context of the EFSA mandate on plant pest surveillance (M‐2017‐0137), at the request of the European Commission. Its purpose is to guide the Member States in preparing data and information for Spodoptera frugiperda surveys. These are required to design statistically sound and risk‐based pest surveys, in line with current international standards.Spodopterafrugiperdais a regulated priority Union quarantine pest in the EU and Member States are therefore required to perform annual surveys. Emergency measures are in place to prevent the introduction into and the spread within the EU. Spodoptera frugiperda is not known to occur in the EU, but it could become established in some coastal Mediterranean regions that remain frost‐free all year. Climate is therefore a limiting factor for the establishment of the pest. The optimum temperature for development from egg to adult is 28°C.Spodopterafrugiperda is a polyphagous pest and detection surveys should mainly target maize, rice and sorghum, while delimiting surveys should cover all host species in the survey area. Due to the high spread capacity of the adults, detection of the mothat low levels of population is crucial to avoid further spread of the pest.Detection surveys tosubstantiate pest freedom should be based on a trapping strategy.After a finding, trapping should be intensified in the neighbouring fields and combined with the visualexamination of host plants for the symptoms and early stages of S. frugiperda. Morphological and molecular procedures are both available for the identification of S. frugiperda. If experience is lacking or the purpose is to identify the early stages of the pest, molecular methods are preferred over the morphological ones."
"Guidelines for statistically sound and risk‐based surveys of
At the request of the European Commission, EFSA prepared these specific guidelines to guide the surveyor through the design of statistically sound and risk‐based surveys for Phyllosticta citricarpa, integrating the key biological information. Based on examples, three different survey designs are simulated:(i) detection surveys to substantiate pest freedom, (ii) delimiting surveys to determine the boundaries of an infested zone, and (iii) buffer zone surveys to monitor a zone ensuring pest detection at low levels of prevalence.The first step of the survey design consists of setting the goals of the survey, characterising the host plant population and the methods used to identify the pest. All survey parameters are quantified taking into accountthe importance of the related assumptions. The more accurateand robust the information used for selecting and estimating the survey parameters, the more robust the conclusions of the survey will be. The second step of the survey design consists of the sample size (i.e. number of trees)calculation using the survey parameters as inputs of the proposed statistical tool (EFSA RiBESS+).The last step of the survey design is the allocation of the samples in the survey area which depends on the information available on the target population and risk factors. The robustness of the conclusions of surveys designed using the proposed approaches strongly depends on the survey preparation. The methodology proposed allows surveys to be compared across time and space, thus contributing to the harmonisation of the P.citricarpasurveys across the EU. The extremely flexible approach allows the surveys to be tailored to each specific situation in the Member States, taking into account the citrus tree distribution and available resources. The success of a good survey design relies on the technical aspects of the survey preparation and on the involvement of the risk managers."
"Guidelines for statistically sound and risk‐based surveys of
At the request of the European Commission, EFSA prepared these specific guidelines to guide the surveyor through the design of statistically sound and risk‐based surveys for Phyllosticta citricarpa, integrating the key biological information. Based on examples, three different survey designs are simulated:(i) detection surveys to substantiate pest freedom, (ii) delimiting surveys to determine the boundaries of an infested zone, and (iii) buffer zone surveys to monitor a zone ensuring pest detection at low levels of prevalence.The first step of the survey design consists of setting the goals of the survey, characterising the host plant population and the methods used to identify the pest. All survey parameters are quantified taking into accountthe importance of the related assumptions. The more accurateand robust the information used for selecting and estimating the survey parameters, the more robust the conclusions of the survey will be. The second step of the survey design consists of the sample size (i.e. number of trees)calculation using the survey parameters as inputs of the proposed statistical tool (EFSA RiBESS+).The last step of the survey design is the allocation of the samples in the survey area which depends on the information available on the target population and risk factors. The robustness of the conclusions of surveys designed using the proposed approaches strongly depends on the survey preparation. The methodology proposed allows surveys to be compared across time and space, thus contributing to the harmonisation of the P.citricarpasurveys across the EU. The extremely flexible approach allows the surveys to be tailored to each specific situation in the Member States, taking into account the citrus tree distribution and available resources. The success of a good survey design relies on the technical aspects of the survey preparation and on the involvement of the risk managers."
"Pest survey card on Spodoptera frugiperda | Autorité européenne de
This pest survey card was prepared in the context of the EFSA mandate on plant pest surveillance (M‐2017‐0137), at the request of the European Commission. Its purpose is to guide the Member States in preparing data and information for Spodoptera frugiperda surveys. These are required to design statistically sound and risk‐based pest surveys, in line with current international standards.Spodopterafrugiperdais a regulated priority Union quarantine pest in the EU and Member States are therefore required to perform annual surveys. Emergency measures are in place to prevent the introduction into and the spread within the EU. Spodoptera frugiperda is not known to occur in the EU, but it could become established in some coastal Mediterranean regions that remain frost‐free all year. Climate is therefore a limiting factor for the establishment of the pest. The optimum temperature for development from egg to adult is 28°C.Spodopterafrugiperda is a polyphagous pest and detection surveys should mainly target maize, rice and sorghum, while delimiting surveys should cover all host species in the survey area. Due to the high spread capacity of the adults, detection of the mothat low levels of population is crucial to avoid further spread of the pest.Detection surveys tosubstantiate pest freedom should be based on a trapping strategy.After a finding, trapping should be intensified in the neighbouring fields and combined with the visualexamination of host plants for the symptoms and early stages of S. frugiperda. Morphological and molecular procedures are both available for the identification of S. frugiperda. If experience is lacking or the purpose is to identify the early stages of the pest, molecular methods are preferred over the morphological ones."
"Pest categorisation of Helicoverpa zea | Autorité européenne de
American cotton bollworm, corn earworm, European Union, migration, pest risk, plant health, plant pest, quarantine
The EFSA Panel on Plant Health performed a pest categorisation of Helicoverpa zea (Lepidoptera: Noctuidae) (American cotton bollworm, corn earworm) for the EU. H. zea is a polyphagous species that feeds on over 100 plant species. The crops most frequently recorded as host plants are maize, sorghum, cotton, beans, peas, chickpeas, tomatoes, aubergines, peppers and, to a lesser extent, clover, okra, cabbages, lettuces, strawberries, tobacco, sunflowers, cucurbits and ornamentals. H. zea preferentially feeds on flowers and fruits of the host. Eggs are laid mostly on maize silks. Larvae feed on the silks and kernels. Pupation takes place in the soil. Hibernation and estivation as pupa are reported. Adults are nocturnal. H. zea is a strong flier, able to fly up to 400 km during migration. Commission Implementing Regulation (EU) 2019/2072 (Annex IIA) regulates H. zea. Fruits and plants for planting, with and without soil, provide potential pathways for entry into the EU. Climatic conditions and the availability of host plants provide conditions to support establishment in the EU. The introduction of H. zea could have an economic impact in the EU through qualitative and quantitative effects on agricultural production (e.g. tomatoes, soybean, sweet corn). Phytosanitary measures are available to reduce the likelihood of entry. H. zea satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. H. zea does not meet the criteria of (a) occurring in the EU, and (b) plants for planting being the principal means of spread for it to satisfy the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union regulated non‐quarantine pest."
"Pest survey card on Geosmithia morbida and its vector Pityophthorus
This pest survey card was prepared in the context of the EFSA mandate on plant pest surveillance (M‐2017‐0137) at the request of the European Commission. Its purpose is to guide the Member States in preparing data and information for Geosmithia morbida and Pityophthorus juglandis surveys. These are required to design statistically sound and risk‐based pest surveys, in line with current international standards.Geosmithia morbida and its vector P. juglandis are clearly defined taxonomic entitiesand the combined activity of the fungus and the insect causes the disease complex thousand canker disease on the plant genera Juglans and Pterocarya. The pest and its vector originate in North America and currently have a restricted distribution in the EU, limited to the northern parts of Italy.However, they are potentially able to become established everywhere in the EU where their host plants occur.Currently, the spread capacity ofP.juglandis is unknown, but the insect vectormay cover large distances by passive dispersal or human‐assisted spread. Risk locations include entry points (e.g. seaports, airports), loading stations, storage facilities and wood processing companies that deal withheat‐treated wood, bark or woodchips of the genera Juglans and Pterocarya originating from countries where the fungus and its vector occur.Trapping is the recommended method for detecting the vector inthe early stages of an epidemic. Following insect trapping, a specific tree inspection should be carried out, looking for external symptoms(e.g. penetration and exit holes, cankers and wilting). The trapping should start when the mean air temperature exceeds 18°C.Morphological identification of the pathogen and its vector should be performed by experts. Molecular assays are also available for both fungal and vector identification."
"Pest categorisation of tomato leaf curl New Delhi virus | Autorité
Begomovirus, virus satellite, Bemisia tabaci, Cucurbits, pest risk, quarantine, plant health
Following a request from the European Commission, the Panel on Plant Health performed a pest categorisation on tomato leaf curl New Delhi virus (ToLCNDV). ToLCNDV is a well‐defined bipartite Begomovirus species, sometimes associated with satellite molecules. It is transmitted by Bemisia tabaci to a wide range of hosts. ToLCNDV is reported from Estonia, Greece, Italy, Portugal and Spain, with limited distribution. The prevalent strain (ToLCNDV‐ES) in these countries is particularly adapted to cucurbits and is different from isolates reported outside the EU, which are better adapted to solanaceous crops and could therefore pose additional risk for EU agriculture. The virus is regulated under Commission Implementing Regulation (EU) 2019/2072. The main pathway of entry identified is plants for planting of susceptible hosts, even if entry could also occur via commodities carrying viruliferous B. tabaci and possibly by seeds. While establishment and local spread rely on B. tabaci, the virus can also be dispersed over long distances by movement of infected plants for planting. Establishment and spread are limited to regions with ecoclimatic conditions suitable for the establishment of vector populations (southern regions of Europe) or can occur as outbreaks wherever crops are grown under protected cultivation. The main uncertainties associated with this pest categorisation are the distribution and prevalence of ToLCNDV in the EU, the magnitude of the virus impact particularly on hosts different from Cucurbitaceae, and seed transmission. ToLCNDV meets all the criteria evaluated by EFSA to qualify as potential Union Quarantine Pest (QP); conversely, ToLCNDV does not meet the criterion of being widespread in the EU to qualify as a Regulated Non‐Quarantine Pest (RNQP). Should new data show that ToLCNDV is widespread in the EU, the possibility would exist for non‐EU isolates to qualify as QP, while ToLCNDV EU isolates (ToLCNDV‐ES) could qualify as RNQP."
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CRISPR/Cas9-mediated Targeted Mutagenesis of TAS4 and MYBA7 Loci in Grapevine Rootstock 101-14
Pierce's disease (PD) of grapevine (Vitis vinifera) is caused by the bacterium Xylella fastidiosa and is vectored by xylem sap-sucking insects, whereas Grapevine Red Blotch Virus (GRBV) causes Red Blotch Disease and is transmitted in the laboratory by alfalfa leafhopper Spissistilus festinus. The significance of anthocyanin accumulations in distinct tissues of grapevine by these pathogens is unknown, but vector feeding preferences and olfactory cues from host anthocyanins may be important for these disease etiologies. Phosphate, sugar, and UV light are known to regulate anthocyanin accumulation via miR828 and Trans-Acting Small-interfering locus4 (TAS4), specifically in grape by production of phased TAS4a/b/c small-interfering RNAs that are differentially expressed and target MYBA5/6/7 transcription factor transcripts for post-transcriptional slicing and antisense-mediated silencing. To generate materials that can critically test these genes' functions in PD and GRBV disease symptoms, we produced transgenic grape plants targeting TAS4b and MYBA7 using CRISPR/Cas9 technology. We obtained five MYBA7 lines all with bi-allelic editing events and no off-targets detected at genomic loci with homology to the guide sequence. We obtained two independent edited TAS4b lines; one bi-allelic, the other heterozygous while both had fortuitous evidences of bi-allelic TAS4a off-target editing events at the paralogous locus. No visible anthocyanin accumulation phenotypes were observed in regenerated plants, possibly due to the presence of genetically redundant TAS4c and MYBA5/6 loci or absence of inductive environmental stress conditions. The editing events encompass single base insertions and di/trinucleotide deletions of Vvi-TAS4a/b and Vvi-MYBA7 at expected positions 3 nt upstream from the guideRNA proximal adjacent motifs NGG. We also identified evidences of homologous recombinations of TAS4a with TAS4b at the TAS4a off-target in one of the TAS4b lines, resulting in a chimeric locus with a bi-allelic polymorphism, supporting independent recombination events in transgenic plants associated with apparent high Cas9 activities. The lack of obvious visible pigment phenotypes in edited plants precluded pathogen challenge tests of the role of anthocyanins in host PD and GRBV resistance/tolerance mechanisms. Nonetheless, we demonstrate successful genome-editing of non-coding RNA and MYB transcription factor loci which can serve future characterizations of the functions of TAS4a/b/c and MYBA7 in developmental, physiological, and environmental biotic/abiotic stress response pathways important for value-added nutraceutical synthesis and pathogen responses of winegrape.
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BxCDP1 From the Pine Wood Nematode Bursaphelenchus Xylophilus Is Recognized as a Novel Molecular Pattern
The migratory plant-parasitic nematode Bursaphelenchus xylophilus is the causal agent of pine wilt disease, which causes serious damage to pine forests in China. Plant immunity plays an important role in plant resistance to multiple pathogens. Activation of the plant immune system is generally determined by immune receptors, including plant pattern recognition receptors, which mediate pattern recognition. However, little is known about molecular pattern recognition in the interaction between pines and B. xylophilus. Based on the B. xylophilus transcriptome at the early stages of infection and Agrobacterium tumefaciens-mediated transient expression and infiltration of recombinant proteins produced by Pichia pastoris in many plant species, a novel molecular pattern (BxCDP1) was characterized in B. xylophilus. We found that BxCDP1 was highly up-regulated at the early infection stages of B. xylophilus, and was similar to a protein in Pararhizobium haloflavum. BxCDP1 triggered cell death in Nicotiana benthamiana when secreted into the apoplast, and this effect was dependent on brassinosteroid-insensitive 1-associated kinase 1, but independent of suppressor of BIR1-1. BxCDP1 also exhibited cell death-inducing activity in pine, Arabidopsis, tomato, pepper, and lettuce. BxCDP1 triggered reactive oxygen species production and the expression of PAMP-triggered immunity marker genes (NbAcre31, NbPTI5, and NbCyp71D20) in N. benthamiana. It also induced the expression of pathogenesis-related genes (PtPR-3, PtPR-4, and PtPR-5) in Pinus thunbergii. These results suggest that as a new B. xylophilus molecular pattern, BxCDP1 can not only be recognized by many plant species, but also triggers innate immunity in N. benthamiana and defence responses of P. thunbergii.
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Development of a Real-Time TaqMan PCR Method for Absolute Quantification of the Biocontrol Agent Esteya vermicola
Esteya vermicola has been used as an effective biocontrol agent for the management of the pinewood nematode, Bursaphelenchus xylophilus. Tools for monitoring the colonization and parasitism patterns of E. vermicola are required for the development of highly effective biocontrol strategies. Because the TaqMan PCR technique is effective for quantification of species in environmental samples, a real-time PCR-based methodology was developed for absolute quantification of E. vermicola via internal standard addition and extrapolation of DNA quantity to hyphal length. Primers and a probe for the 28S ribosomal RNA gene of E. vermicola were designed, and nested TaqMan real-time PCR-based quantification was performed. In addition, internal standard-based yield measurement was correlated to the absolute quantity of target genomic DNA. Moreover, an extrapolation curve obtained by optical microscopy and image analysis of the mycelia was constructed for the measurement of fungal hyphal length. The absolute quantification method developed in the present study provides a sensitive and accurate technique to quantify fungal density in either wood or other substrate samples and can be used as an effective tool for future studies of biocontrol agents.
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First Report of Anthracnose Fruit Rot Caused by Colletotrichum fioriniae on Red Raspberry ( Rubus idaeus) in the Mid-Atlantic Region of the United States
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"Andalusia Declared Free of Xylella
The Regional Government of Andalusia has officially notified the Spanish Ministry of Agriculture that the region is now free of the Xylella fastidiosa bacterium, after its detection in 2018 on ornamental plants at a nursery in El Ejido in the Almeria province of the region. The regional authorities acted according to the National Contingency Plan of the country in place to deal with such incidences, the government's notice said. The infected plant material was isolated and destructed, while the nursery owner was compensated for damage inflicted. Plant material prone to infection from two other nursery facilities that had supplied the El Ejido nursery was also isolated and retained by ministry technicians. Surveillance actions were implemented over a period of two years, including the collection and examination of 936 tree and crop samples from the three nurseries. Consequent analyses carried out at the Plant Production and Health Laboratory of Almeria showed no infection from the pathogen. An inspection zone of one kilometer was created around the nursery facilities and 741 samples of 28 different plant species were examined for infection over the two-year surveillance period, among them olive and almond trees that are particularly susceptible to Xylella, with results showing no contamination. At the same time, the ministry experts examined whether vector host insects that could disperse the disease existed in the area. Two adult specimens of the Neophilaenus campestris, a possible Xylella carrier, were captured and tested negative to the bacterium as well. After all the checks and controls were completed, the regional government announced the eradication of Xylella fastidiosa in Andalusia after the isolated detection of this bacterium registered in 2018 on an ornamental species present in a producer nursery located in El Ejido. In 2017, almond trees in Valencia were found to have been infected with Xylella. Officials destroyed some 300 olive trees as a precaution and sprayed the area for insects such as cicadas and spittlebugs that are known to spread the disease. In 2016, a study confirmed the absence of Xylella in a range of the region’s agriculture. The 600 tests were administered on olive, almond, and citrus trees, as well as ornamental plants — and all in the Andalusian regions of Almería, Granada, Málaga, and Jaén."
"UK Tightens Rules on Olive Tree Imports
The United Kingdom has introduced stringent new measures to protect the country’s trees and plants from harmful threats posed by a range of diseases and pests including deadly Xylella fastidiosa. The U.K.’s Department for Environment, Food and Rural Affairs (Defra) brought in the new regulations amid growing concerns that current EU emergency measures were not enough to prevent the spread of Xylella fastidiosa according to threats highlighted by a pest risk assessment( PRA). In a trade letter, Defra said, “We recognize the challenges that the horticultural sector and individual businesses are facing at the current time due to the coronavirus pandemic, and we have reflected carefully on the timing of these new regulations, but believe it is important to proceed now to protect the UK’s biosecurity.” The revised regulations prohibit the import of Coffea (Coffee plants) and Polygala myrtifolia due to their high disease rate. Other high-risk hosts including olive, almond, lavender and rosemary will face more severe import requirements. Defra issued a statement declaring that the legislation is in response to “significant concerns about the risk of plant material infected with Xylella fastidiosa being moved within the EU, as well as the risk of introductions from third countries.” It also highlights the recent interception of infected olive trees in Belgium and a recent case in Vinca, Italy, events that “demonstrate that there is a risk of infected plants being moved without visual symptoms.” Chief Plant Health Officer Nicola Spence said in a press release, “Xylella is a major threat to our landscape and industry and in this year of International Plant Health it is more imperative than ever that we do all we can to ensure the UK remains a Xylella-free zone” Tighter restrictions will also be applied to plants and trees posing a high risk of spreading emerald ash borer and plane wilt."
"EU 'objections' to UK Xylella import bans and restrictions
Dutch sources say there has been an objection within the European Commission after the UK banned and restricted imports of plants such as olives and lavender."
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