Control of plant pathogens with viruses and related agents

1988 ◽  
Vol 318 (1189) ◽  
pp. 295-317 ◽  
Keyword(s):  
Plant Pathogens ◽  
Systemic Infection ◽  
Pathogenic Fungi ◽  
Plant Viruses ◽  
Life Cycles ◽  
Cross Protection ◽  
Gaeumannomyces Graminis ◽  
Dutch Elm Disease ◽  
Viral Gene ◽  
Intact Virus

Cytoplasmically transmissible agents causing diseases of plant pathogenic fungi characterized by reductions in pathogenicity, ability to form sexual and asexual spores, spore viability and growth rate, are often associated with the presence of one or more specific segments of virus-like double-stranded RNA (dsRNA). In Italy, hypovirulent dsRNA-containing strains of the chestnut blight fungus, Endothia ( Cryphonectria ) parasitica , have become predominant in many areas where blight is no longer a serious problem. dsRNA-containing strains of other pathogens, with various degrees of debilitation, survive in natural populations but have not become predominant or resulted in any great reduction in disease. Examples include the Dutch elm disease fungus, Ophiostoma ( Ceratocystis ) ulmi , and the wheat take-all fungus, Gaeumannomyces graminis var. tritici . Successful biological control of such pathogens could probably be achieved, however, if methods could be developed to suppress the loss of dsRNA that occurs during the sexual and other stages of their life cycles, and to suppress the vegetative incompatibility reactions that reduce the cytoplasmic transmission of dsRNA. Systemic infection with attenuated strains of plant viruses can protect plants from later infection by virulent strains of the same or closely related viruses. Despite some notable successes, e.g. control of citrus tristeza and tomato mosaic viruses, such ‘cross-protection’ has not been widely applied because of the cost and difficulty of application, and caution about the widespread distribution of infectious agents in the environment. These problems could be overcome if cross-protection could be achieved by the expression of a single viral gene rather than infection with intact virus, and consideration of possible mechanisms of cross protection suggests novel ways of producing virus-resistant plants.

scholarly journals CRISPR-Cas-Led Revolution in Diagnosis and Management of Emerging Plant Viruses: New Avenues Toward Food and Nutritional Security

2021 ◽  
Vol 8 ◽  
Author(s):  
Susheel Kumar Sharma ◽  
Om Prakash Gupta ◽  
Neeta Pathaw ◽  
Devender Sharma ◽  
Albert Maibam ◽  
...  
Keyword(s):  
Plant Species ◽  
Plant Pathogens ◽  
Genome Engineering ◽  
Production Systems ◽  
Crop Productivity ◽  
Plant Viruses ◽  
Viral Gene ◽  
Wide Range ◽  
Food And Nutritional Security ◽  
Cas Proteins

Plant viruses pose a serious threat to agricultural production systems worldwide. The world's population is expected to reach the 10-billion mark by 2057. Under the scenario of declining cultivable land and challenges posed by rapidly emerging and re-emerging plant pathogens, conventional strategies could not accomplish the target of keeping pace with increasing global food demand. Gene-editing techniques have recently come up as promising options to enable precise changes in genomes with greater efficiency to achieve the target of higher crop productivity. Of genome engineering tools, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) proteins have gained much popularity, owing to their simplicity, reproducibility, and applicability in a wide range of species. Also, the application of different Cas proteins, such as Cas12a, Cas13a, and Cas9 nucleases, has enabled the development of more robust strategies for the engineering of antiviral mechanisms in many plant species. Recent studies have revealed the use of various CRISPR-Cas systems to either directly target a viral gene or modify a host genome to develop viral resistance in plants. This review provides a comprehensive record of the use of the CRISPR-Cas system in the development of antiviral resistance in plants and discusses its applications in the overall enhancement of productivity and nutritional landscape of cultivated plant species. Furthermore, the utility of this technique for the detection of various plant viruses could enable affordable and precise in-field or on-site detection. The futuristic potential of CRISPR-Cas technologies and possible challenges with their use and application are highlighted. Finally, the future of CRISPR-Cas in sustainable management of viral diseases, and its practical utility and regulatory guidelines in different parts of the globe are discussed systematically.

Fungi on leaves, branches and stems of trees and shrubs of Saint Petersburg suburban parks

2017 ◽  
Author(s):  
М.В. Сидельникова ◽  
А.В. Тобиас ◽  
Д.Ю. Власов
Keyword(s):  
Pathogenic Fungi ◽  
Dutch Elm Disease ◽  
City Center ◽  
Saint Petersburg ◽  
Xylotrophic Fungi ◽  
Fungi Infection ◽  
Mycological Examination ◽  
The Moment ◽  
Available Information ◽  
Trees And Shrubs

Проведены микологические обследования древесной и кустарниковой растительности на территории парковой зоны Санкт-Петербурга и пригородов. Сбор материала проводился в парках южных пригородов Санкт-Петербурга (Павловский парк, Екатерининский парк, Нижний сад и Верхний парк Ораниенбаума, Верхний сад и Нижний парк ГМЗ «Петергоф»). В сравнительных целях был обследован парк при Обуховской больнице в центре Санкт-Петербурга. На древесно-кустарниковых породах парковой зоны нами выявлено 230 видов грибов (микро- и макромицетов). На листьях выявлено 28 видов микромицетов, в числе которых возбудители мучнистой росы, ржавчины и пятнистостей. На ветвях и стволах древесных пород выявлено 150 видов микромицетов, среди которых есть как часто встречающиеся, так и редкие виды грибов. Большинство из них обнаруживается в анаморфной стадии. Наибольшее разнообразие и развитие микромицетов отмечено на сухих ветвях. Высокой вредоносностью характеризуются тиростромоз липы и голландская болезнь вязов. Выявлены устойчивые патогенные комплексы грибов, развитие которых приводит к заметному ухудшению состояния растений. На стволах живых и усыхающих деревьев, а также растительных остатках отмечено 52 вида макромицетов. Среди них выявлены доминирующие и редкие виды. Среди источников заражения древесных растений ксилотрофными грибами выделяются отмершие вязы, усохшие стволы которых можно наблюдать как в пригородных парках, так и в центральной части Санкт-Петербурга. Полученные данные существенно расширяют имеющиеся сведения по микобиоте парков Санкт-Петербурга. Mycological examination of tree and shrub vegetation on the territory of Saint Petersburg park zone and its suburbs was conducted. Material was collected in the parks of southern suburbs of Saint Petersburg (Pavlovsk Park, Catherine Park, Lower Garden and Upper Park in Oranienbaum, Upper Garden and Lower Park in Peterhof). For comparative purposes Park of Obukhov Hospital in Saint Petersburg city center was also examined. At the moment, 230 fungi species (micro- and macrofungi) were identified on trees and shrubs of the park zone. Among them, 28 species of microfungi, including powdery mildew, rust and blights pathogens were found on leaves. Also, 150 species of microfungi, including both common and rare fungi species, were found on branches and trunks. Most of them were found in the anamorphic stage. The greatest diversity and microfungi development were noted on dry branches. Thyrostromose of linden and Dutch elm disease are the most harmful. Stable complexes of pathogenic fungi, which development leads to clear decline of plants' condition, were identified. In addition, 52 species of macrofungi, including dominant and rare species, were observed on trunks of living and drying trees and vegetation residues. Among the sources of xylotrophic fungi infection of woody plants, dead elms are the most distinguished. Their dead trunks can be found in both suburban parks and the central part of Saint Petersburg. The presented data significantly expand available information on mycobiota Saint Petersburg parks.

scholarly journals The Ustilago hordei–Barley Interaction is a Versatile System for Characterization of Fungal Effectors

2021 ◽  
Vol 7 (2) ◽  
pp. 86
Author(s):  
Bilal Ökmen ◽  
Daniela Schwammbach ◽  
Guus Bakkeren ◽  
Ulla Neumann ◽  
Gunther Doehlemann
Keyword(s):  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Expression System ◽  
Pathogenic Fungi ◽  
Effector Proteins ◽  
Mating Partner ◽  
Fungal Virulence ◽  
Functional Studies ◽  
Infection Structures ◽  
Ustilago Hordei

Obligate biotrophic fungal pathogens, such as Blumeria graminis and Puccinia graminis, are amongst the most devastating plant pathogens, causing dramatic yield losses in many economically important crops worldwide. However, a lack of reliable tools for the efficient genetic transformation has hampered studies into the molecular basis of their virulence or pathogenicity. In this study, we present the Ustilago hordei–barley pathosystem as a model to characterize effectors from different plant pathogenic fungi. We generate U. hordei solopathogenic strains, which form infectious filaments without the presence of a compatible mating partner. Solopathogenic strains are suitable for heterologous expression system for fungal virulence factors. A highly efficient Crispr/Cas9 gene editing system is made available for U. hordei. In addition, U. hordei infection structures during barley colonization are analyzed using transmission electron microscopy, showing that U. hordei forms intracellular infection structures sharing high similarity to haustoria formed by obligate rust and powdery mildew fungi. Thus, U. hordei has high potential as a fungal expression platform for functional studies of heterologous effector proteins in barley.

scholarly journals Double Gamers—Can Modified Natural Regulators of Higher Plants Act as Antagonists against Phytopathogens? The Case of Jasmonic Acid Derivatives

2020 ◽  
Vol 21 (22) ◽  
pp. 8681
Author(s):  
Nicolò Orsoni ◽  
Francesca Degola ◽  
Luca Nerva ◽  
Franco Bisceglie ◽  
Giorgio Spadola ◽  
...  
Keyword(s):  
Jasmonic Acid ◽  
Plant Pathogens ◽  
Higher Plants ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Inhibitory Effect ◽  
Fungal Species ◽  
Phytopathogenic Fungi ◽  
Phaeomoniella Chlamydospora ◽  
Horticultural Crops

As key players in biotic stress response of plants, jasmonic acid (JA) and its derivatives cover a specific and prominent role in pathogens-mediated signaling and hence are promising candidates for a sustainable management of phytopathogenic fungi. Recently, JA directed antimicrobial effects on plant pathogens has been suggested, supporting the theory of oxylipins as double gamers in plant-pathogen interaction. Based on these premises, six derivatives (dihydrojasmone and cis-jasmone, two thiosemicarbazonic derivatives and their corresponding complexes with copper) have been evaluated against 13 fungal species affecting various economically important herbaceous and woody crops, such as cereals, grapes and horticultural crops: Phaeoacremonium minimum, Neofusicoccum parvum, Phaeomoniella chlamydospora, Fomitiporia mediterranea, Fusarium poae, F. culmorum, F. graminearum, F. oxysporum f. sp. lactucae,F. sporotrichioides, Aspergillus flavus, Rhizoctonia solani,Sclerotinia spp. and Verticillium dahliae. The biological activity of these compounds was assessed in terms of growth inhibition and, for the two mycotoxigenic species A. flavus and F. sporotrichioides, also in terms of toxin containment. As expected, the inhibitory effect of molecules greatly varied amongst both genera and species; cis-jasmone thiosemicarbazone in particular has shown the wider range of effectiveness. However, our results show that thiosemicarbazones derivatives are more effective than the parent ketones in limiting fungal growth and mycotoxins production, supporting possible applications for the control of pathogenic fungi.

Dynamics of fungal pathogens in host plant tissues

1995 ◽  
Vol 73 (S1) ◽  
pp. 1275-1283 ◽  
Author(s):  
Shigehito Takenaka
Keyword(s):  
Host Plant ◽  
Species Interactions ◽  
Fungal Biomass ◽  
Quantitative Methods ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Molecular Methods ◽  
Plant Colonization ◽  
Fungal Colonization ◽  
Plant Tissues

To develop efficient control measures against fungal plant pathogens, the dynamics of host plant colonization during disease development and the interactions among fungi within host plant tissues need to be clarified. These studies require accurate quantitative estimation of specific fungal biomass in plant tissues. This has been approached by direct-microscopic methods, cultural methods, chemical determinations of fungal components, serological methods, and molecular methods. Among these methods, serological and molecular methods provide rapid, specific, and sensitive quantitative measures of fungal biomass in host plant tissues. Therefore, studies on fungal dynamics of host plant colonization using these two methods are presented. Some examples of species interactions among pathogenic fungi within host plants, such as synergism and competition, are reviewed and the usefulness of serological and molecular methods for studies on these interactions is presented. These quantitative methods will provide helpful information for understanding the ecology of plant pathogenic fungi, such as the dynamics of host plant colonization and species interactions. Key words: quantitative methods, fungal biomass, ELISA, PCR, fungal colonization, species interaction.

Cuticular disruption and mortality of Caenorhabditis elegans exposed to culture filtrate of Byssochlamys nivea Westling

Nematology ◽  
2001 ◽  
Vol 3 (4) ◽  
pp. 355-363 ◽  
Author(s):  
Ja-On Park ◽  
Krishnapillai Sivasithamparam ◽  
Emile Ghisalberti ◽  
Jaih Hargreaves ◽  
Walter Gams ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Culture Filtrate ◽  
Structural Changes ◽  
Phytophthora Cinnamomi ◽  
Pathogenic Fungi ◽  
Gaeumannomyces Graminis ◽  
Pythium Irregulare ◽  
Potato Dextrose Broth ◽  
C Elegans

AbstractA strain of a Byssochlamys nivea, isolated from saline mud in Western Australia as a part of statewide survey of soil fungi for nematophagous activity, was evaluated for its effect on nematodes. Culture filtrate of the fungus grown on potato dextrose broth for 7 days caused structural changes in the cuticle, aggregation of individuals, and mortality of Caenorhabditis elegans. In addition, the culture filtrate completely inhibited hatching of C. elegans eggs. Exudates from agar colonies also caused cuticular disruption and mortality of C. elegans. The cuticular disruption observed, not reported in nematodes before, was initiated in the labial region and spread towards the posterior region of the nematode within 10 min of application. This reaction occurred only in live nematodes. Cuticular disruption and mortality caused by the culture filtrate varied according to growth conditions. The active compound(s) in the culture filtrate were thermostable (100°C for 1 h); however freezing the culture filtrate (-20°C for 2 days) eliminated the activities, as did dialysis (<14 000 molecular weight). Cuticular disruption and mortality were also observed when the nematode was exposed to culture filtrates of two other strains of B. nivea supplied by CBS, The Netherlands. The culture filtrate also inhibited in vitro growth of the plant-pathogenic fungi Fusarium oxysporum, Gaeumannomyces graminis var. tritici, Phytophthora cinnamomi, Pythium irregulare and Rhizoctonia solani.

scholarly journals Spray-induced gene silencing for disease control is dependent on the efficiency of pathogen RNA uptake

2021 ◽  
Author(s):  
Lulu Qiao ◽  
Chi Lan ◽  
Luca Capriotti ◽  
Audrey Ah-Fong ◽  
Jonatan Nino Sanchez ◽  
...  
Keyword(s):  
Disease Management ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Developmental Stages ◽  
Pathogenic Fungi ◽  
Cell Types ◽  
Uptake Efficiency ◽  
Fungal Plant Pathogens ◽  
Plant Disease Management ◽  
Fungal Genes

AbstractRecent discoveries show that fungi can take up environmental RNA, which can then silence fungal genes through environmental RNA interference. This discovery prompted the development of Spray-Induced Gene Silencing (SIGS) for plant disease management. In this study, we aimed to determine the efficacy of SIGS across a variety of eukaryotic microbes. We first examined the efficiency of RNA uptake in multiple pathogenic and non-pathogenic fungi, and an oomycete pathogen. We observed efficient double-stranded RNA (dsRNA) uptake in the fungal plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani, Aspergillus niger, and Verticillium dahliae, but no uptake in Colletotrichum gloeosporioides, and weak uptake in a beneficial fungus, Trichoderma virens. For the oomycete plant pathogen, Phytophthora infestans, RNA uptake was limited, and varied across different cell types and developmental stages. Topical application of dsRNA targeting virulence-related genes in the pathogens with high RNA uptake efficiency significantly inhibited plant disease symptoms, whereas the application of dsRNA in pathogens with low RNA uptake efficiency did not suppress infection. Our results have revealed that dsRNA uptake efficiencies vary across eukaryotic microbe species and cell types. The success of SIGS for plant disease management can largely be determined by the pathogen RNA uptake efficiency.

scholarly journals Antimicrobial activity of essential oils on pathogenic fungi

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Daniele Aparecida do Couto ◽  
Felipe Da Silva Dias ◽  
Mírian Lobo Sáber
Keyword(s):  
Essential Oils ◽  
Eucalyptus Globulus ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Human Beings ◽  
Cymbopogon Winterianus ◽  
Callistemon Viminalis ◽  
Pathogenic Agents ◽  
Citronella Grass ◽  
Mycelial Development

Since the induction of chemical defensives in agriculture, human beings have suffered from our own actions, caused by the indiscriminate and abusive use of those substances; therefore, researches have been motivated to look for alternative ways, aiming to use plant inputs to control pathogenic agents in agriculture. As the essential oils from the species Eucalyptus globulus (eucalyptus), Callistemon viminalis (weeping bottlebrush), Cymbopogon winterianus (citronella grass) and Tetradeniariparia (misty plume bush) have proved effectiveness and an immense applicability, this research studied the use of those essential oils, aiming the effectiveness against plant pathogens. The plants were collected from Universidade do Vale do Sapucaí, Pouso Alegre (MG). The fungi’s samples belong to the mycology collection from the institution and the tests were based on the mycelial development comparison of the control fungi on the dishes with essential oils. Notice that the inhibition caused by the oils over fungi’s mycelial developing and the analysis of the data have been made through Turkey’s statistic. From the data analyzed, it was possible to realize that the citronella’s grass essential oil was efficient to control the mycelial development of fungi analyzed, followed by, in order of efficiency, the eucalyptus oil, the weeping bottlebrush oil and the misty plume bush oil.

scholarly journals Preliminary Study on the Activity of Phycobiliproteins against Botrytis cinerea

Marine Drugs ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. 600
Author(s):  
Hillary Righini ◽  
Ornella Francioso ◽  
Michele Di Foggia ◽  
Antera Martel Quintana ◽  
Roberta Roberti
Keyword(s):  
Spore Germination ◽  
Plant Pathogens ◽  
Disease Incidence ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Gray Mold ◽  
Fungal Plant Pathogens ◽  
Ft Ir ◽  
Preliminary Study ◽  
Ft Raman

Phycobiliproteins (PBPs) are proteins of cyanobacteria and some algae such as rhodophytes. They have antimicrobial, antiviral, antitumor, antioxidative, and anti-inflammatory activity at the human level, but there is a lack of knowledge on their antifungal activity against plant pathogens. We studied the activity of PBPs extracted from Arthrospiraplatensis and Hydropuntiacornea against Botrytiscinerea, one of the most important worldwide plant-pathogenic fungi. PBPs were characterized by using FT-IR and FT-Raman in order to investigate their structures. Their spectra differed in the relative composition in the amide bands, which were particularly strong in A. platensis. PBP activity was tested on tomato fruits against gray mold disease, fungal growth, and spore germination at different concentrations (0.3, 0.6, 1.2, 2.4, and 4.8 mg/mL). Both PBPs reduced fruit gray mold disease. A linear dose–response relationship was observed for both PBPs against disease incidence and H. cornea against disease severity. Pathogen mycelial growth and spore germination were reduced significantly by both PBPs. In conclusion, PBPs have the potential for being also considered as natural compounds for the control of fungal plant pathogens in sustainable agriculture.

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