scholarly journals Phytopathogenic species of fungi and fungal-like organisms identified in plant samples delivered to the Plant Disease Clinic in 2018–2020

2021 ◽  
Vol 61 (3) ◽  
Keyword(s):  
Host Plants ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Ornamental Plants ◽  
Single Species ◽  
Plant Diseases ◽  
Effective Management ◽  
Fusarium Spp ◽  
Molecular Tests ◽  
Disease Clinic

One of the conditions for effective management of farm is an access to quick diagnostics of plant pathogens in order to reduce the occurrence of plant diseases. The Plant Diseases Clinic receives samples of infected plants supplied by growers and gardeners from all over Poland. In the years 2018–2020, a total of 274 samples were tested at the Clinic for the presence of fungi and fungal-like organisms pathogenic for plants. The tests were carried out using the microscopic method, and in case of doubt, the result was confirmed by molecular tests. The most frequently studied plant was tomato (26%), followed by strawberry (9%), cucumber (5%) and tobacco, sugar beet, onion, blueberry, raspberry, lettuce, cauliflower and potato. Conifers were also a large group, such as: thujas, cypresses and pines; a total of 17 host plants. Single species of ornamental plants were very numerous, e.g. gerbera, anthurium, aster, geranium, phlox, chrysanthemum and others. The fungi of the genus Fusarium spp. constituted about 38% of infections. This was followed by Alternaria spp. (26%), Botrytis cinerea (11%) and Cladosporium sp. (10%). The remaining diseases were caused by Pythium sp., Rhizoctonia sp., Colletotrichum sp., Ulocladium sp., Pestalotia sp. and Phytophthora sp. In recent years, the greatest threat to tomatoes and strawberries has been the fungi of the Fusarium genus, and the pathogens of the Pythium genus to cucumbers.

scholarly journals Microbial antagonists against plant pathogens in Iran: A review

2020 ◽  
Vol 5 (1) ◽  
pp. 404-440 ◽  
Author(s):  
Mehrdad Alizadeh ◽  
Yalda Vasebi ◽  
Naser Safaie
Keyword(s):  
Biological Control ◽  
Chemical Control ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Agricultural Products ◽  
Control Measures ◽  
Wide Range ◽  
Plant Disease Management ◽  
Published Research

AbstractThe purpose of this article was to give a comprehensive review of the published research works on biological control of different fungal, bacterial, and nematode plant diseases in Iran from 1992 to 2018. Plant pathogens cause economical loss in many agricultural products in Iran. In an attempt to prevent these serious losses, chemical control measures have usually been applied to reduce diseases in farms, gardens, and greenhouses. In recent decades, using the biological control against plant diseases has been considered as a beneficial and alternative method to chemical control due to its potential in integrated plant disease management as well as the increasing yield in an eco-friendly manner. Based on the reported studies, various species of Trichoderma, Pseudomonas, and Bacillus were the most common biocontrol agents with the ability to control the wide range of plant pathogens in Iran from lab to the greenhouse and field conditions.

scholarly journals Biochar and Trichoderma spp. in management of plant diseases caused by soilborne fungal pathogens: a review and perspective

2021 ◽  
Vol 10 (15) ◽  
pp. e296101522465
Author(s):  
Erika Valente de Medeiros ◽  
Lucas Figueira da Silva ◽  
Jenifer Sthephanie Araújo da Silva ◽  
Diogo Paes da Costa ◽  
Carlos Alberto Fragoso de Souza ◽  
...  
Keyword(s):  
Soil Properties ◽  
Fungal Pathogens ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Management Tool ◽  
Production Plant ◽  
Trichoderma Spp ◽  
Health Concept ◽  
Plant Disease Management

A better understanding of the use of biochar with Trichoderma spp. (TRI), considered the most studied tool for biological control, would increase our ability to set priorities. However, no studies exist using the two inputs on plant disease management. Here, we hypothesized that biochar and TRI would be used for the management of soilborne plant pathogens, mainly due to changes in soil properties and its interactions. To test this hypothesis, this review assesses papers that used biochar and TRI against plant diseases and we summarize the handling mechanisms for each input. Biochar acts by mechanisms: induction to plant resistance, sorption of allelopathic and fungitoxic compounds, increase of beneficial microorganisms, changes the soil properties that promote health and nutrient availability. Trichoderma as biocontrol agents by different mechanisms: mycoparasitism, enzyme and secondary metabolic production, plant promoter agent, natural decomposition agent, and biological agent of bioremediation. Overall, our findings expand our knowledge about the reuse of wastes transformed in biochar combined with Trichoderma has potential perspective to formulate products as alternative management tool of plant disease caused by soilborne fungal pathogen and add important information that can be suitable for development of strategy for use in the global health concept.

Morphological and molecular based identification of Antifungal bacillus licheniformis

2017 ◽  
Vol 17 (1) ◽  
pp. 31-35
Author(s):  
B Oyuntogtokh ◽  
M Byambasuren
Keyword(s):  
Bacillus Licheniformis ◽  
Fungal Pathogens ◽  
Crop Production ◽  
Plant Pathogens ◽  
Control Plant ◽  
Plant Diseases ◽  
Bacillus Species ◽  
Bacterial Strains ◽  
Fusarium Spp ◽  
Bacterial Cultures

At present, plant diseases caused by soil borne plant pathogens have major constraints on crop production. Which include genera Fusarium spp, Phytophtora spp, Sclerotinia and Altenaria. Due to this reason, chemical fungicides are routinely used to control plant disease, which is also true in Mongolian case. However, use of these chemicals has caused various problems including environmental pollution with consequence of toxicity to human health also resistance of some pathogens to these fungicides are present. Fortunately, an alternative method to reduce the effect of these plant pathogens is the use of antagonist microorganisms. Therefore, some species of the genus Bacillus are recognized as one of the most effective biological control agent.Our research was focused to isolate Bacillus licheniformis, with antifungal potential, from indigenous sources. In the current study, 28 bacterial cultures were isolated from soil and fermented mare’s milk also named as koumiss. Isolated bacterial cultures were identified according to simplified key for the tentative identification of typical strain of Bacillus species. As a result 8 strains were positive and further screened for antifungal activity against Fusarium spp and Alternaria solani. Out of these 8 strains 5 strains are selected based on their high effectiveness against fungal pathogens and for further confirmation Polymerase Chain reaction run for effective bacterial strains using specific primers B.Lich-f and B.Lich-r. 

scholarly journals Natural Plant Products as Eco-friendly Fungicides for Plant Diseases Control- A Review

2016 ◽  
Vol 14 (1) ◽  
pp. 134-141 ◽  
Author(s):  
M Zaker
Keyword(s):  
Plant Disease ◽  
Plant Pathogens ◽  
Chemical Compounds ◽  
Plant Diseases ◽  
Agricultural Products ◽  
Higher Plant ◽  
Natural Plant ◽  
Plant Products ◽  
Near Future ◽  
Chemical Pesticides

The use of chemical pesticides for controlling various plant diseases is still a common practice especially in developing countries. Although with the application of chemical fungicides, plant diseases can be controlled but the hazardous impacts of such products in human health and environment are well known. Moreover, with their excess applications pest resistance may exist. Natural plant products have been found effective in plant disease managements and could be safely incorporated as suitable alternatives for synthetic fungicides. It is estimated that there are more than 250,000 higher plant species on earth that can be evaluated for their antimicrobial bioactive chemical compounds. During last several decades researchers have evaluated plant extracts and oils against plant pathogens, valuable results have been achieved and some commercially botanical formulations have been prepared and marketed. If we are supposed to move toward production of safer agricultural products, more attention and effort are still needed for production of more commercially botanical fungicides in the near future. The organic agriculture cannot rely on a limited number of commercially pesticides of natural origin, therefore it seems that more researches in formulating more commercially botanical products as fungicides are still needed.The Agriculturists 2016; 14(1) 134-141

scholarly journals Selection of antagonists for biocontrol of Xanthomonas euvesicatoria

2020 ◽  
pp. 181-189
Author(s):  
Ivana Pajcin ◽  
Vanja Vlajkov ◽  
Dragoljub Cvetkovic ◽  
Maja Ignjatov ◽  
Mila Grahovac ◽  
...  
Keyword(s):  
Biological Control ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Bacterial Spot ◽  
Cultivation Medium ◽  
Microbial Strains ◽  
Xanthomonas Euvesicatoria ◽  
Selection Of

Xanthomonas euvesicatoria is a worldwide causer of pepper bacterial spot, a bacterial plant disease responsible for massive losses of fresh pepper fruits. Considering the current problems in management of bacterial plant diseases, biological control using antagonistic microbial strains with high potential for plant pathogens suppression emerges as a possible solution. The aim of this study was to select suitable antagonists for suppression of X. euvesicatoria among the bacteria, yeast and fungi from the genera Pseudomonas, Lactobacillus, Saccharomyces and Trichoderma, based on in vitro antimicrobial activity testing using the diffusion disc method. The results of this study have revealed that cultivation broth samples of the antagonists Lactobacillus MK3 and Trichoderma reseii QM 9414, as well as supernatant samples of the antagonist Pseudomonas aeruginosa I128, have showed significant potential to be applied in biological control of X. euvesicatoria. Further research would be required to formulate suitable cultivation medium and optimize bioprocess conditions for production of the proposed pepper bacterial spot biocontrol agents.

scholarly journals First report of Fusarium commune causing root and crown rot on maize in Italy

Plant Disease ◽  
2021 ◽  
Author(s):  
Monica Mezzalama ◽  
Vladimiro Guarnaccia ◽  
Ilaria Martino ◽  
Giulia Tabome ◽  
Maria Lodovica GULLINO
Keyword(s):  
Plant Disease ◽  
Tap Water ◽  
Morphological Characteristics ◽  
Plant Diseases ◽  
Crown Rot ◽  
Conidial Suspension ◽  
Fusarium Spp ◽  
First Report ◽  
Root And Crown Rot ◽  
Pathogenicity Tests

Maize (Zea mays L.) is a cereal crop of great economic importance in Italy; production is currently of 62,587,469 t, with an area that covers 628,801 ha, concentrated in northern Italy (ISTAT 2020). Fusarium species are associated with root and crown rot causing failures in crop establishment under high soil moisture. In 2019 maize seedlings collected in a farm located in San Zenone degli Ezzelini (VI, Italy) showed root and crown rot symptoms with browning of the stem tissues, wilting of the seedling, and collapsing due to the rotting tissues at the base of the stem. The incidence of diseased plants was approximately 15%. Seedlings were cleaned thoroughly from soil residues under tap water. Portions (about 3-5 mm) of tissue from roots and crowns of the diseased plants were cut and surface disinfected with a water solution of NaClO at 0.5% for 2 minutes and rinsed in sterile H20. The tissue fragments were plated on Potato Dextrose Agar (PDA) amended with 50 mg/l of streptomycin sulfate and incubated for 48-72 hours at 25oC. Over the 80 tissue fragments plated, 5% were identified as Fusarium verticillioides, 60% as Fusarium spp., 35% developed saprophytes. Fusarium spp. isolates that showed morphological characteristics not belonging to known pathogenic species on maize were selected and used for further investigation while species belonging to F. oxysporum were discarded. Single conidia of the Fusarium spp. colonies were cultured on PDA and Carnation Leaf Agar (CLA) for pathogenicity tests, morphological and molecular identification. The colonies showed white to pink, abundant, densely floccose to fluffy aerial mycelium. Colony reverse showed light violet pigmentation, in rings on PDA. On CLA the isolates produced slightly curved macronidia with 3 septa 28.1 - 65.5 µm long and 2.8-6.3 µm wide (n=50). Microconidia were cylindrical, aseptate, 4.5 -14.0 µm long and 1.5-3.9 µm wide (n=50). Spherical clamydospores were 8.8 ± 2.5 µm size (n=30), produced singly or in pairs on the mycelium, according to the description by Skovgaard et al. (2003) for F. commune. The identity of two single-conidia strains was confirmed by sequence comparison of the translation elongation factor-1α (tef-1α), and RNA polymerase II subunit (rpb2) gene fragments (O’Donnell et al. 2010). BLASTn searches of GenBank, and Fusarium-ID database, using the partial tef-1α (MW419921, MW419922) and rpb2 (MW419923, MW419924) sequences of representative isolate DB19lug07 and DB19lug20, revealed 99% identity for tef-1α and 100% identity to F. commune NRRL 28387(AF246832, AF250560). Pathogenicity tests were carried out by suspending conidia from a 10-days old culture on PDA in sterile H2O to 5×104 CFU/ml. Fifty seeds were immersed in 50 ml of the conidial suspension of each isolate for 24 hours and in sterile water (Koch et al. 2020). The seeds were drained, dried at room temperature, and sown in trays filled with a steamed mix of white peat and perlite, 80:20 v/v, and maintained at 25°C and RH of 80-85% for 14 days with 12 hours photoperiod. Seedlings were extracted from the substrate, washed under tap water, and observed for the presence of root and crown rots like the symptoms observed on the seedlings collected in the field. Control seedlings were healthy and F. commune was reisolated from the symptomatic ones and identified by resequencing of tef-1α gene. F. commune has been already reported on maize (Xi et al. 2019) and other plant species, like soybean (Ellis et al. 2013), sugarcane (Wang et al. 2018), potato (Osawa et al. 2020), indicating that some attention must be paid in crop rotation and residue management strategies. To our knowledge this is the first report of F. commune as a pathogen of maize in Italy. References Ellis M L et al. 2013. Plant Disease, 97, doi: 10.1094/PDIS-07-12-0644-PDN. ISTAT. 2020. http://dati.istat.it/Index.aspx?QueryId=33702. Accessed December 28, 2020. Koch, E. et al. 2020. Journal of Plant Diseases and Protection. 127, 883–893 doi: 10.1007/s41348-020-00350-w O’Donnell K et al. 2010. J. Clin. Microbiol. 48:3708. https://doi.org/10.1128/JCM.00989-10 Osawa H et al. 2020. Journal of General Plant Pathology, doi.org/10.1007/s10327-020-00969-5. Skovgaard K 2003. Mycologia, 95:4, 630-636, DOI: 10.1080/15572536.2004.11833067. Wang J et al. 2018. Plant Disease, 102, doi/10.1094/PDIS-07-17-1011-PDN Xi K et al. 2019. Plant Disease, 103, doi/10.1094/PDIS-09-18-1674-PDN

scholarly journals RNA interference approaches for plant disease control

BioTechniques ◽  
2020 ◽  
Vol 69 (6) ◽  
pp. 469-477
Author(s):  
Yen-Wen Kuo ◽  
Bryce W Falk
Keyword(s):  
Rna Interference ◽  
Disease Control ◽  
Crop Production ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Control Plant ◽  
Cost Effective ◽  
Plant Diseases ◽  
Natural Ecosystems ◽  
Plant Disease Control

Plant diseases caused by a variety of pathogens can have severe effects on crop plants and even plants in natural ecosystems. Despite many effective conventional approaches to control plant diseases, new, efficacious, environmentally sound and cost-effective approaches are needed, particularly with our increasing human population and the effects on crop production and plant health caused by climate change. RNA interference (RNAi) is a gene regulation and antiviral response mechanism in eukaryotes; transgenic and non transgenic plant-based RNAi approaches have shown great effectiveness and potential to target specific plant pathogens and help control plant diseases, especially when no alternatives are available. Here we discuss ways in which RNAi has been used against different plant pathogens, and some new potential applications for plant disease control.

The aerial dispersal of the pathogens of plant disease

1983 ◽  
Vol 302 (1111) ◽  
pp. 451-462 ◽  
Keyword(s):  
Life Cycle ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Random Distribution ◽  
Weak Link ◽  
Plant Diseases ◽  
Classic Model ◽  
Aerial Dispersal

The classic model, the logistic, often fits the course of an epidemic of plant disease although the assumptions of propagules proportional to infected plants and random distribution of the propagules are violated. When a thorough simulation of the life cycle of a pathogen is composed, knowledge of its dissemination is the weak link. Although some plant diseases are caused by bacteria and viruses, some pathogens are not airborne and some plants grow indoors; plant pathogens are distinguished by the prevalence of fungi and the durability of their propagules; their hosts are usually exposed outdoors; the pathogens are unaided in their take-off by coughing or sneezing and their landing by breathing; and they are not carried by perambulating hosts. Thus investigations and models of dissemination of plant pathogens concentrate on ways in which spores can be detached and become airborne, on hardiness and relatively long flight and on settling or impacting on foliage outdoors.

scholarly journals Meta-Learning for Few-Shot Plant Disease Detection

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2441
Author(s):  
Liangzhe Chen ◽  
Xiaohui Cui ◽  
Wei Li
Keyword(s):  
Neural Networks ◽  
Crop Production ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Feature Matching ◽  
Apple Scab ◽  
Plant Diseases ◽  
Deep Impact ◽  
Meta Learning ◽  
Adaptive Processes

Plant diseases can harm crop growth, and the crop production has a deep impact on food. Although the existing works adopt Convolutional Neural Networks (CNNs) to detect plant diseases such as Apple Scab and Squash Powdery mildew, those methods have limitations as they rely on a large amount of manually labeled data. Collecting enough labeled data is not often the case in practice because: plant pathogens are variable and farm environments make collecting data difficulty. Methods based on deep learning suffer from low accuracy and confidence when facing few-shot samples. In this paper, we propose local feature matching conditional neural adaptive processes (LFM-CNAPS) based on meta-learning that aims at detecting plant diseases of unseen categories with only a few annotated examples, and visualize input regions that are ‘important’ for predictions. To train our network, we contribute Miniplantdisease-Dataset that contains 26 plant species and 60 plant diseases. Comprehensive experiments demonstrate that our proposed LFM-CNAPS method outperforms the existing methods.

scholarly journals Structural requirements of the phytoplasma effector protein SAP54 for causing homeotic transformation of floral organs

2019 ◽  
Author(s):  
Marc-Benjamin Aurin ◽  
Michael Haupt ◽  
Matthias Görlach ◽  
Florian Rümpler ◽  
Günter Theißen
Keyword(s):  
Plant Pathogens ◽  
Ornamental Plants ◽  
Effector Proteins ◽  
Plant Diseases ◽  
Scattering Data ◽  
Effector Protein ◽  
Homeotic Transformation ◽  
Structural Requirements ◽  
Floral Organs ◽  
Floral Homeotic

SummaryPhytoplasmas are intracellular bacterial plant pathogens that cause devastating diseases in crops and ornamental plants by the secretion of effector proteins. One of these effector proteins, termed SECRETED ASTER YELLOWS-WITCHES’ BROOM PROTEIN 54 (SAP54), leads to the degradation of a specific subset of floral homeotic proteins of the MIKC-type MADS-domain family via the ubiquitin-proteasome pathway. In consequence, the developing flowers show the homeotic transformation of floral organs into vegetative leaf-like structures. The molecular mechanism of SAP54 action involves physical binding to the keratin-like K-domain of MIKC-type proteins, and to some RAD23 proteins, which translocate ubiquitylated substrates to the proteasome. The structural requirements and specificity of SAP54 function are poorly understood, however. Here we report, based on biophysical and molecular biological analyses, that SAP54 folds into α-helical structures. We also show that the insertion of helix-breaking mutations disrupts correct folding of SAP54, which interferes with the ability of SAP54 to bind to its target proteins and to cause disease phenotypes in vivo. Surprisingly, dynamic light scattering data together with electrophoretic mobility shift assays suggest that SAP54 preferentially binds to multimeric complexes of MIKC-type proteins rather than to dimers or monomers of these proteins. Together with literature data this finding suggests that MIKC-type proteins and SAP54 constitute multimeric α-helical coiled-coils, possibly also involving other partners such as RAD23 proteins. Our investigations clarify the structure-function relationship of an important phytoplasma effector protein and thus may ultimately help to develop treatments against some devastating plant diseases.SIGNIFICANCE STATEMENTPhytoplasmas are bacterial plant pathogens that cause devastating diseases in crops and ornamental plants by the secretion of effector proteins such as SAP54, which leads to the degradation of some floral homeotic proteins. Our study clarifies the structural requirements of SAP54 function and illuminates the molecular mode of interaction and thus may ultimately help to develop treatments against some devastating plant diseases.

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