scholarly journals Fungal pathogens associated with young grapevine decline in the Southern Turkey vineyards

2019 ◽  
Vol 15 ◽  
pp. 01027 ◽  
Author(s):  
D.S. Akgül ◽  
M. Ahioğlu

Young grapevine decline is a common and important disease caused by fungal plant pathogens in Turkey vineyards. Every year many grape growers face this problem in their vineyards and seek solutions to cope with it. The aims of the study were to examine fungal pathogens of young grapevine decline in Southern Turkey and to determine pathogenicity of fungi involved in the disease. Twenty vineyards (2–3 years-old, located in Adana, Mersin and Gaziantep cities) were surveyed in March 2018 and declining whole plants were sampled and processed for mycological procedures. Sub-cultured fungal colonies were examined for colony morphology and conidia-conidiophore shapes under light microscope. For molecular identification, ITS, beta-tubulin, histone and TEF1-alpha gene regions were amplified with PCR using appropriate primers and PCR products were subsequently sequenced. The sequences were compared with those deposited in the NCBI GenBank database using the BLASTn program and fungal identifications were confirmed by getting accession numbers. Pathogenicity tests were fulfilled under greenhouse conditions for two months. The results indicated that Botryosphaeria Dieback and Black Foot fungi were two most common pathogen groups, while Petri Disease and Diaporthe Dieback pathogens had minor incidence. Although a variety of Fusarium species were isolated from declined vines, only F. brachygibbosum and F. solani were found to have considerable role in disease occurrence.

2008 ◽  
Vol 20 (1) ◽  
pp. 62 ◽  
Author(s):  
M. JALLI ◽  
P. LAITINEN ◽  
S. LATVALA

Fungal plant pathogens causing cereal diseases in Finland have been studied by a literature survey, and a field survey of cereal leaf spot diseases conducted in 2009. Fifty-seven cereal fungal diseases have been identified in Finland. The first available references on different cereal fungal pathogens were published in 1868 and the most recent reports are on the emergence of Ramularia collo-cygni and Fusarium langsethiae in 2001. The incidence of cereal leaf spot diseases has increased during the last 40 years. Based on the field survey done in 2009 in Finland, Pyrenophora teres was present in 86%, Cochliobolus sativus in 90% and Rhynchosporium secalis in 52% of the investigated barley fields. Mycosphaerella graminicola was identified for the first time in Finnish spring wheat fields, being present in 6% of the studied fields. Stagonospora nodorum was present in 98% and Pyrenophora tritici-repentis in 94% of spring wheat fields. Oat fields had the fewest fungal diseases. Pyrenophora chaetomioides was present in 63% and Cochliobolus sativus in 25% of the oat fields studied.;


2000 ◽  
Vol 6 (S2) ◽  
pp. 680-681 ◽  
Author(s):  
T. M. Bourett ◽  
K. J. Czymmek ◽  
T. M. Dezwaan ◽  
J. A. Sweigard ◽  
R. J. Howard

Specific gene products of both pathogens and hosts have been implicated as decisive elements during plant pathogenesis. While expression of some of these genes is constitutive, that of others is likely ephemeral and activated only during a particular stage of the interaction. Because the relative timing of expression may be critical, transcription and translation have often been addressed by extracting mRNA and proteins from infected plant tissue. This approach, however, cannot readily detect proteins of low abundance in bulk samples nor offer much useful information on cell-cell interaction. Only a cytological analysis that employs microscopy can resolve the temporal and spatial details of gene expression. Typically, such protein localization studies have required specific antibodies, but these large probe molecules do not diffuse into living or conventionally fixed cells of either fungal pathogens or plant hosts. For TEM analysis, these permeability-imposed limitations have been reduced by thin sectioning to render accessible antibody binding sites.


2006 ◽  
Vol 19 (3) ◽  
pp. 270-279 ◽  
Author(s):  
Chiyumi Shimada ◽  
Volker Lipka ◽  
Richard O'Connell ◽  
Tetsuro Okuno ◽  
Paul Schulze-Lefert ◽  
...  

Pathogenesis of nonadapted fungal pathogens is often terminated coincident with their attempted penetration into epidermal cells of nonhost plants. The genus Colletotrichum represents an economically important group of fungal plant pathogens that are amenable to molecular genetic analysis. Here, we investigated interactions between Arabidopsis and Colletotrichum to gain insights in plant and pathogen processes activating nonhost resistance responses. Three tested nonadapted Colletotrichum species differentiated melanized appressoria on Arabidopsis leaves but failed to form intracellular hyphae. Plant cells responded to Colletotrichum invasion attempts by the formation of PMR4/GSL5-dependent papillary callose. Appressorium differentiation and melanization were insufficient to trigger this localized plant cell response, but analysis of nonpathogenic C. lagenarium mutants implicates penetration-peg formation as the inductive cue. We show that Arabidopsis PEN1 syntaxin controls timely accumulation of papillary callose but is functionally dispensable for effective preinvasion (penetration) resistance in nonhost interactions. Consistent with this observation, green fluorescent protein-tagged PEN1 did not accumulate at sites of attempted penetration by either adapted or nonadapted Colletotrichum species, in contrast to the pronounced focal accumulations of PEN1 associated with entry of powdery mildews. We observed extensive reorganization of actin microfilaments leading to polar orientation of large actin bundles towards appressorial contact sites in interactions with the nonadapted Colletotrichum species. Pharmacological inhibition of actin filament function indicates a functional contribution of the actin cytoskeleton for both preinvasion resistance and papillary callose formation. Interestingly, the incidence of papilla formation at entry sites was greatly reduced in interactions with C. higginsianum isolates, indicating that this adapted pathogen may suppress preinvasion resistance at the cell periphery.


1998 ◽  
Vol 11 (3) ◽  
pp. 218-227 ◽  
Author(s):  
Laura Cavallarin ◽  
David Andreu ◽  
Blanca San Segundo

Cecropins are naturally occurring peptides that play an important role in the immune response of insects. Cecropin A-derived and cecropin A-melittin hybrid peptides, all smaller than the natural compound cecropin A, were synthesized and tested for their ability to inhibit growth of several agronomically important fungal pathogens. We found that an 11-amino-acid sequence, corresponding to the N-terminal amphipathic α-helix domain of cecropin A, exhibited antifungal activity. Differences in susceptibility of the various pathogens were observed, Phytophthora infestans being particularly sensitive to the shortened cecropin A peptides (IC50 = 2 × 10−6 M). Biotoxicity of the shortest cecropin A-derived peptide was variously affected by the presence of proteins extracted from leaves of tobacco and tomato plants, either total extracts or intercellular fluids (ICFs). Overall, there was a greater tolerance to tomato protein extracts than to tobacco extracts. These findings suggest that tobacco should not be used as a model for testing the possible protective effects of transgenically expressed, cecropin-based genes. The feasibility of tailoring cecropin A genes to enhance crop protection in particular plant/fungus combinations is discussed.


2010 ◽  
Vol 37 (10) ◽  
pp. 901 ◽  
Author(s):  
Ann-Maree Catanzariti ◽  
David A. Jones

An understanding of the molecular mechanisms that plant pathogens use to successfully colonise host tissue can be gained by studying the biological activity of pathogen proteins secreted during infection. Several secreted ‘effector’ proteins with possible roles in virulence have been isolated from extracellular fungal pathogens, including three that have been shown to negate host defences. In most cases, significant effector variation is observed between different pathogen isolates, driven by the recognitional capacity of disease resistance proteins arrayed against the pathogen by the host plant. This review summarises what is known about the expression, function and variation of effectors isolated from extracellular fungal pathogens.


2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Yan Ramona ◽  
IDA BAGUS GEDE DARMAYASA ◽  
ANAK AGUNG NGURAH NARA KUSUMA ◽  
Martin Line

Abstract. Ramona Y, Darmayasa IBG, Kusuma AANN, Line MA. 2021. Diversity of biocontrol agents, isolated from several sources, inhibitory to several fungal plant pathogens. Biodiversitas 22: 298-303. This study investigated the inhibitory potential of diversity of antagonist bacteria residing in the rhizosphere zone and mature compost to counter fungal plant pathogens. Soils collected from rhizosphere of lettuce farms in Bali-Indonesia and Tasmania-Australia, mature compost, commercial biocontrol (Dipel®), and laboratory contaminants with significant inhibition against tested fungal pathogens were used as sources of antagonist bacteria. These antagonists were isolated by applying dilution and spread method on trypticase soya agar (TSA) or potato dextrose agar (PDA), and their ability to inhibit Sclerotinia minor, Sclerotinia sclerotiorum, Fusarium spp., and Rhizoctonia solani was assessed in dual culture assays. The results showed that 67 out of more than 100 isolates had antagonistic activity in vitro against at least one of tested fungal pathogens. In the preliminary identification, Bacillus spp. or Pseudomonas spp. were found to be pre-dominant isolates. Following screening studies in a non-replicated glasshouse experiment against S. minor and S. sclerotiorum, 8 of the most promising isolates were further identified using molecular methods based on their 16s rDNA sequences aligned with those deposited at the GeneBank. These 8 isolates were identified as Pseudomonas corrugata, Bacillus megaterium, Bacillus polymyxa, Bacillus mojavensis, Bacillus pumilus, Bacillus thuringiensis, Exiguobacterium acetylicum, and Chryseobacterium indologenes.


2019 ◽  
Author(s):  
Mark Angelo O. Balendres ◽  
Fe M. Dela Cueva

AbstractCymbopogon species are among the most reported essential oils with fungitoxic effect. In this study, mycelial growth of Fusarium oxysporum (banana wilt), Colletotrichum gloeosporioides (mango anthracnose), C. falcatum (sugarcane red rot) and Neopestalotiopsis spp. (mango leaf spot) as influenced by varying concentrations of citronella essential oil (CEO) was assessed in in vitro assays. Following growth inhibition test, spore germination and germ tube elongation of C. gloeosporioides were then examined. Mycelial growth of all test fungal pathogens was strongly inhibited by CEO, but variations were observed among fungal species. This growth inhibition activity was caused by the inhibition of spore germination and germ tube elongation as observed in C. gloeosporioides. The findings of this study show the strong growth-inhibitory activity of CEO to multiple fungal pathogens, indicating CEO’s potential as a chemical control approach against these fungal pathogens. Glasshouse and field experiments would establish CEO as one potential alternative to fungicides.


2021 ◽  
Author(s):  
Frédéric Suffert ◽  
Muriel Suffert

AbstractThe experience presented here relates to 2020, a particularly timely year for plant disease-related communication (‘International Year of Plant Health’ IYPH2020), but also a unique year because of the COVID-19 pandemic. Our goal was to illustrate the diversity and beauty of fungal plant pathogens through a naturalist approach that could be followed by any amateur. We achieved this end through ‘phytopathological strolls’, in which we observed and determined the origin of symptoms on diseased plants found in our garden, in the local streets, in nearby open spaces, and sharing this matter with a broad public. The lockdown imposed in France created an additional motivation to take up the challenge, and to involve our children, even under strong constraints, such as movement restrictions. We observed and described fungal pathogens through hundreds of photographs, shared our findings with a large audience on Twitter, and received feedback. The material used was deliberately simple and transportable: a digital reflex camera, an old microscope, a mobile phone, some books and an Internet connexion. Between March 17 March and December 15, 2020 we found 148 plant pathogens, including 72 rusts, 22 powdery mildews and 22 septoria-like diseases. We discuss here the importance of promoting searches for plant pathogens, their description and conservation, through a combination of classical approaches and digital tools in tune with the times, such as Twitter, by treating pathogen identification like a detective game and, more surprisingly, by making use of the addictive nature of collection approaches, drawing a parallel with Pokémon Go.


OENO One ◽  
2013 ◽  
Vol 47 (2) ◽  
pp. 73 ◽  
Author(s):  
Pablo García Benavides ◽  
Pedro Martin Zamorano ◽  
Carlos Alvar Ocete ◽  
Lara Maistrello ◽  
Rafael Ocete

<p style="text-align: justify;"><strong>Aim</strong>: Grapevine decline caused by wood fungi seriously threatens viticulture worldwide. In Spain, the polyphagous borer <em>Xylotrechus</em> <em>arvicola</em> (Coleoptera, Cerambycidae) is becoming a serious pest in different Qualified Designation of Origin (DOC) wine regions. The aim of the present work was to identify the fungal species growing in the galleries excavated by <em>X. arvicola</em> larvae inside the vine branches and investigate the possible relationship between wood pathogenic fungi and this borer.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Wood samples from branches of Tempranillo vines and <em>Prunus pisardi</em> trees affected by the borer <em>X. arvicola</em> were collected in La Rioja DOC vineyards (Northern Spain) and analyzed for the presence of fungi using both morphological techniques and genetic tools based on Internal Transcribed Spacer 2 (ITS2) sequence. Among the 20 different fungal species/isolates identified, 7 belonged to fungi associated with grapevine decline (esca, Petri disease, and <em>Eutypa</em> dieback), 6 were plant pathogens, 6 were saprophytic and one was entomopathogenic (<em>Beauveria bassiana</em>).</p><p style="text-align: justify;"><strong>Conclusion</strong>: The fact that 65 % of the fungi detected inside <em>X. arvicola</em> galleries belong to species recognized as plant pathogens suggests that this borer, in addition to causing a progressive decay of the branches, could facilitate the transmission of plant diseases, further threatening the vineyards by spreading grapevine decline pathogens.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The present work represents a first step in recognizing the association between the fungal pathogens associated with grapevine decline and the borer <em>X. arvicola</em>, suggesting a possible role of this insect as a vector in the transmission of these fungi.</p>


2003 ◽  
Vol 83 (Special Issue) ◽  
pp. 331-336 ◽  
Author(s):  
R. D. Reeleder

The role of biodiversity as it affects the control of soil-borne fungal pathogens is discussed. Soil-borne fungal plant pathogens have often proven difficult to manage with conventional methods of disease control. Nonetheless, researchers have characterized several naturally occurring “disease-suppressive” soils where crop loss from disease is less than would otherwise be expected. Suppressive soils can also result from the incorporation of various amendments into soil. In most cases, disease control in such soils has been shown to be biological in nature; that is, soil organisms appear to directly or indirectly inhibit the development of disease. Increased knowledge of the identity and functioning of these organisms may support the development of techniques that can be used to develop suppressiveness in soils that are otherwise disease-conducive. Populations of pathogens themselves have been shown to exhibit considerable genetic diversity; the ability of populations to respond to disease control measures should be considered when developing a management strategy. New molecular techniques can be exploited to better characterize soil communities, including the pathogens themselves, as well as community responses to various disease control options. The contributions of Canadian researchers to these areas are discussed and models for further study are proposed. Key words: Biocontrol, molecular technologies, functional diversity, integrated pest management


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