scholarly journals The Occurrence of Charcoal Disease Caused by Biscogniauxia mediterranea on Chestnut-Leaved Oak (Quercus castaneifolia) in the Golestan Forests of Iran

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 876-876 ◽  
Author(s):  
M. Mirabolfathy ◽  
J. Z. Groenewald ◽  
P. W. Crous
Keyword(s):  
Current Knowledge ◽  
Morphological Characteristics ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Northern Iran ◽  
New Host ◽  
Oak Trees ◽  
Mycelial Plug ◽  
Decline Disease ◽  
Charcoal Disease

The chestnut-leaved oak (Quercus castaneifolia) is native to the Alborz Mountains, including the Golestan Forests, in northern Iran. Trees grow up to 35 (-50) m tall with a trunk up to 2.5 (-3.5) m in diameter. During 2010, we received reports of a decline of oak trees in the Ghorogh Region of the Golestan Forests. The decline began with discolorations and browning of the leaves, resulting in drying of the foliage. Viscous liquid exudates were observed on the trunks, resulting in a brown-black discoloration of phloem and bark. In January 2011, all infected trees were dead and exhibited symptoms of charcoal disease with carbonaceous, perithecial stromata erupting from the bark on stems. Perithecia were obovoid, containing short-stipitate, amyloid asci with dark brown, ellipsoid ascospores, 14 to 19 × 7 to 9 μm, with straight germ slits along the spore length. On the basis of these morphological characteristics, the fungus was identified as Biscogniauxia mediterranea. Blast searches of the NCBI GenBank nucleotide database were done using ITS sequences derived from three cultures (CBS 129072 to 129074). GenBank Accession Nos. JF295127 to JF295129 of the isolated fungus differed by one nucleotide from B. mediterranea (GenBank Accession No. AF280624) (1,3). Pathogenicity tests were conducted using an isolate of B. mediterranea under greenhouse conditions. Six-month-old Q. castaneifolia seedlings were inoculated by means of stem wounds with a mycelial plug of colonized potato dextrose agar. After 6 months, typical decline disease symptoms associated with charcoal disease were observed and the same fungus was reisolated. Perithecia were observed on the surface of black carbonaceous stromata, which usually developed on stems of inoculated plants. The decline is known as charcoal disease because fungal growth induces a typical charcoal-black surface on diseased branches and trunks. The pathogen can easily spread through large cavity vessels, colonize bark and woody tissues, and is able to kill the host in a single, growing season. B. mediterranea causes necrosis on stems and branches of Quercus spp., including Q. suber, Q. cerris, Q. frainetto, Q. pubescens (4), Q. alba, Q. ilex, Q. imbricaria, Q. lusitanica, Q. palustris, and Q. pyrenaica (2) in Europe, North America, Africa, New Zealand, and Asia (China and India). On the basis of our current knowledge, Q. castaneifolia represents a new host of B. mediterranea, and this is the first report of this fungal pathogen from Iran causing charcoal disease on Q. castaneifolia trees in the Golestan Forest. Given its new introduction into Iran, it is highly likely that it will spread to species of Fagus, Zelkova, and other woody hosts in the area. References: (1) J. Collado et al. Mycologia 93:875, 2001. (2) D. L. Hawksworth. No. 359. Description of Pathogenic Fungi and Bacteria. CMI, Kew, UK, 1972. (3) A. Mazzaglia et al. Mycol. Res. 105:952, 2001. (4) A. Vannini and G. Scarascia Mugnozza. Eur. J. For. Pathol. 21:193, 1991.

scholarly journals Investigation of oak tree decline in the Auckland region

2007 ◽  
Vol 60 ◽  
pp. 297-303
Author(s):  
M. Braithwaite ◽  
C. Inglis ◽  
M.A. Dick ◽  
T.D. Ramsfield ◽  
N.W. Waipara ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Molecular Techniques ◽  
Tree Decline ◽  
New Host ◽  
Disease Symptoms ◽  
Oak Trees ◽  
Oak Tree ◽  
Intensive Investigation ◽  
Biochemical Testing ◽  
Branch Dieback

Concern about the poor health of oak trees in Auckland was raised in 2001 An intensive investigation of oak trees showing symptoms of decline (twig and branch dieback epicormic growth trunk cankers bark loss and tree death) was conducted in the Auckland area during 2006 Disease symptoms on trees at 13 sites were documented and samples of leaves stems trunks roots and soil collected Soil samples were tested for the presence of soilborne fungi using baiting techniques Fungi and bacteria from plant tissues and soil were identified using either morphological characteristics biochemical testing or molecular techniques The investigation resulted in a range of fungi and bacteria being identified One fungus new to New Zealand was detected and several new host associations observed No particular organism was implicated as the cause of the oak decline but several fungi and bacteria were likely contributors to the tree decline and death in Auckland

Nitric oxide signalling in plant interactions with pathogenic fungi and oomycetes

2020 ◽  
Author(s):  
Tereza Jedelská ◽  
Lenka Luhová ◽  
Marek Petřivalský
Keyword(s):  
Nitric Oxide ◽  
Current Knowledge ◽  
Biotic Interactions ◽  
Decisive Role ◽  
Pathogenic Fungi ◽  
Plant Colonization ◽  
No Production ◽  
Plant Interactions ◽  
Oriented Growth ◽  
Plant Pathogen Interactions

Abstract Nitric oxide (NO) and reactive nitrogen species have emerged as crucial signalling and regulatory molecules across all organisms. In plants, fungi and fungi-like oomycetes, NO is involved in the regulation of multiple processes during their growth, development, reproduction, responses to the external environment and biotic interactions. It has become evident that NO is produced and used as signalling and defence cues by both partners in multiple forms of plant interactions with their microbial counterparts, ranging from symbiotic to pathogenic modes. This review summarizes current knowledge on NO role in plant-pathogen interactions, focused on biotrophic, necrotrophic and hemibiotrophic fungi and oomycetes. Actual advances and gaps in the identification of NO sources and fate in plant and pathogen cells are discussed. We review the decisive role of time- and site-specific NO production in germination, oriented growth and active penetration of filamentous pathogens to the host tissues, as well in pathogen recognition, and defence activation in plants. Distinct functions of NO are highlighted on diverse interactions of host plants with fungal and oomycete pathogens of different lifestyles, where NO in interplay with reactive oxygen species govern successful plant colonization, cell death and resistance establishment.

scholarly journals Polyhydroxyalkanoate/Antifungal Polyene Formulations with Monomeric Hydroxyalkanoic Acids for Improved Antifungal Efficiency

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 737
Author(s):  
Marina Pekmezovic ◽  
Melina Kalagasidis Krusic ◽  
Ivana Malagurski ◽  
Jelena Milovanovic ◽  
Karolina Stępień ◽  
...  
Keyword(s):  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Trichophyton Mentagrophytes ◽  
Microsporum Gypseum ◽  
Medium Chain Length ◽  
Gold Drugs ◽  
Growth Inhibitory Activity ◽  
Transdermal Application ◽  
Antifungal Efficiency

Novel biodegradable and biocompatible formulations of “old” but “gold” drugs such as nystatin (Nys) and amphotericin B (AmB) were made using a biopolymer as a matrix. Medium chain length polyhydroxyalkanoates (mcl-PHA) were used to formulate both polyenes (Nys and AmB) in the form of films (~50 µm). Thermal properties and stability of the materials were not significantly altered by the incorporation of polyenes in mcl-PHA, but polyene containing materials were more hydrophobic. These formulations were tested in vitro against a panel of pathogenic fungi and for antibiofilm properties. The films containing 0.1 to 2 weight % polyenes showed good activity and sustained polyene release for up to 4 days. A PHA monomer, namely 3-hydroxydecanoic acid (C10-OH), was added to the films to achieve an enhanced synergistic effect with polyenes against fungal growth. Mcl-PHA based polyene formulations showed excellent growth inhibitory activity against both Candida yeasts (C. albicans ATCC 1023, C. albicans SC5314 (ATCC MYA-2876), C. parapsilosis ATCC 22019) and filamentous fungi (Aspergillus fumigatus ATCC 13073; Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102). All antifungal PHA film preparations prevented the formation of a C. albicans biofilm, while they were not efficient in eradication of mature biofilms, rendering them suitable for the transdermal application or as coatings of implants.

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.

scholarly journals Calcineurin Controls Growth, Morphology, and Pathogenicity in Aspergillus fumigatus

2006 ◽  
Vol 5 (7) ◽  
pp. 1091-1103 ◽  
Author(s):  
William J. Steinbach ◽  
Robert A. Cramer ◽  
B. Zachary Perfect ◽  
Yohannes G. Asfaw ◽  
Theodor C. Sauer ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Clinical Observation ◽  
Immunocompromised Patient ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Wild Type ◽  
Therapeutic Approaches ◽  
Growth Morphology ◽  
Different Types ◽  
Hyphal Morphology

ABSTRACT Calcineurin is implicated in a myriad of human diseases as well as homeostasis and virulence in several major human pathogenic microorganisms. The fungus Aspergillus fumigatus is a leading cause of infectious death in the rapidly expanding immunocompromised patient population. Current antifungal treatments for invasive aspergillosis are often ineffective, and novel therapeutic approaches are urgently needed. We demonstrate that a mutant of A. fumigatus lacking the calcineurin A (cnaA) catalytic subunit exhibited defective hyphal morphology related to apical extension and polarized growth, which resulted in drastically decreased filamentation. The ΔcnaA mutant lacked the extensive lattice of invading hyphae seen with the wild-type and complemented strains. Sporulation was also affected in the ΔcnaA mutant, including morphological conidial defects with the absence of surface rodlets and the added presence of disjunctors creating long conidial chains. Infection with the ΔcnaA mutant in several distinct animal models with different types of immunosuppression and inoculum delivery led to a profound attenuation of pathogenicity compared to infection with the wild-type and complemented strains. Lung tissue from animals infected with the ΔcnaA mutant showed a complete absence of hyphae, in contrast to tissue from animals infected with the wild-type and complemented strains. Quantitative fungal burden and pulmonary infarct scoring confirmed these findings. Our results support the clinical observation that substantially decreasing fungal growth can prevent disease establishment and decrease mortality. Our findings reveal that calcineurin appears to play a globally conserved role in the virulence of several pathogenic fungi and yet plays specialized roles in each and can be an excellent target for therapeutic intervention.

Neomisticius platypi n. sp. and N. variabilis n. sp. (Tylenchomorpha: Anguinidae) from dead oak trees in Japan

Nematology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Natsumi Kanzaki ◽  
Hayato Masuya ◽  
Keiko Hamaguchi
Keyword(s):  
New Species ◽  
Vas Deferens ◽  
Morphological Characteristics ◽  
Platypus Quercivorus ◽  
Oak Trees ◽  
Two New Species ◽  
Previous Definition ◽  
Rectal Glands ◽  
Stylet Length ◽  
Definition Of

Summary Two new Neomisticius species, typologically and phylogenetically close to each other, are described and illustrated from dead Quercus trees and an ambrosia beetle, Platypus quercivorus. The two species share some stylet morphological characteristics, namely, they both possess a long conus occupying more than half of the total stylet length, a long crustaformeria composed of more than 160 cells (eight rows of more than 20 cells each), and a short and broad female tail with a digitate tip. They are distinguished from each other by N. variabilis n. sp. having a wide, spindle-shaped male bursa with a blunt terminus and N. platypi n. sp. having an oval bursa with a rounded terminus. In addition, the males and females of both species have three large rectal glands and the posterior end of the male testis (distal end of the vas deferens) bears three cells that seemingly function as a valve between the vas deferens and the cloacal tube. These characteristics have not been reported in other tylenchids. Currently, the genus contains only three species: the two new species and N. rhizomorphoides, which has a normal stylet with a short conus, a short crustaformeria, and lacks rectal glands and valve cells in the vas deferens. Therefore, the two new species are readily distinguished from N. rhizomorphoides and, based on the previous definition, may even represent a new genus. However, considering their phylogenetic closeness and biological similarities (e.g., association with ambrosia beetles), the generic definition of Neomisticius was emended to include these new species.

Antifungal activity of chitinolytic bacteria isolated from airtight stored cereal grain

1998 ◽  
Vol 44 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Emma Frändberg ◽  
Johan Schnürer
Keyword(s):  
Streptomyces Coelicolor ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Dual Culture ◽  
Chitinolytic Activity ◽  
Bacterial Colony ◽  
Chitinolytic Bacteria ◽  
Cereal Grain ◽  
Antifungal Chitinase ◽  
Streptomyces Halstedii

Chitinolytic bacteria are used as biocontrol agents of plant pathogenic fungi. They might also potentially inhibit growth of molds, e.g., Aspergillus spp. and Penicillium spp., in stored plant material. We isolated chitinolytic bacteria from airtight stored cereal grain and evaluated their antifungal capacity. Between 0.01 and 0.5% of the total aerobic counts were chitinolytic bacteria. Gram-negative bacteria, mainly Pseudomonadaceae, constituted approximately 80% of the chitinolytic population. Gram-positive isolates belonged predominantly to the Corynebacterium-Arthrobacter group, Streptomyces, and Bacillus. Chitinolytic activity was evaluated using culture filtrates from chitin-grown isolates as the release of p-nitrophenol from p-nitrophenyl N,N'-diacetylchitobiose and as the formation of clearing zones on chitin agar. No correlation between chitinolytic activity and antifungal effects was found when challenging Penicillium roqueforti Dierckx with bacterial isolates on chitin agar in a dual culture bioassay. Fungal hyphae frequently grew seemingly unaffected through the bacterial colony of a high chitinase producer on colloidal chitin. Only 4% of the chitinolytic isolates had strong effects on fungal growth. Among these, Streptomyces halstedii (K122) and Streptomyces coelicolor (K139) inhibited growth of a broad range of fungi. Streptomyces halstedii affected hyphal morphology and decreased the radial growth rate of all fungi investigated. These effects were not caused by volatile metabolites, polyenes, or N-carbamoyl-D-glucosamine.Key words: antifungal, chitinase, Streptomyces halstedii, Streptomyces coelicolor.

scholarly journals First evidence of nocardiosis in farmed red drum (Sciaenops ocellatus, Linnaeus) caused by Nocardia seriolae in the Gulf of Mexico

2021 ◽  
Author(s):  
Rodolfo Enrique del Rio-Rodriguez ◽  
Jose Gustavo Ramirez-Paredes ◽  
Sonia Araceli Soto-Rodriguez ◽  
Yechiam Shapira ◽  
Mariana del Jesus Huchin-Cortes ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Red Drum ◽  
Sciaenops Ocellatus ◽  
Internal Organs ◽  
New Host ◽  
Tissue Samples ◽  
Tissue Sections ◽  
Long Rod ◽  
Nocardia Seriolae

ABSTRACTBetween August and December 2013, the offshore cages of a commercial marine farm culturing red drum Sciaenops ocellatus in Campeche Bay were affected by an outbreak of an ulcerative granulomatous disease, reaching 70% cumulative mortality. Thirty-one adults displaying open ulcers on the skin were submitted to our laboratory for diagnosis. Multiple white-yellowish nodules (0.1-0.5 cm in diameter) were present in all internal organs, where the kidney and the spleen were the most severely affected. Histopathological observations of these organs evinced typical granulomatous formations. Gram and Ziehl-Neelsen stains on tissue imprints, bacterial swabs and tissue sections revealed Gram-positive, acid-fast, branching beaded long rod filamentous bacteria. Tissue samples resulted positive for nocardiosis when a Nocardia genus specific nested PCR was used. Definite identification at the species level and taxonomic positioning of the fastidious pathogen was achieved through a specific Nocardia seriolae PCR and by sequencing the gyrB gene of pure isolates. After application of antibiotics during fry production, a posterior follow-up monitoring (from 2014 to 2017) detected mild but recurrent outbreaks of the bacteria with no seasonality pattern. To the extent of our current knowledge, this is the first report of piscine nocardiosis (in a new host -red drum) in Mexico.

scholarly journals Nematodes of Cithariniella (Pharyngodonidae) from freshwater fishes in Senegal, with a key to species

2010 ◽  
Vol 47 (2) ◽  
pp. 105-114 ◽  
Author(s):  
B. Koubková ◽  
V. Baruš ◽  
I. Hodová
Keyword(s):  
Species Differences ◽  
Morphological Characteristics ◽  
Host Record ◽  
Nematode Species ◽  
Generic Diagnosis ◽  
Key To Species ◽  
New Host ◽  
Oral Aperture ◽  
New Host Record ◽  
First Time

AbstractThree nematode species of Cithariniella (Pharyngodonidae), C. citharini, C. khalili, and C. gonzalesi, were recorded from the recta of squeaker (Mochokidae: Siluriformes) and citharinid (Citharinidae: Characiformes) fishes from Senegal, West Africa. Morphological characteristics obtained by scanning electron microscopy (form of oral aperture and cephalic papillae, presence of lateral alae, distribution and form of cloacal papillae, simple or paired papillae on tail of males, eggs with numerous long filaments on each pole in females) correspond well to the generic diagnosis and represent species differences. The shape and size of the cephalic papillae and lips were identified as a new determination feature. C. gonzalesi is reported for the first time from Senegal and its host, Paradistichodus dimidiatus, represents a new host record. A tentative simple key for differentiating C. citharini, C. khalili, C. gonzalesi and C. petterae is provided based upon these results.

Fungal Production and Manipulation of Plant Hormones

2018 ◽  
Vol 25 (2) ◽  
pp. 253-267 ◽  
Author(s):  
Sandra Fonseca ◽  
Dhanya Radhakrishnan ◽  
Kalika Prasad ◽  
Andrea Chini
Keyword(s):  
Stress Responses ◽  
Current Knowledge ◽  
Critical Role ◽  
Plant Defence ◽  
Pathogenic Fungi ◽  
Plant Responses ◽  
Defensive Strategies ◽  
Hormone Balance ◽  
Living Organisms

Living organisms are part of a highly interconnected web of interactions, characterised by species nurturing, competing, parasitizing and preying on one another. Plants have evolved cooperative as well as defensive strategies to interact with neighbour organisms. Among these, the plant-fungus associations are very diverse, ranging from pathogenic to mutualistic. Our current knowledge of plant-fungus interactions suggests a sophisticated coevolution to ensure dynamic plant responses to evolving fungal mutualistic/pathogenic strategies. The plant-fungus communication relies on a rich chemical language. To manipulate the plant defence mechanisms, fungi produce and secrete several classes of biomolecules, whose modeof- action is largely unknown. Upon perception of the fungi, plants produce phytohormones and a battery of secondary metabolites that serve as defence mechanism against invaders or to promote mutualistic associations. These mutualistic chemical signals can be co-opted by pathogenic fungi for their own benefit. Among the plant molecules regulating plant-fungus interaction, phytohormones play a critical role since they modulate various aspects of plant development, defences and stress responses. Intriguingly, fungi can also produce phytohormones, although the actual role of fungalproduced phytohormones in plant-fungus interactions is poorly understood. Here, we discuss the recent advances in fungal production of phytohormone, their putative role as endogenous fungal signals and how fungi manipulate plant hormone balance to their benefits.

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