scholarly journals Identification, Pathogenicity, and Spore Trapping of Colletotrichum karstii Associated with Twig and Shoot Dieback in California

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1464-1473 ◽  
Author(s):  
Joey S. Mayorquin ◽  
Mohamed T. Nouri ◽  
Beth B. Peacock ◽  
Florent P. Trouillas ◽  
Greg W. Douhan ◽  
...  
Keyword(s):  
Central Valley ◽  
Fungal Species ◽  
Precipitation Event ◽  
Spore Trapping ◽  
Pathogenicity Tests

Colletotrichum Corda, 1831 species are well-documented pathogens of citrus that are associated with leaf and fruit anthracnose diseases. However, their role in twig and shoot dieback diseases of citrus has recently become more prominent. Recent surveys of orchards in the Central Valley of California have revealed C. gloeosporioides and a previously undocumented species, C. karstii, to be associated with twig and shoot dieback. Pathogenicity tests using clementine (cv. 4B) indicated that both C. karstii and C. gloeosporioides are capable of producing lesions following inoculation of citrus stems. Pathogenicity tests also revealed C. karstii to be the most aggressive fungal species producing the longest lesions after 15 months. The majority of spores trapped during this study were trapped during or closely following a precipitation event with the majority of spores being trapped from January through May. These findings confirm C. karstii as a new pathogen of citrus in California.

scholarly journals Incidence and Etiology of Postharvest Fungal Diseases Associated with Bulb Rot in Garlic (Alllium sativum) in Spain

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1063
Author(s):  
Laura Gálvez ◽  
Daniel Palmero
Keyword(s):  
Negative Impact ◽  
Fusarium Species ◽  
Fungal Species ◽  
Postharvest Disease ◽  
Dry Rot ◽  
Fusarium Dry Rot ◽  
Causative Agents ◽  
Postharvest Handling ◽  
Pathogenicity Tests ◽  
Bulb Rot

In recent years, different postharvest alterations have been detected in garlic. In many cases, the symptoms are not well defined, or the etiology is unknown, which further complicates the selection of bulbs during postharvest handling. To characterize the different symptoms of bulb rot caused by fungi, garlic bulb samples were collected from six Spanish provinces in two consecutive years. Eight different fungal species were identified. The most prevalent postharvest disease was Fusarium dry rot (56.1%), which was associated with six Fusarium species. Fusarium proliferatum was detected in more than 85% of symptomatic cloves, followed by F. oxysporum and F. solani. Pathogenicity tests did not show a significant correlation between virulence and mycotoxin production (fumonisins, beauvericin, and moniliformin) or the mycelial growth rate. Penicillium allii was detected in 12.2% of the samples; it was greatly influenced by the harvest season and garlic cultivar, and three different morphotypes were identified. Stemphylium vesicarium and Embellisia allii were pathogenic to wounded cloves. Some of the isolated fungal species produce highly toxic mycotoxins, which may have a negative impact on human health. This work is the first to determine the quantitative importance, pathogenicity, and virulence of the causative agents of postharvest garlic rot in Spain.

scholarly journals Neofusicoccum mediterraneum Is Involved in a Twig and Branch Dieback of Olive Trees Observed in Salento (Apulia, Italy)

Pathogens ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 53
Author(s):  
Angela Brunetti ◽  
Antonio Matere ◽  
Valentina Lumia ◽  
Vittorio Pasciuta ◽  
Valeria Fusco ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Fungal Species ◽  
In Vitro Tests ◽  
Wood Discoloration ◽  
Olive Groves ◽  
Pathogenicity Tests ◽  
Olive Quick Decline Syndrome ◽  
Olive Trees ◽  
Branch Dieback

Olive trees are infected and damaged by Botryosphaeriaceae fungi in various countries. The botryosphaeriaceous fungus Neofusicoccum mediterraneum is highly aggressive and is a major concern for olive groves in Spain and California (USA), where it causes ‘branch and twig dieback’ characterized by wood discoloration, bark canker, and canopy blight. During surveys of olive groves in Apulia (southern Italy), we noticed that—in some areas—trees were heavily affected by severe branch and twig dieback. In addition, chlorosis and the appearance of red-bronze patches on the leaf preceded the wilting of the foliage, with necrotic leaves persisting on the twigs. Given the severity of the manifestation in zones also subject to olive quick decline syndrome (OQDS) caused by Xylella fastidiosa subsp. pauca, we investigated the etiology and provide indications for differentiating the symptoms from OQDS. Isolation from diseased wood samples revealed a mycete, which was morphologically and molecularly identified as N. mediterraneum. The pathogenicity tests clearly showed that this fungus is able to cause the natural symptoms. Therefore, also considering the low number of tested samples, N. mediterraneum is a potential causal agent of the observed disease. Specifically, inoculation of the twigs caused complete wilting in two to three weeks, while inoculation at the base of the stem caused severe girdling wedge-shaped cankers. The growth rate of the fungus in in vitro tests was progressively higher from 10 to 30 °C, failing to grow at higher temperatures, but keeping its viability even after prolonged exposure at 50 °C. The capacity of the isolate to produce catenulate chlamydospores, which is novel for the species, highlights the possibility of a new morphological strain within N. mediterraneum. Further investigations are ongoing to verify whether additional fungal species are involved in this symptomatology.

scholarly journals Seed-Associated Fungal Diversity and the Molecular Identification of Fusarium with Potential Threat to Ginseng (Panax ginseng) in China

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 330-339 ◽  
Author(s):  
Yi Ming Guan ◽  
Jin Chao Deng ◽  
Ying Ying Ma ◽  
Yu Li ◽  
Ya Yu Zhang
Keyword(s):  
Panax Ginseng ◽  
Fungal Diversity ◽  
High Throughput Sequencing ◽  
Fusarium Species ◽  
Fungal Species ◽  
Ginseng Root ◽  
Potential Threat ◽  
Operational Taxonomic Units ◽  
Pathogenicity Tests ◽  
Local Storage

The utility of traditional methods for detecting seed-borne fungi is limited by the fact some fungi are unculturable or difficult to isolate. The seed-borne pathogens affecting Panax ginseng cultivation have not been fully characterized. Seed-borne fungi can be identified based on the high-throughput sequencing of internal transcribed spacer (ITS) amplicons. A hierarchical clustering tree diagram analysis based on operational taxonomic units revealed a relationship between the seed-borne fungi and the region from which the seeds were collected. This study analyzed the fungal diversity on 30 ginseng seed samples from the main ginseng-producing areas of China. The 50 most abundant genera were identified including those responsible for ginseng diseases, Fusarium, Alternaria, Nectria, Coniothyrium, Verticillium, Phoma, and Rhizoctonia. Fusarium species, which are the primary causes of root rot, were detected in all seed samples. The results of a phylogenetic analysis indicated that the seed-borne fungal species originating from the same region were closely related. Fungi on ginseng seeds from eight different regions were divided into eight clades, suggesting they were correlated with the local storage medium. A total of 518 Fusarium isolates were obtained and 10 species identified, all of which can be detrimental to ginseng production. Pathogenicity tests proved that seed-borne Fusarium species can infect ginseng seedlings and 2-year-old ginseng root, with potentially adverse effects on ginseng yield and quality.

Alternaria hydrangeae sp. nov. (Ascomycota: Pleosporaceae) from Hydrangea paniculata in China

Phytotaxa ◽  
2019 ◽  
Vol 401 (4) ◽  
pp. 287
Author(s):  
DONG FANG PEI ◽  
SEIN LAI LAI AUNG ◽  
HAI FENG LIU ◽  
QUAN KE LIU ◽  
ZHI HE YU ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Phylogenetic Analyses ◽  
Botanical Garden ◽  
Fungal Species ◽  
New Taxon ◽  
Leaf Spots ◽  
Pathogenicity Tests ◽  
Cultural Features ◽  
Necrotic Symptoms

In 2017, a new fungal species, Alternaria hydrangeae, was isolated from necrotic leaf spots of Hydrangea paniculata in Shenyang Botanical Garden, Liaoning, China. Phylogenetic analyses based on five genes (ITS, GPDH, Alt a1, RPB2 and TEF1) indicated that the species is a new taxon closely related to Alternaria deserticola in section Porri. Both species were significantly different from each other based on cultural features on SNA and PCA. Previously, A. deserticola was morphologically considered as A. acalyphicola. With respect to conidial characters, the species was distinct from A. acalyphicola in conidia shape, size and transverse septa. Pathogenicity tests indicated that it could induce necrotic symptoms on its host. The species is illustrated here as a new one causing leaf spot on H. paniculata.

scholarly journals Ascochyta fabae and A. lentis: Host Specificity, Teleomorphs (Didymella), Hybrid Analysis, and Taxonomic Status

Plant Disease ◽  
1997 ◽  
Vol 81 (7) ◽  
pp. 809-816 ◽  
Author(s):  
W. J. Kaiser ◽  
B.-C. Wang ◽  
J. D. Rogers
Keyword(s):  
Faba Bean ◽  
Rapd Markers ◽  
Random Amplified Polymorphic Dna ◽  
Morphological Characteristics ◽  
Taxonomic Status ◽  
Fungal Species ◽  
Hybrid Progeny ◽  
Banding Patterns ◽  
Pathogenicity Tests ◽  
Ascochyta Fabae

Isolates of Ascochyta fabae from faba bean (Vicia faba) and A. lentis from lentil (Lens culinaris) collected from different countries were used in this study. The Didymella teleomorph (sexual state) of each fungus was induced to develop and mature on inoculated sterile lentil stems. Both fungi were heterothallic, with two mating types, designated MAT1-1 and MAT1-2. When certain isolates of A. fabae and A. lentis were crossed, hybrid pseudothecia developed. Growth, sporulation, colony appearance, morphology, and pathogenicity of the hybrid progeny frequently differed greatly from the parent isolates. Inoculations with single-ascospore progeny from matings among compatible isolates of A. fabae caused disease in faba bean but not in lentil; inoculations with single-ascospore progeny from matings among compatible isolates of A. lentis incited disease in lentil but not in faba bean. Inoculations with single-ascospore progeny from crosses between faba bean and lentil isolates did not induce disease in either host. Asci from crosses between A. fabae and A. lentis mostly contained fewer than eight ascospores that were, on average, larger than those from eight-spored asci. Matings among certain isolates of A. fabae resulted in production of pseudothecia with ascospores considerably larger than is typical for D. fabae. Random amplified polymorphic DNA (RAPD) banding patterns of Ascochyta isolates from faba bean and lentil are clearly different, and banding patterns from hybrid progeny from crosses between A. fabae and A. lentis confirmed hybridity. RAPD markers proved useful in supporting identifications of ascospore isolates from faba bean to known Ascochyta species. Dendrogram analysis indicated similarity between the two fungal species was low. The pathogenicity tests, morphological characteristics, and RAPD markers indicate that A. fabae and A. lentis represent distinct taxa. D. lentis, with its anamorph, A. lentis, is proposed as a new species that is distinct from D. fabae, with its anamorph, A. fabae.

scholarly journals Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California

2015 ◽  
Vol 105 (12) ◽  
pp. 1555-1567 ◽  
Author(s):  
X. Q. Zhu ◽  
C. L. Xiao
Keyword(s):  
Dna Sequences ◽  
Central Valley ◽  
Morphological Characters ◽  
Fruit Rot ◽  
Postharvest Quality ◽  
Plasma Membrane Atpase ◽  
Factors Affecting ◽  
Molecular Approaches ◽  
Alternaria Species ◽  
Pathogenicity Tests

Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit.

scholarly journals Identification of Fungal Species Associated with Branch Dieback of Olive and Resistance of Table Cultivars to Neofusicoccum mediterraneum and Botryosphaeria dothidea

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 306-316 ◽  
Author(s):  
Juan Moral ◽  
Carlos Agustí-Brisach ◽  
Mario Pérez-Rodríguez ◽  
Carlos Xaviér ◽  
M. Carmen Raya ◽  
...  
Keyword(s):  
Dna Analysis ◽  
Large Subunit ◽  
Fungal Species ◽  
Control Measures ◽  
Nuclear Ribosomal Dna ◽  
Botryosphaeria Dothidea ◽  
Immature Fruit ◽  
Pathogenicity Tests ◽  
Olive Trees ◽  
Branch Dieback

Over two consecutive seasons, 16 olive orchards with trees exhibiting dieback symptoms on branches were surveyed in southern Spain. The six dominant fungal species recovered were characterized by means of phenotypic observations, DNA analysis (by sequencing of the internal transcribed spacer, β-tubulin, and large subunit nuclear ribosomal DNA regions), and pathogenicity tests. Additionally, three isolates collected from Tunisian olive trees showing similar dieback symptoms, one isolate of Colletotrichum godetiae, and a reference isolates of Neofusicoccum mediterraneum were included. The resistance of the 11 most important table cultivars to N. mediterraneum and Botryosphaeria dothidea, the causal agent of “escudete” (small shield) of fruit, was studied by the inoculation of branches and immature fruit, respectively. The species Cytospora pruinosa, N. mediterraneum, Nothophoma quercina, Comoclathris incompta, and Diaporthe sp. were identified. Only N. mediterraneum and C. incompta were able to induce the typical dieback symptoms and cankers that affected the development of the plants. The species N. mediterraneum was the most virulent among the evaluated species, although differences in virulence among its isolates were observed. The remaining fungal species were weakly pathogenic to nonpathogenic on plants. According to resistance tests, ‘Gordal Sevillana’ and ‘Manzanilla Cacereña’ were the most susceptible to branch dieback caused by N. mediterraneum. Furthermore, the fruit of ‘Aloreña de Atarfe’ and ‘Manzanilla de Sevilla’ were the most susceptible to B. dothidea. Knowledge of the etiology and cultivar resistance of these diseases will help to establish better control measures.

scholarly journals Mushroom Emergence Detected by Combining Spore Trapping with Molecular Techniques

2017 ◽  
Vol 83 (13) ◽  
Author(s):  
Carles Castaño ◽  
Jonàs Oliva ◽  
Juan Martínez de Aragón ◽  
Josu G. Alday ◽  
Javier Parladé ◽  
...  
Keyword(s):  
Real Time ◽  
Fruiting Body ◽  
Real Time Pcr ◽  
Fungal Species ◽  
Fruiting Bodies ◽  
Quantitative Real Time Pcr ◽  
Mushroom Production ◽  
Spore Abundance ◽  
Spore Trapping ◽  
Species Specific

ABSTRACT Obtaining reliable and representative mushroom production data requires time-consuming sampling schemes. In this paper, we assessed a simple methodology to detect mushroom emergence by trapping the fungal spores of the fruiting body community in plots where mushroom production was determined weekly. We compared the performance of filter paper traps with that of funnel traps and combined these spore trapping methods with species-specific quantitative real-time PCR and Illumina MiSeq to determine the spore abundance. Significantly more MiSeq proportional reads were generated for both ectomycorrhizal and saprotrophic fungal species using filter traps than were obtained using funnel traps. The spores of 37 fungal species that produced fruiting bodies in the study plots were identified. Spore community composition changed considerably over time due to the emergence of ephemeral fruiting bodies and rapid spore deposition (lasting from 1 to 2 weeks), which occurred in the absence of rainfall events. For many species, the emergence of epigeous fruiting bodies was followed by a peak in the relative abundance of their airborne spores. There were significant positive relationships between fruiting body yields and spore abundance in time for five of seven fungal species. There was no relationship between fruiting body yields and their spore abundance at plot level, indicating that some of the spores captured in each plot were arriving from the surrounding areas. Differences in fungal detection capacity by spore trapping may indicate different dispersal ability between fungal species. Further research can help to identify the spore rain patterns for most common fungal species. IMPORTANCE Mushroom monitoring represents a serious challenge in economic and logistical terms because sampling approaches demand extensive field work at both the spatial and temporal scales. In addition, the identification of fungal taxa depends on the expertise of experienced fungal taxonomists. Similarly, the study of fungal dispersal has been constrained by technological limitations, especially because the morphological identification of spores is a challenging and time-consuming task. Here, we demonstrate that spores from ectomycorrhizal and saprotrophic fungal species can be identified using simple spore traps together with either MiSeq fungus-specific amplicon sequencing or species-specific quantitative real-time PCR. In addition, the proposed methodology can be used to characterize the airborne fungal community and to detect mushroom emergence in forest ecosystems.

scholarly journals Characterization of Fusarium and Neocosmospora Species Associated With Crown Rot and Stem Canker of Pistachio Rootstocks in California

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1931-1939 ◽  
Author(s):  
Maria Crespo ◽  
Daniel P. Lawrence ◽  
Mohamed T. Nouri ◽  
David A. Doll ◽  
Florent P. Trouillas
Keyword(s):  
Rna Polymerase Ii ◽  
Fusarium Species ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Stem Canker ◽  
The United States ◽  
Fungal Species ◽  
Crown Rot ◽  
Pathogenicity Tests ◽  
Pistachio Trees

California produces 99.1% of pistachios grown in the United States, and diseases affecting pistachio rootstocks represent a constant challenge to the industry. Field surveys of fungi associated with pistachio rootstocks with symptoms of crown rot and stem canker in three central California counties followed by phylogenetic analyses of translation elongation factor 1-α and second largest subunit of RNA polymerase II gene fragments identified three Fusarium species (Fusarium equiseti, Fusarium oxysporum, and Fusarium proliferatum) and two Neocosmospora species (Neocosmospora falciformis and Neocosmospora solani). F. oxysporum and N. falciformis were the fungal species most frequently recovered from symptomatic pistachio trees. Inoculations of detached twigs of cultivar Kerman pistachio Pioneer Gold I and clonal University of California, Berkeley I (UCBI) rootstocks showed that all five species could colonize pistachio wood and cause vascular discolorations. Pathogenicity tests in potted pistachio trees completed Koch’s postulates and confirmed that F. oxysporum, F. proliferatum, N. falciformis, and N. solani were capable of producing rot and discoloration in stems of clonal UCBI rootstocks, the most widely planted pistachio rootstock in California. To our knowledge, this study is the first to present insights into the biodiversity and biology of Fusarium and Neocosmospora species associated with pistachio trees in California.

scholarly journals Identification and Pathogenicity of Fungal Species Associated with Canker Diseases of Pistachio in California

Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2397-2411 ◽  
Author(s):  
Mohamed T. Nouri ◽  
Daniel P. Lawrence ◽  
Leslie A. Holland ◽  
David A. Doll ◽  
Craig E. Kallsen ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Schizophyllum Commune ◽  
Elongation Factor ◽  
Fungal Species ◽  
Elongation Factor 1Α ◽  
Translation Elongation ◽  
Brown Discoloration ◽  
Pathogenicity Tests ◽  
Branch Dieback ◽  
Translation Elongation Factor 1Α

A survey was conducted during 2015 and 2016 in pistachio orchards throughout the San Joaquin Valley of California to investigate the occurrence of canker diseases and identify the pathogens involved. Cankers and dieback symptoms were observed mainly in orchards aged >15 years. Symptoms of canker diseases included brown to dark brown discoloration of vascular tissues, wood necrosis, and branch dieback. In total, 58 fungal isolates were obtained from cankers and identified based on multilocus phylogenetic analyses (internal transcribed spacer, glyceraldehyde 3-phosphate dehydrogenase, β-tubulin, calmodulin, actin 1, and translation elongation factor 1α) representing 11 fungal species: Colletotrichum karstii, Cytospora californica, Cytospora joaquinensis, Cytospora parapistaciae, Cytospora pistaciae, Diaporthe ambigua, Didymella glomerata, Diplodia mutila, Neofusicoccum mediterraneum, Phaeoacremonium canadense, and Schizophyllum commune. Pathogenicity tests conducted in the main pistachio cultivars Kerman, Golden Hills, and Lost Hills using the mycelium-plug method indicated that all fungal species were pathogenic to Pistacia vera. All species tested caused cankers in pistachio branches, although virulence among species varied from high to moderate. Overall, N. mediterraneum and Cytospora spp. were the most widespread and virulent species associated with canker diseases of pistachio in California.

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