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

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.

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Phomopsis Stem Canker: A Reemerging Threat to Sunflower (Helianthus annuus) in the United States

Phytopathology ◽

10.1094/phyto-11-14-0336-fi ◽

2015 ◽

Vol 105 (7) ◽

pp. 990-997 ◽

Cited By ~ 28

Author(s):

Febina M. Mathew ◽

Kholoud M. Alananbeh ◽

James G. Jordahl ◽

Scott M. Meyer ◽

Lisa A. Castlebury ◽

...

Keyword(s):

United States ◽

Helianthus Annuus ◽

Great Plains ◽

Phylogenetic Analyses ◽

Elongation Factor ◽

Stem Canker ◽

The United States ◽

Northern Great Plains ◽

Type Specimens ◽

Internal Transcribed Spacer Region

Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012. Although Diaporthe helianthi was assumed to be the sole causal agent in the United States, a newly described species, D. gulyae, was found to be the primary cause of Phomopsis stem canker in Australia. To determine the identity of Diaporthe spp. causing Phomopsis stem canker in the Northern Great Plains, 275 infected stems were collected between 2010 and 2012. Phylogenetic analyses of sequences of the ribosomal DNA internal transcribed spacer region, elongation factor subunit 1-α, and actin gene regions of representative isolates, in comparison with those of type specimens, confirmed two species (D. helianthi and D. gulyae) in the United States. Differences in aggressiveness between the two species were determined using the stem-wound method in the greenhouse; overall, D. helianthi and D. gulyae did not vary significantly (P ≤ 0.05) in their aggressiveness at 10 and 14 days after inoculation. These findings indicate that both Diaporthe spp. have emerged as sunflower pathogens in the United States, and have implications on the management of this disease.

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Root Rot Caused by Species of Fusarium on Brassica carinata in South Dakota

Plant Health Progress ◽

10.1094/php-04-18-0012-rs ◽

2018 ◽

Vol 19 (3) ◽

pp. 188-192

Author(s):

Paul N. Okello ◽

Kristina Petrović ◽

Brian Kontz ◽

Shaukat Ali ◽

Laura F. Marek ◽

...

Keyword(s):

South Dakota ◽

Root Rot ◽

Rating Scale ◽

Fusarium Species ◽

Phylogenetic Analyses ◽

Elongation Factor ◽

The United States ◽

Brassica Carinata ◽

Oilseed Crop ◽

Root Diseases

Brassica carinata is an emerging oilseed crop in the United States, and root diseases caused by Fusarium have the potential to cause yield losses in production. In this study, B. carinata plants were randomly sampled at vegetative and seed development plant stages from South Dakota State University experimental plots. Reddish-brown lesions were observed on roots of sampled plants from which F. acuminatum, F. oxysporum, F. solani, and F. sporotrichioides were recovered. The Fusarium species were identified based on morphology and phylogenetic analyses of the translation elongation factor 1-α gene region. Pathogenicity of the four Fusarium species was evaluated on five B. carinata accessions using a modified inoculum layer method in the greenhouse. At 21 days after inoculation, root rot severity caused by Fusarium on the B. carinata accessions was assessed on a rating scale of 0 to 4 and evaluated using relative treatment effects (RTEs). The F. oxysporum isolate caused significant differences in RTE (P = 0.01) among the B. carinata accessions. However, there were no significant differences in RTE among the B. carinata accessions in response to F. acuminatum (P = 0.82), F. solani (P = 0.76), and F. sporotrichioides (P = 0.47) isolates.

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

Plant Disease ◽

10.1094/pdis-10-18-1717-re ◽

2019 ◽

Vol 103 (9) ◽

pp. 2397-2411 ◽

Cited By ~ 6

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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Lasiodiplodia pseudotheobromae causes stem canker of Chinese hackberry in China

Journal of Forestry Research ◽

10.1007/s11676-019-01049-x ◽

2019 ◽

Vol 31 (6) ◽

pp. 2571-2580

Author(s):

Lu Liang ◽

Huan Li ◽

Lifeng Zhou ◽

Fengmao Chen

Keyword(s):

Rna Polymerase Ii ◽

Southern China ◽

Elongation Factor ◽

Stem Canker ◽

Disease Spread ◽

Phylogenetic Information ◽

Outbreak Period ◽

Pathogenicity Tests ◽

Xylem Tissue ◽

Celtis Sinensis

Abstract Chinese hackberry (Celtis sinensis Pers.) is an adaptable species widely growing in southern China. The symptoms of canker on stems of seedlings were discovered mid-July 2017 in Shuyang, Jiangsu Province. The diseased portions of the stems were dark brown due to discoloured xylem. Some seedlings showed symptoms of wilting, leaf fall, twig dieback, and tissue discolouration. The outbreak period was concentrated in July and August, suggesting that the disease spread during summer months. Possible fungal causal agents were isolated from naturally infected canker tissue and discoloured xylem. The isolate from xylem tissue with a high frequency (> 50%) was named Ls7 type. Pathogenicity tests were carried out on 4-year-old seedlings. The symptoms of canker began to develop 20 days after inoculation with Ls7 isolate and by day 35, there were dark, enlarged longitudinal lesions. A phylogenetic tree of the isolate was developed using the internal transcribed spacer, elongation factor-1α (tef1-α), β-tubulin gene (TUB) and RNA polymerase II subunit primer genes (RPB2). Based on morphological features and phylogenetic information, the pathogen was identified as Lasiodiplodia pseudotheobromae. This is the first report of L. pseudotheobromae causing canker on Chinese hackberry stems in China.

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Dieback of Euonymus alatus (Celastraceae) Caused by Cytospora haidianensis sp. nov. in China

Forests ◽

10.3390/f11050524 ◽

2020 ◽

Vol 11 (5) ◽

pp. 524 ◽

Cited By ~ 1

Author(s):

Xian Zhou ◽

Meng Pan ◽

Haoyu Li ◽

Chengming Tian ◽

Xinlei Fan

Keyword(s):

Rna Polymerase Ii ◽

Phylogenetic Analyses ◽

Economic Value ◽

Carbon Sources ◽

Elongation Factor ◽

Causal Agent ◽

Optimum Growth ◽

Translation Elongation ◽

Euonymus Alatus ◽

Pathogenicity Tests

Euonymus alatus (Celastraceae) is widely cultivated in China for its economic value and landscape benefits. Euonymus alatus dieback occurs due to members of Cytospora and has become one of the most severe diseases affecting its cultivation in China. In this study, we examined the causal agent of bough dieback on campuses of University Road, Beijing, China. Among the strains, three were morphologically consistent with Cytospora, showing hyaline and allantoid conidia. Based on phylogenetic analyses of the concatenated actin (ACT), internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-alpha (TEF1-α) and beta-tubulin (TUB2) gene sequences, along with morphological and physiological features, we propose C. haidianensis as a novel species. It was confirmed as a causal agent of dieback of E. alatus by pathogenicity tests. Mycelial growth of Cytospora haidianensis occurred at pH values ranging from 3.0 to 11.0, with optimum growth at 8.3, and at temperatures from 5 to 35 °C, with optimum growth at 19.8 °C. We also tested the growth of C. haidianensis in the presence of six carbon sources. Sucrose, maltose and glucose were highly efficient and xylose was the least. The ability of C. haidianensis to grow at 19.8 °C may help to explain its occurrence causing dieback of E. alatus in Beijing during the autumn season.

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Wilt, Crown, and Root Rot of Common Rose Mallow (Hibiscus moscheutos) Caused by a NovelFusariumsp.

Plant Disease ◽

10.1094/pdis-05-16-0717-re ◽

2017 ◽

Vol 101 (2) ◽

pp. 354-358 ◽

Cited By ~ 3

Author(s):

S. L. Lupien ◽

F. M. Dugan ◽

K. M. Ward ◽

K. O’Donnell

Keyword(s):

Rna Polymerase Ii ◽

Root Rot ◽

Molecular Phylogenetics ◽

Phylogenetic Analyses ◽

Elongation Factor ◽

Crown Rot ◽

Root And Crown Rot ◽

Fusarium Sp ◽

Crown And Root Rot ◽

Rot Disease

A new crown and root rot disease of landscape plantings of the malvaceous ornamental common rose mallow (Hibiscus moscheutos) was first detected in Washington State in 2012. The main objectives of this study were to complete Koch’s postulates, document the disease symptoms photographically, and identify the causal agent using multilocus molecular phylogenetics. Results of the pathogenicity experiments demonstrated that the Fusarium sp. could induce vascular wilt and root and crown rot symptoms on H. moscheutos ‘Luna Rose’. Maximum-likelihood and maximum-parsimony phylogenetic analyses of portions of translation elongation factor 1-α and DNA-directed RNA polymerase II largest and second-largest subunit indicated that the Hibiscus pathogen represents a novel, undescribed Fusarium sp. nested within the Fusarium buharicum species complex.

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Stem Canker on Cyclocarya paliurus Is Caused by Botryosphaeria dothidea

Plant Disease ◽

10.1094/pdis-11-18-1990-re ◽

2020 ◽

Vol 104 (4) ◽

pp. 1032-1040 ◽

Cited By ~ 1

Author(s):

Xiang-rong Zheng ◽

Mao-jiao Zhang ◽

Xu-lan Shang ◽

Sheng-zuo Fang ◽

Feng-mao Chen

Keyword(s):

Dna Sequences ◽

Phylogenetic Analyses ◽

Elongation Factor ◽

Its Region ◽

Stem Canker ◽

Morphological Observation ◽

Botryosphaeria Dothidea ◽

Cyclocarya Paliurus ◽

Potted Plants ◽

Pathogenicity Tests

Cyclocarya paliurus, an important endangered plant in China, has considerable medicinal, timber, and horticultural value. However, little is known about diseases that affect its health. In recent years, stem canker diseases on C. paliurus have been observed frequently in newly established nurseries in Jiangsu Province, China. Symptomatic trees showed elliptical, sunken lesions on the bark, with internal discoloration, leading to enlarging cankers with delineated margins. Pathogenicity tests with fungi isolated from symptomatic samples reproduced typical canker symptoms on both detached branches and potted plants of C. paliurus. Moreover, conidia from pycnidia of isolate ZB-23 could also cause stem canker on C. paliurus. Through combined morphological observation and DNA sequences of ITS region, β-tubulin, and translation elongation factor 1-α genes, the pathogen was identified as Botryosphaeria dothidea. Multigene maximum likelihood and maximum parsimony phylogenetic analyses further supported the identification of the pathogen. To our knowledge, this is the first report of B. dothidea causing stem canker on C. paliurus in China.

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

Foods ◽

10.3390/foods10051063 ◽

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.

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Multilocus phylogenies reveal three new truffle-like taxa and the traces of interspecific hybridization in Octaviania (Boletaceae, Boletales)

IMA Fungus ◽

10.1186/s43008-021-00066-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Takamichi Orihara ◽

Rosanne Healy ◽

Adriana Corrales ◽

Matthew E. Smith

Keyword(s):

Rna Polymerase Ii ◽

Phylogenetic Analyses ◽

Large Subunit ◽

Gene Tree ◽

Phylogenetic Network ◽

Elongation Factor ◽

Morphological Observation ◽

Tree Comparison ◽

Unknown Species ◽

The Usa

ABSTRACTAmong many convergently evolved sequestrate fungal genera in Boletaceae (Boletales, Basidiomycota), the genus Octaviania is the most diverse. We recently collected many specimens of Octaviania subg. Octaviania, including several undescribed taxa, from Japan and the Americas. Here we describe two new species in subgenus Octaviania, O. tenuipes and O. tomentosa, from temperate to subtropical evergreen Fagaceae forests in Japan based on morphological observation and robust multilocus phylogenetic analyses (nrDNA ITS and partial large subunit [LSU], translation elongation factor 1-α gene [TEF1] and the largest subunit of RNA polymerase II gene [RPB1]). Based on specimens from the Americas as well as studies of the holotype, we also taxonomically re-evaluate O. asterosperma var. potteri. Our analysis suggests that O. asterosperma var. potteri is a distinct taxon within the subgenus Octaviania so we recognize this as O. potteri stat. nov. We unexpectedly collected O. potteri specimens from geographically widespread sites in the USA, Japan and Colombia. This is the first verified report of Octaviania from the South American continent. Our molecular analyses also revealed that the RPB1 sequence of one O. tenuipes specimen was identical to that of a closely related species, O. japonimontana, and that one O. potteri specimen from Minnesota had an RPB1 sequence of an unknown species of O. subg. Octaviania. Additionally, one O. japonimontana specimen had an unusually divergent TEF1 sequence. Gene-tree comparison and phylogenetic network analysis of the multilocus dataset suggest that these heterogenous sequences are most likely the result of previous inter- and intra-specific hybridization. We hypothesize that frequent hybridization events in Octaviania may have promoted the high genetic and species diversity found within the genus.

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Phylogeny and Mycotoxin Profile of Pathogenic Fusarium Species Isolated from Sudden Decline Syndrome and Leaf Wilt Symptoms on Date Palms (Phoenix dactylifera) in Tunisia

Toxins ◽

10.3390/toxins13070463 ◽

2021 ◽

Vol 13 (7) ◽

pp. 463

Author(s):

Amal Rabaaoui ◽

Chiara Dall’Asta ◽

Laura Righetti ◽

Antonia Susca ◽

Antonio Logrieco ◽

...

Keyword(s):

Rna Polymerase Ii ◽

Fusarium Solani ◽

Fusarium Species ◽

Elongation Factor ◽

Phoenix Dactylifera ◽

Fusarium Proliferatum ◽

Fruit Rot ◽

Morphological Identification ◽

Single Strain ◽

Date Palms

In 2017–2018, extensive symptoms of sudden decline and fruit rot were observed on date palms in southern Tunisia. Samples of diseased plants were randomly collected in six localities. Based on morphological identification, Fusarium was the most frequent fungal genus detected. A sequencing of translation elongation factor, calmodulin, and second largest subunit of RNA polymerase II genes was used to identify 63 representative Fusarium strains at species level and investigate their phylogenetic relationships. The main species detected was Fusarium proliferatum, and at a much lesser extent, Fusarium brachygibbosum, Fusarium caatingaense, Fusarium clavum, Fusarium incarnatum, and Fusarium solani. Pathogenicity on the Deglet Nour variety plantlets and the capability to produce mycotoxins were also assessed. All Fusarium species were pathogenic complying Koch’s postulates. Fusarium proliferatum strains produced mainly fumonisins (FBs), beauvericin (BEA), and, to a lesser extent, enniatins (ENNs) and moniliformin (MON). All F. brachygibbosum strains produced low levels of BEA, diacetoxyscirpenol, and neosolaniol; two strains produced also T-2 toxin, and a single strain produced HT-2 toxin. Fusarium caatingaense, F. clavum, F. incarnatum produced only BEA. Fusarium solani strains produced MON, BEA, and ENNs. This work reports for the first time a comprehensive multidisciplinary study of Fusarium species on date palms, concerning both phytopathological and food safety issues.

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