scholarly journals Biological and molecular characterization of seven Diaporthe species associated with kiwifruit shoot blight and leaf spot in China

2021 ◽  
Vol 60 (2) ◽  
pp. 177-198
Author(s):  
Yamin DU ◽  
Xianhong WANG ◽  
Yashuang GUO ◽  
Feng XIAO ◽  
Yuhong PENG ◽  
...  
Keyword(s):  
Disease Management ◽  
Leaf Spot ◽  
Phylogenetic Analyses ◽  
Actinidia Chinensis ◽  
Diseased Leaf ◽  
Leaf Spots ◽  
Shoot Blight ◽  
Pathogenicity Tests ◽  
Production Areas

Diaporthe species are significant pathogens, saprobes, and endophytes, with comprehensive host association and geographic distribution. These fungi cause severe dieback, cankers, leaf spots, blights, and stem-end rot of fruits on different plant hosts. This study, explored the occurrence, diversity and pathogenicity of Diaporthe spp. associated with Actinidia chinensis and A. deliciosa in the main kiwifruit production areas of China. Diaporthe isolates (284) derived from 106 diseased leaf and branch samples were examined. Multi-locus phylogenetic analyses and morphology of 43 representative isolates revealed that seven Diaporthe species were obtained, including D. alangii, D. compactum, D. eres, D. hongkongensis, D. sojae, D. tectonae, and D. unshiuensis. Pathogenicity tests were performed on kiwifruit fruits, leaves and branches. Koch’s postulates confirmed all species were pathogenic. D. alangii and D. tectonae were the most aggressive species, followed by D. eres, D. sojae, D. hongkongensis, D. unshiuensis, and D. compactum. Host range evaluation showed that the seven Diaporthe species could also infect apricot, apple, peach, pear, and plum.  This is the first report of D. alangii, D. compactum, D. sojae, D. tectonae, and D. unshiuensis infecting kiwifruit in China, increasing understanding of the Diaporthe complex causing diseases of kiwifruit plants, to assist effective disease management.

scholarly journals Characterization of Leaf Spot Pathogens from Several Spinach Production Areas in the United States

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1994-2004
Author(s):  
Bo Liu ◽  
Larry Stein ◽  
Kimberly Cochran ◽  
Lindsey J. du Toit ◽  
Chunda Feng ◽  
...  
Keyword(s):  
United States ◽  
South Carolina ◽  
Leaf Spot ◽  
The United States ◽  
Leaf Damage ◽  
Leaf Spots ◽  
Pathogenicity Tests ◽  
Agar Media ◽  
Production Areas

Leaf spot diseases have become a major concern in spinach production in the United States. Determining the causal agents of leaf spots on spinach, their prevalence and pathogenicity, and fungicide efficacy against these pathogens is vital for effective disease management. Spinach leaves with leaf spots were collected from Texas, California, Arizona, and South Carolina from 2016 to 2018, incubated in a moist chamber, and plated on potato dextrose and tryptic soy agar media. Fungal and bacterial colonies recovered were identified based on morphology and sequence analysis of the internal transcribed spacer rDNA and 16S rRNA, respectively. Two predominant genera were isolated: (i) Colletotrichum spp., which were identified to species based on sequences of both introns of the glutamate synthetase (GS-I) and glyceraldehyde-3-phosphate dehydrogenase (gapdh-I) genes; and (ii) Stemphylium spp., identified to species based on sequences of the gapdh and calmodulin (cmdA) genes. Anthracnose (Colletotrichum spinaciae) and Stemphylium leaf spot (Stemphylium vesicarium and S. beticola) were the predominant diseases. Additional fungi recovered at very limited frequencies that were also pathogenic to spinach included Colletotrichum coccodes, C. truncatum, Cercospora beticola, and Myrothecium verrucaria. All of the bacterial isolates were not pathogenic on spinach. Pathogenicity tests showed that C. spinaciae, S. vesicarium, and S. beticola caused significant leaf damage. The fungicides Bravo WeatherStik (chlorothalonil), Dithane F-45 (mancozeb), Cabrio (pyraclostrobin), and Merivon (fluxapyroxad and pyraclostrobin) were highly effective at reducing leaf spot severity caused by an isolate of each of C. spinaciae and S. vesicarium, when inoculated individually and in combination.

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 Three New Fungal Leaf Spot Diseases of Spinach in the United States and the Evaluation of Fungicide Efficacy for Disease Management

Plant Disease ◽  
2021 ◽  
pp. PDIS-04-20-0918
Author(s):  
Bo Liu ◽  
Larry Stein ◽  
Kimberly Cochran ◽  
Lindsey J. du Toit ◽  
Chunda Feng ◽  
...  
Keyword(s):  
United States ◽  
Sequence Analysis ◽  
Leaf Spot ◽  
The United States ◽  
Leaf Spots ◽  
Fungicide Efficacy ◽  
Windblown Sand ◽  
Pathogenicity Tests ◽  
Spinach Leaf ◽  
Production Areas

Leaf spot diseases of spinach, caused by Colletotrichum spinaciae, has become a major production constraint in several production areas, including Texas, in recent years. Leaf spot symptoms were observed in several fields in Texas in 2016 and 2017, with typical anthracnose-like symptoms and leaves with small, circular, and sunken lesions that appeared similar to injury from windblown sand. The lesions were plated on potato dextrose agar, from which fungal cultures were recovered. The fungi were identified based on morphology and sequence analysis of the introns of glutamate synthetase and glyceraldehyde-3-phosphate dehydrogenase (for isolates determined to be Colletotrichum spp.) and the internal transcribed spacer ribosomal DNA (for isolates determined to be Myrothecium spp.). Based on foliar symptoms, fungal colony and spore morphology, pathogenicity tests of fungal isolates on the spinach cultivar ‘Viroflay’, and DNA sequence analysis of the isolates, the symptoms on spinach leaves for two sets of samples were caused by Colletotrichum coccodes and Colletotrichum truncatum, and leaf spots resembling damage from windblown sand were caused by Myrothecium verrucaria. This is the first report of spinach leaf spot diseases caused by C. coccodes, C. truncatum, and M. verrucaria in the United States. C. coccodes and C. truncatum caused severe symptoms on the spinach cultivar ‘Viroflay’, whereas M. verrucaria caused symptoms of intermediate severity. Fungicide efficacy tests demonstrated that chlorothalonil, mancozeb, pyraclostrobin, fluxapyroxad + pyraclostrobin, and penthiopyrad were completely effective at preventing leaf spots caused by any of these pathogens when applied 24 h before inoculation of ‘Viroflay’ plants in greenhouse trials.

scholarly journals First Report of Leaf Spot Caused by Alternaria alternata on Kiwifruit in Italy

Plant Disease ◽  
1999 ◽  
Vol 83 (5) ◽  
pp. 487-487 ◽  
Author(s):  
L. Corazza ◽  
L. Luongo ◽  
M. Parisi
Keyword(s):  
New Zealand ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Southern Italy ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
First Report ◽  
Leaf Spots ◽  
Detached Leaves ◽  
Pathogenicity Tests

A leaf spot of kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferg.) leaves was recently observed on plants of the cultivar Hayward in an orchard near Salerno, in southern Italy. The affected plants showed early severe defoliation. The fungus isolated from the infected leaves was identified as Alternaria alternata (Fr.:Fr.) Keissl., based on conidial morphological characteristics. Pathogenicity tests were made by inoculating detached leaves of male pollinator cultivar Tomuri and the female cultivars Hayward and Bruno with a 7-mm disk taken from actively growing cultures of the fungus on potato dextrose agar (PDA). After 14 days, necrotic leaf spots developed and A. alternata was consistently isolated from the inoculated leaves. A. alternata has been observed as a pathogen on leaves and fruits in New Zealand. In the Mediterranean, it has been reported in Israel (2) and in the island of Crete (1). This is the first report of Alternaria leaf spot on kiwifruit in Italy. References: (1) V. A. Bourbos and M. T. Skoudridakis. Petria 7:111, 1997. (2) A. Sive and D. Resnizky. Alon Hanotea 41:409, 1987.

scholarly journals Identification and Characterization of Diaporthe spp. Associated with Twig Cankers and Shoot Blight of Almonds in Spain

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1062 ◽  
Author(s):  
Maela León ◽  
Mónica Berbegal ◽  
José M. Rodríguez-Reina ◽  
Georgina Elena ◽  
Paloma Abad-Campos ◽  
...  
Keyword(s):  
New Species ◽  
Sequence Analysis ◽  
Phylogenetic Species ◽  
Shoot Blight ◽  
Pathogenicity Tests ◽  
Almond Orchards ◽  
One Year ◽  
Prevalent Species ◽  
Identification And Characterization

Two hundred and twenty-five Diaporthe isolates were collected from 2005 to 2019 in almond orchards showing twig cankers and shoot blight symptoms in five different regions across Spain. Multilocus DNA sequence analysis with five loci (ITS, tub, tef-1α, cal and his), allowed the identification of four known Diaporthe species, namely: D. amygdali, D. eres, D. foeniculina and D. phaseolorum. Moreover, a novel phylogenetic species, D. mediterranea, was described. Diaporthe amygdali was the most prevalent species, due to the largest number of isolates (85.3%) obtained from all sampled regions. The second most frequent species was D. foeniculina (10.2%), followed by D. mediterranea (3.6%), D. eres and D. phaseolorum, each with only one isolate. Pathogenicity tests were performed using one-year-old almond twigs cv. Vayro and representative isolates of the different species. Except for D. foeniculina and D. phaseolorum, all Diaporthe species were able to cause lesions significantly different from those developed on the uninoculated controls. Diaporthe mediterranea caused the most severe symptoms. These results confirm D. amygdali as a key pathogen of almonds in Spain. Moreover, the new species, D. mediterranea, should also be considered as a potential important causal agent of twig cankers and shoot blight on this crop.

scholarly journals Biological and Molecular Characterization of Four Botryosphaeria Species Isolated from Pear Plants Showing Stem Wart and Stem Canker in China

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 716-726 ◽  
Author(s):  
Lifeng Zhai ◽  
Meixin Zhang ◽  
Gang Lv ◽  
Xiaoren Chen ◽  
Nana Jia ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Phylogenetic Analyses ◽  
Stem Canker ◽  
Morphological Characterization ◽  
The Other ◽  
Internal Transcribed Spacer Region ◽  
Pathogenicity Tests ◽  
The Common ◽  
Stem Cankers

Pear stem wart and pear stem canker, which have been considered as two different fungal diseases caused by pathogens belonging to Botryosphaeria spp., commonly occur and cause serious damage in the main pear-producing areas in China. To identify the species of this genus infecting pear in China, 131 Botryosphaeria isolates were recovered from pear samples exhibiting symptoms collected from 20 different provinces and areas. Morphological characterization and phylogenetic analyses of the ribosomal DNA internal transcribed spacer region and the β-tubulin and EF1-α genes revealed that Botryosphaeria dothidea, B. rhodina, B. obtusa, and B. parva were associated with different pear stem wart and stem canker symptoms. Remarkably, all isolates of B. dothidea were obtained from the samples showing either stem wart or stem canker lesions; however, the isolates of the other three species were obtained only from the samples showing stem canker. Pathogenicity tests on the pear shoots showed that B. dothidea isolates could induce stem wart or stem canker lesions but all the isolates of the other three species could only induce stem cankers. However, the isolates of B. parva, B. rhodina, and B. obtusa exhibited higher virulence than that of the B. dothidea isolates on the pear fruit. Our results suggest that B. dothidea is the common causal agent for these two diseases (a pear stem wart and a pear-related stem canker), whereas B. parva, B. rhodina, and B. obtusa only cause pear stem canker diseases. To our knowledge, this study represents the first report for biological and molecular characterization of four Botryosphaeria spp. isolated from pear plants showing stem wart and stem canker in China.

scholarly journals Identification and Characterization of Leaf-Inhabiting Fungi from Castanea Plantations in China

2021 ◽  
Vol 7 (1) ◽  
pp. 64
Author(s):  
Ning Jiang ◽  
Xinlei Fan ◽  
Chengming Tian
Keyword(s):  
New Species ◽  
New Taxa ◽  
Leaf Spot ◽  
New Genus ◽  
Fungal Species ◽  
New Family ◽  
Leaf Spots ◽  
Chestnut Leaf ◽  
Identification And Characterization

Two Castanea plant species, C. henryi and C. mollissima, are cultivated in China to produce chestnut crops. Leaf spot diseases commonly occur in Castanea plantations, however, little is known about the fungal species associated with chestnut leaf spots. In this study, leaf samples of C. henryi and C. mollissima were collected from Beijing, Guizhou, Hunan, Sichuan and Yunnan Provinces, and leaf-inhabiting fungi were identified based on morphology and phylogeny. As a result, twenty-six fungal species were confirmed, including one new family, one new genus, and five new species. The new taxa are Pyrisporaceae fam. nov., Pyrispora gen. nov., Aureobasidium castaneae sp. nov., Discosia castaneae sp. nov., Monochaetia castaneae sp. nov., Neopestalotiopsis sichuanensis sp. nov. and Pyrispora castaneae sp. nov.

scholarly journals Characterization of New Small-Spored Alternaria Species Isolated from Solanaceae in Algeria

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1291
Author(s):  
Nabahat Bessadat ◽  
Bruno Hamon ◽  
Nelly Bataillé-Simoneau ◽  
Kihal Mabrouk ◽  
Philippe Simoneau
Keyword(s):  
New Species ◽  
Leaf Spot ◽  
Phylogenetic Analyses ◽  
Tomato Plants ◽  
Growing Seasons ◽  
The North ◽  
Alternaria Species ◽  
One New Species ◽  
North Western

Although large-spored Alternaria species of the section Porri are considered to be the major agents responsible for leaf spot and blight of Solanaceae, small-spored Alternaria species are also frequently isolated from symptomatic tissues. A survey of the north-western regions of Algeria during the 2017–2018 growing seasons revealed that amongst the 623 Alternaria isolates from tomato, potato, pepper, eggplant and black nightshade, 8% could not be morphologically assigned to either section Porri or section Alternaria. In order to more precisely determine the taxonomic position of these isolates, detailed morphological characterizations and multi-locus phylogenetic analyses were performed. Based on these analyses, the isolates were grouped into four main clades: section Ulocladioides, section Infectoriae, including two new species, section Embellisioides, and section Eureka, including one new species. These isolates were also characterized for their virulence under green-house conditions. They were able to produce leaf spot symptoms on tomato plants but with variable levels.

scholarly journals First Report of Fusicoccum aesculi Causing Leaf Spots of Paeonia suffruticosa in Henan Province, China

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1691-1691
Author(s):  
M. Zhang ◽  
H. Y. Wu ◽  
Y. H. Geng ◽  
S. Q. Yu
Keyword(s):  
New York ◽  
Leaf Spot ◽  
Its Region ◽  
Henan Province ◽  
Paeonia Suffruticosa ◽  
Tree Peony ◽  
First Report ◽  
Leaf Spots ◽  
Pathogenicity Tests ◽  
Fusicoccum Aesculi

Tree peony (Paeonia suffruticosa) is regarded as the national flower of China and is cultivated throughout the country. In early August 2010, a moderately severe leaf spot was observed on tree peony cultivated in a garden of Zhengzhou, Henan Province, where approximately 15% of trees were diseased. In 2011, a less damaging leaf spot was also observed in another area of the city with approximately 10% of trees diseased. Early symptoms appeared as small, round, pale-brown lesions on the leaves. Lesions expanded into 5- to 20-mm-diameter spots that were elliptical or irregular, brown to dark brown. A fungus was consistently isolated from the leaf spots on potato dextrose agar (PDA) in grey-black colonies, but produced few pycnidia. Black pycnidia were ostiolate, globose, papillate, formed in uniloculate or multiloculate stromata that were immersed in the leaf, and became erumpent at maturity. Conidiophores or conidiogenous cells were hyaline and cylindrical. Conidia were hyaline, granular, fusoid to ellipsoid, aseptate, with a sub-truncate base, and 20 to 28 × 4.5 to 7.5 μm (mean dimensions of 50 conidia: 24.5 × 5.2 μm). The pathogen was identified as Fusicoccum aesculi, anamorphic stage of Botryosphaeria dothidea, on the basis of morphology (2). The identity of the fungus was confirmed to be F. aesculi by DNA sequence analysis of the internal transcribed spacer (ITS) region (GenBank Accession No. JQ323001), which was 100% identical to those of other F. aesculi isolates (GenBank Accession Nos. GU997686.1 and GU723469.1) (1). Pathogenicity tests were done by inoculating each of 10 leaves on one 7-year-old tree with a mycelial plug (0.5 cm diameter) harvested from the periphery of a 7-day-old colony. An equal number of leaves on the same tree, serving as controls, were mock-inoculated with plugs of PDA medium. Inoculated leaves were covered with plastic for 24 h to maintain high relative humidity and incubated at about 25°C. The plugs were removed after 48 h. After 7 days, 80% of the inoculated leaves showed symptoms identical to those observed in the field under natural conditions, whereas controls remained symptom-free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was F. aesculi. Pathogenicity tests were repeated on the other two trees by the same methods with the same results. To our knowledge, this is the first report of F. aesculi infecting P. suffruticosa in China. References: (1) S. Mohali et al. Mycol. Res. 110:405, 2006. (2) B. C. Sutton. The Coelomycetes. CABI Publishing, New York, 1980.

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