scholarly journals First Report of Alternaria arborescens Causing Early Blight on Tomato in Iraq

2021 ◽  
Vol 34 (1) ◽  
pp. 230-232
Author(s):  
Nisreen J. Razak ◽  
Mohammed H. Abass

In this paper, the isolation of the fungal species Alternaria arborescens was done from symptomatic tomato leaves and diagnosed morphologically and molecularly using ITS primers. Subsequently, pathogenicity determination was achieved for the diagnosed fungal species on tomato plant. It’s noteworthy, this work on A. arborescens was not previously recorded as a potential pathogen on the shoot system of tomato in Iraq.

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 497
Author(s):  
Rafał Ogórek ◽  
Mateusz Speruda ◽  
Justyna Borzęcka ◽  
Agata Piecuch ◽  
Magdalena Cal

Most underground ecosystems are heterotrophic, fungi in these objects are dispersed in the air in the form of spores, and they may be potentially hazardous to mammals. Research in underground sites has focused on mesophilic airborne fungi and only a few concerned cold-adapted species. Therefore, the goal of our research was the first report of psychrophilic and psychrotolerant aeromycota in the Brestovská Cave using culture-based techniques with genetic and phenotypic identification. Plates with PDA medium containing sampled biological material were incubated at 8 ± 0.5 °C. The density of mycobiota inside the cave ranged from 37.4 to 71 CFU 1 m−3 of air and 63.3 CFU 1 m−3 of air outside the cave. Thus, the level of fungal spores did not exceed the standards for the mycological quality of the air. A total of 18 species were isolated during the study, and some species may be potentially dangerous to people with weakened immune system. All fungal species were present inside the cave and only seven of them were outside. Cladosporium cladosporioides dominated in the external air samples and Mortierella parvispora was cultured most frequently from internal air samples. To our knowledge, this is the first discovery of the fungal species such as Coniothyrium pyrinum, Cystobasidium laryngis, Filobasidium wieringae, Leucosporidium drummii, M. parvispora, Mrakia blollopis, Nakazawaea holstii, and Vishniacozyma victoriae in the air inside the underground sites. Moreover, C. pyrinum, C. laryngis, L. drummii, M. blollopis, and N. holstii have never been detected in any component of the underground ecosystems. There are possible reasons explaining the detection of those species, but global warming is the most likely.


2019 ◽  
Vol 102 (1) ◽  
pp. 235-236
Author(s):  
Anam Moosa ◽  
Ayaz Farzand ◽  
Muhammad Fahim Abbas ◽  
Shahbaz Talib Sahi ◽  
Sajid Aleem Khan ◽  
...  

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1157-1157 ◽  
Author(s):  
A. Milosavljević ◽  
E. Pfaf-Dolovac ◽  
M. Mitrović ◽  
J. Jović ◽  
I. Toševski ◽  
...  

Celery (Apium graveolens var. dulce) is a very important vegetable crop intensively cultivated in eastern and southern Serbia. During a field survey in August and September 2012, we observed symptoms similar to those of Cercospora early blight in eastern Serbia, with some of the affected fields showing up to 80% disease severity. The lesions on leaves were amphigenous, subcircular to angular and more or less confluent. Lesions enlarged and merged with age, followed by the development of necrotic area causing a continuous deterioration of the plant. Conidiophores arising from the stromata formed dense fascicles, sometimes appearing solitary, brown at the base, paler toward the apex, simple, straight to slightly curved, and rarely geniculate (dimensions 40 to 90 × 5 to 8 μm). Conidia were solitary, hyaline, at first cylindro-obclavate then acicular to acicular-obclavate, straight to slightly curved, subacute to obtuse at the apex, while truncated and thickened at the base (dimensions 45 to 160 × 4 to 5 μm), 5 to 13 septate. Based on the morphological features, we identified the pathogen as Cercospora apii Fresen. (2). In order to obtain monosporic isolates of the fungus, single conidia were cultivated on potato dextrose agar (PDA). To confirm the pathogenicity of the isolates, 5 mm-diameter mycelial plugs from the PDA plates were placed upside down on the adaxial leaf surface of 2-week-old celery seedlings of cv. Yuta. Control plants were inoculated with a sterile PDA plug. Three leaves per plant were disinfected with 70% ethanol, epidermis was scratched with a sterile needle to promote the infection, and inoculated. A total of 12 plants were inoculated with the mycelial plugs and 12 were used as control plants. Inoculated and control plants were kept in a moist chamber for 48 h and then transferred to a greenhouse at 25 ± 2°C. After 2 weeks, the first necrotic spots appeared on inoculated leaves, similar to the symptoms manifested in the field, while control plants remained symptomless. The pathogen was re-isolated and its identity was verified based on morphological and molecular features. To confirm the pathogen's identity, three isolates (CAC4-1, CAC24, and CAC30) were subjected to molecular identification based on the internal transcribed spacer region (ITS) using the ITS1/ITS4 universal primers (5), a partial calmodulin gene (CAL) using CAL-228F/CAL2Rd primers (1,4), and partial histone H3 gene (H3) using CYLH3F/CYLH3R primers (3). Sequences of the amplified regions were deposited in GenBank under accessions KJ210596 to KJ210604. The BLAST analyses of the ITS sequences revealed 100% identity with several Cercospora species (e.g., C. apii [JX143532], C. beticola [JX143556], and C. zebrina [KC172066]), while sequences of CAL and H3 showed 100% identity solely with sequences of C. apii (JX142794 and JX142548). Based on combined morphological and molecular data, the pathogen infecting celery was identified as C. apii, which to our knowledge represents the first report of the presence of the causal agent of Cercospora early blight disease in Serbia. References: (1) I. Carbone and L.M. Kohn. Mycologia 91:553, 1999. (2) P. W. Crous and U. Braun. CBS Biodivers. Ser. 1:1, 2003. (3) P. W. Crous et al. Stud. Mycol. 50:415, 2004. (4) J. Z. Groenewald. Stud. Mycol. 75:115, 2013. (5) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, Inc., San Diego, CA, 1990.


Plant Disease ◽  
2001 ◽  
Vol 85 (12) ◽  
pp. 1285-1285 ◽  
Author(s):  
C. Barrau ◽  
B. de los Santos ◽  
F. Romero

An anthracnose disease was observed affecting leaves of high-bush blueberry plants (Vaccinium corymbosum L. ‘Sharpblue’) in small areas within two production fields in Huelva Province of Andalucía, in southwestern Spain. The first symptoms observed in late spring were circular, necrotic lesions, red to salmon in color, and ranging from 3 to 20 mm in diameter. Later, lesions became salmon colored in the center with a brilliant red halo. Fungal isolations were made from the lesions. Infected tissues were surface-disinfected in 1% sodium hypochlorite for 1 min, blotted dry on sterile filter paper, and plated on 2% water agar. The plates were incubated at 25°C for 5 to 10 days. Fungal colonies isolated from the tissues were transferred to potato dextrose yeast agar (PDYA). Only one fungal species was consistently isolated from affected leaf tissues and was identified as Colletotrichum acutatum J.H. Simmonds based on morphological characteristics (2) and enzyme-linked immunosorbent assay (1). Colonies of the fungus on PDYA showed a white-to-gray dense mycelium covered with salmon-colored spore masses. The reverse of the plates was a pink-salmon color. Colony diameter on PDYA averaged 50 mm after 7 days at 25°C. Conidia were hyaline, aseptate, fusiform to cylindrical, and 12.5 × 3.2 μm. Inoculation of leaves and fruits of blueberry cv. Misty with a conidial suspension (106 conidia per ml) of C. acutatum produced lesions on the leaves and fruits similar to those observed on diseased plants in the field. The pathogen was isolated from lesions on inoculated plants. To our knowledge, this is the first report of C. acutatum in high-bush blueberry plants in Spain. References: (1) T. A. Cooke et al. EPPO Bull. 25:57, 1995. (2) B. C. Sutton. The Coelomycetes. CMI, Kew, England, 1980.


Plant Disease ◽  
2021 ◽  
Author(s):  
Cinthia C. Cazal-Martínez ◽  
Yessica Magaliz Reyes Caballero ◽  
Alice Chávez ◽  
Pastor Enmanuel Pérez Estigarribia ◽  
Alcides Rojas ◽  
...  

The genus Pyricularia contains several fungal species known to cause diseases on plants in the Poaceae family (Klaubauf et al. 2014; Wang et al. 2019). While sampling for P. oryzae during March-2015 and April-2018, common weed Cenchrus echinatus L. was observed with leaf lesions in and around experimental wheat fields in the departments of Canindeyú and Itapúa. C. echinatus samples from both locations displayed similar leaf lesions, varying from small light brown pinpoint to elliptical brown lesions with greyish center. Symptomatic leaves were surface disinfested and cultured on potato dextrose agar (PDA) amended with 1% gentamicin at 25°C. Two monosporic isolates were obtained, one from Itapúa (ITCeh117) and the other from Canindeyú (YCeh55). The isolates were subsequently grown on oatmeal agar (OA) and PDA under a 12-h photoperiod at 25°C and evaluated after ten days for colony diameter, sporulation, macroscopic and microscopic features. Colonies on OA reached up to 4.8 cm diameter and were light grey, whereas colonies on PDA reached up to 5.3 cm diameter and were brown with grey centers, with cottony mycelium and broad white rims. Mycelium consisted of smooth, hyaline, branched, septate hyphae 4-4.5 µm diameter. Conidiophores were erect, straight or curved, unbranched, medium brown and smooth. Conidia were solitary, pyriform, pale brown, smooth, granular, 2-septate, 32-33 × 9-10 μm; truncated with protruding hilum and varied in length from 1.0 to 1.5 μm and diameters from 2.0 to 2.2 μm. Both isolates were similar and identified as Pyricularia pennisetigena, according to morphological and morphometric characteristics (Klaubauf et al. 2014). Subsequently, genomic DNA was extracted from each isolate using the primers described in Klaubauf et al. (2014) to amplify and sequence the internal transcribed spacers (ITS), partial large subunit (LSU), partial RNA polymerase II large subunit gene (RPB1), partial actin gene (ACT), and partial calmodulin gene (CAL). Sequences from each isolate (YCeh55/ITCeh117) were deposited in GenBank with the following submission ID for ITS: MN947521/MN947526, RPB1: MN984710/MN984715, LSU: MN944829/MN944834, ACT: MN917177/MN917182, and CAL: MN984688/MN984693. Phylogenetic analysis was conducted using the software Beast v1.10.4. The results obtained from the concatenated matrix of the five loci placed these isolates in the P. pennisetigena clade. To confirm pathogenicity, each isolate was adjusted to 5×104 conidia/ml of sterile water and C. echinatus plants were sprayed with the conidial suspension for isolate YCeh55, ITCeh117 or sterile water using an oilless airbrush sprayer until runoff. The three treatments were kept in the greenhouse at 25-28°C and about 75% relative humidity under natural daylight. Each treatment included three to five inoculated plants and 10 leaves were evaluated per treatment. Symptoms were observed 8-15 days after inoculation and were similar to those originally observed in the field for both isolates, whereas the control plants remained asymptomatic. P. pennisetigena was re-isolated from the inoculated leaves fulfilling Koch’s postulates. To our knowledge, this is the first report of leaf blight on C. echinatus caused by P. pennisetigena in Paraguay. The occurrence of P. pennisetigena in the region and its ability to infect economically important crops such as wheat and barley (Klaubauf et al. 2014; Reges et al., 2016, 2018) pose a potential threat to agriculture in Paraguay.


Plant Disease ◽  
2021 ◽  
Author(s):  
Na Wang ◽  
Fumei Chi ◽  
Zhirui Ji ◽  
Zongshan Zhou ◽  
Junxiang Zhang

Passion fruit (Passiflora edulis) is widely cultivated in tropic and subtropic regions. Because of its unique and intense flavour and high acidity, passion fruit juice concentrate is used in making delectable sauces, desserts, candy, ice cream, sherbet, or blending with other fruit juices. Anthracnose of passion fruit is favored by frequent rainfall and average temperatures above 27°C. In August 2018, anthracnose on passion fruit was observed in commercial plantings in Lincang, Yunnan, China (23.88 N, 100.08 E). Symptoms included lesions of oval to irregular shapes with brown to dark brown borders. Infection covered most of the fruit surface with pink-to-dark sporulation as reported by Tarnowski and Ploetz (2010). A conidial mass from an individual sorus observed on an infected fruit was isolated and cultured on potato dextrose agar (PDA) supplemented with 50 μg ml-1 of streptomycin. From a single microscopic field, two monospore isolates were dissected using a sterile needle, subcultured, and referred to as BXG-1 and BXG-2. Morphological characters including conidia colour, size, and shape were similar between the two isolates. Conidia were aseptate and cylindrical with apex and rounded base. Conidial length ranged from 12.3 to 16.1 µm (avg. 13.5) and width ranged from 5.5 to 6.2 µm (avg. 5.7). Morphologic data were consistent with Colletotrichum constrictum (Damm et al., 2012). To further confirm the fungal species, the ribosomal internal transcribed spacer (ITS), partial sequences of actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and β-tubulin 2 (TUB2) were amplified and sequenced. Primers and PCR amplification were described by Damm et al. (2012). The sequences were compared to type sequences in GenBank. The results showed the ITS (GenBank accession MW828148 and MW828149), ACT (MW855882 and MW855883), CHS-1 (MW855884 and MW855885), GAPDH (MW855886 and MW855887), and TUB2 (MW855888 and MW855889) sequences of the isolates BXG-1 and BXG-2 were 98% identical with sequence data from strain CBS:128504 of C. constrictum. A maximum likelihood tree was constructed using MEGA-X version 10.1.6 (Kumar et al., 2018) based on a combined dataset of the ITS, ACT, CHS-1, GAPDH, and TUB2 sequences of BXG-1 and BXG-2, and those of 18 Colletotrichum spp. previously deposited in GenBank (Damm et al., 2012). The phylogenetic analysis showed that BXG-1 and BXG-2 belong to the C. constrictum clade. Based on morphology and DNA sequencing, BXG-1 and BXG-2 were identified as C. constrictum. To verify pathogenicity, passion fruit were sprayed with a suspension of 1 × 105 conidia ml–1. Control fruit were sprayed with sterilized water. After inoculation, fruit were incubated in an Artificial Climate Box at 27°C and 80% RH. Necrotic symptoms appeared 8 days after inoculation and were similar to those observed on fruit form the field. The pathogen was reisolated from lesions thus fulfilling Koch’s postulates. C. constrictum has been reported to cause anthracnose of citrus from Australia (Wang et al., 2021) and mango from Italy (Ismail et al., 2015). To our knowledge, this is the first report of C. constrictum causing anthracnose on passion fruit worldwide, and these data will provide useful information for developing effective control strategies.


Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 654-654
Author(s):  
S. M. Tian ◽  
P. Ma ◽  
D. Q. Liu ◽  
M. Q. Zou

Cercospora leaf blotch disease of potato (Solanum tuberosum L.) caused by Cercospora concors (Casp.) Sacc (synonym Mycovellosiella concors (Casp.) Deighton) occurs worldwide but mainly has been reported in the cool and temperate climates of Europe, Asia, North America, and eastern Africa. Cercospora leaf blotch is usually a minor disease and may go unnoticed since it commonly occurs simultaneously with other potato leaf diseases such as late blight (caused by Phytophthora infestans) and early blight (caused by Alternaria solani) (2). Symptoms of Cercospora leaf blotch first appear on lower leaves as small, yellowish green, irregular blotches and later may appear on middle and upper leaves. As the leaves expand, the blotches enlarge and become purplish brown or black. Conidiophores and conidia form on the underside of the lesions, giving the lesions a mildewed appearance similar to late blight. Necrotic lesions are distinguished from those caused by the early blight pathogen A. solani by the lack of concentric rings (1). In more severe epidemics of Cercospora leaf blotch, potato leaves may be killed, stem lesions become dark and entire plants die, but no resulting yield loss from the disease has been documented. Potato tubers are not infected. From August to September of 2005, yellow-brown lesions appeared on the upper side of potato leaves (cv. Zihuabai, certified virus free) and gray mildew developed on the underside of leaves in potato field trials conducted in Jining County, 41°N, 113°E of Inner Mongolia, North China. The infections were observed mostly on lower and middle leaves of plants; 20 to 30% of plants were infected. In the laboratory, the mildew was scraped with a sterile scalpel and examined microscopically. The conidiophores were irregular in width, grayish, and highly branched. The conidia were numerous, light to dark, straight or slightly bent, cylindrical or obclavate, with conspicuous scars, and zero to six septa. The mature spores were from 16 to 59 μm long and 4 to 6 μm wide. The teleomorph of the fungus was not found. On the basis of the morphological characters, the causal agent was identified as C. concors. C. concors has been previously identified from potato leaves in the Engshi District of Hubei Province, China (3), but to our knowledge, this is the first report of the fungus causing Cercospora leaf blotch of potato in Inner Mongolia, North China. References: (1) G. D. Franc and B. I. Christ. Page 22 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson et al., eds. American Phytopathological Society, St. Paul, MN, 2001. (2) E. R. French. Page 19 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson et al., eds. American Phytopathological Society, St. Paul, MN, 2001. (3) S. M. Tian et al. China Potato J. 1:13, 1997.


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