scholarly journals Stagonosporopsis pogostemonis: A Novel Ascomycete Fungus Causing Leaf Spot and Stem Blight on Pogostemon cablin (Lamiaceae) in South China

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1093
Author(s):  
Zhang-Yong Dong ◽  
Ying-Hua Huang ◽  
Ishara S. Manawasinghe ◽  
Dhanushka N. Wanasinghe ◽  
Jia-Wei Liu ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
South China ◽  
Leaf Spot ◽  
Large Subunit ◽  
Fungal Species ◽  
Leaf Spot Disease ◽  
Causal Organism ◽  
Stem Blight ◽  
Southern Chinese ◽  
Pogostemon Cablin

Pogostemon cablin is one of the well-known Southern Chinese medicinal plants with detoxification, anti-bacterial, anti-inflammatory, and other pharmacological functions. Identification and characterization of phytopathogens on P. cablin are of great significance for the prevention and control of diseases. From spring to summer of 2019 and 2020, a leaf spot disease on Pogostemon cablin was observed in Guangdong Province, South China. The pathogen was isolated and identified based on both morphological and DNA molecular approaches. The molecular identification was conducted using multi-gene sequence analysis of large subunit (LSU), the nuclear ribosomal internal transcribed spacer (ITS), beta-tubulin (β-tubulin), and RNA polymerase II (rpb2) genes. The causal organism was identified as Stagonosporopsis pogostemonis, a novel fungal species. Pathogenicity of Stagonosporopsis pogostemonis on P. cablin was fulfilled via confining the Koch's postulates, causing leaf spots and stem blight disease. This is the first report of leaf spot diseases on P. cablin caused by Stagonosporopsis species worldwide.

scholarly journals First Report of a Leaf Spot on Snow Lotus Caused by Alternaria carthami in China

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 318-318
Author(s):  
S. Zhao ◽  
G. Xie ◽  
H. Zhao ◽  
H. Li ◽  
C. Li
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Tianshan Mountain ◽  
Causal Organism ◽  
Saussurea Involucrata ◽  
First Report ◽  
Spot Disease ◽  
Initial Symptoms ◽  
Snow Lotus

Snow lotus (Saussurea involucrata Karel. & Kir. ex Sch. Bip.) is an economically important medicinal herb increasingly grown in China in recent years. In June of 2005, a leaf spot disease on commercially grown plants was found in the QiTai Region, south of the Tianshan Mountain area of Xinjiang, China at 2,100 m above sea level. Disease incidence was approximately 60 to 70% of the plants during the 2006 and 2007 growing seasons. Initial symptoms appeared on older leaves as irregularly shaped, minute, dark brown-to-black spots, with yellow borders on the edge of the leaflet blade by July. As the disease progressed, the lesions expanded, causing the leaflets to turn brown, shrivel, and die. A fungus was consistently isolated from the margins of these lesions on potato dextrose agar. Fifty-eight isolates were obtained that produced abundant conidia in the dark. Conidia were usually solitary, rarely in chains of two, ellipsoid to obclavate, with 6 to 11 transverse and one longitudinal or oblique septum. Conidia measured 60 to 80 × 20 to 30 μm, including a filamentous beak (13 to 47 × 3.5 to 6 μm). According to the morphology, and when compared with the standard reference strains, the causal organism of leaf spot of snow lotus was identified as Alternaria carthami (1,4). Pathogenicity of the strains was tested on snow lotus seedlings at the six-leaf stage. The lower leaves of 20 plants were sprayed until runoff with conidial suspensions of 1 × 104 spores mL–1, and five plants sprayed with sterile distilled water served as controls. All plants were covered with a polyethylene bag, incubated at 25°C for 2 days, and subsequently transferred to a growth chamber at 25°C with a 16-h photoperiod. Light brown lesions developed within 10 days on leaflet margins in all inoculated plants. The pathogen was reisolated from inoculated leaves, and isolates were deposited at the Key Oasis Eco-agriculture Laboratory of Xinjiang Production and Construction Group, Xinjiang and the Institute of Biotechnology, Zhejiang University. No reports of a spot disease caused by A. carthami on snow lotus leaves have been found, although this pathogen has been reported on safflower in western Canada (3), Australia (2), India (1), and China (4). To our knowledge, this is the first report of a leaf spot caused by A. carthami on snow lotus in China. References: (1) S. Chowdhury. J. Indian Bot. Soc. 23:59, 1944. (2) J. A. G. Irwin. Aust. J. Exp. Agric. Anim. Husb. 16:921, 1976. (3) G. A. Petrie. Can. Plant Dis. Surv. 54:155, 1974. (4) T. Y. Zhang. J. Yunnan Agric. Univ.17:320, 2002.

Paraboeremia yungensis sp. nov., a new fungal species isolated from Las Yungas, South America, with promising tyrosinase production potential

Phytotaxa ◽  
2021 ◽  
Vol 528 (3) ◽  
pp. 191-201
Author(s):  
MARIA PATRICIA PERALTA ◽  
JOAQUÍN ALIAGA ◽  
OSVALDO DANIEL DELGADO ◽  
JULIA INÉS FARIÑA ◽  
BERNARDO ERNESTO LECHNER
Keyword(s):  
South America ◽  
Rna Polymerase Ii ◽  
Single Gene ◽  
Large Subunit ◽  
Fungal Species ◽  
Malt Extract ◽  
South American ◽  
South American Species ◽  
Morphological Studies ◽  
Identification Approach

In the context of a bioprospection programme for tyrosinase/L-DOPA- and melanin-producing fungal strains for biotechnological purposes, a hyperproducer isolate was obtained from Las Yungas rainforest, a relevant biodiverse ecoregion in North-Western Argentina. The selected strain was preliminarily identified as Paraboeremia sp. This is, to the best of our knowledge, the first native reported species of this genus in South America. Single-gene and multi-locus analyses of the internal transcribed spacer nuclear ribosomal RNA gene region (ITS), partial large subunit 28S nrDNA region (LSU), RNA polymerase II region (RPB2) and partial β-tubulin gene (TUB2) alignments were carried out to define the phylogenetic identity of this strain. As part of a polyphasic identification approach, these results were combined with morphological studies of active cultures growing on malt extract, oatmeal and potato dextrose agar plates. Incubation was performed under diverse conditions to stimulate sporulation for the subsequent micromorphological analysis. Microphotographs of pycnidia and conidia were taken with a scanning electron microscope. Maximum likelihood and Bayesian Inference analyses supported the location of the strain within the genus Paraboeremia, whilst morphological features allowed distinguishing it from previously described species within this genus. Based on the results herein reported, the new South-American species Paraboeremia yungensis is described and proposed.

scholarly journals Morphology and Molecular Characteristics of Alternaria sonchi Causing Brown Leaf Spot on Sonchus asper in Korea

2021 ◽  
Vol 27 (3) ◽  
pp. 107-114
Author(s):  
Huan Luo ◽  
Myung Soo Park ◽  
Jun Myoung Yu
Keyword(s):  
Rna Polymerase Ii ◽  
Leaf Spot ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Leaf Spot Disease ◽  
Molecular Characteristics ◽  
Internal Transcribed Spacer Region ◽  
Sonchus Asper ◽  
Brown Leaf Spot ◽  
Brown Leaf

During a disease survey on weeds and minor cultivated crops in Korea, a brown leaf spot disease was observed on Sonchus asper. Leaf lesions were round or irregular in shape, and grayish brown to brown with a purple margin. In severe infection, lesions enlarged and coalesced, resulting in blighting of the leaves. The isolates from these leaf lesions were identified as Alternaira sonchi based on morphological characteristics and phylogenetic analyses of Internal transcribed spacer region, Alternaria allergen a1, glyceraldehyde 3-phosphate dehydrogenase, RNA polymerase II, and translation elongation factor genes. This study provides a comprehensive description of the morphological characteristics and phylogenetical traits of A. sonchi causing brown leaf spot on S. asper in Korea.

scholarly journals Description of Lepiotaceous Fungal Species of the Genera Chlorophyllum, Clarkeinda, Macrolepiota, Pseudolepiota, and Xanthagaricus, from Laos and Thailand

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 666
Author(s):  
Phongeun Sysouphanthong ◽  
Naritsada Thongklang ◽  
Jian-Kui Liu ◽  
Else C. Vellinga
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Internal Transcribed Spacer ◽  
Phylogenetic Analyses ◽  
Large Subunit ◽  
Fungal Species ◽  
Ongoing Research ◽  
Line Drawings ◽  
Dna And Rna ◽  
First Time

In our ongoing research on lepiotaceous taxa (Agaricaceae s.l.) in Laos and northern Thailand, we focus here on Chlorophyllum, Clarkeinda, Macrolepiota, Pseudolepiota, and Xanthagaricus. Collections were obtained from various habitats, including agricultural habitats, grasslands, and rainforests. A total of 12 taxa were examined and investigated. Of these 12, two are new for science; viz. Xanthagaricus purpureosquamulosus with brownish-grey to violet-brown squamules on a pale-violet to violet background; it shares the pileus color with X. caeruleus and X. ianthinus, but differs in other characters; and Macrolepiota excelsa, rather similar to M. procera but related toM. detersa. Two species, Pseudolepiota zangmui and Xanthagaricus necopinatus are recorded for the first time in Thailand. Four species of Chlorophyllum and a total of four species of Macrolepiota were found, viz., C. demangei and C. hortense with white basidiospores, C. molybdites and C. globosum with green basidiospores, M. detersa, M. dolichaula, the new M. excelsa, and M. velosa. Another rather common striking species is Clarkeinda trachodes, with yellow-green basidiospores. Each species is described in detail, with color photographs and line drawings. Phylogenetic analyses based on internal transcribed spacer (nrITS) region, the large subunit nuclear ribosomal (nrLSU) DNA and RNA polymerase II second largest subunit (rpb2) genes provide evidence for the placement of the species covered.

scholarly journals First Report of a Leaf Blight Caused by Pyricularia pennisetigena on Cenchrus echinatus in Paraguay

Plant Disease ◽  
2021 ◽  
Author(s):  
Cinthia C. Cazal-Martínez ◽  
Yessica Magaliz Reyes Caballero ◽  
Alice Chávez ◽  
Pastor Enmanuel Pérez Estigarribia ◽  
Alcides Rojas ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Large Subunit ◽  
Fungal Species ◽  
Leaf Blight ◽  
Internal Transcribed Spacers ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Potential Threat ◽  
First Report ◽  
Microscopic Features

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.

scholarly journals Status of Bacterial Leaf Spot Disease of Anthurium in Trinidad and Characterization of Native Isolates of the Causal Organism, Acidovorax anthurii

HortScience ◽  
2015 ◽  
Vol 50 (7) ◽  
pp. 1023-1027
Author(s):  
Annelle W.B. Holder ◽  
Winston Elibox ◽  
Pathmanathan Umaharan
Keyword(s):  
Leaf Spot ◽  
Strong Association ◽  
Cultivar Differences ◽  
Leaf Spot Disease ◽  
Bacterial Leaf Spot ◽  
Causal Organism ◽  
Spot Disease ◽  
Potassium Tartrate ◽  
Geographical Regions ◽  
Minimal Media

Bacterial leaf spot disease (BLS) of anthurium (Anthurium andraeanum Linden ex André), caused by Acidovorax anthurii has contributed to the decline of the anthurium industry in Trinidad along with bacterial blight disease caused by Xanthomonas axonopodis pv. dieffenbachiae. This study investigated the status of BLS 12 years after its first discovery in 10 commercial anthurium farms located in nine geographically isolated areas in Trinidad. The disease was prevalent in only four farms located in Arima, Carapo, Brazil, and Grand Couva, and was a problem only in the wet season. Severity of BLS showed a strong association with prevalence of BLS (r = 0.92; P < 0.01) and rainfall (r = 0.64; P < 0.05). Cultivar differences in susceptibility to BLS were manifested as variation in the severity of foliar symptoms in adult plants and as frequency of systemic infection and plant death in juvenile plants. The native A. anthurii isolates showed morphophysiological and biochemical properties similar to isolates reported from the French West Indies, but with some differences. Native isolates did not grow at 41 °C or produce acid from arabinose, although some isolates produced acid from sucrose and mannitol. Two isolates were negative for urease activity, and one isolate did not elicit a hypersensitive reaction on the tobacco variety, ‘Samsun NN’. The native A. anthurii isolates were positive for Tween 80 hydrolysis, negative for acid production from potassium tartrate, and variable for production of acid from ethanol. There were significant differences between isolate colony diameters on minimal media, potassium tartrate, mannitol, ethanol, and glycerol. However, growth in minimal media amended with glycerol produced the largest colony diameters (mean of 8.6 mm). Although there were differences (P < 0.001) between the native isolates with respect to aggressiveness, significant cultivar × isolate interaction was not observed. Isolates collected from different geographical regions did not differ in aggressiveness. These results show that there is greater variation in morphophysiology of A. anthurii isolates than previously reported.

Arcopilus amazonicus (Chaetomiaceae), a new fungal species from the Amazon rainforest native plant Paullinia cupana

Phytotaxa ◽  
2020 ◽  
Vol 456 (2) ◽  
pp. 145-156
Author(s):  
THIAGO F. SOUSA ◽  
ALINE O. DOS SANTOS ◽  
FELIPE M.A. DA SILVA ◽  
FERNANDA F. CANIATO ◽  
CLÁUDIA A. DE QUEIROZ ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
High Performance ◽  
Large Subunit ◽  
Laboratory Culture ◽  
Morphological Characterization ◽  
Culture Conditions ◽  
Fungal Species ◽  
Native Plant ◽  
Paullinia Cupana ◽  
Chemical Profiles

Arcopilus is a genus recently proposed after the taxonomic restructuring of Chaetomium with only seven described species so far. During the characterization of the microbiome of the Amazonian guarana plant (Paullinia cupana var. sorbilis), nine red pigment-producing strains of fungi were isolated. These strains were identified through morphological characterization and phylogenetic analysis based on the internal transcribed spacer (ITS), 28S large subunit (LSU), partial second largest subunit of RNA polymerase II (RPB2) and β-tubulin (TUB2) regions. Moreover, chemical profiles were obtained via high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS), in which the isolated strains were able to produce significant amounts of the polyketide oosporein. The obtained results indicate the occurrence of a new fungal species, A. amazonicus. Chemical analyses showed that oosporein is overproduced by these strains under laboratory culture conditions.

scholarly journals The morphology and cytology of bacterium malvacearum, E. F. S. Part II.—Reproduction and cell-fusion

1932 ◽  
Vol 111 (769) ◽  
pp. 46-52 ◽  
Keyword(s):  
Cell Fusion ◽  
Cell Body ◽  
Leaf Spot ◽  
Staining Technique ◽  
Leaf Spot Disease ◽  
Causal Organism ◽  
Spot Disease ◽  
Cotton Plants ◽  
Cytological Changes ◽  
Chromatic Material

In a earlier paper (Stoughton, 1929) an account was given of certain observation on the morphological and cytological changes undergone by Bacterium (Pseudomonas) malvacearum , E. F. S., the causal organism of the angular leaf-spot disease of cotton plants. A central, deeply-staining body was demonstrated in the bacterium, and by means of a special staining technique the changes through which it passes were traced. The structure divides simultaneously with the division of the cell-body and the method of this was described. Further evidence was assuced tending to show that this body is of the nature of a true bacterial nucleus or, alternatively, a nucleus embedded in a matrix of “chromatic” material. The formation and liberation of very small deeply-staining bodies, which appear to be identical with the “gonidia” of other workers, were described.

scholarly journals First Report of Paramyrothecium breviseta Causing Leaf Spot Disease of Coffea canephora in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Weihuai Wu ◽  
Mengfeng Zhu ◽  
YanQiong Liang ◽  
Xuehui Bai ◽  
Ying Lu ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Leaf Spot ◽  
Coffea Arabica ◽  
Coffea Canephora ◽  
Bootstrap Support ◽  
Leaf Spot Disease ◽  
Single Spore ◽  
First Report ◽  
Spot Disease ◽  
Β Tubulin

Coffee is a tropical plant with two widely cultivated species, namely Coffea arabica and Coffea canephora. A leaf spot disease causing brownish and necrotic lesions was broken out on the C. canephora coffee seedlings in a nursery in Ruili County, Yunnan Province, China, during 2018 to 2019. The incidence of the disease was 15% ~ 20%. Ten diseased leaf samples from five diseased plants were collected for pathogen isolation by tissue separation method. Leaf pieces were cut from the margin of the necrotic lesions (4 × 6 mm), surface-sterilized for 30 s in 75% ethanol, followed by 0.1% arsenic mercury solution for 15 s, then washed 3~4 times with sterilized distilled water and transferred onto potato dextrose agar (PDA) medium in petri plates. Four morphologically similar isolates were obtained from lesions and cultivated on PDA at 25°C. Initial colonies of isolates were round, neat edge, white, floccose mycelium and developed dark green-to-black concentric rings that were sporodochia bearing viscid spore masses after 5~7 days. Conidia were acetates, hyaline and cylindrical with both rounded ends and 4.8 to 6.4 µm long × 1.6 to 2.6 µm wide. Koch's test were conducted on three healthy plants leaves of original source variety C. canephora No.2 and C.arabica Catimor CIFC7963 (control plants) with spore suspension (1 × 106/mL), respectively. Meanwhile, equal numbers of healthy plants were inoculated with water as controls. After inoculation, the plants were transferred into an incubator at 25℃ with saturated humidity. After 10 days of inoculation, all the tested plants presented similar typical symptoms with the diseased leaves under natural conditions; whereas the controls remained healthy. Koch’s postulates were performed by re-isolating the fungus from the inoculated leaves and verifying its colony and morphological characters. Two single spore isolates cultured on PDA medium were selected for DNA extraction. The ribosomal internal transcribed spacer (ITS) was PCR amplified by using primers ITS1 and ITS4 (White et al., 1990), β-tubulin gene by Bt2a and Bt2b (Glass and Donaldson, 1995), the RNA polymerase II second largest subunit (rpb2) by RPB2-5F2 and RPB2-7cR (O’Donnell et al, 2007), calmodulin (cmda) gene by CAL-228F and CAL2Rd (Groenewald et al., 2013). The sequences of ITS (MT853067 ~ MT853068), β-tubulin (MT897899 ~ MT897900), rpb2 (MW256264~ MW286265) and cmda (MT897897~ MT897898) were deposited in GenBank databases. BLAST analysis revealed that the representative isolates sequences shared 99.31%~99.65% similarities to the ITS sequence of Paramyrothecium breviseta (Accession Nos. NR_155670.1), 99.43% similarities to the β-tubulin sequence of P. breviseta (Accession Nos. KU846406.1), 98.98% similarities to the rpb2 sequence of P. breviseta (Accession Nos. KU846351.1), and 98.54%~98.71% similarities to the cmda sequence of P. breviseta (Accession Nos. KU846262.1). As it shown in the phylogenetic tree derived from combined ITS, β-tubulin, rpb2, and cmda gene sequences, the two representative isolates were clustered together with P. breviseta CBS 544.75 with 98% strong bootstrap support, which confirmed that P. breviseta is the causal agent of leaf spot of Coffea canephora. To our knowledge, this is the first report of a leaf spot disease caused by P. breviseta on C. canephora in China, which raised the caution that P. breviseta is also pathogenic to Coffea Arabica.

scholarly journals First Report of Alternaria longipes Causing Leaf Spot of Potato Cultivar Sante in Pakistan

Plant Disease ◽  
2014 ◽  
Vol 98 (12) ◽  
pp. 1742-1742 ◽  
Author(s):  
A. Shoaib ◽  
N. Akhtar ◽  
S. Akhtar ◽  
R. Hafeez
Keyword(s):  
Leaf Spot ◽  
Potato Crop ◽  
Disease Incidence ◽  
Potato Cultivar ◽  
Leaf Spot Disease ◽  
Infected Leaf ◽  
Malt Extract ◽  
Fungal Culture ◽  
Causal Organism ◽  
First Report

Potato (Solanum tuberosum) is one of the most important vegetable crops worldwide, including Pakistan. During surveys from November to February of 2011 to 2013 in Sahiwal (Punjab), a severe leaf spot disease, new to farmers, was recorded. Symptoms consisted of 1- to 3-mm diameter black circular necrotic spots and appeared on the leaves of 2- to 3-week-old plants. Disease incidence was ~70 to 80%. This disease was localized to few fields in Sahiwal on potato variety Sante and to our knowledge, this has not been found on other areas or potato varieties in Pakistan. Fungi were isolated from randomly selected diseased plants. Ten infected plants were brought to the laboratory in sterilized polyethylene bags. One infected leaf per plant was selected for pathogen isolation. Infected parts of leaves were cut into ~2 mm2 pieces. Leaf pieces were surface sterilized for 1 min with 0.5% sodium hypochlorite and then inoculated aseptically onto 2% malt extract agar (MEA) (Sigma, Dorset, UK) and incubated at 25 ± 2°C for 3 to 4 days in the dark. Hyphal tip transfer from emerging colonies was performed to obtain pure cultures. Initial microscopic examination of pure fungal colonies revealed Alternaria as the likely causal organism. For morphology-based identification, five isolates from separate infected leaves were grown on MEA as well as potato carrot agar (PCA) for 7 days. All isolates showed similar morphological characters including dusty greenish black, floccose colonies with regular and smooth margins reaching 3 to 4.5 cm in diameter on MEA and sporulation with well-defined zones of growth. Aerial hyphae produced long branches that bore lateral chains of 1 to 7 conidia. Conidia were pointed at the tip, ovoid or ellipsoid, ranged from 18 to 40 × 5 to 12 μm with 4 to 8 transverse and 0 to 1 longitudinal septa. No conidial beak was present. Conidial color darkened from dull olive to brown as the culture matured. Based on morphology, the pathogen was identified as Alternaria longipes (1). A pure culture of a fungal pathogen was submitted to First Fungal Culture Bank of Pakistan (FCBP1355) for future reference. To confirm the morphology-based identification, the rDNA internal transcribed spacer (ITS) nucleotide sequence was amplified using ITS1 forward and ITS4 reverse primers (2). The amplicon of 537 bp was sequenced and submitted to GenBank under accession KJ806191. A BLASTn search using the KJ806191 sequence revealed it to be 99% identical to around 20 different strains of A. longipes deposited in GenBank including leaf spot pathogens of another Solanaceaeous member, Nicotiana tabacum (AY154684) and Asteraceous plant, Atractylodes macrocepha (JQ004404). Pathogenicity testing was performed in the greenhouse at 30 ± 2°C. Pots (16 × 9 cm) were filled with sterilized soil. Since spores of Alternaria sp. are known to survive in soil or plant debris, soil was sterilized and inoculated with 106 spore suspension of the isolated pathogen before sowing the potato seeds. Control pots were not inoculated. Approximately 10 days after plant germination, the previously observed disease symptoms appeared on leaves and A. longipes was re-isolated from the necrotic areas of leaves, thus fulfilling Koch's postulates. Plants in control treatments were asymptomatic. Pathogenicity tests were repeated three times. To our knowledge, this is the first report of A. longipes leaf spot of potato cultivar Sante from Pakistan. However, the distribution of this disease is confined to the area where it was observed, but it could be a threat for potato crop if not managed timely. References: (1) E. G. Simmons. Alternaria: An identification manual. CBS, Fungal Biodiversity Center Utrecht, The Netherlands, 2007. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

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