scholarly journals Survey and prevalence of species causing Alternaria leaf spots on brassica species in Pernambuco

2012 ◽  
Vol 30 (2) ◽  
pp. 345-348 ◽  
Author(s):  
Sami J Michereff ◽  
Marissônia A Noronha ◽  
Maria S Xavier Filha ◽  
Marcos PS Câmara ◽  
Ailton Reis
Keyword(s):  
Chinese Cabbage ◽  
Brassica Species ◽  
Alternaria Brassicicola ◽  
Leaf Spot Disease ◽  
Vegetable Crops ◽  
Growing Seasons ◽  
Leaf Spots ◽  
Brassica Crops ◽  
Brassicaceae Species ◽  
Alternaria Species

Brassicaceae family comprises plant species that are very important as vegetable crops, such as the species complex Brassica oleracea and Brassica rapa. Alternaria brassicicola and A. brassicae are among the most important pathogens of Brassicaceae causing Alternaria leaf spot disease. The occurrence and prevalence of Alternaria species causing leaf spots in brassica crops in Pernambuco was acessed, as well as the existence of a possible preference by vegetable host for these pathogens. Twenty-eight fields were surveyed in the Agreste region of Pernambuco state, in the 2005 and 2006 growing seasons. In each year, 10 Chinese cabbage, six cabbage, six cauliflower and six broccoli fields were visited. In each field, 50 leaves showing at least five lesions were randomly collected. Species identification was performed taking into account morphology of the conidia that was compared with literature data. Among the two Alternaria species found, A. brassicae was found in all Chinese cabbage fields while A. brassicicola was found in all fields of cabbage, cauliflower and broccoli. Overall, A. brassicicola was more prevalent than A. brassicae. In Chinese cabbage there was predominance of A. brassicae, with mean prevalence of 91.0% and 96.5% in 2005 and 2006. On the other hand, in broccoli and cabbage there was high predominance of A. brassicicola, with mean prevalence between 95.1% and 99.8%. In cauliflower, although the prevalence has been of A. brassicicola, high frequency of A. brassicae was noted. The frequency of co-occurrence of both Alternaria species was very low. The results of this study reinforce the hypothesis of existence of host preference within species of Alternaria that cause leaf spots in brassica crops, especially when Chinese cabbage, broccoli and cabbage are considered. This information is critical to developing strategies for managing Alternaria leaf spots in Brassicaceae species.

scholarly journals Morphological and Molecular Characterization of Alternaria Species Isolated from Different Plants

2021 ◽  
pp. 61-71
Author(s):  
Pooja Singh ◽  
Sushma Nema ◽  
Keerti Tantwai
Keyword(s):  
Infected Plant ◽  
Alternaria Brassicicola ◽  
Leaf Spots ◽  
The Family ◽  
Ctab Method ◽  
Alternaria Species ◽  
Alternaria Sp ◽  
Thermal Cycler ◽  
Almost All

Alternaria belongs to the family of Pleosporaceae, the order of Pleosporales, the class of Dothideomycetes in the phyllum of Ascomycota. This fungal genus is characterized by its ability to produce a number of enzymes able to injured many types of crops. The symptoms of Alternaria blight on different agricultural crops such as cabbage, cauliflower, coriander, fenugreek, brinjal, onion, faba bean, dahlia, dracaena, hollyhock, carrot, marigold, tomato and wheat were observed. Alternaria produces distinctive "bulls eye" patterned leaf spots in almost all the infected plants. Nineteen Alternaria isolates were obtained from fourteen infected plant samples. The observations were recorded from the seven day old culture for colony characteristics on PDA. Based on morphology 10 isolates of Alternaria alternata, two isolates Alternaria tenuissima and Alternaria longipes and one Alternaria porri, Alternaria brassicae, Alternaria brassicicola and Alternaria sp. were identified. Alternaria species grow rapidly and produced flat, downy to woolly grayish green to black colonies. All the isolates exhibited characteristics dark-coloured multicelled conidia with longitudinal and transverse septa (phaeo-dictyospores) and a beak or tapering apical cells. DNA isolation of all isolates of Alternaria was carried out using CTAB method. Isolated DNA was subjected to amplification with ITS1 and ITS4 primers in a thermal cycler. The amplified products ranged from 580-600bp. These amplified products were sequenced and identify the species of different Alternaria isolates using BLASTn in NCBI online. All the sequences were published in NCBI public domain. The resulting sequences of all isolates were compared to other sequences in the GenBank as 90-100% identical. Genetic variability was conducted by phylogenetic analysis.

scholarly journals Distribution and pathogenic peculiarities of fungi of the Alternaria genus on vegetable crops in Lithuania

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 395-398
Author(s):  
A. Shidlauskienė ◽  
E. Survilienė
Keyword(s):  
Alternaria Solani ◽  
Alternaria Brassicicola ◽  
Alternaria Brassicae ◽  
Vegetable Crops ◽  
Plant Cultivation ◽  
Antagonistic Microorganisms ◽  
Alternaria Dauci ◽  
Alternaria Species ◽  
Streptomyces Griseoviridis ◽  
Plant Activator

In 1999–2001 the investigation of Alternaria species on vegetable crops: cabbage, cucumber, tomato and carrot was carried out and fungi species were isolated from vegetables and substrata used for plant cultivation. Isolated micromycetes: Alternaria alternata, Alternaria tenuissima, Alternaria brassicae, Alternaria brassicicola, Alternaria cucurbitae, Alternaria dauci, Alternaria radicina and Alternaria solani differed in pathogenic peculiarities, frequency of occurrence and their various reaction to fungicides (a.s. azoxystrobin, dichlofluanid, Cooper hydroxide, mancozeb, propamocarb hydrochloride), plant activator Bion (benzothadiazole) and antagonistic microorganisms (Trichoderma harzianum, Streptomyces griseoviridis).

scholarly journals A New Bacterial Disease on Bluberry (Vaccinium Corymbosum) Caused by Pseudomonas Spp.

2013 ◽  
Vol 53 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Monika Kałużna ◽  
Joanna Puławska ◽  
Beata Meszka
Keyword(s):  
Hypersensitivity Reaction ◽  
Pseudomonas Syringae ◽  
Vaccinium Corymbosum ◽  
Leaf Spot Disease ◽  
Bacterial Disease ◽  
Pseudomonas Spp ◽  
Leaf Spots ◽  
Pectolytic Activity ◽  
Young Leaves ◽  
First Time

Abstract In 2011, leaf spot disease was observed on the blueberry (Vaccinium corymbosum) cv. Nelson growing on a commercial field located in Central Poland. The disease symptoms could be seen as russet brown, irregular spots. The diameter of the spots was 0.3-0.5 cm, and the spots often coalesced. From these leaf spots, a fluorescent bacterium was repeatedly isolated in almost pure culture. Polymerase chain reaction (PCR) using primers Ps-for and Ps-rev, specific for Pseudomonas spp. confirmed that they belong to this genus. Based on LOPAT tests [levan production from sucrose (L), presence of oxidase (O), pectolytic activity on potato (P), the presence of arginine dihydrolase (A), hypersensitivity reaction on tobacco (T)], 6 isolates were classified to the LOPAT group Ib - group of Pseudomonas syringae subsp. savastanoi and Pseudomonas delphini, and one isolate to group Ia - P. syringae. All isolates caused a hypersensitivity reaction on tobacco plants, and symptoms similar to those under natural conditions, when young leaves of blueberry cv. Nelson were inoculated. Sequence analysis of 16S rRNA and rpoB genes showed the highest similarity of 6 studied strains to the species P. avellanae. Further taxonomic study is necessary to enable definitive classification of these isolates. It is the first time that a bacterial disease caused by the Pseudomonas spp. was observed in Poland.

scholarly journals Thlaspi arvense, a New Host for Alternaria brassicicola

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 960-960 ◽  
Author(s):  
A. C. Cobb ◽  
H. R. Dillard
Keyword(s):  
Leaf Spot ◽  
Production Systems ◽  
Geographic Location ◽  
Alternaria Brassicicola ◽  
New Host ◽  
Cornell University ◽  
Thlaspi Arvense ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Field Pennycress

A leaf spot was observed on cruciferous weeds growing in a cabbage field located in Geneva, NY, on 1 August 1996. The leaf spots on the weeds were dark gray to black in color and varied in size from pinpoints to 1 mm in diameter. The cabbage (Brassica oleracea L. var. capitata L.) was infected with Alternaria brassicicola (Schwein.) Wiltshire, the cause of Alternaria leaf spot. The weeds were identified as Thlaspi arvense L., a winter annual commonly referred to as field pennycress, stinkweed, or fanweed depending on geographic location. Isolations from the diseased weed tissue yielded A. brassicicola (2). The numerous conidia occurred in chains of 10 or more, ranged in size from 14 to 53 μm in length, were 5 to 18 μm wide, contained from 1 to 6 transverse septa with rare longitudinal septa, and were olivaceous in color. An apical beak was absent. On potato dextrose agar (PDA) the colony was dark olive-green to black in color and velvety. Seed was collected from the T. arvense plannts in the spring of 1997. One hundred seeds were placed in petri plates containing PDA amended with 0.01% of chloramphenicol and streptomycin sulfate. A. brassicicola was not isolated from the seeds. A different area of the field was planted to cabbage in 1997 and the cruciferous weeds were allowed to grow. The 1997 population of T. arvense consisted of plants from the previous season that flowered early and plants from seeds that germinated late in the season but did not flower. A. brassicicola was isolated from nonflowering weeds in September and from flowering weeds in October. Nonflowering plants were removed from the field in November, planted in pots, and placed in the greenhouse to induce flowering. Identity of both plant populations was confirmed as T. arvense (Warren Lamboy, Cornell University, Geneva, NY). Pathogencity of A. brassicicola isolates from T. arvense was demonstrated on cabbage and T. arvense by following Koch's postulates. Conidia (105) from a 5-day-old culture isolated from T. arvense grown on PDA were atomized onto field pennycress and cabbage plants with a Preval sprayer. The plants were enclosed in plastic bags and put under lathe shading in the greenhouse. The pathogen was reisolated from symptomatic tissue of both plants after 5 days. This weed could serve as a potential source of A. brassicicola inoculum because it is not controlled by herbicides used in crucifer production systems. Alternaria raphani has been reported on T. arvense in Canada (1). This is believed to be the first report of A. brassicicola on T. arvense. References: (1) K. Mortensen et al. Can. Plant Dis. Surv. 73:129, 1993. (2) P. Neergaard. 1945. Danish Species of Alternaria and Stemphylium. Oxford University Press, London. pp. 137–138.

scholarly journals First Report of a Leaf Spot Disease of Bells-of-Ireland (Moluccella laevis) Caused by Cercospora apii in California

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 203-203
Author(s):  
S. T. Koike ◽  
S. A. Tjosvold ◽  
J. Z. Groenewald ◽  
P. W. Crous
Keyword(s):  
Leaf Spot ◽  
Sequence Data ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Spot Disease ◽  
Leaf Spots ◽  
Initial Symptoms

Bells-of-Ireland (Moluccella laevis) (Lamiaceae) is an annual plant that is field planted in coastal California (Santa Cruz County) for commercial cutflower production. In 2001, a new leaf spot disease was found in these commercially grown cutflowers. The disease was most serious in the winter-grown crops in 2001 and 2002, with a few plantings having as much as 100% disease incidence. All other plantings that were surveyed during this time had at least 50% disease. Initial symptoms consisted of gray-green leaf spots. Spots were generally oval in shape, often delimited by the major leaf veins, and later turned tan. Lesions were apparent on both adaxial and abaxial sides of the leaves. A cercosporoid fungus having fasciculate conidiophores, which formed primarily on the abaxial leaf surface, was consistently associated with the spots. Based on morphology and its host, this fungus was initially considered to be Cercospora molucellae Bremer & Petr., which was previously reported on leaves of M. laevis in Turkey (1). However, sequence data obtained from the internal transcribed spacer region (ITS1, ITS2) and the 5.8S gene (STE-U 5110, 5111; GenBank Accession Nos. AY156918 and AY156919) indicated there were no base pair differences between the bells-of-Ireland isolates from California, our own reference isolates of C. apii, as well as GenBank sequences deposited as C. apii. Based on these data, the fungus was subsequently identified as C. apii sensu lato. Pathogenicity was confirmed by spraying a conidial suspension (1.0 × 105 conidia/ml) on leaves of potted bells-of-Ireland plants, incubating the plants in a dew chamber for 24 h, and maintaining them in a greenhouse (23 to 25°C). After 2 weeks, all inoculated plants developed leaf spots that were identical to those observed in the field. C. apii was again associated with all leaf spots. Control plants, which were treated with water, did not develop any symptoms. The test was repeated and the results were similar. To our knowledge this is the first report of C. apii as a pathogen of bells-of-Ireland in California. Reference: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Cornell University Press, Ithaca, New York, 1954.

scholarly journals First Report of a Leaf Spot Caused by Alternaria brassicae on the Invasive Weed Lepidium draba in North America

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 846-846 ◽  
Author(s):  
A. J. Caesar ◽  
R. T. Lartey
Keyword(s):  
North America ◽  
Chinese Cabbage ◽  
Leaf Spot ◽  
The United States ◽  
Alternaria Brassicae ◽  
Voucher Specimen ◽  
First Report ◽  
Leaf Spots ◽  
Black Spots ◽  
Lepidium Draba

The exotic, rangeland weed Lepidium draba L., a brassicaceous perennial, is widely distributed in the United States. For example, Oregon contains 100,000 ha of land infested with L. draba (2). Because it is capable of aggressive spread and has the potential to reduce the value of wheat-growing land (4), it is the target of biological control research. The application of multiple pathogens has been advocated for control of other brassicaceous weeds, including the simultaneous application of biotrophic and necrotrophic pathogens (3). In pursuit of this approach, in 2007, we discovered the occurrence of leaf spots on approximately 90% of L. draba plants near Shepherd, MT, which were distinct from leaf lesions caused by Cercospora bizzozeriana (1). The lesions were initially tiny, black spots enlarging over time to become circular to irregular and cream-colored around the initial black spots and sometimes with dark brown borders or chlorotic halos. Conidia from the lesions were light brown, elongate and obclavate, produced singly from short conidia, with 8 to 12 transverse septa, and 2 to 6 longitudinal septa. The spore body measured 25 to 35 × 200 to 250 μm with a beak cell 42 to 100 μm long. On the basis of conidial and cultural characteristics, the fungus was identified as Alternaria brassicae (Berk.) Sacc. Leaf tissues bordering lesions were plated on acidified potato dextrose agar. Colonies on V8 and alfalfa seed agar were black with concentric rings, eventually appearing uniformly black after 10 to 14 days. The internal transcribed spacer region of rDNA was amplified using primers ITS1 and ITS4 and sequenced. BLAST analysis of the 575-bp fragment showed a 100% homology with a sequence of A. brassicae Strain B from mustard (GenBank Accession No. DQ156344). The nucleotide sequence has been assigned GenBank Accession No. FJ869872. For pathogenicity tests, aqueous spore suspensions approximately 105/ml were prepared from cultures grown at 20 to 25°C for 10 to 14 days on V8 agar and sprayed on leaves of three L. draba plants. Inoculated plants were enclosed in plastic bags and incubated at 20 to 22°C for 72 to 80 h. In addition, three plants of the following reported hosts of A. brassicae were inoculated: broccoli, canola, Chinese cabbage, collards, broccoli raab, kale, mustard greens, radish, rape kale, and turnip. Within 10 days, leaf spots similar to those described above developed on plants of radish, canola, Chinese cabbage, and turnip and A. brassicae was reisolated and identified. Control plants sprayed with distilled water remained symptomless. These inoculations were repeated and results were the same. To our knowledge, this is the first report of a leaf spot disease caused by A. brassicae on L. draba in North America. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI No. 878750A). References: (1) A. J. Caesar et al. Plant Dis. 93:108, 2009. (2) G. L. Kiemnec and M. L. McInnis. Weed Technol. 16:231, 2002. (3) A. Maxwell and J. K. Scott. Adv. Bot. Res. 43:143, 2005. (4) G. A. Mulligan and J. N. Findlay. Can. J. Plant Sci. 54:149, 1974.

Alternaria telliensis sp. nov., a new species isolated from Solanaceae in Algeria

Phytotaxa ◽  
2020 ◽  
Vol 440 (2) ◽  
pp. 89-100
Author(s):  
NABAHAT BESSADAT ◽  
BRUNO HAMON ◽  
NELLY BATAILLE-SIMONEAU ◽  
KIHAL MABROUK ◽  
PHILIPPE SIMONEAU
Keyword(s):  
New Species ◽  
Elongation Factor ◽  
Translation Elongation ◽  
Biodiversity Survey ◽  
Growing Seasons ◽  
Elongation Factor 1 Alpha ◽  
Alternaria Species ◽  
Pathogenicity Tests ◽  
North Western ◽  
A New Species

During a biodiversity survey of Alternaria associated with leaf spot and blight of Solanaceae, a large collection of strains was obtained from samples collected in north-western regions of Algeria in 2013–2018 growing seasons. Amongst these strains, three isolates recovered from tomato and potato had morphological traits different from that usually observed for Alternaria species previously reported on Solanaceae. Based on analysis of a sequence dataset corresponding to portions of the glyceraldehyde-3-phosphate dehydrogenase (gpd), translation elongation factor 1-alpha (tef1) and RNA polymerase second largest subunit (rpb2) genes along with morphological observations, isolates were identified as a new species in the section Japonicae. This novel species, described here as Alternaria telliensis, is phylogenetically and morphologically distinct from A. japonica and A. nepalensis in this section. Pathogenicity tests were performed and isolates were found to be weakly pathogenic to tomato and potato (Solanaceae) while highly aggressive on radish, cabbage and turnip (Brassicaceae) plants.

Pathogenic fungal protein-induced resistance and its effects on vegetable diseases

2017 ◽  
Vol 155 (7) ◽  
pp. 1069-1081 ◽  
Author(s):  
T.-C. LIN ◽  
C.-L. LIN ◽  
W.-C. CHUNG ◽  
K.-R. CHUNG ◽  
J.-W. HUANG
Keyword(s):  
Chinese Cabbage ◽  
Fungal Pathogens ◽  
Plant Defence ◽  
Black Spot ◽  
Sweet Pepper ◽  
Alternaria Brassicicola ◽  
Biotic And Abiotic Stress ◽  
Promote Plant Growth ◽  
Test Plants ◽  
Reduce Disease Severity

SUMMARYPlant defence systems can be induced by biotic and abiotic stress. Experiments were undertaken to explore the feasibility of different fungal proteins for the reduction of vegetable diseases. Total proteins purified from three soil-borne and five foliar fungal pathogens had no fungistatic effects nor did they trigger hypersensitive reactions on test plants. The abilities to promote plant growth and to reduce disease severity varied among test proteins and plants. Depending on test proteins, experiments have demonstrated that exogenous application of fungal proteins could reduce Alternaria brassicicola-induced black spot severity on cabbage, Colletotrichum spp.-induced anthracnose on Chinese cabbage and cucumber, Rhizoctonia solani-induced damping-off on sweet pepper and Chinese cabbage, and powdery mildew on cucumber seedlings. An Alternariaprotein effector 1 (Ape1)-coding gene was cloned from two Alternaria spp. and expressed in Escherichia coli. The expressed Ape1 reduced anthracnose incidence on cucumber leaves, indicating that Ape1 was the primary activator in the crude protein extracts responsible for disease reduction. Application of Alternaria proteins onto Chinese cabbage seedlings caused an increase of phenylalanine ammonia lyase and peroxidase activities in treated seedlings, which may have played a role in host defence.

scholarly journals Host–pathogen interactions in relation to management of light leaf spot disease (caused by Pyrenopeziza brassicae) on Brassica species

2018 ◽  
Vol 69 (1) ◽  
pp. 9 ◽  
Author(s):  
Chinthani S. Karandeni Dewage ◽  
Coretta A. Klöppel ◽  
Henrik U. Stotz ◽  
Bruce D. L. Fitt
Keyword(s):  
Leaf Spot ◽  
Fungal Pathogens ◽  
Molecular Mechanisms ◽  
Brassica Species ◽  
Leaf Spot Disease ◽  
Yield Losses ◽  
Sources Of Resistance ◽  
Management Tools ◽  
Brussels Sprouts ◽  
Main Component

Light leaf spot, caused by Pyrenopeziza brassicae, is the most damaging disease problem in oilseed rape (Brassica napus) in the United Kingdom. According to recent survey data, the severity of epidemics has increased progressively across the UK, with yield losses of up to £160M per annum in England and more severe epidemics in Scotland. Light leaf spot is a polycyclic disease, with primary inoculum consisting of airborne ascospores produced on diseased debris from the previous cropping season. Splash-dispersed conidia produced on diseased leaves are the main component of the secondary inoculum. Pyrenopeziza brassicae is also able to infect and cause considerable yield losses on vegetable brassicas, especially Brussels sprouts. There may be spread of light leaf spot among different Brassica species. Since they have a wide host range and frequent occurrence of sexual reproduction, P. brassicae populations are likely to have considerable genetic diversity, and evidence suggests population variations between different geographic regions, which need further study. Available disease-management tools are not sufficient to provide adequate control of the disease. There is a need to identify new sources of resistance, which can be integrated with fungicide applications to achieve sustainable management of light leaf spot. Several major resistance genes and quantitative trait loci have been identified in previous studies, but rapid improvements in the understanding of molecular mechanisms underpinning B. napus–P. brassicae interactions can be expected through exploitation of novel genetic and genomic information for brassicas and extracellular fungal pathogens.

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