scholarly journals Morphological, physiological and pathogenic variability of small-spore Alternaria sp. causing leaf blight of Solanaceous plants in Algeria

2014 ◽  
Vol 8 (37) ◽  
pp. 3422-3434 ◽  
Author(s):  
Nabahat BESSADAT ◽  
Philippe SIMONEAU ◽  
Soumaya BENICHOU ◽  
Benali SETTI ◽  
Mabrouk Kihal ◽  
...  
Keyword(s):  
Leaf Blight ◽  
Alternaria Sp ◽  
Small Spore ◽  
Pathogenic Variability ◽  
Solanaceous Plants

scholarly journals Cultural, Morphological and Pathogenic Variability of Exserohilum turcicum causing Turcicum Leaf Blight in Maize

2019 ◽  
Vol 8 (11) ◽  
pp. 302-313
Author(s):  
Gee ta ◽  
D.S. Aswathanarayana ◽  
M.K. Naik ◽  
Mallikarjun Kenganal ◽  
Prakash H. Kuchanur
Keyword(s):  
Leaf Blight ◽  
Exserohilum Turcicum ◽  
Pathogenic Variability

Alternaria spp. associated with leaf blight of maize in Heilongjiang Province, China

Plant Disease ◽  
2021 ◽  
Author(s):  
Xi Xu ◽  
Li Zhang ◽  
Xilang Yang ◽  
Hanshui Cao ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Population Expansion ◽  
Leaf Blight ◽  
Economic Losses ◽  
Heilongjiang Province ◽  
Maize Leaves ◽  
Alternaria Species ◽  
Alternaria Sp

Maize is a major economic crop worldwide. Maize can be infected by Alternaria species causing leaf blight that can result in significant economic losses. In this study, 168 Alternaria isolates recovered from symptomatic maize leaves were identified based on morphological characteristics, pathogenicity, and multi-locus sequence analyses of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the internal transcribed spacer of ribosomal DNA (rDNA ITS), the RNA polymerase II second largest subunit (RPB2), and histone 3 (HIS3). Maize isolates grouped to four Alternaria species including Alternaria tenuissima, A. alternata, A. burnsii, and Alternaria sp. Notably, A. tenuissima (71.4%) was the most prevalent of the four isolated species, followed by A. alternata (21.5%), Alternaria sp. (4.1%), and A. burnsii (3.0%). Pathogenicity tests showed that all four Alternaria species could produce elliptic to nearly round, or strip lesions on leaves of maize, gray white to dry white in the lesions center and reddish brown in the edge. The average disease incidence (58.47%) and average disease index (63.55) of maize leaves inoculated with A. alternata were significantly higher than levels resulting from A. tenuissima (55.28% and 58.49), Alternaria sp. (55.34% and 58.75), and A. burnsii (56% and 55). Haplotype analyses indicated that there were 14 haplotypes of A. tenuissima and 5 haplotypes of A. alternata in Heilongjiang province and suggested the occurrence of a population expansion. Results of the study showed that Alternaria species associated with maize leaf blight in Heilongjiang province are more diverse than those have been previously reported. This is the first report globally of A. tenuissima, A. burnsii, and an unclassified Alternaria species as causal agents of leaf blight on maize.

Morphological and Molecular Characterization of Alternaria Species Causing Leaf Blight on Watermelon in China

Plant Disease ◽  
2021 ◽  
Vol 105 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Guoping Ma ◽  
Shuwen Bao ◽  
Juan Zhao ◽  
Yuan Sui ◽  
Xuehong Wu
Keyword(s):  
Rna Polymerase Ii ◽  
Disease Incidence ◽  
Disease Index ◽  
Leaf Blight ◽  
Economic Losses ◽  
Rdna Its ◽  
Detached Leaves ◽  
Alternaria Species ◽  
Alternaria Sp ◽  
The One

Watermelon is an economically important crop in China and is commonly affected by Alternaria-like leaf blight that can result in significant economic losses. In this study, 830 Alternaria isolates, recovered from symptomatic watermelon leaves, were identified based on morphological traits, pathogenicity, and multilocus sequence analyses of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone 3 (HIS3), the internal transcribed spacer of ribosomal DNA (rDNA ITS), and the RNA polymerase II second largest subunit (RPB2). Watermelon isolates grouped to five Alternaria species and one unclassified Alternaria species. They were A. tenuissima, A. alternata, A. cucumerina, A. infectoria, A. gaisen, and Alternaria sp. Notably, A. tenuissima was the most prevalent (73.5%) of the six isolated species, followed by A. alternata (25.0%), A. cucumerina (1.1%), Alternaria sp. (0.2%), A. infectoria (0.1%), and A. gaisen (0.1%). Pathogenicity tests demonstrated that all six Alternaria species could produce brown necrotic lesions on detached leaves of watermelon. The average disease incidence (75.1%) and average disease index (60.8) of watermelon resulting from inoculation of leaves with A. cucumerina were significantly higher than levels resulting from A. alternata (52.9% and 37.2) and A. tenuissima (47.5% and 30.8). Inoculation with Alternaria sp. resulted in a disease incidence (70.0%) and disease index (51.5), which were lower than those of A. cucumerina. The disease incidence and disease index in watermelon leaves inoculated with the one isolate of A. infectoria and the one isolate of A. gaisen present in the inoculated leaves were 28.9% and 16.4, and 48.9% and 31.4, respectively. Results of the study indicate that Alternaria species associated with watermelon leaf blight in China are more diverse than that has been previously reported. This is the first report globally of A. infectoria, A. gaisen, and an unclassified Alternaria species as causal agents of leaf blight on watermelon.

Chemical Control of Alternaria sp. Causing Leaf Blight of Wheat

1970 ◽  
Vol 16 (3) ◽  
pp. 522-524
Author(s):  
A. B. Mishra ◽  
S. P. Singh ◽  
S. M. Harne ◽  
S. V. Velenkar
Keyword(s):  
Chemical Control ◽  
Leaf Blight ◽  
Alternaria Sp

scholarly journals Pathogenic variability in Exserohilum turcicum and identification of resistant sources to turcicum leaf blight of maize (Zea mays L.)

2016 ◽  
Vol 8 (3) ◽  
pp. 1523-1529
Author(s):  
M. Ashraf Ahangar ◽  
Z. A. Bhat ◽  
F. A. Sheikh ◽  
Z. A. Dar ◽  
Ajaz A. Lone ◽  
...  
Keyword(s):  
Leaf Blight ◽  
Limiting Factor ◽  
Exserohilum Turcicum ◽  
Maize Production ◽  
Maize Genotypes ◽  
Pathogenic Variation ◽  
Early Maturing ◽  
Differential Hosts ◽  
Pathogenic Variability ◽  
Moderately Resistant

Turcicum leaf blight of maize incited by Exserohilum turcicum (Pass.) Leonard and Suggs is the major limiting factor of maize production in temperate agro-ecologies. Disease management through host plant resistance is the most effective strategy. In the present study among 26 maize genotypes which were initially screened for resistance against E. turcicum under field conditions, 8 genotypes viz., PS 39, CML 451, CML 470, CML 472, VL 1030, VL 1018140, VL1018527 and SMI178-1 were found resistant when screened against twelve isolates of E. turcicum under artificial epiphytotic conditions. Eight genotypes viz., PS45, CML165, CML459, VL1249, VL0536, SMC-5, SMC-3 and KDL 211 were found moderately resistant with disease grade ranged from 2.1-2.5. These maize genotypes possess resistance to turcicum leaf blight can be used successfully in developing high yielding early maturing varieties for high altitude temperate agro-ecologies. The fungus E. turcicum is highly variable in nature. Variability studies on pathogenicity were conducted on twelve isolates of E. turcicum on eleven putative differential maize lines. During the present study a wide pathogenic variation was observed among the twelve isolates of E. turcicum. Cluster analysis on the basis of similarity or dissimilarity in reaction types exhibited by the differential hosts, clustered the isolates into 6 pathogenic groups. The isolates belonged to higher altitudes (Kti 10, Kti11, Kti5) were found to be more aggressive as compared to the isolates of low altitude areas.

scholarly journals Alternaria spp. implicated in a disease complex of onion leaf blight in the tropics.

1969 ◽  
Vol 95 (1-2) ◽  
pp. 57-78
Author(s):  
Jessie Fernández ◽  
Lydia I. Rivera-Vargas ◽  
Irma Cabrera-Asencio ◽  
Sharon A. Cantrell
Keyword(s):  
Culture Media ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Western Hemisphere ◽  
Molecular Characteristics ◽  
Growing Seasons ◽  
Rdna Its ◽  
Alternaria Species ◽  
Alternaria Sp ◽  
Plant Life Cycle

Alternaria isolates were collected from onion foliage at different stages of the plant life cycle. Incidence of Alternaria species in cultivars 'Mercedes' and 'Excallbur' was determined during two consecutive growing seasons in fields located In southern Puerto Rico. Leaves showing purple to brown sunken elliptical lesions with chlorotic halos were taken at random. Five leaf sections (0.5 cm) from each sample were superficially disinfested, transferred to culture media and incubated, and isolations were documented. Disease incidence ranged from 25 to 52% in 60- to 100-day-old plants. An increase in Alternaria incidence was observed in response to high relative humidity in the fields. A total of 280 isolates were obtained, and 35 were selected for morphological, pathogenic and molecular characterization. A complex of five different Alternaria species is associated with onion leaf blight on the island. Alternaria destruens, A. tenuissima, A. palandui, A. allii and a group of small-spore Alternaria sp., belonging to a taxonomically undescribed group, were identified. Sixty-two percent of selected isolates belong to this group having an A. arborescens intermediate sporulation pattern. Alternaria destruens and A. palandui have not been previously reported as associated with onions in the Caribbean or in the Western Hemisphere. Pathogenicity tests showed that A. allii, A. tenuissima and Alternaria sp. were pathogenic to onion foliage, with A. allii as the most virulent. Molecular characteristics of the isolates were determined by using the ITS of the rDNA gene. Phylogenetic relationships based on rDNA ITS sequences from Alternaria isolates and other Pleosporaceae distinguished three clades. The first clade of large filiform-beaked spores included A. allii from this study, as well as isolates from the GenBank (A. porri, A. solani, A. macrospora, A. zinniae and A. sesamicola). These formed a monophyletic group, discrete from other members of the genus. The second clade included a diverse group of smallspore Alternaria: A. tenuissima, A. alternata, A. palandui, A. destruens and Alternaria sp.; the third clade included Stemphylium spp.

scholarly journals Fungal Species Causing Maize Leaf Blight in Different Agro-Ecologies in India

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1621
Author(s):  
Vimla Singh ◽  
Dilip K. Lakshman ◽  
Daniel P. Roberts ◽  
Adnan Ismaiel ◽  
Alok Abhishek ◽  
...  
Keyword(s):  
Management Strategies ◽  
Resistance Breeding ◽  
Fungal Species ◽  
Leaf Blight ◽  
Economic Losses ◽  
Bipolaris Maydis ◽  
Maize Production ◽  
Maize Leaf ◽  
Ecological Zones ◽  
Alternaria Sp

Foliar diseases of maize cause severe economic losses in India and around the world. The increasing severity of maize leaf blight (MLB) over the past ten years necessitates rigorous identification and characterization of MLB-causing pathogens from different maize production zones to ensure the success of resistance breeding programs and the selection of appropriate disease management strategies. Although Bipolaris maydis is the primary pathogen causing MLB in India, other related genera such as Curvularia, Drechslera, and Exserohilum, and a taxonomically distant genus, Alternaria, are known to infect maize in other countries. To investigate the diversity of pathogens associated with MLB in India, 350 symptomatic leaf samples were collected between 2016 and 2018, from 20 MLB hotspots in nine states representing six ecological zones where maize is grown in India. Twenty representative fungal isolates causing MLB symptoms were characterized based on cultural, pathogenic, and molecular variability. Internal Transcribed Spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GADPH) gene sequence-based phylogenies showed that the majority of isolates (13/20) were Bipolaris maydis. There were also two Curvularia papendorfii isolates, and one isolate each of Bipolaris zeicola, Curvularia siddiquii, Curvularia sporobolicola, an unknown Curvularia sp. isolate phylogenetically close to C. graminicola, and an Alternaria sp. isolate. The B. zeicola, the aforesaid four Curvularia species, and the Alternaria sp. are the first reports of these fungi causing MLB in India. Pathogenicity tests on maize plants showed that isolates identified as Curvularia spp. and Alternaria sp. generally caused more severe MLB symptoms than those identified as Bipolaris spp. The diversity of fungi causing MLB, types of lesions, and variation in disease severity by different isolates described in this study provide baseline information for further investigations on MLB disease distribution, diagnosis, and management in India.

Ultrastructure of Melanin Formation in Curvularia sp., Alternaria sp., and Drechslera Sorokiniana

1977 ◽  
Vol 35 ◽  
pp. 398-399
Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
A. A. Bell
Keyword(s):  
Potassium Phosphate ◽  
Thielaviopsis Basicola ◽  
Wild Type ◽  
Potassium Phosphate Buffer ◽  
Transmission Microscopy ◽  
Electron Transmission ◽  
Melanin Formation ◽  
Before And After ◽  
Alternaria Sp ◽  
Electron Transmission Microscopy

(+)-Scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2Hj-naphthalenone] and 1,8-di- hydroxynaphthalene (DHN) have been proposed as intermediates of melanin synthesis in the fungi Verticillium dahliae (1, 2, 3, 4) and Thielaviopsis basicola (4, 5). Scytalone is enzymatically dehydrated by V. dahliae to 1,3,8-trihydroxynaphthalene which is then reduced to (-)-vermelone [(-)-3,4- dihydro-3,8-dihydroxy-1(2H)-naphthalenone]. Vermelone is subsequently dehydrated to DHN which is enzymatically polymerized to melanin.Melanin formation in Curvularia sp., Alternaria sp., and Drechslera soro- kiniana was examined by light and electron-transmission microscopy. Wild-type isolates of each fungus were compared with albino mutants before and after treatment with 1 mM scytalone or 0.1 mM DHN in 50 mM potassium phosphate buffer, pH 7.0. Both chemicals were converted to dark pigments in the walls of hyphae and conidia of the albino mutants. The darkened cells were similar in appearance to corresponding cells of the wild types under the light microscope.

Sign in / Sign up

Export Citation Format

Share Document