Pathogenic variability of Colletotrichum sublineolum isolates on sorghum differentials under greenhouse conditions in Jimma, Ethiopia

2021 ◽  
pp. 1-19
Author(s):  
Binyam Tsedaley ◽  
Girma Adugna ◽  
Fikre Lemessa ◽  
Louis K. Prom
Keyword(s):  
Colletotrichum Sublineolum ◽  
Pathogenic Variability

scholarly journals Genetic Diversity and Pathogenic Variability Among Isolates of Colletotrichum Species from Strawberry

2003 ◽  
Vol 93 (2) ◽  
pp. 219-228 ◽  
Author(s):  
Béatrice Denoyes-Rothan ◽  
Guy Guérin ◽  
Christophe Délye ◽  
Barbara Smith ◽  
Dror Minz ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Sequence Data ◽  
Random Amplified Polymorphic Dna ◽  
Molecular Data ◽  
Its2 Sequence ◽  
Host Specialization ◽  
Pathogenicity Tests ◽  
Colletotrichum Spp ◽  
Rapd Polymorphism ◽  
Pathogenic Variability

Ninety-five isolates of Colletotrichum including 81 isolates of C. acutatum (62 from strawberry) and 14 isolates of C. gloeosporioides (13 from strawberry) were characterized by various molecular methods and pathogenicity tests. Results based on random amplified polymorphic DNA (RAPD) polymorphism and internal transcribed spacer (ITS) 2 sequence data provided clear genetic evidence of two subgroups in C. acutatum. The first subgroup, characterized as CA-clonal, included only isolates from strawberry and exhibited identical RAPD patterns and nearly identical ITS2 sequence analysis. A larger genetic group, CA-variable, included isolates from various hosts and exhibited variable RAPD patterns and divergent ITS2 sequence analysis. Within the C. acutatum population isolated from strawberry, the CA-clonal group is prevalent in Europe (54 isolates of 62). A subset of European C. acutatum isolates isolated from strawberry and representing the CA-clonal and CA-variable groups was assigned to two pathogenicity groups. No correlation could be drawn between genetic and pathogenicity groups. On the basis of molecular data, it is proposed that the CA-clonal subgroup contains closely related, highly virulent C. acutatum isolates that may have developed host specialization to strawberry. C. gloeosporioides isolates from Europe, which were rarely observed were either slightly or nonpathogenic on strawberry. The absence of correlation between genetic polymorphism and geographical origin in Colletotrichum spp. suggests a worldwide dissemination of isolates, probably through international plant exchanges.

scholarly journals Morphological and Pathogenic Variability amongMacrophomina phaseolinaIsolates Associated with Mungbean (Vigna radiataL.) Wilczek from Pakistan

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Umer Iqbal ◽  
Tariq Mukhtar
Keyword(s):  
Macrophomina Phaseolina ◽  
Morphological Characters ◽  
Geographic Origins ◽  
Low Weight ◽  
Breeding Programmes ◽  
Diverse Origin ◽  
Pathogenic Variability ◽  
Slow Growing ◽  
Highly Virulent ◽  
Medium Weight

Macrophomina phaseolinais a serious pathogen of many crops. In the present studies, 65 isolates ofMacrophomina phaseolinafrom different agroecological regions of Punjab and Khyber Pakhtunkhwa provinces of Pakistan were analyzed for morphological and pathogenic variability. Regardless of their geographic origins, significant differences were detected among 65 isolates in their radial growth, sclerotial size, and weight as well as in pathogenicity. Sixteen isolates were rated as fast growing, 11 as slow growing, and the rest of the isolates as medium growing. Nine isolates were classified as large sized, 26 as small sized, and the remaining 30 isolates as medium sized. Thirty five isolates were ranked as heavy weight, 12 as low weight, and the rest of isolates were grouped as medium weight. Ten fungal isolates appeared to be least virulent, whereas eight isolates of diverse origin proved to be highly virulent against mungbean cultivars. The remaining isolates were regarded as moderately virulent. No relationship was found among the morphological characters and pathogenicity of the isolates. These morphological and pathogenic variations in various isolates ofM. phaseolinamay be considered important in disease management systems and will be useful in breeding programmes of mungbean cultivars resistant to charcoal rot.

Host range and physiologic specialization in Rhynchosporium secalis

1974 ◽  
Vol 25 (1) ◽  
pp. 21 ◽  
Author(s):  
SM Ali ◽  
WJR Boyd
Keyword(s):  
Genetic Diversity ◽  
Host Range ◽  
Environmental Conditions ◽  
Host Specialization ◽  
Rhynchosporium Secalis ◽  
Host Reaction ◽  
Genetic Studies ◽  
Barley Cultivars ◽  
Adequate Sampling ◽  
Pathogenic Variability

The pathogenic variability of isolates of R. secalis collected in Western Australia has been examined on different host genera of the Gramineae and on selected barley cultivars. Depending on the host-isolate combination and the conditions of the test, evidence has been obtained of inter- and intra-isolate variability in both host reaction and isolate pathogenicity. This complicates definitive interpretation of the results, militates against identification of conventional 'races' of the pathogen and shows that R. secalis does not exhibit strict host specialization. Hosts which consistently express resistance or susceptibility under different environmental conditions, and isolates which express their pathogenic characteristics consistently, have been identified. The need for more precise genetic studies and adequate sampling of genetic diversity is emphasized.

scholarly journals Pathogenic Variability of Pyricularia grisea from the High- and Mid-Elevation Zones of Bhutan

2000 ◽  
Vol 90 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Thinlay ◽  
R. S. Zeigler ◽  
M. R. Finckh
Keyword(s):  
Rice Cultivar ◽  
High Elevation ◽  
Individual Plant ◽  
Growing Seasons ◽  
Reaction Index ◽  
Agroecological Zones ◽  
Pathogenic Variability ◽  
Almost All ◽  
High Elevations ◽  
Virulence Spectrum

Thirty isolates of P. griseacollected from rice during a blast epidemic in 1995 in the high (1,800 to 2,600 m) and middle (1,200 to 1,800 m) elevations of Bhutan and 80 isolates collected from one rice cultivar from two high- and two mid-elevation sites in 1996 were analyzed for virulence. Differential varieties were indica CO39, with five near-isogenic lines (NILs) for resistance genes in the genetic background of CO39, and japonica Lijiangxintuanheigu (LTH), with five NILs for LTH. Twelve selected Bhutanese landraces also were studied. In addition, 10 blast nurseries consisting of the NIL sets, important local landraces, and representatives of international differential groups were established in the 1996 and 1997 growing seasons in the mid- and high-elevation agroecological zones. The 110 isolates were differentiated into 53 pathotypes based on the 2 NIL sets. Thirteen isolates were avirulent on all of the NILs but were compatible with some landraces. Several isolates were able to attack one of the NILs of CO39 but not CO39. These results strongly suggest that both CO39 and LTH possess previously unidentified resistance. The landraces were not uniform in their reactions to the isolates. When a reaction index taking into account all individual plant reactions was used, isolates that had been assigned to the same pathotype could be further differentiated, indicating that the NIL sets could not completely discriminate virulences in Bhutanese P. grisea populations. In the trap nurseries, disease was always present in the middle elevations, but disease was very low during July 1996 in the high elevations and only present during August and September 1997. Almost all varietal groups were more frequently attacked in the middle than in the high elevations, indicating that the virulence spectrum is wider and the conduciveness of the environment is greater in the middle elevations. Landraces from the high elevations were most susceptible, followed by international differential groups 7 and 8. The results suggest that selection has yielded landraces with more complete and complex resistance in the more disease-conducive mid-elevation environment. At the same time, the pathogen population also possesses a wider virulence spectrum in that environment.

scholarly journals Identification of Phaeoisariopsis griseola pathotypes from five States in Brazil

2002 ◽  
Vol 27 (1) ◽  
pp. 78-81 ◽  
Author(s):  
ALOISIO SARTORATO
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Resistance Genes ◽  
Leaf Spot ◽  
Angular Leaf Spot ◽  
Phaeoisariopsis Griseola ◽  
Moist Chamber ◽  
Differential Cultivars ◽  
Pathogenic Variability ◽  
Resistant Genotypes

Due to the increased importance of angular leaf spot of common bean (Phaseolus vulgaris) in Brazil, monitoring the pathogenic variability of its causal agent (Phaeoisariopsis griseola) is the best strategy for a breeding program aimed at developing resistant genotypes. Fifty one isolates of P. griseola collected in five Brazilian States were tested on a set of 12 international differential cultivars in the greenhouse. When inoculated plants showed symptoms but no sporulation was observed, they were transferred to a moist chamber for approximately 20-24 h. After this period of time, if no sporulation was observed, the plants were considered resistant; otherwise, they were considered susceptible. From the fifty-one tested isolates, seven different pathotypes were identified. No Andean pathotypes were identified; consequently, all isolates were classified as Middle American pathotypes. Pathotype 63-31 was the most widespread. Pathotype 63-63 overcame resistance genes present in all differential cultivars and also the resistance gene(s) present in the cultivar AND 277. This fact has important implications for breeding angular leaf spot resistance in beans, and suggests that searching for new resistance genes to angular leaf spot must be pursued.

scholarly journals Response of Sorghum Accessions from Four African Countries against <i>Colletotrichum sublineolum</i>, Causal Agent of Sorghum Anthracnose

2012 ◽  
Vol 03 (01) ◽  
pp. 125-129 ◽  
Author(s):  
Louis K. Prom ◽  
John Erpelding ◽  
Ramasamy Perumal ◽  
Thomas Isakeit ◽  
Hugo Cuevas
Keyword(s):  
Causal Agent ◽  
African Countries ◽  
Colletotrichum Sublineolum ◽  
Sorghum Anthracnose

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

scholarly journals Pathogenic Variation of Colletotrichum lindemuthianum causing Anthracnose of Beans (Phaseolus vulgaris) in Uganda

2017 ◽  
Vol 5 (3) ◽  
pp. 89-98
Author(s):  
Moses J. Kiryowa ◽  
Aston Ebinu ◽  
Vincent Kyaligonza ◽  
Stanley T. Nkalubo ◽  
Pamela Paparu ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Single Gene ◽  
Colletotrichum Lindemuthianum ◽  
Breeding Programs ◽  
Pathogenic Variation ◽  
Broad Spectrum Resistance ◽  
Differential Cultivars ◽  
Differential Cultivar ◽  
Bean Anthracnose ◽  
Pathogenic Variability

Colletotrichum lindemuthianum is a highly variable pathogen of common beans that easily overcomes resistance in cultivars bred with single-gene resistance. To determine pathogenic variability of the pathogen in Uganda, samples of common bean tissues with anthracnose symptoms were collected in eight districts of Uganda, namely Kabarole, Sironko, Mbale, Oyam, Lira, Kapchorwa, Maracha and Kisoro. 51 isolates sporulated successfully on Potato Dextrose Agar and Mathur’s media and were used to inoculate 12 differential cultivars under controlled conditions. Five plants per cultivar were inoculated with each isolate and then evaluated for their reaction using the 1 – 9 severity scale. Races were classified using the binary nomenclature system proposed by Pastor Corrales (1991). Variation due to cultivar and isolate effects was significant (P≤0.001) for severity. The 51 isolates from eight districts grouped into 27 different races. Sironko district had the highest number of races followed by Mbale and Kabarole. Races 2047 and 4095 were the most frequently found, each with 10 isolates grouped under them. Race 4095 was the most virulent since it caused a susceptible (S) reaction on all 12 differential cultivars and the susceptible check. This was followed by races 2479, 2047 and 2045 respectively. Two races, 4094 and 2479, caused a susceptible reaction on the differential cultivar G2333, which nevertheless, showed the most broad spectrum resistance followed by cultivars Cornell 49-242, TU, and AB136 respectively. These cultivars are recommended for use in breeding programs aiming at breeding for broad spectrum resistance to bean anthracnose in Uganda.

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