Studies on sunflower rust. X. Specialization of Puccinia helianthi on wild sunflowers in Texas

1972 ◽  
Vol 50 (9) ◽  
pp. 1871-1877 ◽  
Author(s):  
C. M. R. Hennessy ◽  
W. E. Sackston
Keyword(s):  
Helianthus Annuus ◽  
Host Species ◽  
Rust Resistance ◽  
Puccinia Helianthi ◽  
Race 1 ◽  
Race 2 ◽  
High Degree ◽  
Race 4 ◽  
Adaptive Variability

Sunflower rust (Puccinia helianthi) was collected in Texas on wild Helianthus spp. believed to be ancestors of the cultivated sunflower (Helianthus annuus). Race 1, the least pathogenic on the standard "Canadian" differentials, was the most common. Races 1 and 2 predominated on H. annuus and H. debilis, race 2 on H. praecox, and race 4 on H. petiolaris. Most host species proved to be heterozygous for rust resistance; cross-infectivity tests between them were inconclusive. Puccinia helianthi shows a high degree of adaptive variability, which suggests that local specialization may be relatively unimportant.

STUDIES ON SUNFLOWER RUST: III. OCCURRENCE, DISTRIBUTION, AND SIGNIFICANCE OF RACES OF PUCCINIA HELIANTHI SCHW.

1962 ◽  
Vol 40 (11) ◽  
pp. 1449-1458 ◽  
Author(s):  
W. E. Sackston
Keyword(s):  
Helianthus Annuus ◽  
Rust Resistance ◽  
Resistance Factors ◽  
Helianthus Annuus L ◽  
Puccinia Helianthi ◽  
Race 1 ◽  
Differential Varieties ◽  
Derivatives Of

Discovery of rust-resistant sunflower seedlings in 1952 made it possible to distinguish races of Puccinia helianthi Schw. occurring on cultivated sunflowers (Helianthus annuus L.). The races isolated in 1954 helped to identify two discrete factors for resistance derived from wild annual sunflowers from the Renner, Texas, area. The four races which theoretically could be distinguished with two resistance factors have all been found in Manitoba. Collections from other provinces, countries, and continents, with few exceptions were classified on the Canadian differentials as race 1. Differences among isolates of race 1 were observed on resistant derivatives of H. argophyllus T. and G. Use of the four rust races described made it possible to identify different factors for resistance in sister selections of sunflowers with identical rust reactions in the field, and to demonstrate that the original rust resistant accessions 953-88 and 953-102 each contained at least two distinct resistance factors. Use of the races has also made it possible to recognize the existence in H. argophyllus of factors for rust resistance which appear to differ from those in the Canadian differential varieties.

scholarly journals Virulence and Molecular Genotyping Studies of Sporisorium reilianum Isolates in Sorghum

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 523-529 ◽  
Author(s):  
Louis K. Prom ◽  
Ramasamy Perumal ◽  
Saradha R. Erattaimuthu ◽  
John E. Erpelding ◽  
Noe Montes ◽  
...  
Keyword(s):  
Fragment Length Polymorphism ◽  
South Texas ◽  
Pathogen Virulence ◽  
Inoculation Techniques ◽  
Sporisorium Reilianum ◽  
Race 1 ◽  
Race 2 ◽  
Small Clusters ◽  
Race 4 ◽  
Syringe Injection

Head smut, caused by the fungal pathogen Sporisorium reilianum, has been reported with increasing frequency in the grain sorghum growing areas of Texas. To facilitate analysis of changes in pathogen virulence, four inoculation techniques were examined: soil and teliospore mixture, seed coating, media placement, and syringe injection. Of the four, syringe injection was determined to be the most effective. Inoculations of sorghum host differentials BTx643, BTx7078, BTx635, SC170-6-17 (TAM2571), SA281 (Early Hegari), and Tx414 showed 23 of 32 Texas isolates were race 4. Two isolates from College Station, TX, were classified as race 1, but no race 2 or 3 isolates were found. New, virulent races 5 and 6 were identified among isolates from south Texas. Using 16 amplified fragment length polymorphism (AFLP) primer combinations, genetic diversity was assessed in DNA samples from 49 S. reilianum isolates, including 44 sorghum isolates from Texas, two from Uganda, and one from Mali; and two maize isolates from Mexico. Single-base extensions with EcoRI and MseI primers in the selective amplification increased the number of informative polymorphic bands. High genetic dissimilarity (50%) was observed between isolates originating from maize and those originating from sorghum. The resultant dendrogram, made using cluster analysis, grouped the Texas S. reilianum isolates into four small clusters with ≥82% similarity. Other than for two race 6 isolates from Weslaco, TX, no evidence for geographical or other restrictions on gene flow was evident.

Characterisation of Strains of Fusarium oxysporum f.sp. cubense by Production of Volatiles

1991 ◽  
Vol 39 (2) ◽  
pp. 161 ◽  
Author(s):  
NY Moore ◽  
PA Hargreaves ◽  
KG Pegg ◽  
JAG Irwin
Keyword(s):  
Fusarium Oxysporum ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Compatibility Group ◽  
Race 1 ◽  
Race 2 ◽  
Race 4

The production of volatiles on steamed rice by Australian isolates of Fusarium oxysporum f. sp. cubense correlated well with race and vegetative compatibility group (VCG). All race 4 isolates (VCGs 0120, 0129) produced distinctive volatile odours which gave characteristic gas chromatograms where the num- ber of peaks equated to VCG. Race 1 (VCGs 0124, 0125) and race 2 (VCG 0128) isolates, as well as non-pathogenic isolates of F. oxysporum from the banana rhizosphere, did not produce detectable volatiles and gave chromatograms without significant peaks.

Studies on sunflower rust. XI. Effect of temperature and light on germination and infection of sunflowers by Puccinia helianthi

1972 ◽  
Vol 50 (9) ◽  
pp. 1879-1886 ◽  
Author(s):  
P. N. Sood ◽  
W. E. Sackston
Keyword(s):  
Light Intensity ◽  
Incubation Period ◽  
Dark Period ◽  
Effect Of Temperature ◽  
Appressorium Formation ◽  
Leaf Discs ◽  
Puccinia Helianthi ◽  
Race 2 ◽  
Race 4

Urediospores of four races of Puccinia helianthi incubated on water agar for 6 h or on sunflower leaf discs for 16 h germinated equally well from 10 to 25 °C, but significantly less at 30° and least at 5 °C. Appressorium formation was highest at 10 to 25 °C, lower at 30 °C, and lowest at 5 °C for races 1 and 3; none occurred at 30 and 5° in races 2 and 4. The optimum for penetration by races 1 and 3 was 20 °C, for race 2, 15° to 20 °C, and for race 4, 20° to 25 °C. Results were the same on susceptible and resistant hosts.Germination percentage on water agar was reduced with increasing light intensity from 2200 to 17 600 lx during incubation for 6 h. Germination on sunflower leaf discs was reduced with increasing light intensity during incubation for 16 h. Appressorium formation and penetration were adversely affected by increasing light intensity.Inhibition by light was overcome during a subsequent dark period when inoculated leaf discs were exposed to various cycles of light and dark during a 16-h incubation period.

scholarly journals Race Determination and Vegetative Compatibility Grouping of Fusarium oxysporum f. sp. melonis from South Africa

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 231-234 ◽  
Author(s):  
W. Schreuder ◽  
S. C. Lamprecht ◽  
G. Holz
Keyword(s):  
South Africa ◽  
Fusarium Oxysporum ◽  
South African ◽  
Geographic Region ◽  
Vegetative Compatibility ◽  
Vegetative Compatibility Group ◽  
Compatibility Group ◽  
Race 1 ◽  
Race 2 ◽  
High Degree

Isolates of Fusarium oxysporum f. sp. melonis (72 total) obtained from 30 fields in 17 melonproducing regions in South Africa were race typed, using differential cvs. CM 17187, Doublon, Perlita, and Topmark, and grouped on the basis of vegetative compatibility. Fifty-four isolates were identified as race 0, eight as race 1, and ten as race 2. Race 0 occurred in 15 of 17 regions, whereas race 1 was sporadically recovered. Race 2 was obtained from only four fields located in one geographic region. Perlita plants (carrying the gene Fom3) inoculated with local isolates of races 0 and 2 and reference isolates of race 0 became stunted, and their leaves became yellow, thickened, and brittle. Using two inoculation methods, similar symptoms were induced by reference and local isolates of race 0 on Perlita seedlings. The results indicated that Fom3 in Perlita confers a tolerant reaction compared with the resistant reaction of gene Fom1 in Doublon and, therefore, should not be used alone in race determination tests. All isolates belonged to vegetative compatibility group 0134, indicating a high degree of genetic homogeneity among the South African F. oxysporum f. sp. melonis population.

scholarly journals Molecular Diversity of Ralstonia solanacearum Isolated from Ginger in Hawaii

2003 ◽  
Vol 93 (9) ◽  
pp. 1124-1130 ◽  
Author(s):  
Q. Yu ◽  
A. M. Alvarez ◽  
P. H. Moore ◽  
F. Zee ◽  
M. S. Kim ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Genetic Similarity ◽  
Molecular Diversity ◽  
Zingiber Officinale ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Race 1 ◽  
Race 2 ◽  
High Degree ◽  
Degree Of Similarity

The genetic diversity of Ralstonia solanacearum strains isolated from ginger (Zingiber officinale) growing on the island of Hawaii was determined by analysis of amplified fragment length polymorphisms (AFLPs). Initially 28 strains of R. solanacearum collected from five host plant species worldwide were analyzed by AFLP. A second analysis was conducted on 55 R. solanacearum strains collected from three ginger farms along the Hamakua Coast of Hawaii, the principle area of ginger cultivation in the state. From the initial analysis, R. solanacearum strains from ginger in Hawaii showed a high degree of similarity at 0.853. In contrast, the average genetic similarity between R. solanacearum strains from heliconia and ginger was only 0.165, and strains from ginger showed little similarity with strains from all other hosts. The second analysis of 55 strains from ginger on different Hawaiian farms confirmed that they were distinct from race 1 strains from tomato. Strains from ginger also showed greater diversity among themselves in the second analysis, and the greatest diversity occurred among strains from a farm where ginger is frequently imported and maintained. Our results provide evidence that R. solanacearum strains from ginger in Hawaii are genetically distinct from local strains from tomato (race 1) and heliconia (race 2).

Pathogenic specialisation within Colletotrichum trifolii in Australia, and lucerne cultivar reactions to all known Australian pathotypes

2003 ◽  
Vol 54 (9) ◽  
pp. 829 ◽  
Author(s):  
J. M. Mackie ◽  
J. M. Musial ◽  
N. R. O'Neill ◽  
J. A. G. Irwin
Keyword(s):  
North American ◽  
Crown Rot ◽  
Sources Of Resistance ◽  
Colletotrichum Trifolii ◽  
Race 1 ◽  
Host Origin ◽  
New Races ◽  
Race 2 ◽  
Race 4 ◽  
First Time

Anthracnose and crown rot, caused by Colletotrichum trifolii, are serious diseases of lucerne (Medicago sativa L.) in humid regions of the world. A race survey was conducted by inoculating individual lucerne clones (genotypes) with C. trifolii isolates collected from a range of Medicago hosts, locations, and years in south-eastern Queensland. This survey revealed for the first time in Australia the presence of race 2 (virulence on anthracnose resistance gene An1) and the first world report of race 4 (virulence on An2). A collection of North American race 1 and race 2 C. trifolii isolates, when inoculated onto the Australian differential clones, gave responses that were in agreement with their North American reactions. A RAPD analysis was conducted on 9 Australian C. trifolii isolates including races 1, 2, and 4; two C. destructivum and one C. gloeosporioides isolate were included as known outliers. For the C. trifolii isolates, 94.6% similarity was found regardless of host origin or race, compared with 2.2% similarity between this group and the C. gloeosporioides and C. destructivum isolates, confirming that the new races belong to C. trifolii. Currently, it is hypothesised that only plants carrying genes An1 and An2 are resistant to the 3 races. Of 22 cultivars screened against the 3 races, only UQL-1, Hallmark, and Pioneer 54Q53 had >30% of plants resistant to the 3 races in separate screenings. The research highlights the need to find new sources of resistance to C. trifolii in lucerne.

scholarly journals A New Race of Colletotrichum trifolii Identified on Alfalfa in Ohio

Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1362-1362 ◽  
Author(s):  
J. J. Ariss ◽  
L. H. Rhodes
Keyword(s):  
United States ◽  
North American ◽  
The United States ◽  
Morphological Characters ◽  
First Report ◽  
Anthracnose Resistance ◽  
Colletotrichum Trifolii ◽  
Race 1 ◽  
Race 2 ◽  
Race 4

Anthracnose of alfalfa (Medicago sativa L.), caused by the fungus Colletotrichum trifolii Bain & Essary, was identified as a potential problem of alfalfa in the United States in the late 1960s. Races 1 and 2 are known in the United States, and recently, race 4 was described in Australia (1). An additional race, race 3, had previously been reported in the United States, but isolates of this proposed race were not preserved and its status as a distinct race of C. trifolii is unclear. In June 2003, an isolate of C. trifolii was collected in Columbus, OH from a 4-year-old alfalfa stand of cv. 520. The isolate was obtained from typical anthracnose stem lesions. Stem sections with lesions were scraped with a sterile inoculation loop, and conidia were directly streaked onto acidified potato dextrose agar. Individual colonies were transferred to half-strength oatmeal agar. Morphological characters (conidia, acervuli, and setae) of this isolate, designated OH-WA-520, were consistent with those of other C. trifolii isolates and clearly distinguishable from C. destructivum or other Colletotrichum spp. that occur on alfalfa. The alfalfa differential cultivars Arc (resistant to race 1 and susceptible to race 2 of C. trifolii), Saranac AR (resistant to race 1 and race 2), and Saranac (susceptible to both races) were inoculated with conidia of isolate OH-WA-520 per the North American Alfalfa Improvement Conference standard protocol for determining anthracnose resistance (2). Isolate OH-WA-520 was avirulent on Arc but virulent on Saranac AR and Saranac. In each of three repetitions of the protocol, more than 65% of Arc plants survived, while less than 18% of Saranac and Saranac AR plants survived. These results indicate a physiological race inconsistent in reaction with C. trifolii race 1 or race 2, but similar in reaction to race 4 isolates previously described only from Australia (1). To our knowledge, this is the first report of a C. trifolii isolate virulent on Saranac AR but avirulent on Arc. This is also the first report of C. trifolii race 4 in the United States. References: (1) J. M. Mackie et al. Aust. J. Agric. Res. 54:829, 2003. (2) N. R. O'Neill. Anthracnose resistance. Page D-1 in: Standard Tests to Characterize Alfalfa Cultivars. Online publication. North American Alfalfa Improvement Conference, Beltsville, MD, 1991.

scholarly journals Comparative Whole-Genome Sequence Analyses of Fusarium Wilt Pathogen (Foc R1, STR4 and TR4) Infecting Cavendish (AAA) Bananas in India, with a Special Emphasis on Pathogenicity Mechanisms

2021 ◽  
Vol 7 (9) ◽  
pp. 717
Author(s):  
Thangavelu Raman ◽  
Esack Edwin Raj ◽  
Gopi Muthukathan ◽  
Murugan Loganathan ◽  
Pushpakanth Periyasamy ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Genome Assembly ◽  
Molecular Mechanisms ◽  
Whole Genome Sequence ◽  
Rate Of Spread ◽  
Compatibility Group ◽  
Race 1 ◽  
Race 2 ◽  
Serious Disease ◽  
Race 4

Fusarium wilt is caused by the fungus Fusarium oxysporum f. sp. cubense (Foc) and is the most serious disease affecting bananas (Musa spp.). The fungus is classified into Foc race 1 (R1), Foc race 2, and Foc race 4 based on host specificity. As the rate of spread and the ranges of the devastation of the Foc races exceed the centre of the banana’s origin, even in non-targeted cultivars, there is a possibility of variation in virulence-associated genes. Therefore, the present study investigates the genome assembly of Foc races that infect the Cavendish (AAA) banana group in India, specifically those of the vegetative compatibility group (VCG) 0124 (race 1), 0120 (subtropical race 4), and 01213/16 (tropical race 4). While comparing the general features of the genome sequences (e.g., RNAs, GO, SNPs, and InDels), the study also looked at transposable elements, phylogenetic relationships, and virulence-associated effector genes, and sought insights into race-specific molecular mechanisms of infection based on the presence of unique genes. The results of the analyses revealed variations in the organisation of genome assembly and virulence-associated genes, specifically secreted in xylem (SIX) genes, when compared to their respective reference genomes. The findings contributed to a better understanding of Indian Foc genomes, which will aid in the development of effective Fusarium wilt management techniques for various Foc VCGs in India and beyond.

A NEW RACE OF FUSARIUM OXYSPORUM f. PISI

1966 ◽  
Vol 46 (4) ◽  
pp. 343-347 ◽  
Author(s):  
A. T. Bolton ◽  
V. W. Nuttall ◽  
L. H. Lyall
Keyword(s):  
Fusarium Oxysporum ◽  
Host Range ◽  
Wilt Disease ◽  
The Other ◽  
Cultural Characteristics ◽  
New Era ◽  
Race 1 ◽  
New Race ◽  
Race 2 ◽  
Race 4

Pea varieties resistant to Fusarium wilt and near-wilt developed a wilt disease when grown in a field disease nursery at Ottawa. Two isolates of Fusarium oxysporum f. pisi (Linford) were obtained from infected plants. When tested, one of these was similar to F. oxysporum f. pisi race 2 (near-wilt) in host range and cultural characteristics. The other resembled F. oxysporum f. pisi race 1 (wilt) in morphology and cultural characteristics, but caused severe symptoms on New Era and Wisconsin 183, varieties resistant to races 1 and 2. It was concluded that this latter isolate is a new race; it is proposed that it be designated as F. oxysporum f. pisi race 4.

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