Identification of Races of Fusarium oxysporum f.sp. ciceris, Inciting Wilt of Chickpea in Andhra Pradesh and Parts of Telangana

Author(s):  
K. Venkataramanamma ◽  
B.V. Bhaskara Reddy ◽  
R. Sarada Jayalakshmi ◽  
V. Jayalakshmi ◽  
K.V. Hari Prasad

Background: Fusarium oxysporum f.sp. ciceris (Foc) is one of the most important pathogen, causing wilt of chickpea. It is soil and seed borne pathogen. A serious threat in Foc is the evolution of new races, which reduces exploitation of wilt resistance in the crop in a particular area. Eight races (race 0, 1A, 1B/C, 2, 3, 4, 5 and 6) were reported in the world and among them four races (race 1, 2, 3, 4) were from India. Race 1 was reported from Andhra Pradesh. It is very important to monitor the variation regularly in new isolates collected from different varieties or genotypes and different geographical regions to identify the racial pattern. Development of SCAR markers for identification of Foc isolates is also important as they are highly reliable. Methods: Twenty isolates of Fusarium oxysporum f.sp. ciceris were obtained from wilt infected plants of chickpea covering different places of Andhra Pradesh including two isolates from Telangana and confirmed the pathogen based on pathogenicity test. They were tested on host differentials of chickpea for races identification. Among these twenty isolates five most virulent isolates (Foc-6, Foc-10, Foc-12, Foc-17 and Foc-24) were selected for RAPD based on pathogenicity test and SCAR marker was developed based on DNA banding pattern during RAPD for one isolate.Result: Based on the disease reaction on differentials, concluded that 17 of them out of 20 were matched with race-1 reaction. Two isolates were matched with race-6 reaction and one is not matched with none of the races. An amplified product of polymorphic band of approximately 700 bp in the isolate Foc-12, obtained during RAPD analysis was selected for SCAR marker development and two SCAR markers were developed and validated. Identification of races mainly helps in development of resistant cultivars to specific races and might be contributed to development of integrated disease management practices for Fusarium wilt.

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2481-2488
Author(s):  
Anthony P. Keinath ◽  
Virginia B. DuBose ◽  
Melanie M. Katawczik ◽  
W. Patrick Wechter

Fusarium wilt of watermelon (Citrullus lanatus), caused by the soilborne fungus Fusarium oxysporum f. sp. niveum, is the most serious disease of watermelon in South Carolina and other southeastern U.S. states. Isolates of F. oxysporum collected from field-grown plants, greenhouse-grown seedlings, and field soil between 1999 and 2018 were inoculated onto three differential watermelon cultivars to identify races. Of 197 isolates obtained from plants, 12% were nonpathogenic, 2% were race 0, 23% were race 1, and 63% were race 2. One collection of isolates from greenhouse seedlings was exclusively race 1 and the other was exclusively race 2. Seventeen of 81 soil isolates were pathogenic: five were race 1 and 12 were race 2. Reactions of C. amarus PI 296341-FR, Carolina Strongback, and SP-6, cultigens with resistance to race 2, did not differ significantly among five highly virulent race 2 isolates and a standard race 2 isolate, indicating a lack of a race 3 phenotype. Forma specialis-specific primers matched phenotypic race identification for 74% of the isolates. Race-specific primers based on a secreted-in-xylem elicitor present in race 0 and 1 isolates matched phenotypic race identification for 66% of the isolates. Because a majority of the F. oxysporum f. sp. niveum isolates from South Carolina were race 2, integrated management practices should be used until commercial cultivars with resistance to race 2 are available.


Author(s):  
K Venkataramanamma ◽  
B V Bhaskara Reddy ◽  
R Sarada Jayalakshmi ◽  
V Jayalakshmi ◽  
K V Hari Prasad ◽  
...  

Thirty two isolates of Fusarium oxysporum f.sp. ciceris (Foc) were collected from six districts of Andhra Pradesh (A.P) and three districts of Telangana. Based on wilting % in pathogenicity test, the isolates were grouped into three categories. All the isolates differed in cultural characters like mycelium colour, margin, texture, pigmentation and morphological characters like macro conidia, micro conidia length, width and chlamydospores diameter. There was no correlation between cultural and morphological characters of Foc isolates except three isolates (Foc-6, Foc-12 and Foc-17). These three isolates have white mycelium, cream colour pigmentation, slow radial growth and highly pathogenic (100% wilt incidence) in nature. Sporulation ability and radial growth of all isolates were also measured. All the isolates exhibited genetic variation in RAPD banding pattern and three major clusters (I, II and III) were found in the dendrogram. Maximum genetic similarity of 80.3% was observed between Foc-27 and Foc-28 isolates.


2018 ◽  
Vol 10 (3) ◽  
pp. 886-893
Author(s):  
Kalavati Teli ◽  
H. M. Shweta ◽  
M. K. Prasanna Kumar ◽  
Bharath Kunduru ◽  
B. S. Chandra Shekar

Bacterial wilt caused by Ralstonia solanacearum, is the major threat to tomato cultivation in all tomato growing areas of Karnataka.  R. solanacearum was isolated from the infected host plants collected from different locations of southern Karnataka. The identity of the isolates was established using morphological, biochemical, and molecular analysis using species specific PCR primers. The race and biovar specificity of pathogen was determined through pathogenicity test on different host plants and the ability of isolates to use carbohydrates, respectively. Phylotype classification was done by phylotype specific multiplex PCR using phylotype specific primers. All the bacterial isolates showed the characteristic creamy white fluidal growth with pink centre on the Tetrazolium chloride medium. Further, the isolates amplified at 280 bp, which confirmed the identity of pathogen as Ralstonia solanacearum. Our results showed that all isolates belonged to Race 1 of the pathogen. Among different isolates obtained, four isolates each were identified to be Biovar III and Biovar IIIA, repectively, while two isolates were identified as Biovar IIIB. All the ten isolates were affiliated to Phylotype I of Ralstonia solanaceraum species complex. These findings may help in devising the management practices for bacterial wilt of tomato in southern Karnataka.


Plant Disease ◽  
1999 ◽  
Vol 83 (10) ◽  
pp. 967-967 ◽  
Author(s):  
V. M. Stravato ◽  
R. Buonaurio ◽  
C. Cappelli

During the summer of 1997, symptoms of Fusarium wilt were observed on tomato (Lycopersicon esculentum Mill.) cvs. Monica F1 and PS 110, which bear the I gene for resistance to race 1 of Fusarium oxysporum Schlechtend.:Fr. f. sp. lycopersici (Sacc.) W.C. Snyder & H.N. Hans., in two commercial production greenhouses in Latium (Fondi) and one greenhouse in Sardinia (Oristano). Infected plants showed yellowing, stunting, vascular discoloration, and premature death. A fungus from tomato stems with discolored vascular tissue was consistently isolated on potato dextrose agar (PDA) and, based on morphological features, was identified as F. oxysporum. To verify the pathogenicity of four fungal isolates, cv. Bonny Best tomato plants, which do not carry genes for Fusarium wilt resistance, were inoculated by dipping roots of 2-week-old seedlings in a suspension of 105 microconidia per ml for 30 s. Inocula were obtained from 1-week-old fungal cultures grown on PDA. Roots of control plants were dipped in water. Seedlings were transplanted to pots containing peat and river sand (1:1, vol/vol) and placed in a greenhouse at 20 to 25°C. One month after inoculation, all fungal isolates provoked wilting of inoculated plants. No symptoms were observed on control plants. The morphological features of the fungus reisolated from diseased plants were similar to those of the original isolates. Based on the pathogenicity test, we concluded that the fungal isolates belong to F. oxysporum f. sp. lycopersici. To determine the races of the fungal isolates, differential tomato lines VFN8 (I gene for resistance to race 1), Florida MH-1 (I and I2 genes for resistance to races 1 and 2), and I3R (I, I2, and I3 genes for resistance to races 1, 2, and 3) were inoculated with the four fungal isolates, using the same procedure described for the pathogenicity test. Because disease symptoms were detected on VFN8 but not on Florida MH-1 and I3R, we deduced that the fungal isolates belong to F. oxysporum race 2. This is the first report of F. oxysporum f. sp. lycopersici race 2 in Italy. Previous research indicated that race 1 is present in Italy (1). Currently, many commercially acceptable cultivars resistant to races 1 and 2 are available to Italian greenhouse growers. Reference: (1) M. Cirulli. Phytopathol. Mediterr. 4:63, 1965.


2018 ◽  
Vol 46 (2) ◽  
pp. 509-516
Author(s):  
Fang WANG ◽  
Ling XIA ◽  
Shun LV ◽  
Chunxiang XU ◽  
Yuqing NIU ◽  
...  

The use of resistant cultivars is an effective method for the control of banana (Musa spp.) Fusarium wilt caused by race 4 of Fusarium oxysporum f. sp. cubense (Foc4). However, selection of disease-resistant cultivars requires large-scale field evaluations and is time-consuming. Development of early, reliable, and reproducible selection strategies can speed up this process. Sequence characterized amplified region (SCAR) markers have been widely employed in the resistant breeding of many crops. However, to date, there have been no reports about the presence of plant disease resistance-related SCAR markers in mitochondrial genome yet, which also plays a very important role in plant defenses. In the present study, a sequence-related amplified polymorphism (SRAP) marker, a specific fragment of 829 bp, was identified. This fragment could be amplified from Foc4-susceptible but not from the resistant cultivars. It was located in banana mitochondrial genome and mapped near the putative cytochrome c biogenesis ccmB-like mitochondrial protein. This fragment was then successfully converted into a SCAR marker, namely Mito-Foc-S001, which was found to be able to discriminate the resistance from susceptibility to Fusarium wilt disease of bananas with the discriminatory power of the new mark being 96.88%. Thus, this marker can be used in banana (Musa AAA Cavendish) breeding for Fusarium wilt disease resistance.


2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Altus Viljoen ◽  
Diane Mostert ◽  
Tomas Chiconela ◽  
Ilze Beukes ◽  
Connie Fraser ◽  
...  

Fusarium wilt, caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc), poses a major threat to banana production globally. A variant of Foc that originated in Southeast Asia, called tropical race 4 (TR4), was detected on a Cavendish banana export plantation (Metocheria) in northern Mozambique in 2013. Foc TR4 was rapidly disseminated on the farm, and affected approximately half a million plants within 3 years. The fungus was also detected on a second commercial property approximately 200 km away (Lurio farm) a year later, and on a small-grower’s property near Metocheria farm in 2015. Surveys in Mozambique showed that non-Cavendish banana varieties were only affected by Foc race 1 and race 2 strains. The testing of Cavendish banana somaclones in northern Mozambique revealed that GCTCV-119 was most resistant to Foc TR4, but that GCTCV-218 produced better bunches. The occurrence of Foc TR4 in northern Mozambique poses a potential threat to food security on the African continent, where banana is considered a staple food and source of income to millions of people. Cavendish somaclones can be used, in combination with integrated disease management practices, to replace susceptible Cavendish cultivars in southern Africa. The comprehensive testing of African cooking bananas for resistance to Foc TR4 is required, along with the improvement of biosecurity and preparedness of growers on the African continent.


Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 237-240 ◽  
Author(s):  
Matias Pasquali ◽  
Flavia Dematheis ◽  
Giovanna Gilardi ◽  
Maria Lodovica Gullino ◽  
Angelo Garibaldi

Fusarium oxysporum f. sp. lactucae, the causal agent of Fusarium wilt of lettuce, has been reported in three continents in the last 10 years. Forty-seven isolates obtained from infected plants and seed in Italy, the United States, Japan, and Taiwan were evaluated for pathogenicity and vegetative compatibility. Chlorate-resistant, nitrate-nonutilizing mutants were used to determine genetic relatedness among isolates from different locations. Using the vegetative compatibility group (VCG) approach, all Italian and American isolates, type 2 Taiwanese isolates, and a Japanese race 1 were assigned to the major VCG 0300. Taiwanese isolates type 1 were assigned to VCG 0301. The hypothesis that propagules of Fusarium oxysporum f. sp. lactucae that caused epidemics on lettuce in 2001-02 in Italian fields might have spread via import and use of contaminated seeds is discussed.


2007 ◽  
Vol 25 (3) ◽  
pp. 451-454 ◽  
Author(s):  
Ailton Reis ◽  
Leonardo S Boiteux

Fusarium wilt, caused by three races of Fusarium oxysporum f. sp. lycopersici, is one of the most important tomato diseases. In Brazil, all three races were reported, however, race 3 has been so far restricted only to Espírito Santo State. In the present work, seven F. oxysporum isolates obtained from wilted plants of the race 1 and 2-resistant tomato hybrids 'Giovana', 'Carmen' and 'Alambra' in São José de Ubá and Itaocara (Rio de Janeiro State, Brazil) were characterized at race level. Virulence assays were performed using a set of race differential cultivars: 'Ponderosa' (susceptible to all races), 'IPA-5' (resistant to race 1), 'Floradade' (resistant to races 1 and 2), 'BHRS-2,3' (resistant to all three races). Two wild tomato accessions (Solanum pennellii 'LA 716' e S. chilense 'LA 1967') previously reported as resistant to all Brazilian isolates of F. oxysporum f. sp. lycopersici were also evaluated. Isolates from São José de Ubá and Itaocara were highly virulent to 'Ponderosa', 'IPA-5' and 'Floradade'. They were also able to infect a few plants of 'BHRS-2,3', inducing vascular browning and wilt symptoms. Solanum pennellii and S. chilense accessions displayed an extreme (immune-like) resistant response. These results indicated that all seven isolates could be classified as F. oxysporum f. sp. lycopersici race 3, expanding the geographical distribution of this pathogen within Brazil. The hypothesis of transmission via contaminated seeds is reinforced after the present report, which confirms the almost simultaneous outbreak of race 3 in two geographically isolated tomato-growing areas in Brazil (Espirito Santo and Rio de Janeiro). Evaluation of commercial seed lots imported into Brazil for contamination with the pathogen would be necessary in order to avoid nation-wide spread of this serious disease.


2020 ◽  
pp. 17-21
Author(s):  
L.U. Bashir ◽  
A. Abdulkadir ◽  
M. M. Shah ◽  
A. Hamisu ◽  
U. Sharif ◽  
...  

This study investigated the phytochemical constituents and antifungal potential of Citrus limon peels using aqueous and methanol extracts against Fusarium oxysporum and Rhizopus stolonifer causing rots in water melon. The result of phytocemical screening revealed the presence of Saponin, Tannin, Phenols, Alkaloid and Flavanoid. Pathogenicity test conducted showed that F. oxysporum and R. stolonifer causes rots of Citrullus lanatus. The extracts inhibited the growth of F. oxysporum (76.67% and 60.00 %) methanol and aqueous respectively. R. stolonifer growth was inhibited (85.93% and 71.11%) methanol and aqueous extracts. The fungitoxicity of synthetic fungicide Benomyl was 95.56%. The methanol extracts has highest inhibitory activity than aqueous extract. The result of the findings indicates the Biofungicide potentials of Citrus limon peels as alternative to synthetic fungicide in management of phyto-pathogens of water lemon.


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