Distribution and prevalence of Fusarium subglutinans in mango trees affected by malformation

1994 ◽  
Vol 72 (1) ◽  
pp. 7-9 ◽  
Author(s):  
R. C. Ploetz

Infection of malformed and nonmalformed mango (Mangifera indica) trees by Fusarium subglutinans was assessed in Florida. All malformed floral panicles, but only 50% of the nonmalformed panicles, were infected by the fungus. When within-panicle infection was evaluated, an average of 84.5 % of the small pedicel and peduncle tissue pieces from malformed panicles were infected. When malformed and nonmalformed panicles were both assessed, 68.3% of the tissues from malformed panicles, but only 11.7% from nonmalformed panicles, were infected. Slight infection (2.2%) was observed in branch tissue that supported malformed panicles, and the fungus was never isolated from branches that supported nonmalformed panicles. In nutritional complementation tests with nitrate nonutilizing (nit) mutants, 55 of 64 isolates of F. subglutinans from malformed mango panicles were in the same vegetative compatibility group. The data indicate that mango malformation in the study area was significantly correlated (P < 0.0001) with infection by genetically related populations of F. subglutinans. The far greater prevalence of F. subglutinans in malformed than in asymptomatic panicles suggests that malformation symptoms develop in floral tissues only after they are extensively colonized by this fungus. Key words: Fusarium subglutinans, mango malformation, vegetative compatibility.

1991 ◽  
Vol 69 (8) ◽  
pp. 1756-1763 ◽  
Author(s):  
Katherine J. Lewis ◽  
Everett M. Hansen

The importance of spore infection in the spread of Inonotus tomentosus was assessed using vegetative compatibility and protein electrophoresis. Isolates were collected from diseased spruce (Picea glauca × engelmannii) trees from five sites. Each site had several small (two or three trees) discrete disease centres, or larger patchy centres, or both. Within each site, the vegetative compatibility group and protein profiles of isolates were examined in all combinations of paired isolates. Vegetatively compatible isolates had identical protein profiles in 74% of the comparisons. Vegetatively incompatible isolates had different protein profiles 97% of the time. Usually isolates differed by only one or two protein bands. Isolates from a discrete centre were usually vegetatively compatible with identical protein patterns. Larger patchy centres consisted of multiple vegetatively compatible groups. The number of unique vegetatively compatible groups found suggests that spores are an important course of infection. Key words: vegetative compatibility, disease centre, protein electrophoresis.


1990 ◽  
Vol 68 (6) ◽  
pp. 1357-1363 ◽  
Author(s):  
R. C. Ploetz

A worldwide collection of 96 isolates of Fusarium oxysporum f.sp. cubense (incitant of fusarial wilt of banana or Panama disease) from 12 countries was used to assess population structure in the pathogen; isolates were diverse for vegetative compatibility (11 vegetative compatibility groups) and race-specific virulence (races 1, 2, and 4). Rates of radial growth on potato dextrose agar differed at temperatures ranging from 8–36 °C for isolates in different VCGs and races (P < 0.05). On a KClO3-amended medium used to generate nitrate-nonutilizing (nit) mutants, variability in chlorate (a toxic analog of nitrate) sensitivity and the time required before nit mutants arose on the medium (mutability) was related primarily to vegetative compatibility group. In addition, cultural morphology on modified Komada's medium and potato dextrose agar was related primarily to vegetative compatibility group, whereas race was not as consistently related to these traits. In studies on the population biology and diversity in F. oxysporum f.sp. cubense, vegetative compatibility was a more useful character than race. On the basis of these results, it is suggested that F. oxysporum f.sp. cubense has had diverse origins.


2007 ◽  
Vol 97 (12) ◽  
pp. 1584-1589 ◽  
Author(s):  
Yu Chen ◽  
Jian-Xin Wang ◽  
Ming-Guo Zhou ◽  
Chang-Jun Chen ◽  
Shan-Kui Yuan

Monoconidial isolates of 33 carbendazim-sensitive isolates and 31 carbendazim-resistant isolates of Fusarium graminearum were selected from three regions of China for vegetative compatibility group (VCG) analysis. A total of 213 and 224 nit mutants were recovered from the 33 sensitive and the 31 resistant isolates, respectively. Of all the nit mutants, the frequency of the different phenotypes was 44.6, 46.5, 5.7, and 3.2% for nit1, nit3, nitM, and nitA, respectively. VCG analysis identified 30 different VCGs among the 33 sensitive- and the 31 carbendazim-resistant isolates, with VCG diversity 0.91 and 0.97, respectively. Both, a carbendazim-sensitive and a -resistant isolate from the same field belonged to the same VCG. In all then, a total of 59 VCGs were identified among the 64 isolates with an overall VCG diversity 0.92. Direct hyphal fusion was observed in six pairs of vegetatively compatible complements, which is evidence of heterokaryon formation. It was hypothesized that carbendazim resistance could not be transferred by hyphal fusion or there is a small chance to be transferred between two compatible isolates. Three stable sexual recombinants of F. graminearum were randomly chosen from each of the three genetic crosses to study their biological properties. There were no significant differences in mycelial linear growth and pathogenicity between recombinants and their parents, but they differ in sporulation ability and capacity to produce perithecia. We concluded that sexual recombination presumably played a role in the development of carbendazim resistance under field conditions.


Agrikultura ◽  
2016 ◽  
Vol 27 (3) ◽  
Author(s):  
Sri Sri Hartati ◽  
Ummu Salamah Rustiani ◽  
Lindung Tri Puspasari ◽  
Wawan Kurniawan

ABSTRACTVegetatif compatibility of Fusarium oxysporum on various hostsMany strains or race of Fusarium oxysporum can be grouped based on compatibility reproduction from a variety of different strains called Vegetative Compatibility Group (VCG). This study was aimed to determine how the grouping of several isolates of F. oxysporum and grouping of several hosts of the fungus by vegetative compatibility group. Fusarium oxysporum isolated from chickpea plants that showed symptoms of fusarium wilt. The isolates of F. oxysporum of chili and tomatoes obtained from the culture collections of Mycology Laboratory of IPB. Stages of vegetative compatibility testing assayed through recovery of nit mutants, the identification of phenotype of nit mutant, and complementation test. There are 29 mutants isolated from the isolates of F. oxysporum. Nit1 mutant was obtained from all isolates of beans, tomatoes and peppers. NitM and Nit3 mutant isolates were obtained from chickpea 4 and chili sequentially. Two VCG and one single self compatibility (SSC) were assayed from isolates of F. oxysporum based on complementation testing.Keywords: Beans, Fusarium wilt, Nit mutant, SSC, VCGABSTRAKJamur Fusarium oxysporum memiliki banyak forma spesialis dan ras. Jamur ini dapat dikelompokkan berdasarkan kompatibilitas reproduksi dari berbagai strain yang berbeda disebut dengan vegetative compatibility group (VCG). Penelitian ini bertujuan untuk mengetahui cara pengelompokkan F. oxysporum dan pengelompokkan jamur tersebut dari beberapa inang berdasarkan kelompok kompatibilitas vegetatifnya. Isolasi F. oxysporum dilakukan dari tanaman kacang panjang yang menunjukkan gejala layu fusarium. Isolat F. oxysporum dari cabai dan tomat berasal dari koleksi Laboratorium Mikologi IPB. Tahapan pengujian kompatibilitas vegetatif melalui pembiakan nit mutan, identifikasi fenotipe nit mutan, dan pengujian komplementasi. Isolasi mutan F. oxysporum didapatkan 29 mutan. Mutan nit1 didapatkan dari semua isolat yang diperoleh dari semua inang yang berbeda yaitu kacang panjang, tomat dan cabai. Mutan nitM hanya didapatkan dari isolat kacang panjang 4 dan mutan nit3 hanya didapatkan dari isolat cabai. Berdasarkan uji komplementasi F. oxysporum yang diuji terdiri dari dua VCG dan satu single self compatibility (SSC).Kata Kunci: Kacang panjang, Layu fusarium, Nit mutant, SSC, VCG


Plant Disease ◽  
2004 ◽  
Vol 88 (6) ◽  
pp. 645-649 ◽  
Author(s):  
D. J. Vakalounakis ◽  
Z. Wang ◽  
G. A. Fragkiadakis ◽  
G. N. Skaracis ◽  
D.-B. Li

Thirty-four isolates of Fusarium oxysporum, obtained in China from cucumber plants showing either Fusarium wilt (F. oxysporum f. sp. cucumerinum) or root and stem rot (F. oxysporum f. sp. radicis-cucumerinum) symptoms, were characterized by pathogenicity, vegetative compatibility, and random amplified polymorphic DNA (RAPD). Of these, 23 isolates were identified by pathogenicity as F. oxysporum f. sp. cucumerinum, and one as F. oxysporum f. sp. radicis-cucumerinum, while 10 isolates were avirulent on cucumber, melon, sponge gourd, and pumpkin. The Chinese isolates of F. oxysporum f. sp. cucumerinum were assigned to RAPD groups III and XXI and to vegetative compatibility group (VCG) 0183, four new VCGs, 0184 to 0187, and a single-member VCG included in the artificial VCG 018-. The Chinese isolate of F. oxysporum f. sp. radicis-cucumerinum was assigned to RAPD group I and bridging VCG 0260/0261. The occurrence of F. oxysporum f. sp. radicis-cucumerinum on cucumber is reported for the first time in China.


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.


1991 ◽  
Vol 39 (2) ◽  
pp. 161 ◽  
Author(s):  
NY Moore ◽  
PA Hargreaves ◽  
KG Pegg ◽  
JAG Irwin

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.


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