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 ◽  
...  

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.

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.


Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1133
Author(s):  
Freddy Magdama ◽  
Lorena Monserrate-Maggi ◽  
Lizette Serrano ◽  
José García Onofre ◽  
María del Mar Jiménez-Gasco

The continued dispersal of Fusarium oxysporum f. sp. cubense Tropical race 4 (FocTR4), a quarantine soil-borne pathogen that kills banana, has placed this worldwide industry on alert and triggered enormous pressure on National Plant Protection (NPOs) agencies to limit new incursions. Accordingly, biosecurity plays an important role while long-term control strategies are developed. Aiming to strengthen the contingency response plan of Ecuador against FocTR4, a population biology study—including phylogenetics, mating type, vegetative compatibility group (VCG), and pathogenicity testing—was performed on isolates affecting local bananas, presumably associated with race 1 of F. oxysporum f. sp. cubense (Foc). Our results revealed that Foc populations in Ecuador comprise a single clonal lineage, associated with VCG0120. The lack of diversity observed in Foc populations is consistent with a single introduction event from which secondary outbreaks originated. The predominance of VCG0120, together with previous reports of its presence in Latin America countries, suggests this group as the main cause of the devastating Fusarium wilt epidemics that occurred in the 1950s associated to the demise of ‘Gros Michel’ bananas in the region. The isolates sampled from Ecuador caused disease in cultivars that are susceptible to races 1 and 2 under greenhouse experiments, although Fusarium wilt symptoms in the field were only found in ‘Gros Michel’. Isolates belonging to the same VCG0120 have historically caused disease on Cavendish cultivars in the subtropics. Overall, this study shows how Foc can be easily dispersed to other areas if restriction of contaminated materials is not well enforced. We highlight the need of major efforts on awareness and monitoring campaigns to analyze suspected cases and to contain potential first introduction events of FocTR4 in Ecuador.


Plant Disease ◽  
1997 ◽  
Vol 81 (9) ◽  
pp. 1095-1095 ◽  
Author(s):  
B. J. Gwynne ◽  
T. R. Gordon ◽  
R. M. Davis

In 1996, cantaloupe (Cucumis melo L. cv. Durango) vines in two fields exhibited wilt, vascular discoloration, and necrotic streaks on the stems. Fusarium oxysporum Schlechtend.:Fr. was isolated from the stems of vines from both fields. One isolate from each field was compared with known isolates of F. oxysporum f. sp. melonis (Leach & Currence) W.C. Snyder & H.N. Hansen races 1 and 2 in a differential host range experiment in the greenhouse. Three-week-old seedlings were root-dip inoculated with monoconidial isolates at a concentration of 5 × 105 spores per ml. Control plants were dipped in water. In two experiments, the test isolates killed the susceptible varieties Top Mark and Magnum .45 and the race 2 resistant varieties Durango, Gold Mine, and Perlita FR. Seedlings of variety Charentais with the Fom2 gene conferring resistance to race 1 were resistant to both test isolates. It was determined that both of these isolates are associated with vegetative compatibility group (VCG) 0134 (1). This is the first report of race 1 and VCG 0134 of F. oxysporum f. sp. melonis causing Fusarium wilt of muskmelon in the Central Valley of California, and the first reported occurrence of race 1 in California since 1973 (2). Cantaloupe varieties currently grown in California are susceptible to race 1 of F. oxysporum f. sp. melonis References: (1) D. J. Jacobson and T. R. Gordon. Phytopathology 78:668, 1988. (2) J. V. Leary and W. D. Wilbur. Phytopathology 66:15, 1976.


Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 523-529 ◽  
Author(s):  
Louis K. Prom ◽  
Ramasamy Perumal ◽  
Saradha R. Erattaimuthu ◽  
John E. Erpelding ◽  
Noe Montes ◽  
...  

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.


Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1326-1332 ◽  
Author(s):  
Anthony P. Keinath ◽  
Richard L. Hassell

Fusarium wilt of watermelon, caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. niveum race 2, is a serious, widespread disease present in major watermelon-growing regions of the United States and other countries. ‘Fascination,’ a high yielding triploid resistant to race 1, is grown in southeastern states in fields that contain a mixture of races 1 and 2. There is some benefit to using cultivars with race 1 resistance in such fields, even though Fascination is susceptible to Fusarium wilt caused by race 2. Experiments in 2012 and 2013 were done in fields infested primarily with race 2 and a mixture of races 1 and 2, respectively. Fascination was grafted onto four rootstock cultivars: bottle gourd (Lagenaria siceraria) ‘Macis’ and ‘Emphasis’ and interspecific hybrid squash (Cucurbita maxima× C. moschata) ‘Strong Tosa’ and ‘Carnivor.’ Nongrafted and self-grafted Fascination were used as susceptible control treatments. In both experiments, mean incidence of plants with symptoms of Fusarium wilt was ≥52% in the susceptible control treatments and ≤6% on the grafted rootstocks. Disease incidence did not differ between rootstock species or cultivars. In both years, Fascination grafted onto Strong Tosa and Macis produced more marketable-sized fruit than the susceptible control treatments. Grafted Emphasis and Carnivor also produced more fruit than the control treatments in 2012. The cucurbit rootstocks suppressed Fusarium wilt caused by race 2 and increased marketable yield of triploid watermelon grown in infested soil.


2007 ◽  
Vol 97 (4) ◽  
pp. 461-469 ◽  
Author(s):  
X. G. Zhou ◽  
K. L. Everts

Eighty-eight isolates of Fusarium oxysporum f. sp. niveum, collected from wilted watermelon plants and infested soil in Maryland and Dela-ware, were characterized by cross pathogenicity to muskmelon, race, and vegetative compatibility. Four isolates (4.5%) were moderately pathogenic to ≥2 of 18 muskmelon cultivars in a greenhouse test, and one representative isolate also was slightly pathogenic in field microplots. The four isolates all were designated as race 2, and were in vegetative compatibility group (VCG) 0082. Of the 74 isolates to which a VCG could be assigned, 41 were in VCG 0080, the VCG distributed most widely; 27 were in VCG 0082, and were distributed in half of the 20 watermelon fields surveyed; and 6 were in the newly described VCG 0083, and were restricted to three fields. Among the isolates in VCG 0080, 8 were designated as race 0, 21 as race 1, and 12 as race 2. Of the isolates in VCG 0082, 6 were designated as race 0, 11 as race 1, and 10 as race 2. All isolates in VCG 0083 were designated as race 2. Isolates from more than one race within the same VCG or isolates from more than one VCG were recovered from single plants and fields. No differences in aggressiveness on differential watermelon cultivars were observed among isolates from different VCGs of the same race. A diverse association between virulence and VCG throughout the Mid-Atlantic region suggests that the pathotypes of F. oxysporum f. sp. niveum may be of local origin or at least long existent in the region.


Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 592-596 ◽  
Author(s):  
T. L. Zuniga ◽  
T. A. Zitter ◽  
T. R. Gordon ◽  
D. T. Schroeder ◽  
D. Okamoto

Forty-six isolates of Fusarium oxysporum f. sp. melonis obtained from soil samples throughout melon-producing areas in New York State were identified on the basis of pathogenicity and colony morphology. Physiological races 1 and 2 were identified by their reaction on a set of differential melon cultivars. Race 1 was widely distributed, occurring in six of the seven New York counties surveyed. Twenty-seven of the 28 race 1 isolates were associated with vegetative compatibility group (VCG) 0134, whereas one was incompatible with all known VCGs of F. oxysporum f. sp. melonis. Twelve out of 18 race 2 isolates were associated with VCG 0131, and occurred in four counties in eastern and western New York. Five isolates of race 2, associated with VCG 0130, were recovered from a farm in Washington County, as was a single race 2 isolate which was incompatible with all known VCGs of F. oxysporum f. sp. melonis. Restriction fragment length polymorphisms in the nuclear DNA revealed variability among the isolates examined, but race 1/VCG 0134 isolates from New York and Maryland were identical or nearly so, as were race 2/VCG 0131 isolates from the two states. These findings suggest a close relationship between the populations of F. oxysporum f. sp. melonis in New York and Maryland. Race 2 isolates were more virulent than race 1 isolates, based on the number of days to first symptoms and death of melon seedlings.


Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 255-266 ◽  
Author(s):  
A. P. Keinath ◽  
R. L. Hassell

Grafting watermelon (Citrullus lanatus var. lanatus) onto rootstocks of interspecific hybrid squash (Cucurbita moschata × C. maxima), bottle gourd (Lagenaria siceraria), or citron (Citrullus lanatus var. citroides) has been used in Asia and Israel to mange Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. niveum. The objectives of this study were to determine the frequency of infection of six rootstocks by F. oxysporum f. sp. niveum races 1 and 2 and the field performance of grafted rootstocks in Charleston, SC. Grafted and nongrafted watermelon and rootstock plants were inoculated in the greenhouse with race 1, race 2, or water (the control treatment). With both races, the frequency of recovery of F. oxysporum from scion and rootstock portions of inoculated watermelon plants grafted onto ‘Ojakkyo’ citron was greater than from watermelon plants grafted onto ‘Shintosa Camel’ and ‘Strong Tosa’ interspecific hybrid squash, and from plants grafted onto ‘Emphasis’, ‘Macis’, and ‘WMXP 3945’ bottlegourd. For nongrafted plants inoculated with race 1, percent recovery also was greater from Ojakkyo than from interspecific hybrid squash and bottlegourd. For nongrafted plants inoculated with race 2, F. oxysporum was recovered from the base of ≥79% of all inoculated plants. More than two-thirds (15) of 21 isolates recovered from the tops or scions of inoculated plants were pathogenic on watermelon. In spring 2010 and 2011, the six rootstocks were grafted with seedless watermelon ‘Tri-X 313’, which is susceptible to both races, and transplanted in a field infested with races 1 and 2 of F. oxysporum f. sp. niveum. Disease incidence for nongrafted and self-grafted Tri-X 313 (the control treatments) and Tri-X 313 grafted onto Ojakkyo citron did not differ significantly. Grafted watermelon plants produced greater weights and numbers of fruit than plants of the two control treatments. Nonpathogenic isolates of F. oxysporum and isolates of F. oxysporum f. sp. niveum colonized interspecific hybrid squash, bottlegourd, and grafted watermelon. The rootstocks evaluated, however, restricted movement of F. oxysporum f. sp. niveum into the watermelon scion, suppressed wilt symptoms, and increased fruit yields in an infested field.


2021 ◽  
Author(s):  
Lei Zhang ◽  
Lina Liu ◽  
Shu Li ◽  
Alberto Cenci ◽  
Mathieu Rouard ◽  
...  

Abstract Background: Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is the causal agent of Fusarium wilt, and is the most destructive soil-borne and vascular invasive fungus of banana. The sap circulating in vascular cells transports proteins including those that might be involved in disease-resistance processes. However, there is no research to analyze changes in banana vascular sap protein response to TR4 to date. Results: To gain an integrated understanding of differential protein abundance in banana vascular sap during TR4 infection, we performed a comparative proteomic analysis of vascular sap of the resistant ‘Pahang’ and the susceptible ‘Brazilian’ bananas inoculated with TR4. We identified 129 differential expression proteins (DEPs) between resistant and susceptible tested combinations. Of these DEPs, hypersensitive-induced response protein 1 (HIR1) and E3 ubiquitin ligase (E3) decreased in abundance in Pahang with no change in Brazilian under TR4 infection; chalcone isomerase (CHI) and glycine-rich RNA-binding protein (GRP) increased in abundance in Pahang but no significant changes in Brazilian under TR4 infection; carboxylesterase (CXE) and GDSL lipase (GLIP) were specifically in higher abundance in Pahang response to TR4 compared to that of Brazilian. It suggested that these proteins played important roles in bananas against TR4. Conclusions: Our study identified 129 DEPs in vascular sap between resistant and susceptible tested combinations. Of which, HIR1, E3, CHI, GRP, CXE and GLIP played important roles in bananas response to TR4. To our knowledge, this is first report to analyze changes in banana vascular sap proteins in response to TR4, which help us to explore the molecular mechanisms of banana defense to Fusarium wilt.


Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 199-199
Author(s):  
R. C. Ploetz ◽  
J. L. Haynes

Race 3 of Fusarium oxysporum f. sp. lycopersici, cause of Fusarium wilt of tomato, Lycopersicon esculentum, was first recognized in Florida in 1982 on the west coast (Hillsborough and Manatee counties) (2). Approximately 10 years later, race 3 was reported in northeastern production areas of the state (Gadsden County) (1) and was observed on the east coast (Ft. Pierce area) (D. O. Chellemi, personal communication). During the 1998 to 1999 season, mature plants of Sanibel, a commercial tomato cultivar with resistance to races 1 and 2, were observed with symptoms of Fusarium wilt at the University of Florida's Tropical Research and Education Center in Homestead. Approximately 20% of the plants were conspicuously wilted, chlorotic, and necrotic in all or unilateral portions of the canopy. Internal, vascular discoloration in affected plants extended far into the canopy, distinguishing the disease from Fusarium crown rot, caused by F. oxysporum f. sp. radicis-lycopersici. Pure colonies of fungi were isolated from surface-disinfested (10 s with 70% ethanol, 2 min with 10% bleach) stem segments on potato dextrose agar (PDA) amended with streptomycin (100 mg/liter), rifamycin (50 mg/liter), and a commercial miticide (Danitol 2EHC [4 drops/liter]). Isolates were identified as F. oxysporum due to their production of typical falcate macroconidia with foot-shaped basal cells, microconidia borne in false heads only on mono-phialides, and chlamydospores. In replicated (three) greenhouse trials, six single-spore isolates were used to root-dip inoculate (107 conidia per ml) seedlings of differential tomato cultivars (Bonnie Best, no resistance; Manapal, race 1 resistance; Walter, race 1 and race 2 resistance). All isolates were pathogenic on each of the differential cultivars, and one isolate, 2-1, caused severe damage on Walter (mean rating of 3.5 on a 1 to 5 scale). The results were repeated in a second trial with the most virulent isolate. In both trials, pure colonies of F. oxysporum were recovered from symptomatic seedlings. Southeastern Florida is the last major tomatoproduction area in Florida to be affected by race 3 of F. oxysporum f. sp. lycopersici. References: (1) D. O. Chellemi and H. A. Dankers. Plant Dis. 76:861, 1992. (2) R. B. Volin and J. P. Jones. Proc. Fla. State Hortic. Soc. 95:268, 1982.


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