scholarly journals Genetics of Chickpea Resistance to Five Races of Fusarium Wilt and a Concise Set of Race Differentials for Fusarium oxysporum f. sp. ciceris

Plant Disease ◽  
2005 ◽  
Vol 89 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Kamal Dev Sharma ◽  
Weidong Chen ◽  
Fred J. Muehlbauer

Genetics of resistance in chickpea accession WR-315 to Fusarium wilt was investigated, and a concise set of differentials was developed to identify races of Fusarium oxysporum f. sp. ciceris. A population of 100 F7 recombinant inbred lines (RILs) from a cross of WR-315 (resistant) and C-104 (susceptible) was used to study genetics of resistance to races 1A, 2, 3, 4, and 5 of F. oxysporum f. sp. ciceris, and a population of 26 F2 plants from a cross between the same two parents was used to study inheritance of resistance to race 2. Segregations of the RILs for resistance to each of the five races suggest that single genes in WR-315 govern resistance to each of the five races. A 1:3 resistant to susceptible ratio in the F2 population indicated that resistance in WR-315 to race 2 was governed by a single recessive gene. A race-specific slow disease progress reaction was observed in chickpea line FLIP84-92C(3) to infection by race 2, a phenomenon termed as slow wilting, that is different from previously reported late wilting with respect to latent period, disease progress rate, and final disease rating. Twenty-nine germ plasm lines (27 Cicer arietinum and two C. reticulatum) including previously used differentials were evaluated for their reactions to infection by the five races. Only eight of the 29 germ plasm lines differentiated at least one of the five races based on either resistant or susceptible reactions, whereas the remaining germ plasm lines were either susceptible or resistant to all five races or differentiated them by intermediate reactions. A concise set of eight chickpea lines comprised of four genotypes and four F7 RILs with vertical resistance was developed as differentials for race identification in F. oxysporum f. sp. ciceris. These differential lines were characterized by early appearance of wilt symptoms, and clear and consistent disease phenotypes based on no wilt or 100% wilt incidence, which offers important improvements over previously available differential sets and provides more precise and unambiguous identification of the races.

2021 ◽  
Vol 22 (2) ◽  
pp. 822
Author(s):  
Owen Hudson ◽  
Sumyya Waliullah ◽  
James C. Fulton ◽  
Pingsheng Ji ◽  
Nicholas S. Dufault ◽  
...  

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum (FON), is pathogenic only to watermelon and has become one of the main limiting factors in watermelon production internationally. Detection methods for this pathogen are limited, with few published molecular assays available to differentiate FON from other formae speciales of F. oxysporum. FON has four known races that vary in virulence but are difficult and costly to differentiate using traditional inoculation methods and only race 2 can be differentiated molecularly. In this study, genomic and chromosomal comparisons facilitated the development of a conventional polymerase chain reaction (PCR) assay that could differentiate race 3 from races 1 and 2, and by using two other published PCR markers in unison with the new marker, the three races could be differentiated. The new PCR marker, FNR3-F/FNR3-R, amplified a 511 bp region on the “pathogenicity chromosome” of the FON genome that is absent in race 3. FNR3-F/FNR3-R detected genomic DNA down to 2.0 pg/µL. This marker, along with two previously published FON markers, was successfully applied to test over 160 pathogenic FON isolates from Florida, Georgia, and South Carolina. Together, these three FON primer sets worked well for differentiating races 1, 2, and 3 of FON. For each marker, a greater proportion (60 to 90%) of molecular results agreed with the traditional bioassay method of race differentiation compared to those that did not. The new PCR marker should be useful to differentiate FON races and improve Fusarium wilt research.


1963 ◽  
Vol 16 (1) ◽  
pp. 55 ◽  
Author(s):  
A Kerr

At least four fungal pathogens are involved in the root rot-Fusarium wilt complex of peas which is a serious problem following intensive cropping of peas in South Australia. The pathogens are Fusarium oxysporum f. pisi race 2 Snyder & Hansen, F. solani f. pisi Snyder & Hansen, Pythium ultimum Trow, and Ascochyta pinodella L. K. Jones. In susceptible pea cultivars there is a marked interaction between F. oxysporum and P. ultimum. P. ultimum alone causes initial stunting from which plants gradually recover; F. OX1Jsporum alone probably CRuses little damage; both fungi together CRuse initial stunting followed by severe wilt symptom about 6 weeks after sowing and death 2 weeks later. The importance ofF. solani and A. pinodella has not been fully determined, but they probably cause only minor damage.


2005 ◽  
Vol 30 (4) ◽  
pp. 409-412 ◽  
Author(s):  
Juliano C. da Silva ◽  
Wagner Bettiol

This study was done to evaluate the efficiency of non-pathogenic Fusarium oxysporum isolates (141/3, 233, 233/1, 245, 245/1, 251, 251/2, 251/5, and 257) in controlling vascular wilt caused by F. oxysporum f. sp. lycopersici, race 2 (isolates C-21A, TO11, and TO245) in tomato (Lycopersicon esculentum) cv. Viradoro seedlings. In order to determine the effect of non-pathogenic F. oxysporum isolates in tomato plants, the root system of 30-day-old seedlings was immersed in conidial suspensions (10(6) ml-1) of each isolate and the seedlings were transplanted to a cultivation substrate. Thirty-five days after transplanting it was observed that the non-pathogenic F. oxysporum isolates were not pathogenic to the cv. Viradoro nor did they affect seedling development. The efficiency of the non-pathogenic F. oxysporum isolates in controlling Fusarium wilt was determined by immersing the tomato seedling roots in the conidial suspension (10(6) ml-1) of each isolate and then transplanting them into substrates previously infested with isolates of F. oxysporum f.sp. lycopersici, race 2 (10(5) conidia ml-1 of substrate). Evaluations were performed 35 days after transplanting, for severity in scale with 1=healthy plant to 6=dead plant or plant showing vessel browning and wilted leaves up to the leader shoot and seedling height. The non-pathogenic F. oxysporum isolates were efficient in reducing the severity of the disease and maintaining normal plant development. These results provide evidence of the antagonistic activity of non-pathogenic F. oxysporum isolates in controlling vascular wilt caused by F. oxysporum f. sp. lycopersici race 2 in tomato.


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.


Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 92-98 ◽  
Author(s):  
X. G. Zhou ◽  
K. L. Everts ◽  
B. D. Bruton

Three races (0, 1, and 2) of Fusarium oxysporum f. sp. niveum have been previously described in watermelon (Citrullus lanatus) based on their ability to cause disease on differential watermelon genotypes. Four isolates of F. oxysporum f. sp. niveum collected from wilted watermelon plants or infested soil in Maryland, along with reference isolates of races 0, 1, and 2, were compared for virulence, host range, and vegetative compatibility. Race identification was made on the watermelon differentials Sugar Baby, Charleston Gray, Dixielee, Calhoun Gray, and PI-296341-FR using a root-dip, tray-dip, or pipette inoculation method. All four Maryland isolates were highly virulent, causing 78 to 100% wilt on all differentials, one of which was PI-296341-FR, considered highly resistant to race 2. The isolates also produced significantly greater colonization in the lower stems of PI-296341-FR than a standard race 2 reference isolate. In field microplots, two of the isolates caused over 90% wilt on PI-296341-FR, whereas no disease was caused by a race 2 isolate. All four isolates were nonpathogenic on muskmelon, cucumber, pumpkin, and squash, confirming their host specific pathogenicity to watermelon. The Maryland isolates were vegetatively compatible to each other but not compatible with the race 2 isolates evaluated, indicating their genetic difference from race 2. This study proposes that the Maryland isolates belong to a new race, race 3, the most virulent race of F. oxysporum f. sp. niveum described to date.


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.


HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 261-262 ◽  
Author(s):  
Mark J. Henning ◽  
Henry M. Munger ◽  
Molly M. Jahn

`PMR Delicious 51' is a new and improved version of the `Delicious 51' eastern type melon (Cucumis melo L.). It was developed in the Department of Plant Breeding at the Cornell University Agricultural Experiment Station in Ithaca, N.Y. It is well adapted for northeastern U.S. conditions and shows potential for good adaptation in the northwest. It is well suited for home gardeners, market gardeners, and commercial growers who want to grow an open-pollinated (OP) melon. `PMR Delicious 51' has excellent resistance to powdery mildew races 1 and 2 (Podosphaera xanthi) and resistance to fusarium wilt (Fusarium oxysporum f. sp. melonis) race 2.


2021 ◽  
Author(s):  
Daniel Heck ◽  
Gabriel Alves ◽  
Eduardo S. G. Mizubuti

AbstractDispersal of propagules of a pathogen has remarkable effects on the development of epidemics. Previous studies suggested that insect pests play a role in the development of Fusarium wilt (FW) epidemics in banana fields. We provided complementary evidence for the involvement of two insect pests of banana, the weevil borer (Cosmopolites sordidus L. - WB) and the false weevil borer (Metamasius hemipterus L. - FWB), in the dispersal of Fusarium oxysporum f. sp. cubense (Foc) using a comparative epidemiology approach under field conditions. Two banana plots located in a field with historical records of FW epidemics were used, one was managed with Beauveria bassiana to reduce the population of weevils, and the other was left without B. bassiana applications. The number of WB and FWB was monitored biweekly and the FW incidence was quantified bimonthly during two years. The population of WB and the incidence (6.7%) of FW in the plot managed with B. bassiana were lower than in the plot left unmanaged (13%). The monomolecular model best fitted the FW disease progress data and, as expected, the average estimated disease progress rate was lower in the plot managed with the entomopathogenic fungus (r = 0.0024) compared to the unmanaged plot (r = 0.0056). Aggregation of FW was higher in the field with WB management. WB affected the spatial and temporal dynamics of FW epidemics under field conditions and brought evidence that managing the insects may reduce FW of bananas intensity.


Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 111-111 ◽  
Author(s):  
Z. M. Sheu ◽  
T. C. Wang

Fusarium wilt caused by Fusarium oxysporum Schlechtend.:Fr. f. sp. lycopersici (Sacc.) W.C. Snyder & N.H. Hans. is a destructive disease of tomato crops worldwide. The use of resistant varieties is the best strategy for disease control. There are three reported races of the pathogen. Recent surveys indicated that many of the commercial cultivars with resistance to F. oxysporum f. sp. lycopersici race 1 planted in Taiwan displayed Fusarium wilt symptoms. Yellowing on the older leaves was observed on one side of the stems close to fruit maturity. The yellowing gradually affected most of the foliage and was accompanied by wilting of the plants. The vascular tissue was usually dark brown and discoloration extended to the apex. The wilting became more extensive until plants collapsed and died. A total of 87 isolates obtained from typical diseased plants throughout Taiwan from 2002 to 2005 were analyzed to determine the race and distribution of this pathogen in Taiwan. Isolates were confirmed at the species level using F. oxysporum-specific primers FOF1 and FOR1 (4). Subsequently, isolates were characterized for pathogenicity, race and restriction fragment length polymorphisms of the intergenic spacer region of rDNA (IGS-RFLP) with two reference isolates, Fol 11A (race 1) and Fol 34-1 (race 2). Pathogenicity tests and race determination were conducted using root-dip inoculation (3) on 2-week-old seedlings of host differentials Bonny Best (no resistance), UC82-L (resistant to race 1), and Florida MH-1 (resistant to races 1 and 2). Thirty-six seedlings of each cultivar were arranged into three replications and inoculated with each isolate. Disease reaction was evaluated 3 weeks after inoculation. The disease severity rating (DSR) was determined on individual plants according to the following scale: 0 = plant healthy without external symptoms; 1 = slight vascular discoloration with or without stunted growth; 2 = severe vascular discoloration usually with stunted growth; and 3 = plant wilted beyond recovery or dead. The presence of severe vascular discoloration indicated a susceptible reaction. All isolates were race 2, and over 70% of the isolates showed strong virulence with a DSR >2 on cvs. Bonny Best and UC-82L. This result was different from a previous report of race 1 from Taiwan (2). Two IGS-RFLP haplotypes generated by EcoRI, RsaI, and HaeIII digestions (1) were identified. Eighty-six isolates displayed one banding pattern, and one unique isolate displayed a second banding pattern. The results demonstrated the predominance of race 2 and low diversity within the Taiwan population. To our knowledge, this is the first report regarding the predominant race and IGS-RFLP haplotype identification of F. oxysporum f. sp. lycopersici in Taiwan. Our study indicates that tomato varieties in Taiwan should possess resistance to race 2. References: (1) G. Cai et al. Phytopathology 93:1014, 2003. (2) K. S. Elias and R. W. Schneider. Phytopathology 82:1421, 1992. (3) J. W. Gerdemann and A. M. Finley. Phytopathology 41:238, 1951. (4) P. K. Mishra et al. FEMS Microbiol. Lett. 218:329, 2003.


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