Abstract
Sudden death syndrome (SDS) of soybean was detected initially in Argentina during 1991-1992 in the Pampas Region and 1992-1993 in the Northwest Region. The first report of the fulfillment of Koch's postulates of SDS caused by Fusarium solani f. sp. glycines in Argentina was published in 2003 (3). Subsequently, analyses have shown that F. solani f. sp. glycines represents several morphologically and phylogenetically distinct species, including F. tucumaniae in Argentina and F. virguliforme in the United States (1). Isolations were made from plants that exhibited typical SDS symptoms (interveinal foliar chlorosis and necrosis leading to defoliation of the leaflets but not the petioles) from fields in Santa Fe and Buenos Aires provinces in 2001, 2002, and 2003. To determine which species are responsible for SDS in Argentina, cultures of eight slow growing isolates that developed bluish pigmentation and produced abundant macroconidia in sporodochia on potato dextrose agar were subjected to morphological and molecular phylogenetic analyses and pathogenicity tests. Morphological analyses demonstrated that three of the isolates were F. virguliforme and five were F. tucumaniae. Isolates of F. tucumaniae produced long and narrow sporodochial conidia while F. virguliforme produced diagnostic comma-shaped conidia. Molecular phylogenetic analyses of DNA sequences from multiple loci confirmed morphology-based identifications and showed that the soybean SDS pathogen in the United States, F. virguliforme, was also present in Argentina. To our knowledge, this is the first report of F. virguliforme in Argentina and of this pathogen outside the United States. Five isolates of F. tucumaniae and three isolates of F. virguliforme were used for pathogenicity tests. F. virguliforme isolate 171 provided by J. Rupe (University of Arkansas, Fayetteville) was used as a positive control. Soybean cultivars Ripley, RA 702, Pioneer 9492RR, Spencer, and A-6445RG were inoculated with each of the isolates tested in a greenhouse assay using soil infestation and toothpick methods (2). All eight isolates produced typical foliar SDS symptoms 15 to 25 days after inoculation. Severity of foliar symptoms averaged 3.3 for F. virguliforme, 2.6 for F. tucumaniae, and 3.3 for the positive control using a disease severity scale in which 1 = no symptoms and 5 = severely infected or dead plants. Under these conditions, F. virguliforme appeared to be more virulent than F tucumaniae. Noninoculated plants remained symptomless. Koch's postulates were confirmed with soybean cultivars RA 702 and A6445RG. Isolates recovered from symptomatic plants inoculated by the soil infestation and toothpick methods were identical to those used to inoculate the plant. Strains were recovered at frequencies of 100 and 60% from plants inoculated by the toothpick and soil infestation methods, respectively. To our knowledge, this is the first report of the fulfillment of Koch's postulates for F. tucumaniae and F. virguliforme in Argentina. References: (1) T. Aoki et al. Mycologia 95:660, 2003. (2) K. W. Roy et al. Plant Dis. 81:1100, 1997 (3) M. Scandiani et al. Plant Dis. 87:447, 2003.
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Claims 14
Claim · model-written summary
This is the first report of F. virguliforme in Argentina and of this pathogen outside the United States.
- Taxon
- Soybean
Glycine maxt0 - Interactor
- F. virguliformeFusarium virguliformee0pathogen
- Outcome
- first report of F. virguliformee0
- Setting
- Argentinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the first report of F. virguliforme in Argentina and of this pathogen outside the United States”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Morphological analyses identified three of the eight isolates as F. virguliforme.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. virguliformeFusarium virguliformee0pathogen
- Outcome
- isolates were F. virguliformee0
- Value
- three of the isolatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Morphological analyses demonstrated that three of the isolates were F. virguliforme and five were F. tucumaniae”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Morphological analyses identified five of the eight isolates as F. tucumaniae.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. tucumaniaeFusarium tucumaniaee0pathogen
- Outcome
- isolates were F. virguliforme and five were F. tucumaniaee0
- Value
- fivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Morphological analyses demonstrated that three of the isolates were F. virguliforme and five were F. tucumaniae”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
F. tucumaniae isolates produced long and narrow sporodochial conidia, while F. virguliforme produced diagnostic comma-shaped conidia.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. tucumaniaeFusarium tucumaniaee0pathogen
- Second interactor
- F. virguliformeFusarium virguliformee0pathogen
- Outcome
- sporodochial conidiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Isolates of F. tucumaniae produced long and narrow sporodochial conidia while F. virguliforme produced diagnostic comma-shaped conidia”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Molecular phylogenetic analyses of multiple loci confirmed the morphological identifications and showed that F. virguliforme, the US soybean SDS pathogen, is also present in Argentina.
- Taxon
- soybeanGlycine maxe0
- Interactor
- F. virguliformeFusarium virguliformee0pathogen
- Outcome
- F. virguliforme, was also present in Argentinae0
- Setting
- Argentinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Molecular phylogenetic analyses of DNA sequences from multiple loci confirmed morphology-based identifications and showed that the soybean SDS pathogen in the United States, F. virguliforme, was also present in Argentina”
Claim · model-written summary
All eight isolates produced typical foliar SDS symptoms 15 to 25 days after inoculation.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- inoculatione0
- Outcome
- typical foliar SDS symptomse0
- Qualifier
- 15 to 25 days after inoculatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All eight isolates produced typical foliar SDS symptoms 15 to 25 days after inoculation”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Foliar symptom severity averaged 3.3 for F. virguliforme isolates, on a scale where 1 is no symptoms and 5 severely infected or dead plants.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. virguliformeFusarium virguliformee0pathogen
- Outcome
- Severity of foliar symptomse0
- Value
- 3.3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Severity of foliar symptoms averaged 3.3 for F. virguliforme, 2.6 for F. tucumaniae, and 3.3 for the positive control”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Foliar symptom severity averaged 2.6 for F. tucumaniae isolates.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. tucumaniaeFusarium tucumaniaee0pathogen
- Outcome
- Severity of foliar symptomse0
- Value
- 2.6e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Severity of foliar symptoms averaged 3.3 for F. virguliforme, 2.6 for F. tucumaniae, and 3.3 for the positive control”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
F. virguliforme appeared more virulent than F. tucumaniae under these conditions.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. virguliformeFusarium virguliformee0pathogen
- Second interactor
- F tucumaniaeFusarium tucumaniaee0pathogen
- Outcome
- virulente0
- Direction
- more virulente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“F. virguliforme appeared to be more virulent than F tucumaniae”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Noninoculated soybean plants remained symptomless.
- Taxon
- SoybeanGlycine maxt0
- Outcome
- symptomlesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Noninoculated plants remained symptomless”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Koch's postulates were confirmed with soybean cultivars RA 702 and A6445RG.
- Taxon
- soybeanGlycine maxe0
- Material
- RA 702 and A6445RGe0
- Outcome
- Koch's postulates were confirmede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Koch's postulates were confirmed with soybean cultivars RA 702 and A6445RG”
Claim · model-written summary
Strains were recovered at a frequency of 100% from plants inoculated by the toothpick method.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- toothpicke0
- Outcome
- Strains were recoverede0
- Value
- 100e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains were recovered at frequencies of 100 and 60% from plants inoculated by the toothpick and soil infestation methods, respectively”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
Strains were recovered at a frequency of 60% from plants inoculated by the soil infestation method.
- Taxon
- SoybeanGlycine maxt0
- Treatment
- soil infestation methodse0
- Outcome
- Strains were recoverede0
- Value
- 60%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains were recovered at frequencies of 100 and 60% from plants inoculated by the toothpick and soil infestation methods, respectively”
t0“Soybean Sudden Death Syndrome”
Claim · model-written summary
This is the first report of the fulfillment of Koch's postulates for F. tucumaniae and F. virguliforme in Argentina.
- Taxon
- SoybeanGlycine maxt0
- Interactor
- F. tucumaniaeFusarium tucumaniaee0pathogen
- Second interactor
- F. virguliformeFusarium virguliformee0pathogen
- Outcome
- first report of the fulfillment of Koch's postulatese0
- Setting
- Argentinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this is the first report of the fulfillment of Koch's postulates for F. tucumaniae and F. virguliforme in Argentina”
t0“Soybean Sudden Death Syndrome”
The same questions in other papers
inoculation · survival · Glycine max (soybean)Positive and negative results
4 papers in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- negative
4 papers more in this group
See all 8 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.