Abstract
Four physiologic forms of the imperfect fungus Cladosporium fulvum Cooke, causal agent of the leaf mold disease of tomatoes, have been differentiated by differences in pathogenicity. Cultural studies likewise have shown that this species is a composite of physiologic forms.Saltant strains of differing degrees of stability have been isolated repeatedly from cultures arising from single one-celled spores. Since each cell of a conidium contains a single nucleus, these saltant strains are considered to arise as a result of mutations, in the broad sense of the term.Four main classes of reaction to C. fulvum have been defined: complete susceptibility, two types of partial resistance, and immunity.The reaction between pure lines of host and parasite is plastic. Environmentally conditioned variations in each of the four reaction types have been described. Of such variations the seasonal fluctuations in the reaction of Lyco-persicum esculentum var. Stirling Castle to Form 1 are outstanding. It has been shown that the failure of the expression of the inherent resistance of this variety during midwinter at Toronto is due largely to the reduced light experience of plants grown at this time, while the failure of such plants to support sporulation is caused by the low relative humidity then prevalent in the greenhouses.The genetics of the three types of resistance was fully analyzed. The Red Currant tomato, L. pimpinellifolium, carries, in addition to the dominant factor for immunity, an independently segregating dominant factor which, in the absence of the immunity factor, governs resistance to all four forms of C. fulvum. The resistance of Stirling Castle to Forms 1 and 3 has been shown to be due to another dominant factor.Conspicuous among the genetic factors in the host which modify the main reaction types is the recessive lutescence factor in the homozygous condition. Its most striking effect is the production, on genetically immune individuals, of small inconspicuous infection spots whose increase in size is arrested very soon after symptoms appear.As a result of linkage studies the three resistance factors have been located in MacArthur's (12) chromosome maps of the tomato.The conflicting reports concerning the resistance of esculentum tomato varieties to C. fulvum are discussed in the light of physiologic specialization and of a plastic host reaction.
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Claims 13
Claim · model-written summary
Four physiologic forms of Cladosporium fulvum were differentiated by differences in pathogenicity on tomato.
- Taxon
- tomatoes
Solanum lycopersicume0 - Interactor
- Cladosporium fulvum
Fulvia fulvae1pathogen - Outcome
- physiologic formse1
- Qualifier
- by differences in pathogenicitye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e1“Four physiologic forms of the imperfect fungus Cladosporium fulvum Cooke, causal agent of the leaf mold disease of tomatoes, have been differentiated by differences in pathogenicity”
Claim · model-written summary
Saltant strains of Cladosporium fulvum were isolated repeatedly from cultures arising from single one-celled spores.
- Taxon
- tomatoesSolanum lycopersicume0
- Outcome
- Saltant strainse2
- Qualifier
- isolated repeatedly from cultures arising from single one-celled sporese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e2“Saltant strains of differing degrees of stability have been isolated repeatedly from cultures arising from single one-celled spores”
Claim · model-written summary
Cladosporium fulvum reactions on tomato form four main classes: complete susceptibility, two types of partial resistance, and immunity.
- Taxon
- tomatoesSolanum lycopersicume0
- Interactor
- C. fulvumFulvia fulvae3pathogen
- Outcome
- classes of reactione3
- Qualifier
- complete susceptibility, two types of partial resistance, and immunitye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e3“Four main classes of reaction to C. fulvum have been defined: complete susceptibility, two types of partial resistance, and immunity”
Claim · model-written summary
The reaction between pure lines of tomato and the fungus is plastic.
- Taxon
- tomatoesSolanum lycopersicume0
- Outcome
- reaction between pure lines of host and parasitee4
- Qualifier
- plastice4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e4“The reaction between pure lines of host and parasite is plastic”
Claim · model-written summary
Environmental conditions cause variations in each of the four tomato reaction types to Cladosporium fulvum.
- Taxon
- tomatoesSolanum lycopersicume0
- Outcome
- variations in each of the four reaction typese5
- Qualifier
- Environmentally conditionede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e5“Environmentally conditioned variations in each of the four reaction types have been described”
Claim · model-written summary
Seasonal fluctuations in the reaction of Lycopersicon esculentum var. Stirling Castle to physiologic Form 1 are outstanding.
Verbatim
e6“Of such variations the seasonal fluctuations in the reaction of Lyco-persicum esculentum var. Stirling Castle to Form 1 are outstanding”
Claim · model-written summary
Failure of the inherent resistance of Stirling Castle in midwinter at Toronto is largely due to the reduced light experience of plants grown at that time.
Verbatim
e6“Of such variations the seasonal fluctuations in the reaction of Lyco-persicum esculentum var. Stirling Castle to Form 1 are outstanding”
e7“the failure of the expression of the inherent resistance of this variety during midwinter at Toronto is due largely to the reduced light experience of plants grown at this time”
Claim · model-written summary
Failure of plants to support sporulation of Cladosporium fulvum is caused by the low relative humidity in the greenhouses.
Verbatim
e6“Of such variations the seasonal fluctuations in the reaction of Lyco-persicum esculentum var. Stirling Castle to Form 1 are outstanding”
e1“while the failure of such plants to support sporulation is caused by the low relative humidity then prevalent in the greenhouses”
Claim · model-written summary
The Red Currant tomato carries an independently segregating dominant factor that governs resistance to all four forms of Cladosporium fulvum.
- Taxon
- L. pimpinellifoliume1
- Material
- Red Currant tomatoe1
- Interactor
- C. fulvumFulvia fulvae1pathogen
- Gene
- independently segregating dominant factore1
- Outcome
- resistance to all four forms of C. fulvume1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The Red Currant tomato, L. pimpinellifolium, carries, in addition to the dominant factor for immunity, an independently segregating dominant factor which, in the absence of the immunity factor, governs resistance to all four forms of C. fulvum”
Claim · model-written summary
Resistance of Stirling Castle to Cladosporium fulvum Forms 1 and 3 is due to another dominant factor.
Verbatim
e6“Of such variations the seasonal fluctuations in the reaction of Lyco-persicum esculentum var. Stirling Castle to Form 1 are outstanding”
e2“The resistance of Stirling Castle to Forms 1 and 3 has been shown to be due to another dominant factor”
Claim · model-written summary
A recessive lutescence factor in the homozygous condition modifies the main reaction types of tomato to Cladosporium fulvum.
- Taxon
- tomatoesSolanum lycopersicume0
- Gene
- recessive lutescence factore3
- Outcome
- main reaction typese3
- Qualifier
- in the homozygous conditione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e3“Conspicuous among the genetic factors in the host which modify the main reaction types is the recessive lutescence factor in the homozygous condition”
Claim · model-written summary
The recessive lutescence factor produces small inconspicuous infection spots on genetically immune tomato plants, whose growth is arrested soon after symptoms appear.
- Taxon
- tomatoesSolanum lycopersicume0
- Material
- genetically immune individualse4
- Gene
- recessive lutescence factore3
- Outcome
- small inconspicuous infection spotse4
- Qualifier
- whose increase in size is arrested very soon after symptoms appeare4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causal agent of the leaf mold disease of tomatoes”
e3“Conspicuous among the genetic factors in the host which modify the main reaction types is the recessive lutescence factor in the homozygous condition”
e4“Its most striking effect is the production, on genetically immune individuals, of small inconspicuous infection spots whose increase in size is arrested very soon after symptoms appear”
Claim · model-written summary
Three resistance factors of tomato were located on MacArthur chromosome maps by linkage studies.
- Taxon
- tomatoSolanum lycopersicume1
- Gene
- three resistance factorse1
- Outcome
- locatede1
- Qualifier
- As a result of linkage studiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“As a result of linkage studies the three resistance factors have been located in MacArthur's (12) chromosome maps of the tomato”