Interactions of the nonhost French bean plant (Phaseolus vulgaris) with parasitic and saprophytic fungi. IV. Effect of preinoculation with the bean rust fungus on growth of parasitic fungi nonpathogenic on beans

1991 ◽  
Vol 69 (8) ◽  
pp. 1642-1646 ◽  
Author(s):  
Myriam R. Fernandez ◽  
Michèle C. Heath
Keyword(s):  
Rust Fungus ◽  
Fungal Growth ◽  
Hyphal Growth ◽  
French Bean ◽  
Bean Rust ◽  
Protein Synthesis Inhibitors ◽  
Rust Infection ◽  
Parasitic Fungi ◽  
Wall Appositions ◽  
Bean Leaves

Bean leaves inoculated 24 h previously with the bean rust fungus were inoculated with spores of Cochliobolus heterostrophus, Stemphylium sarcinaeforme, Stemphylium botryosum, or Cladosporium fulvum. For all species except C. fulvum, hyphal growth resulting from stomatal penetrations was greater than that in leaves that were not rust-infected but did not continue for more than about 24 h. The incidence of direct penetrations for these three fungi also was increased by prior rust infection, and the incidence of epidermal wall appositions was reduced. Growth of C. fulvum in rust-infected leaves only exceeded that in control leaves when spores were injected into the intercellular spaces of the mesophyll tissue. Rust infection either had little effect on the incidence of cell death, normally induced by all of the tested fungi except C. fulvum, or it enhanced this response in association with greater fungal growth. From this and previous studies, it seems that successful rust infection increases the growth of a wider array of fungi nonparasitic to beans than treatments with growth regulators or intercellular washing fluids from rusted tissue. Its effect is most closely mimicked by preinoculation treatments with heat or protein synthesis inhibitors, but it does not induce indiscriminate susceptibility. Its effect may, in part, be due to the suppression of defenses involving wall modifications. Key words: Uromyces appendiculatus, induced susceptibility, nonhost resistance.

Interactions of the nonhost French bean plant (Phaseolus vulgaris) with parasitic and saprophytic fungi. I. Fungal development on and in killed, untreated, heat-treated, or blasticidin S treated leaves

1989 ◽  
Vol 67 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Myriam R. Fernandez ◽  
Michèle C. Heath
Keyword(s):  
Phaseolus Vulgaris ◽  
Fungal Growth ◽  
French Bean ◽  
Phaseolus Vulgaris L ◽  
Subsequent Growth ◽  
Parasitic Fungi ◽  
Heat Treated ◽  
Leaf Resistance ◽  
Blasticidin S ◽  
Bean Leaves

Germination, penetration, and subsequent growth of four saprophytic and five parasitic fungi nonpathogenic on French bean (Phaseolus vulgaris L. cv. Pinto) were examined on, or in, killed, untreated, and heat-treated or blasticidin S treated leaves in the presence (saprophytes only) or absence of additional nutrients. The saprophytes required either an external supply of nutrients or a diffusate from autoclaved leaves to germinate, and they subsequently did not attempt to penetrate untreated or heat-treated living leaves. In contrast, the parasites germinated well, and penetrated untreated tissue almost exclusively through stomata. For some parasites, preinoculation heat treatment increased the incidence of direct penetration and the degree of fungal growth in the tissue. The saprophytes and nonbiotrophic parasites all penetrated and grew well in leaves that had been killed by autoclaving or freezing. The data suggest that living, intact bean leaves are resistant to the fungal saprophytes tested because these fungi lack pathogenicity factors necessary for germination on, and penetration of, the leaf. Resistance to the parasites, in contrast, appears to reside in heat-sensitive and heat- or blasticidin S insensitive defenses in the leaf that may differ with the fungus.

Light and electron microscopy of the interaction between the sunflower rust fungus (Puccinia helianthi) and leaves of the nonhost plant, French bean (Phaseolus vulgaris)

1986 ◽  
Vol 64 (11) ◽  
pp. 2476-2486 ◽  
Author(s):  
Lesley A. Wood ◽  
Michèle C. Heath
Keyword(s):  
Heat Treatment ◽  
Cell Walls ◽  
Rust Fungus ◽  
Light And Electron Microscopy ◽  
Fungal Growth ◽  
Mesophyll Cell ◽  
French Bean ◽  
Puccinia Helianthi ◽  
Mother Cells ◽  
Bean Leaves

Growth of the sunflower rust fungus (Puccinia helianthi Schw.) was compared by light microscopy in sunflower leaves, in untreated French bean leaves, in bean leaves given a preinoculation heat treatment, and on collodion membranes. Results suggested that fungal growth was slightly reduced and the formation of haustorial mother cells was inhibited in untreated bean leaves. Haustorial mother cells, when present, did not form haustoria and adjacent mesophyll cell walls usually were highly refractive. Preinoculation heat treatment reduced the incidence of refractive cell walls and increased that of haustorial mother cells and haustoria. Ultrastructurally, infection hyphae in unheated bean leaves appeared unusually vacuolate and often contained wall appositions where they touched the plant cells. Silicalike deposits were present in and on mesophyll cell walls at most infection sites. In heated plants, necrotic haustoria with small bodies were seen at the few sites that lacked silicalike deposits. At other sites, the fungus appeared to have stopped growing during the formation of the penetration peg or the haustorial neck, and such necks were encrusted with silicalike material. At most sites, penetration pegs were occluded resulting in the unusual situation in which the haustorial mother cell remained seemingly alive in spite of the necrosis of the haustorium.

An evalution of the nitrous acid – 3-methyl-2-benzothiazolinone hydrazone hydrochloride – ferric chloride assay for chitin in rust fungi and rust-infected tissue

1982 ◽  
Vol 60 (12) ◽  
pp. 2575-2580 ◽  
Author(s):  
Susan G. W. Kaminskyj ◽  
Michèle C. Heath
Keyword(s):  
Ferric Chloride ◽  
Nitrous Acid ◽  
Rust Fungus ◽  
Infected Plant ◽  
French Bean ◽  
Rust Fungi ◽  
Bean Rust ◽  
Reactive Component ◽  
Comparison Of The Results ◽  
Fungus Growth

The growth of the bean rust and cowpea rust fungi was examined in cultivars of French bean and cowpea using light microscopy and the nitrous acid – 3-methyl-2-benzothiazolinone hydrazone hydrochloride – ferric chloride assay for chitin. Comparison of the results indicated that the chitin assay did not detect changes in vegetative growth but only detected substances present in mature and developing urediospores. Examination of urediospores indicated that the reactive component(s) was hexosamine, probably glucosamine, but not chitin. The presence of strongly reactive substances in the urediospores, and the apparent low level of chitin in vegetative mycelium compared with that in the mycelium of the commercial mushroom, suggest that this chitin assay is of little value in estimating rust fungus growth in infected plant tissue.

scholarly journals Isolates of Uromyces appendiculatus with Specific Virulence to Landraces of Phaseolus vulgaris of Andean Origin

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 108-113 ◽  
Author(s):  
Craig M. Sandlin ◽  
James R. Steadman ◽  
Carlos M. Araya ◽  
Dermot P. Coyne
Keyword(s):  
Phaseolus Vulgaris ◽  
Rapd Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Rust Fungus ◽  
Distinct Group ◽  
Uromyces Appendiculatus ◽  
Bean Rust ◽  
Banding Patterns ◽  
Highly Virulent ◽  
Specific Virulence

Five isolates of the bean rust fungus Uromyces appendiculatus were shown to be specifically virulent on bean genotypes of Andean origin. This specificity was demonstrated by the virulence of five pairs of isolates on a differential set of 30 Phaseolus vulgaris landraces. Each isolate pair was from a different country in the Americas and consisted of one Andean-specific isolate and one nonspecific isolate. Of the differential P. vulgaris landraces, 15 were of Middle American origin and 15 were of Andean origin. The Andean-specific rust isolates were highly virulent on Andean landraces but not on landraces of Middle American origin. Rust isolates with virulence to Middle American landraces were also generally virulent on Andean material; no truly Middle American-specific isolates were found. Random amplified polymorphic DNA (RAPD) analysis of the rust isolates also distinguished the two groups. Four of the Andean-specific rust isolates formed a distinct group compared to four of the nonspecific isolates. Two of the isolates, one from each of the two virulence groups, had intermediate RAPD banding patterns, suggesting that plasmagomy but not karyogamy occurred between isolates of the two groups.

scholarly journals Distinct Biphasic mRNA Changes in Response to Asian Soybean Rust Infection

2007 ◽  
Vol 20 (8) ◽  
pp. 887-899 ◽  
Author(s):  
Martijn van de Mortel ◽  
Justin C. Recknor ◽  
Michelle A. Graham ◽  
Dan Nettleton ◽  
Jaime D. Dittman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Time Course ◽  
Expression Profiles ◽  
Fungal Growth ◽  
Initial Response ◽  
Soybean Rust ◽  
Specific Response ◽  
Susceptible Genotype ◽  
Rust Infection ◽  
Asian Soybean Rust

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, is now established in all major soybean-producing countries. Currently, there is little information about the molecular basis of ASR–soybean interactions, which will be needed to assist future efforts to develop effective resistance. Toward this end, abundance changes of soybean mRNAs were measured over a 7-day ASR infection time course in mock-inoculated and infected leaves of a soybean accession (PI230970) carrying the Rpp2 resistance gene and a susceptible genotype (Embrapa-48). The expression profiles of differentially expressed genes (ASR-infected compared with the mock-inoculated control) revealed a biphasic response to ASR in each genotype. Within the first 12 h after inoculation (hai), which corresponds to fungal germination and penetration of the epidermal cells, differential gene expression changes were evident in both genotypes. mRNA expression of these genes mostly returned to levels found in mock-inoculated plants by 24 hai. In the susceptible genotype, gene expression remained unaffected by rust infection until 96 hai, a time period when rapid fungal growth began. In contrast, gene expression in the resistant genotype diverged from the mock-inoculated control earlier, at 72 h, demonstrating that Rpp2-mediated defenses were initiated prior to this time. These data suggest that ASR initially induces a non-specific response that is transient or is suppressed when early steps in colonization are completed in both soybean genotypes. The race-specific resistance phenotype of Rpp2 is manifested in massive gene expression changes after the initial response prior to the onset of rapid fungal growth that occurs in the susceptible genotype.

scholarly journals Radiochemical determination of a unique sequence around the reactive serine residue of a di-isopropyl phosphorofluoridate-sensitive plant carboxypeptidase and a yeast peptidase

1972 ◽  
Vol 128 (2) ◽  
pp. 229-235 ◽  
Author(s):  
D. C. Shaw ◽  
J. R. E. Wells
Keyword(s):  
Amino Acids ◽  
French Bean ◽  
Unique Sequence ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Serine Carboxypeptidase ◽  
Serine Residue ◽  
Radiochemical Determination ◽  
Bean Leaves

Phaseolain, a carboxypeptidase from French-bean leaves, and a partially purified peptidase from baker's yeast are inhibited by reaction with di-isopropyl phosphorofluoridate. Radioactive di-isopropyl [32P]phosphorofluoridate was used to show that the site of reaction is a unique serine residue and that the sequence of amino acids adjacent to the reactive serine is Glu-Ser-Tyr. This sequence is different from those of other ‘serine’ enzymes previously reported and, for phaseolain, represents an unequivocal example of a ‘serine’ carboxypeptidase.

Host-parasite relationships in bean cultivars of varying susceptibility to bean rust

2000 ◽  
Vol 77 (11) ◽  
pp. 1551-1559 ◽  
Author(s):  
M W Harding ◽  
J C Stutz ◽  
R W Roberson
Keyword(s):  
Phaseolus Vulgaris ◽  
Latent Period ◽  
Rust Fungus ◽  
Freeze Substitution ◽  
Infected Leaf ◽  
Bean Rust ◽  
Infection Efficiency ◽  
Host Cytoplasm ◽  
Short Latent Period ◽  
Host Parasite

Components of disease development were measured in three cultivars of Phaseolus vulgaris L. (common bean) infected with Uromyces appendiculatus (Pers.:Pers.) Unger (bean rust fungus) race O. Disease measurements and light and electron microscope data of host-parasite relationships were obtained and analyzed. Uredinial size, infection efficiency, latent period, and fungal colony radius were measured from infected bean leaves that were grown under controlled conditions. Phaseolus vulgaris cultivar Pinto 111, a highly susceptible check, displayed the largest uredinia, the highest infection efficiency, large colony radii, and a short latent period. Cultivars Early Gallatin and Kentucky Wonder (K.W.) 814 displayed moderate and low susceptibility, respectively. Cultivar Early Gallatin had smaller uredinia, reduced infection efficiency, and longer latent period when compared with cv. Pinto 111. Cultivar K.W. 814 was characterized by minute pustules, restricted colony expansion, and the longest latent period. Ultrastructural data of host-parasite relationships were collected from infected leaf tissues and prepared for transmission electron microscopy by high-pressure cryofixation and freeze substitution. In 'Pinto 111' the collars around haustorial necks were composed of a fibrillar network embedded in an electron transparent matrix. Ultrastructural observations indicated that Cultivars K.W. 814 and Early Gallatin deposited more collar material than 'Pinto 111.' Networks of tubular endomembranes developed near the host-parasite interface in the host cytoplasm of cultivars K.W. 814 and Early Gallatin. The tubules showed continuity with the extrahaustorial membrane and contained an amorphous, electron-dense material in the lumen. Tubular endomembranes were not seen in the highly susceptible cultivar Pinto 111.

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