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.

A method for 13 C-labeling of metabolic carbohydrates within French bean leaves (Phaseolus vulgaris L.) for decomposition studies in soils

2009 ◽  
Vol 23 (12) ◽  
pp. 1792-1800 ◽  
Author(s):  
Cyril Girardin ◽  
Daniel P. Rasse ◽  
Philippe Biron ◽  
Jaleh Ghashghaie ◽  
Claire Chenu
Keyword(s):  
Phaseolus Vulgaris ◽  
French Bean ◽  
Phaseolus Vulgaris L ◽  
Bean Leaves

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. II. Fungal development after inoculation by injection or wounding

1989 ◽  
Vol 67 (3) ◽  
pp. 670-675
Author(s):  
Myriam R. Fernandez ◽  
Michèle C. Heath
Keyword(s):  
Phaseolus Vulgaris ◽  
Guard Cells ◽  
French Bean ◽  
Cladosporium Fulvum ◽  
Phaseolus Vulgaris L ◽  
Fungal Development ◽  
Wound Site ◽  
Parasitic Fungi ◽  
Potential Pathogenicity ◽  
Germination And Growth

Germination and growth of four saprophytic and five parasitic fungi nonpathogenic on French bean (Phaseolus vulgaris L. cv. Pinto) were examined in leaves after the epidermis was bypassed by injection or wounding. In unheated leaves, only the parasites had the ability to spread from the wound site and to germinate and grow inside the tissue after injection. The saprophytes behaved similarly only after the leaves were given a preinoculation heat treatment, suggesting a sensitivity to heat-sensitive inhibitors. For two of the saprophytes, evidence for the presence of heat-insensitive inhibitors also was found. Unlike the intercellular growth following stomatal penetration, growth of all of the parasites was affected by heat-sensitive defenses once the epidermis was bypassed. The greater intercellular growth after injection as compared with stomatal penetration suggested that the guard cells play a significant role in the resistance of intact, unheated leaves to Cladosporium fulvum Cooke. Of the saprophytes examined, Neurospora crassa Shear & Dodge appeared to posses a number of attributes that might be considered as potential pathogenicity factors.

Interactions of the nonhost French bean plant (Phaseolus vulgaris) with parasitic and saprophytic fungi. III. Cytologically detectable responses

1989 ◽  
Vol 67 (3) ◽  
pp. 676-686 ◽  
Author(s):  
Myriam R. Fernandez ◽  
Michèle C. Heath
Keyword(s):  
Cell Wall ◽  
Phaseolus Vulgaris ◽  
General Feature ◽  
Fungal Spores ◽  
French Bean ◽  
Cell Necrosis ◽  
Phaseolus Vulgaris L ◽  
Fungal Cell ◽  
Parasitic Fungi ◽  
Nonhost Plant

Cytologically detectable responses of the nonhost French bean (Phaseolus vulgaris L. cv. Pinto) to saprophytic and parasitic fungi were examined when fungal spores were introduced into heated or unheated leaves via wounds or by injection. Although similar types of responses were observed in interactions with all the fungi, some of these responses were characteristic of each group (saprophytes vs. parasites) in the frequency and (or) extent with which they were elicited. Differences in responses between and within each of these groups of fungi were more related to their degree of adaptation for parasitism than to their taxonomic relationships. Certain responses that were typically elicited by the saprophytes occurred to a lesser extent in tissue responding to the parasites, suggesting that the ability to not trigger, or suppress, these responses may be a general feature of parasitic fungi. None of the fungi elicited significant levels of plant cell necrosis, and for two of the saprophytes, dead spores elicited a lower frequency of responses than live ones. The data indicate that many of the responses of a nonhost plant to living fungi may be the result of reactions to fungal activity rather than to constitutive recognition molecules such as components of the fungal cell wall.

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