Isolation, partial characterization and specificity of glycoprotein elicitors from culture filtrates, mycelium and cell walls of Cladosporium fulvum (syn. Fulvia fulva)

Apoplastic fluid recovered from healthy (uninfected) tomato leaves and from leaves infected with races of Fulvia fulva (Cooke) Ciferri (syn. Cladosporium fulvum (Cooke)) contained heat-labile lytic activities that solubilised carbohydrates from plant cell walls. Total activity was slightly enhanced in apoplastic fluid from infected plants. Material solubilised from uniformly 14C-labelled plant cell walls by apoplastic fluid from compatible and incompatible interactions and from the uninfected plant was analysed. 14C-Labelled poly-, oligo-, and mono-saccharides were detected, suggesting that both exo- and endo-hydrolase activities were present; endoactivity predominated during the early stages of infection. Fluid collected from incompatible interactions as early as 5–7 days postinoculation contained enhanced levels of an activity that solubilised arabinose-rich polysaccharide; by 9–11 days postinoculation, this activity had decreased and was comparable to that of the healthy plant. A similar activity was also seen in fluid from compatible interactions, but this was enhanced slightly later in the infection and increased rapidly during days 9–11 postinoculation. We suggest that the early and short-lived enhanced expression of an endohydrolase that attacks an arabinose-rich polymer may be related to disease resistance. Key words: tomato, Fulvia fulva (Cooke) Ciferri (syn. Cladosporium fulvum (Cooke)), apoplastic fluid, cell wall degrading enzymes, compatibility, oligosaccharin.

Download Full-text

Accumulation of phytoalexins in the compatible interaction between Cladosporium fulvum and tomato in relation to colonization

Canadian Journal of Botany ◽

10.1139/b91-107 ◽

1991 ◽

Vol 69 (4) ◽

pp. 822-830 ◽

Cited By ~ 8

Author(s):

Ulisses G. Batista ◽

Verna J. Higgins

Keyword(s):

Suspension Culture ◽

Germ Tube ◽

Plant Cells ◽

Cladosporium Fulvum ◽

In Vitro Experiments ◽

Compatible Interaction ◽

Leaf Mold ◽

Production And Distribution ◽

Fulvia Fulva

The production and distribution of the phytoalexin falcarindiol in tomato foliage infected with leaf mold was examined to determine how the fungus Cladosporium fulvum is able to colonize and sporulate in an apparently antifungal environment. In a compatible interaction (cv. Potentate – C. fulvum race 2.3), by 12 and 15 days after inoculation, solvent-extractable falcarindiol and two other phytoalexins from tomato, compound 2 (probably falcarinol) and compound 3 (unidentified), reached concentrations considerably in excess of ED50 values for inhibition of the fungus. In contrast, intercellular (apoplastic) fluids obtained from similarly infected leaflets contained only traces of falcarindiol. ED50 values for germination and germ-tube growth of C. fulvum increased as the incubation time was extended, suggesting that adaptation or recovery was possible at the concentrations tested. In in vitro experiments, C. fulvum appeared to readily metabolize falcarindiol, as did a Lycopersicon cell suspension culture. Binding of falcarindiol to living and dead fungal and plant cells was also observed. Falcarindiol, injected into tomato leaflets, decreased rapidly and was only recovered in trace amounts by 24 h. The results suggest that falcarindiol and probably the two other phytoalexins do not reach sufficient concentrations in the apoplast of an infected susceptible leaf to have an effect on growth and sporulation of C. fulvum. Key words: leaf mold, Fulvia fulva, falcarindiol, falcarinol.

Download Full-text