ISSN:
1573-8469
Keywords:
appressoria
;
hemibiotrophy
;
hypersensitivity
;
infection process
;
melanin
;
phytoalexins
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The infection process of Colletotrichum destructivum, a hemibiotrophic anthracnose fungus, was studied by light microscopy in two cowpea (Vigna unguiculata) cultivars which differ in disease reaction type. Large, multilobed, intracellular infection vesicles, followed by necrotrophic, radiating, secondary hyphae were produced in tissues of the susceptible cv. IT82E-60. In the resistant cv. TVx 3236, both the production of appressoria and their melanisation were impaired, resulting in reduced penetration. Where penetration occurred, the initially-infected epidermal cells underwent a hypersensitive response, restricting the growth of multilobed vesicles and thereby blocking the destructive necrotrophic phase of disease development. The phytoalexins kievitone and phaseollidin accumulated earlier and more rapidly in stem tissues of the resistant cultivar, associated with the appearance of delimited, necrotic spots on inoculated surfaces. In contrast, delayed and slower accumulation of these compounds occurred in the compatible interaction, together with the development of typical spreading, water-soaked, anthracnose lesions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008765013572
Permalink
