Ultrastructure of wilt syndrome caused by Verticillium dahliae. II. In sunflower leaves

Ultrastructural changes occurred in sunflower leaves that were infected by Verticillium dahliae Kleb. during the appearance of foliar symptoms. Early in symptom development major degenerative changes took place in the leaf mesophyll tissue particularly in the vicinity of the xylem of the major veins. During these early stages vessel wall breakdown occurred in the vicinity of the fungus, but this degradation was not accompanied by swelling. Occlusion of the vessel elements by fungus, fibrillar material, or electron-dense plugs was not significant until late in disease development. Comparison of these observations with those that were made in a previous parallel study of Verticillium-infected chrysanthemum suggested that the ultrastructural changes induced by the fungus in the two hosts are similar but that the timing is different. In chrysanthemum, degenerative changes in the mesophyll are not extensive until after chlorosis, but vessel blockage is advanced before wilting is noticeable. The significance of this difference in the development of foliar symptoms is discussed in relation to the plugging and toxin theories of wilt induction in fungus-caused vascular diseases.

Download Full-text

Ultrastructure of wilt syndrome caused by Verticillium dahliae. I. In chrysanthemum leaves

Canadian Journal of Botany ◽

10.1139/b75-107 ◽

1975 ◽

Vol 53 (9) ◽

pp. 901-913 ◽

Cited By ~ 20

Author(s):

Jane Robb ◽

Lloyd Busch ◽

B. C. Lu

Keyword(s):

Verticillium Dahliae ◽

Ultrastructural Changes ◽

Xylem Parenchyma ◽

Mesophyll Cells ◽

Fibrillar Material ◽

Foliar Symptoms ◽

Leaf Mesophyll ◽

Before And After ◽

Cytological Changes ◽

Verticillium Dahliae Kleb

Ultrastructural changes occurred in chrysanthemum leaves infected by Verticillium dahliae Kleb. before and after the appearance of foliar symptoms. Before visual symptoms appeared, xylem vessels in the leaves contained large amounts of fungus and fibrillar material; by the time wilting occurred many vessels, particularly at the vein ends, were occluded by electron-dense plugs and swollen gelated vessel walls. Some of the chloroplasts in the mesophyll cells had started to degenerate before the first signs of flaccidity were noticeable, but other cytological changes were minimal until chlorosis occurred, at which time the xylem parenchyma had collapsed. Since plugging of leaf vessels preceded wilt and wilt preceded major ultrastructural changes in leaf mesophyll cells, we suggest that plugging of the xylem vessels is the major factor in inducing wilt in Verticillium-infected chrysanthemum.

Download Full-text

Histopathology of Verticillium dahliae within mature roots of Russet Burbank potatoes

Canadian Journal of Botany ◽

10.1139/b83-384 ◽

1983 ◽

Vol 61 (12) ◽

pp. 3405-3421 ◽

Cited By ~ 21

Author(s):

James W. Perry ◽

Ray. F. Evert

Keyword(s):

Verticillium Dahliae ◽

Solanum Tuberosum L ◽

Hydrolytic Enzymes ◽

Structural Response ◽

Cortical Layer ◽

Russet Burbank ◽

Vessel Elements ◽

Dense Substance ◽

Perforation Plates ◽

Verticillium Dahliae Kleb

Roots of Russet Burbank potatoes (Solanum tuberosum L.) inoculated with Verticillium dahliae Kleb. were examined, primarily with the electron microscope. Penetration hyphae entered epidermal cells directly, apparently aided by hydrolytic enzymes. In most instances, penetration took place without eliciting any structural response. Most hyphae failed to penetrate deeper than the epidermal layer, owing primarily to the formation by exodermal cells of lignitubers that ensheathed the penetration hyphae. Apparently lignitubers were sometimes initiated as callose-like appositions opposite encounter sites. All cortical layers were capable of lignituber production. Few hyphae were encountered within cells deeper than the second cortical layer, and intercellular colonization was not extensive. Nonetheless, vascular infection of unwounded roots occurred. Wilt symptoms were first noted 2 days after hyphae were found in vessel elements of the root. Walls and pit membranes of colonized tracheary elements were coated with an electron-dense substance. As the disease progressed, hyphae invaded all tissues in the vascular cylinder and eventually grew back out into the cortex. The soft-walled tissues were destroyed. In wounded roots many severed vessels contained membranous remnants, conidia, and hyphae that tended to be accumulated at the perforation plates.

Download Full-text

Ultrastructure of wilt syndrome caused by Verticillium dahliae. III. Chronological symptom development in sunflower leaves

Canadian Journal of Botany ◽

10.1139/b77-022 ◽

1977 ◽

Vol 55 (2) ◽

pp. 139-152 ◽

Cited By ~ 9

Author(s):

Jane Robb ◽

Lloyd Busch ◽

Jean D. Brisson ◽

B. C. Lu

Keyword(s):

Phenolic Compounds ◽

Verticillium Dahliae ◽

Temporal Order ◽

Band 3 ◽

Xylem Vessel ◽

Ultrastructural Changes ◽

Symptom Expression ◽

Symptom Development ◽

Mesophyll Tissue ◽

Foliar Symptom

When sunflowers are infected by the vascular pathogen Verticillium dahliae, the first visible foliar symptom is the appearance of tiny chlorotic flecks. An attempt was made to determine the temporal order in which early ultrastructural changes leading to symptom expression occur. The evidence indicates that ultrastructural changes occur in the following order: (1) degradation of xylem vessel walls, (2) initiation of the necrotic band, (3) degeneration of the mesophyll tissue remote from the vein, and (4) degeneration of the phloem. The possible importance of xylem vessel plugs and of phenolic compounds to the initiation of symptom development is also discussed.

Download Full-text

Phytotoxicity of Verticillium dahliae Kleb. on sunflower sprouts

сборник статей всероссийской научной конференции с международным участием "Растениеводство и луговодство" ◽

10.26897/978-5-9675-1762-4-2020-87 ◽

2020 ◽

Author(s):

A.A. Vypritskaya ◽

◽

A.A. Kuznetsov

Keyword(s):

Verticillium Dahliae ◽

The Family ◽

Verticillium Dahliae Kleb

Data on the prevalence in the Tambov region of the pathogen Verticillium dahliae Kleb (Verticillium dahliae) and the phytotoxicity of filtrates of the pathogen isolated from sunflower and a wild weed of the family of compound flowers (Xantium strumarium) are presented.

Download Full-text

Interaction of Meloidogyne hapla and Verticillium dahliae, and the chemical control of wilt in strawberry

Australian Journal of Experimental Agriculture ◽

10.1071/ea9700493 ◽

1970 ◽

Vol 10 (45) ◽

pp. 493 ◽

Cited By ~ 2

Author(s):

JW Meagher ◽

PT Jenkins

Keyword(s):

Broad Spectrum ◽

Verticillium Dahliae ◽

Methyl Bromide ◽

Chemical Control ◽

Soil Fumigation ◽

Meloidogyne Hapla ◽

Root Knot Nematode ◽

Methyl Isothiocyanate ◽

Severity Of Disease ◽

Verticillium Dahliae Kleb

In a field experiment with strawberries, pre-plant treatments with broad-spectrum fumigants methyl bromide-chloropicrin (450 kg/ha) or methyl isothiocyanate-dichloropropene (500 l/ha) (and 300 l/ha) controlled wilt caused by Verticillium dahliae Kleb and resulted in increased yields. Soil fumigation with the nematicide ethylene dibromidz (105 l/ha) also improved yields. It controlled the root-knot nematode (Meloidogyne hapla Chitwood), delayed the onset of wilt symptoms and reduced the severity of disease. This indicated a nematode-fungus interaction and is the first report of a Meloidogyne-Verticillium interaction in strawberry.

Download Full-text

The effect of vitamin B deficiency on reproduction

Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character ◽

10.1098/rspb.1925.0028 ◽

1925 ◽

Vol 98 (688) ◽

pp. 147-171 ◽

Cited By ~ 5

Keyword(s):

Similar Condition ◽

Degenerative Changes ◽

Vitamin B ◽

Adult Rats ◽

Vitamin B Deficiency ◽

Made In

A number of investigators have observed atrophy and degenerative changes in the testes of animals fed on diets deficient in the factor termed Vitamin B. Funk and Douglas (5) reported that the testicles of pigeons showing symptoms of avian polyneuritis were greatly atrophied, and that the tubules were diminished in size and contained no spermatozoa. Drummond (3) observed a similar condition in the testes of adult rats deprived of vitamin B, whilst McCarrison (8) found the atrophy of the male gonads to be very much more severe in pigeons with beri-beri than in monkeys with that disease. Allen examined the testes of rats which had been fed on Osborne and Mendels’ diet deficient in vitamin B, and found considerable derangements, to which further reference will be made in the section on Histology.

Download Full-text