Physiologic specialization of the parasitic fungi. II

Mountain regions harbour high biodiversity; however, in numerous areas, they are strongly degraded by human activity. Our study reconstructs the development of the submontane forest belt (400 and 650 m a.s.l.) in the Beskid Wyspowy Mountains (Western Carpathians, Central Europe) affected by climate, humans, fire, and parasitic fungi during the Holocene. This forest belt is considered the most transformed by the human in the Carpathian region. Our multi-proxy study included analyses of pollen, non-pollen palynomorphs (NPPs), plant macrofossils, micro- and macrocharcoal (size fraction >100 µm, analysed in contiguous sampling), geochemical, and sedimentological markers. The results revealed that Picea abies dominated on the fen subjected to study at ca. 8510–5010 cal. BP. Tilia cordata was a substantial component of the submontane forest between ca. 8510 and 2970 cal. BP and it survived a probable Kretzschmaria deusta outbreak, as well as a period of increased fire activity (ca. 6000 cal. BP). The final retreat of forests with a substantial contribution of Tilia was induced by the expansion of Abies alba, Fagus sylvatica, and partly Carpinus betulus and was preceded by the period of increased fire activity and erosion. From ca. 900 cal. BP human-induced deforestations and agricultural and pastoral activity increased. The modern presence of woodlands with Pinus sylvestris and Larix decidua, in the submontane zone in the Beskid Wyspowy Mountains, is a result of sub-recent anthropogenic afforestation on overgrazed areas. The example of the Zbludza site reveals that changes related to fire and pathogen infections, if they have low magnitudes and new competitive taxa are absent, may be reversible in a forest composed of fire-intolerant tree taxa as Tilia. Nonetheless, the widespread submontane ecosystem degradation and the introduction of alien species hamper the regeneration of forest vegetation typical of the submontane zone.

Download Full-text

Evolution of the grapevine (Vitis vinifera L.) imprinted by natural and human factorsThis review is one of a selection of papers presented at the symposium on Vitis at the XVII International Botanical Congress held in Vienna, Austria, in 2005.

Canadian Journal of Botany ◽

10.1139/b07-060 ◽

2007 ◽

Vol 85 (8) ◽

pp. 679-690 ◽

Cited By ~ 7

Author(s):

Roger Bessis

Keyword(s):

Vegetative Reproduction ◽

Molecular Characteristics ◽

Vitis Vinifera L ◽

Biological Interactions ◽

Direct Effects ◽

Parasitic Fungi ◽

International Botanical ◽

International Botanical Congress ◽

Environmental Agents ◽

Selection Of

This paper is concerned with vegetative reproduction, which is the only mode of propagation in cultivated grapevines. After a brief summary of the systematics of the Vitaceae the question of the nomenclature of cultivated grapevines is discussed. Intra-varietal variability is discussed using morphological and molecular characteristics. The origins of variation are presented: mutations, foreign nucleic acids, and memory of previous environmental conditions. Grapevines provide characteristic products, leading viticulturalists to make selections among the diversity observed in the vineyard, thus decreasing diversity. Grapevines interact with various environmental agents. One example, the natural defence provided by resveratrol, is analysed, showing its direct effects against parasitic fungi and its indirect effects, both metabolic and genetic, on other organisms. Thus, the grapevine, viticulturalists, and their environment form a web of biological interactions.

Download Full-text

Physiologic specialization ofPuccinia reconditaf. sp.triticiin Canada in 1987

Canadian Journal of Plant Pathology ◽

10.1080/07060668809501712 ◽

1988 ◽

Vol 10 (4) ◽

pp. 354-358 ◽

Cited By ~ 4

Author(s):

J.A. Kolmer

Keyword(s):

Physiologic Specialization

Download Full-text

Co-operative action by endo- and exo-β-(1→3)-glucanases from parasitic fungi in the degradation of cell-wall glucans of Sclerotinia sclerotiorum (Lib.) de Bary

Biochemical Journal ◽

10.1042/bj1400047 ◽

1974 ◽

Vol 140 (1) ◽

pp. 47-55 ◽

Cited By ~ 57

Author(s):

David Jones ◽

Alex. H. Gordon ◽

John S. D. Bacon

Keyword(s):

Cell Wall ◽

Sclerotinia Sclerotiorum ◽

Culture Filtrate ◽

Cell Walls ◽

Trichoderma Viride ◽

Major Constituent ◽

Coniothyrium Minitans ◽

Parasitic Fungi ◽

Complete Breakdown

1. Two fungi, Coniothyrium minitans Campbell and Trichoderma viride Pers. ex Fr., were grown on autoclaved crushed sclerotia of the species Sclerotinia sclerotiorum, which they parasitize. 2. in vitro the crude culture filtrates would lyse walls isolated from hyphal cells or the inner pseudoparenchymatous cells of the sclerotia, in which a branched β-(1→3)-β-(1→6)-glucan, sclerotan, is a major constituent. 3. Chromatographic fractionation of the enzymes in each culture filtrate revealed the presence of several laminarinases, the most active being an exo-β-(1→3)-glucanase, known from previous studies to attack sclerotan. Acting alone this brought about a limited degradation of the glucan, but the addition of fractions containing an endo-β-(1→3)-glucanase led to almost complete breakdown. A similar synergism between the two enzymes was found in their lytic action on cell walls. 4. When acting alone the endo-β-(1→3)-glucanase had a restricted action, the products including a trisaccharide, tentatively identified as 62-β-glucosyl-laminaribiose. 5. These results are discussed in relation to the structure of the cell walls and of their glucan constituents.

Download Full-text