Multiplication cellulaire et production lipidique en culture in vitro chez Taphrina insititiae et Taphrina pruni, parasites de Prunus domestica

Cellular Multiplication and Lipid Synthesis during in vitro Culture of Taphrina insititiae and Taphrina pruni, Parasites of Prunus domestica. Two Taphrina species were grown on “yeast extract/glucose” and harvested at regular intervals. Their growth was estimated by dry mycelial weight and cell nitrogen. Lipids were recovered and measured by weighing. Phospholipids, which form the major portion of polar lipids, were measured by phosphorus assay. Lipidic and nitrogenous products were studied with regard to the evolution of the cultures during the phase of active growth. The cells accumulated fats, but during the phase of autolysis, fat content decreased. Production of nitrogenous components was maximal during the autolytic phase. Phospholipids varied as nitrogenous and inversely to neutral lipids. There was apparently an antagonism between nitrogen assimilation and synthesis of neutral lipids. Different functions of neutral and polar lipids may be involved, so that the former act as a reserve material and the latter represent an essential structural cell constituent. Fatty acids were analysed by gas liquid chromatography at various culture periods. Fatty acids from polar as well as those from neutral lipids exhibited great variations with regard to culture evolution. The ratio insaturated/saturated fatty acids is greater in polar lipids than in neutral lipids. These variations are discussed with regard to their consequences for the function of cell membranes.     

Fluorescent Glycosides Accumulated in Taphrina wiesneri-infected Cherry Stems

It was observed that three kinds of fluorescent glycosides (FG-1, FG-2, and FG-3) were more abundantly accumulated in Taphrina wiesneri-infected cherry (Prunus yedoensis) stems than in healthy ones. The contents of FG-1, FG-2, and FG-3 in infected stems were, respectively, 2.7, 7.2, and 4.3 times those in healthy stems. In dryed infected stems, FG-1, FG-2, and FG-3, amounted respectively to 0.005, 0.18, and 0.12% in the bark part; and to 0.003, 0.048, and 0.008% in the wood part.

FG-1 was isolated in crystalline form, and was identified with gentisic acid-5-β-d-glucopyranoside by the comparison of its chemical and physical properties with those of synthesized gentisic acid-5- or 2-β-d-glucopyranoside.     

A Taphrina on Potentilla erecta new in Slovakia

A species of Taphrina was collected on Potentilla erecta in Slovakia for the first time. It causes yellowish thickening of stems and leaves. The fungus was identified as Taphrina tormentillae, that is quite common on Potentilla erecta in the north Europe.     

The origin of ascospore-delimiting membranes in Taphrina deformans

Summary The origin of ascospore-delimitig membranes in Taphrina deformans has been studied in material fixed in KMnO₄ and stained either in lead citrate or selectively with a phosphotungstic acid-chromic acid mixture (PTA-CA). Structural continuities exist between the ascus plasmalemma and the delimiting membranes. Both of these membrane systems stain preferentially with PTA-CA while other cell membranes do not stain. The spore-delimiting membranes are formed by invagination of the ascus plasmalemma at specific sites adjacent to nuclei. An ascus vesicle is not formed.     

Identification of Cladosporium delicatulum as a mycoparasite of Taphrina pruni

From 2012 until 2014, surveys and frequent visiting the orchards of Hamedan province, west of Iran, have provided strong evidence for the existence of a mycoparasite. The olive green to dark brown velvet colonies, which were observed on infected fruit with Taphrina pruni, Pocket Plum gall, were collected. Morphological characteristics were investigated on Synthetic Nutrient Agar medium. A portion of the translation elongation factor 1-α gene was amplified by using the EF1-526-F and EF1-156-R primers and then sequenced. A mycoparasitic ability was performed by spraying a conidial suspension of Taphrina pruni (1 × 10⁵ spores/mL) and sterile water on leaves. Symptoms appeared in 4–5 days of post-inoculation. The leaves were examined by a light microscope and a scanning electron microscope, and the results of examinations revealed that Cladosporium delicatulum, which had never been reported as a mycoparasite, was in Taphrina pruni.     

Morphology,development and cytology of Taphrina maculans Butler

Morphology, development and nuclear behavior of the ascogenous stroma and asci in the infection spots have been described inTaphrina maculans Butler. The fungus forms subcuticular and intercellular mycelium in the leaf tissues and the ascogenous layers originate through division of the subcuticular hyphal cells in the infection sites. Germination of ascogenous cells starts with their elongation in the uppermost layer forming asci and ascospores without formation of stalk cells. Meiosis of the fusion (diploid) nucleus occurs in the young ascus as in otherTaphrina species devoid of stalk cells. The haploid chromosome complement in this species consists of 3 chromosomes (n=3). All the cells in the stromatic layer are potential ascogenous cells and ascus formation continues, until all of them are exhausted in the infection spot. Eight ascospores are normally formed in each ascus, but multi-plication of ascospores may occurin situ later. Three morphologically distinct types of ascus opening are encountered, which are apparently not correlated with prevalent environment. Multiplication of ascospores after their discharge from mature asci occurs by budding proceded by a mitotic division of the spore nucleus. Blastospores (budded cells) germinate into short hyphae and binucleate condition of cells originates by mitotic division of the nucleus. Occurrence of giant cells containing 2 nuclei is often observed. Possible origin of Uredinales fromTaphrina-like ancestors has been indicated due to their close resemblance.     

Production of Melilotic Acid by Action of Taphrina wiesneri

The in vitro action of Taphrina wiesneri on coumarin and its related compounds were examined. Melilotic acid, which accumulates in larger amounts in infected cherry leaves than in healthy leaves, was produced from coumarin, 3,4-dihydrocoumarin, o-coumaric acid or o-coumaryl glucoside by the action of acetone-dried cells of the fungus. From the results it is suggested that in cherry plants infected with the fungus melilotic acid may be formed from these precursors contained as ordinary components in cherry leaves. Possible mechanisms of the conversion of coumarin to melilotic acid are also discussed.     

Biphasic diurnal cycle of ascus development of Taphrina maculans Butler

Taphrina maculans Butler inciting the brown leaf spot disease of turmeric (Curcuma longa L.) produces cuboid ascogenous cells several layers in depth in the subcuticular interspaces of the epidermis. The ascogenous cells germinate to produce asci centrifugally maturing toward the periphery of the stroma, expelling octosporous microcolonies of asco-blastospores on the leaf surface inciting secondary infection in favorable environment. Occurrence of a rhythmic cycle of ascus development and ascospore discharge giving 2 peaks of ascospore discharge each day has been demonstrated in Taphrina maculans. The cycle is directly affected by atmospheric temperature, availability of free moisture on the leaf surface and sunlight. Free moisture on a leaf surface appropriately soaks the infection spots (ascogenous cells) and induces ascus elongation and ascospore discharge, when a suitable atmospheric temperature is reached. Sunlight may adversely affect the cycle by increasing the temperature and lowering humidity in the atmosphere.     

Phylogenetic relationships among Taphrina, Saitoella, and other higher fungi

To determine the phylogenetic placement of the major groups of higher fungi, we sequenced the DNA sequences from the small-subunit ribosomal RNA (18S rRNA) coding regions from Taphrina wiesneri (synonym: T. cerasi) and Saitoella complicata and compared them to 18S rRNA sequences from the oomycetes, chytridiomycetes, zygomycetes, ascomycetes, and basidiomycetes. Here we demonstrate that the ascomycetes have at least two major evolutionary lineages. Taphrina wiesneri and Saitoella complicata form a monophyletic branch that diverged prior to the separation of other ascomycetes. The same treatment could be accorded to Schizosaccharomyces pombe.      

Cell wall degradation by Taphrina deformans in host leaf cells

Curled peach leaves, naturally infected by Taphrina deformans, were studied by scanning and transmission electron microscopy, combined with cytochemistry, in order to observe the modifications induced by the pathogen in the host cells, particularly in the wall-to-wall boundary zone. It was found that the asci, which are formed only on the upper leaf surface, perforate the cuticle by lysis and not only by mechanical action; hyphae growing in the intercellular spaces cause a partial dissolution of the leaf cell walls by secretion of polysaccharide-degrading enzymes including cellulase. Alteration of the host plasma membrane often accompanies cell wall degradation. It was also found that in the curled areas the palisade layer is replaced by a less differentiated tissue, while the spongy parenchyma is always well recognizable, notwithstanding cellular alteration.     

Taphrina maculans reduces the therapeutic value of turmeric (Curcuma longa)

Rhizomes of turmeric are used in several culinary preparations. They have been used as household remedies since time immemorial. Phenolics are found in plants only and they play a great role in human health. The high performance liquid chromatography of different parts of healthy and infected plants reveals that the phenolic acid content is reduced in diseased tissues including rhizomes which are commonly consumed by human beings in several countries of the world. Results also showed that the infected leaves had maximum phenolic acids as compared to healthy leaves which indicate that due to infection the amount of phenolic acids increased. We report for the first time that leaf spot (Taphrina maculans) of turmeric (Curcuma longa), which is an important disease, reduces the quantity and number of phenolics thereby damaging the therapeutic properties of turmeric.     

Distribution of carotenoids and sterols in relation to the taxonomy of Taphrina and Protomyces

Species of the genera Taphrina Fr. and Protomyces Unger were screened for the presence of carotenoid pigments and the sterols ergosterol and brassicasterol. All strains produced carotenoids in variable amounts: Taphrina: 0.3–39 g/g dry weight; Protomyces: 65–99 g/g dry weight. It was concluded that the tow genera cannot be separated on the basis of presence or absence of carotenoids. Thirty strains (24 species) of Taphrina produced brassicasterol as the principal sterol; twenty-one strains (17 species) did not form ergosterol. Only four isolates (4 species) produced ergosterol without formation of brassicasterol. Brassicasterol was the major sterol in 3 species of Protomyces, whereas ergosterol was absent. Brassicasterol is a rather unique sterol within the fungal kingdom and has hitherto not been found in the red yeasts. Therefore, this sterol is of taxonomic significance in contrast with ergosterol, which is widespread among fungi.     

The control of peach leaf curl (Taphrina deformans) with Off-Shoot T

Effective control of peach leaf curl disease (Taphrina deformans) was obtained with two winter sprays of a 63 % mixture of fatty alcohols (Off-Shoot T) applied at 5 % a.i. Phototoxicity was insignificant.     

Description of Taphrina antarctica f.a. sp. nov., a new anamorphic ascomycetous yeast species associated with Antarctic endolithic microbial communities and transfer of four Lalaria species in the genus Taphrina

In the framework of a large-scale rock sampling in Continental Antarctica, a number of yeasts have been isolated. Two strains that are unable to grow above 20 °C and that have low ITS sequence similarities with available data in the public domain were found. The D1/D2 LSU molecular phylogeny placed them in an isolated position in the genus Taphrina, supporting their affiliation to a not yet described species. Because the new species is able to grow in its anamorphic state only, the species Taphrina antarctica f.a. (forma asexualis) sp. nov. has been proposed to accommodate both strains (type strain DBVPG 5268^T, DSM 27485^T and CBS 13532^T). Lalaria and Taphrina species are dimorphic ascomycetes, where the anamorphic yeast represents the saprotrophic state and the teleomorph is the parasitic counterpart on plants. This is the first record for this genus in Antarctica; since plants are absent on the continent, we hypothesize that the fungus may have focused on the saprotrophic part of its life cycle to overcome the absence of its natural host and adapt environmental constrains. Following the new International Code of Nomenclature for Algae, Fungi and Plants (Melbourne Code 2011) the reorganization of Taphrina–Lalaria species in the teleomorphic genus Taphrina is proposed. We emend the diagnosis of the genus Taphrina to accommodate asexual saprobic states of these fungi. Taphrina antarctica was registered in MycoBank under MB 808028.