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The type specimens or representative specimens of the potentially dothidealean genera Bagnisiella, Botryochora, Coccostromella, Columnosphaeria, Delphinella, Dictyodothis, Discosphaerina, Dothidea, Dothiora, Endodothiora, Jaffuela, Mycoporis, Omphalospora, Pachysacca, Plowrightia, Saccothecium, Stylodothis, Sydowia and Yoshinagaia were examined while, fresh specimens of Aureobasidium pullulans, Dothidea insculpta, Plowrightia ribesia and Saccothecium sepincola were made from Italy and Thailand. An introduction and the history of these genera, their family placement, morphology, and molecular phylogeny are provided. Morphology plus GenBank data are used to provide a systematic treatment of Dothideales. Phylogenetic analysis of LSU, SSU and ITS gene regions was carried out and in the resulting phylogenetic tree the taxa cluster in two clades with high bootstrap support. Clade A comprises Dothideaceae, the family type of Dothideales. The family Dothioraceae is not recognized as a distinct family and is synonymized under Dothideaceae. Neocylindroseptoria is introduced to accommodate Cylindroseptoria pistaciae as it forms a well-supported distinct clade in Dothideaceae. Clade B comprises Aureobasidium, Kabatiella, Pseudoseptoria, Saccothecium and Selenophoma species and Columnosphaeria fagi, for which we propose a new family, Aureobasidiaceae. The recently introduced Sydowia eucalypti also clustered within Clade B and therefore based on morphology and molecular phylogeny a new genus Pseudosydowia is introduced for Sydowia eucalypti. Celosporium laricicola is separated in a distinct clade, and therefore it is placed in Dothideales, genera, incertae sedis. The genera Bagnisiella, Botryochora, Coccostromella, Jaffuela, Lucidascocarpa, Mycoporis, Omphalospora, Pachysacca and Yoshinagaia are excluded from Dothideales and their placements are discussed. [ABSTRACT FROM AUTHOR]

We examined the taxonomic position of Leptosphaerulina japonica, a parasitic fungus on male strobili of Japanese cedar ( Cryptomeria japonica) using morphology and molecular phylogeny. Because neither specimens nor illustrations were designated in the original paper, this name is neotypified with a fresh specimen collected from the type locality, Yamagata, Japan. Leptosphaerulina japonica has asci produced in a broad layer arising from the entire base of the locule, stipitate acervuli, and a hormonema-like synanamorph. These characteristics are not typical of the genus Leptosphaerulina ( Didymellaceae, Pleosporales). In a molecular phylogenetic analysis of ITS sequences, L. japonica was placed into the Dothideaceae/Dothioraceae, Dothideales. Although muriform ascospores and an anamorph with long stipitate acervuli have not been reported for species in Sydowia, the other morphology and phylogeny support placement of L. japonica in that genus. Thus, a new combination, Sydowia japonica, is proposed. [ABSTRACT FROM AUTHOR]

In this paper, we re-examine, re-describe and illustrate all sexual generic type specimens of Planistromellaceae including Comminutispora agavacearum, Eruptio acicola, Loratospora aestuarii, Microcyclus angolensis, Mycosphaerellopsis myricariae, Planistroma yuccigenum and Planistwmella yuccifoliorum. We also use molecular data from GenBank to show the taxonomic placement of some of these genera. Members of family Planistromellaceae {Botryosphaeriales) are saprobes or pathogens on various plants and characterized by multi or uniloculate ascostromata which are erumpent through cracking or splitting of host tissues and have periphysate ostioles. The ascostromata comprise several layers of brown to black thick-walled cells, pseudoparaphyses are not obvious in mature specimens, and asci are bitunicate. The asexual morphs were previously reported to be found in the genera Aposphaeria-like, Fusicladium, Hyphospora, Kellermania, Lecanosticta, Pazschkeella and Piptarthron. Following this study, phylogenetic analyses based on molecular data from LSU and ITS genes provide strong support for the monophyly of the Planistromellaceae in the Botryosphaeriales, while the Planistromellaceae clade separates into three different groups represented by the type species of Piptarthron, Planistroma and Kellermania, respectively. We accept Kellermania (= Planistromella and possibly Piptarthron), Planistroma and Mycosphaerellopsis (the latter with no molecular support) in Planistromellaceae, while four other genera are redisposed of as follows: Comminutispora clusters in Capnodiales, Eruptio and Microcyclus have been shown to be members of Mycosphaerellaceae, and Loratospora has been shown to belong in Phaeosphaeriaceae. [ABSTRACT FROM AUTHOR]

The duration of the incubation period of Guignardia bidwellii on leaves and clusters of Wis vinifera strongly correlates to temperature. To describe this relationship mathematically, a new, cumulative degree-day-based model was developed. According to this model, first symp-toms on leaves appear after reaching a threshold of 175 cumulative degree-days (calculated as the sum of average daily temperatures between 6 and 24°C starting on the day after the infection). On clusters, the duration of the incubation period is additionally affected by their respective developmental stages. For 'Riesling', the duration of the incubation period on clusters corresponds to the duration on leaves until reaching the phenological stage "berries beginning to touch" but extends continuously with ongoing phenological develop-ment. Therefore, a correction factor recognizing cluster phenology was derived to calculate the cumulative degree-day thresholds for the occurrence of first symptoms on clusters after reaching "majority of berries touching". Hence, this present model allows the estimation of fungal development and forecasts the appearance of new symptoms on leaves as well as on clusters, enabling growers to more precisely sche-dule curative as well as protective fungicide applications against grape black rot. [ABSTRACT FROM AUTHOR]

A range of novel carboxamide fungicides, inhibitors of the succinate dehydrogenase enzyme (SDH, EC 1.3.5.1) is currently being introduced to the crop protection market. The aim of this study was to explore the impact of structurally distinct carboxamides on target site resistance development and to assess possible impact on fitness. We used a UV mutagenesis approach in Mycosphaerella graminicola, a key pathogen of wheat to compare the nature, frequencies and impact of target mutations towards five subclasses of carboxamides. From this screen we identified 27 amino acid substitutions occurring at 18 different positions on the 3 subunits constituting the ubiquinone binding (Qp) site of the enzyme. The nature of substitutions and cross resistance profiles indicated significant differences in the binding interaction to the enzyme across the different inhibitors. Pharmacophore elucidation followed by docking studies in a tridimensional SDH model allowed us to propose rational hypotheses explaining some of the differential behaviors for the first time. Interestingly all the characterized substitutions had a negative impact on enzyme efficiency, however very low levels of enzyme activity appeared to be sufficient for cell survival. In order to explore the impact of mutations on pathogen fitness in vivo and in planta, homologous recombinants were generated for a selection of mutation types. In vivo, in contrast to previous studies performed in yeast and other organisms, SDH mutations did not result in a major increase of reactive oxygen species levels and did not display any significant fitness penalty. However, a number of Qp site mutations affecting enzyme efficiency were shown to have a biological impact in planta. Using the combined approaches described here, we have significantly improved our understanding of possible resistance mechanisms to carboxamides and performed preliminary fitness penalty assessment in an economically important plant pathogen years ahead of possible resistance development in the field. [ABSTRACT FROM AUTHOR]

A new species belonging to the Dothideomycete genus Acanthostigvna is described from bark of two Nothofagus species from Argentina. Its identity as a new species is based on both morphology and molecular sequence data. Acanthostigma patagonica differs from other species in the genus by having larger ascomata and setae and wider, asymmetrical ascospores. An amended key to Acanthostigma species is provided along with a discussion of other species previously described from South America. [ABSTRACT FROM AUTHOR]

Peach (Pronos persien) is one of the most important and widely grown frtuit trees in China; however, perennial gummosis on trunks and branches is a major problem in peach orchards of Hnbei Province, one of the most important peach production areas of China. In order to ideistify the gurnmosis-causing agents, diseased trunks and branches were collected from II peach orchards in Hubei Province. Fungal isolates writ obtained fruits these samples, yielding three species: Botrvosplineriu dotlndeo (unamorph Fosicncrnm oencrdi), B. rhodinn (anantorph Leniodiplodia theobrornee), and B. obtusa (anamorph Diplodia seriata). They were identified bused on eonidiul morphology and cultural characteristics, as well as analyses of itnelentide sequences of three genomie regions; the internal transcribed spacer region, a partial sequence of the α-tubulin gene, and the translation elongation factor l-α gene. Fuoicoccson aesculi was found in ati It orchards hot C theobrosnae was found only in Shayang County in the Jingmen region and D. oeriato only in Gong'an County in the Jingehou region. Via artificial iuocutation using mycelia on woattded twigs or branches, these three species were alt toond to be pathogenic, causing dark lesions on the twigs and branches and, sometimes, gum exudation from diseased parts. Isolates of L. theobronme were the most virulent and caused the largest lesions and most copious gommosis, and D. seriutu had less gum than the other two species. This reporl represents the lirst description of L. thenbroroae and D. sonata as causal agents of gummosis on peach in China. [ABSTRACT FROM AUTHOR]

The poorly known marine ascomycete Manglicola guatemalensis from Trang and Trat provinces, Thailand, were collected in 2005 and 2006 on the brackish water palm Nypa fruticans. This fungus is known only from two previous collections. This paper reports on the morphological characteristics and molecular phylogeny of this unique marine bitunicate ascomycete. Manglicola guatemalensis has large clavate to obtusely fusiform ascomata, wide ostioles, bitunicate asci, cylindrical, thick-walled, unequally one-septate ascospores, constricted at the septum, apical cell larger, chestnut-brown and a smaller light brown basal cell. Ascospores germinate readily, always from the basal cell. Four isolates from different locations were selected for the phylogenetic study. Regions of the rDNA gene, including SSU and LSU, were sequenced and combined. Molecular data places M. guatemalensis in the Jahnulales with high bootstrap support; all strains are monophyletic. In the combined SSU and LSU analyses the Jahnulales comprises four subclades, A, B, C and D. Subclade A comprises Jahnula species and two anamorphic fungi, Brachiosphaera tropicalis and Xylomyces chlamydosporus. In subclade B Manglicola strains form a sister group of the Aliquandostipite species Aliquandostipite crystallinus, A. khaoyaiensis, Jahnula siamensiae and Patescospora separans. Subclade C comprises Jahnula species, Jahnula aquatica, J. granulosa and J. rostrata, while Megalohypha aqua-dulces constitutes subclade D. Therefore Manglicola forms another lineage of marine fungi. [ABSTRACT FROM AUTHOR]

This study examined the effects of temperature and wetness duration in vitro and in vivo as well as the effects of fruit age on germination and appressoria formation by conidia of Guignardia psidii, the causal agent of black spot disease in guava fruit. The temperatures tested for in vitro and in vivo experiments were 10, 15, 20, 25, 30, 35 and 40°C. The wetness periods studied were 6, 12, 24, 36 and 48 h in vitro and 6, 12 and 24 h in vivo. Fruit 10, 35, 60, 85 and 110-days old were inoculated and maintained at 25°C, with a wetness period of 24 h. Temperature and wetness duration affected the variables evaluated in vitro and in vivo. All variables reached their maximum values at between 25 and 30°C with a wetness duration of 24 h in vivo and 48 h in vitro. These conditions resulted in 31.3% conidia germination, 33.6% appressoria formation and 32.5% appressoria melanization in vitro, and 50.4% conidia germination and 9.5% appressoria formation in vivo. Fruit age also influenced these factors. As fruit age increased, conidia germination and appressoria formation gradually increased. Conidia germination and appressoria formation were 10.8% and 2.3%, respectively, in 10-day-old fruits. In 110-day-old fruits, conidia germination and appressoria formation were 42.5% and 23.2% respectively. [ABSTRACT FROM AUTHOR]

Susceptibility to black spot [caused by Mycosphaerella pinodes (Berk. and Blox.) Vestergr.] and weak stem strength in field pea (Pisum sativum L.) are major restrictions to yield, seed quality, and ease of harvest. Previous studies have established that additive genetic variance is present for both traits, and that stem strength is strongly associated with a field test of compressed stem thickness at the base of the stem. This study aimed to improve these two complex traits simultaneously by recurrent selection. Heritabilities and responses to selection for resistance to black spot and stem strength were evaluated during two cycles of recurrent selection after intercrossing diverse genotypes. Response to selection was indicated by a reduction of 10% in the mean black spot leaf disease in the F2 of cycle 2 compared with the F2 of cycle 1, when considered as a percentage of the mean of cycle 1 parents in the same trials. Likewise, there was a 15% increase in stem strength, based on the mean compressed stem thickness in the F2 of cycle 2 compared with the F2 of cycle 1. Broad sense heritability for resistance to black spot leaf disease was moderate (H = 0.63 ± 0.35 across cycles 1 and 2) and for compressed stem thickness was also moderate (H = 0.66 ± 0.34). Genetic gains were realized for both traits simultaneously in the first two cycles and were predicted to be rapid over the next five to six cycles based on a random mating quantitative genetics model. [ABSTRACT FROM AUTHOR]

A new fungus collected from submerged wood in Costa Rica and Ecuador has ascostromatic ascomata with fissitunicate asci and lacks pseudoparaphyses, characters that place it in the Dothideaceae (Dothideales). It is unusual in the order because it has white ascomata. Based on other morphological characters however this fungus could not be accommodated in any existing genus in the Dothideaceae and it is described herein as a new genus and species, Lucidascocarpa pulchella. These morphological features are characteristic of L. pulchella: ascomata glistening, white, each with a long, periphysate neck; a membranous peridium composed of 5-7 thin-walled, hyaline cells; pseudoparaphyses absent; asci fissitunicate, clavate, eight-spored; ascospores sevenseptate, hyaline, multiguttulate, verruculose, surrounded by a large, regular, gelatinous sheath. [ABSTRACT FROM AUTHOR]

With respect to disease risk for the quarantine fungus Guignardia citricarpa on citrus fruit an accurate diagnosis for routine analysis is required. Also, when inspections have to be performed on imported citrus fruits, a fast detection method is urgently needed. A fast automated DNA extraction method based on magnetic beads combined with a real-time PCR assay was optimized to improve and advance the routine diagnosis of citrus black spot disease. Real-time PCR was used for detection of the pathogen G. citricarpa in planta. A specific primer/TaqMan probe combination that discriminates between G. citricarpa and the harmless citrus endophyte Guignardia mangiferae, was designed based on the internal transcribed spacer region of the multi-copy rDNA gene. Co-amplification of target DNA along with an internal competitor DNA fragment made the diagnostic assay more reliable to check for false negatives. The real-time PCR was specific, since no cross reaction was observed with a series of citrus pathogens and related species. The diagnostic assay was performed on lesions dissected from imported diseased oranges. Comparison between the conventional PCR and the real-time PCR methods showed that the TaqMan method was more sensitive. [ABSTRACT FROM AUTHOR]

Citrus black spot was recorded as present in New Zealand in international databases on the basis of one isolate (ICMP 8336) identified by morphological features as Guignardia citricarpa. This isolate was from a soft rot, not a typical symptom of citrus black spot, on a Seminole tangerine fruit grown in the northern region of New Zealand. Sequence analysis of the internal transcribed spacer (ITS) region (ITS1, 5·8S and ITS2) showed that this isolate was 99% identical to the ITS region of G. mangiferae, a closely related saprotroph. Despite climatic conditions being suitable for this disease, citrus black spot symptoms have never been seen on citrus fruits grown in New Zealand. Thus the absence of symptoms on citrus in New Zealand is probably because G. citricarpa is not present. On the basis of these results, the record of citrus black spot occurring in New Zealand should be re-examined. [ABSTRACT FROM AUTHOR]

Greasy spot, caused by Mycosphaerella citri, produces leaf and fruit lesions and defoliates trees, resulting in reduced yields and fruit size. Techniques now available allow production of large numbers of ascospores and the quantification of epiphytic growth. The effects of ascospore dose, leaf age, and the timing of fenbuconazole sprays on epiphytic growth and disease severity was determined primarily on rough lemon seedlings in the greenhouse. Inoculation of leaves with 104 ascospores/ml resulted in rapid development of epiphytic growth and symptoms. At lower doses, epiphytic growth and symptoms developed more slowly and were less severe. There was a linear relationship between log10 of the ascospore dose and ratings of epiphytic growth and symptoms, and a linear relationship between the amount of epiphytic growth and symptom severity in greenhouse tests. On grapefruit trees treated with different fungicides in six field experiments, there also was a significant linear relationship between epiphytic growth of M. citri measured in August and symptom severity rated in February to March of the following year, but coefficients of determination were much lower than in greenhouse experiments. Leaf age from 10 to 60 days did not affect susceptibility of leaves to M. citri. Fenbuconazole applied up to 50 days prior to inoculation still reduced epiphytic growth and greasy spot severity under greenhouse conditions, but the postinoculation treatments were effective for only 30 days. [ABSTRACT FROM AUTHOR]

We compared genetic variation and population differentiation at RFLP marker loci with seven quantitative characters including fungicide resistance, temperature sensitivity, pycnidial size, pycnidial density, colony size, percentage of leaves covered by pycnidia (PLACP) and percentage of leaves covered by lesions (PLACL) in Mycosphaerella graminicola populations sampled from four regions. Wide variation in population differentiation was found across the quantitative traits assayed. Fungicide resistance, temperature sensitivity, and PLACP displayed a significantly higher QST than GST, consistent with selection for local adaptation, while pycnidial size, pycnidial density and colony size displayed a lower or significantly lower QST than GST, consistent with constraining selection. There was not a statistical difference between QST and GST in PLACL. We also found a positive and significant correlation between genetic variation in molecular marker loci and quantitative traits at the multitrait scale, suggesting that estimates of overall genetic variation for quantitative traits in M. graminicola could be derived from analysis of the molecular genetic markers. [ABSTRACT FROM AUTHOR]

Cladosporium fulvum is an asexual fungus for which no sexual stage is currently known. Molecular data, however, support C. fulvum as a member of the Mycosphaerellaceae, clustering with other taxa having Mycosphaerella teleomorphs . C. fulvum has recently been placed in the anamorph genus Passalora as P. fulva. Its taxonomic disposition is supported by its DNA phylogeny, as well as the distinct scars on its conidial hila, which are typical of Passalora, and unlike Cladosporium s.s., which has teleomorphs that reside in Davidiella, and not Mycosphaerella. The presently known sole host of C. fulvum is tomato (members of the genus Lycopersicon). C. fulvum is mainly a foliar pathogen. Disease symptoms are most obvious on the abaxial side of the leaf and include patches of white mould that turn brown upon sporulation. Due to stomatal clogging, curling of leaves and wilting can occur, leading to defoliation. The interaction between C. fulvum and tomato is governed by a gene-for-gene relationship. A total of eight Avr and Ecp genes, and for four of these also the corresponding plant Cf genes, have been cloned. Obtaining conclusive evidence for gene-for-gene relationships is complicated by the poor availability of genetic tools for most Mycosphaerellaceae –plant interactions. Newly developed tools, including Agrobacterium-mediated transformation and RNAi, added to the genome sequence of its host tomato, which will be available within a few years, render C. fulvum attractive as a model species for plant pathogenic Mycosphaerellaceae. ; [ABSTRACT FROM AUTHOR]

We used the PCR to study the presence of two plant pathogens in archived wheat samples from a long-term experiment started in 1843. The data were used to construct a unique 160-yr time-series of the abundance of Phaeosphaeria nodorum and Mycosphaerella graminkola, two important pathogens of wheat. During the period since 1970, the relative abundance of DNA of these two pathogens in the samples has reflected the relative importance of the two wheat diseases they cause in U.K. disease surveys. Unexpectedly, changes in the ratio of the pathogens over the 160-yr period were very strongly correlated with changes in atmospheric pollution, as measured by SO2 emissions. This finding suggests that long-term, economically important, changes in pathogen populations can be influenced by anthropogenically induced environmental changes. [ABSTRACT FROM AUTHOR]

Daily and seasonal spore dispersal of Mycosphaerella pinodes (Berk & Bloxam) Vestergren and the relationship of spore dispersal to distance and disease severity were investigated in a pea field in western Canada during two consecutive years. Most ascospores were released in response to rain events, during the first 23–27 d after the inoculum source area was infested with naturally diseased pea residue, whereas most pycnidiospores were trapped during the first 20 d. For both ascospores and pycnidiospores, the highest peaks of spore release occurred during the first 14–20 d after infestation. Few spores were trapped after day 27 after infestation. Daily peaks of ascospore and pycnidiospore release occurred between 1700 and 0400 hours. Most ascospores were released 1–2 d after a rain event and the largest peak appeared the first day after rain. In contrast, most pycnidiospores were released on the same day as rain occurred or the following day. The release of both spore types was associated with rainfall events ≥2 mm during the first 27 d after infestation but not with rainfall events after 27 d. Ascospore density was negatively correlated with distance from the inoculum source (r ≤ –0.92) and positively related to the disease severity (r ≥ 0.92). Disease severity decreased with increasing distance from the inoculum source. The patterns of spore dispersal associated with rain events have practical applications in the disease forecasting and spraying of chemicals to control the disease. [ABSTRACT FROM AUTHOR]

Abstract: A protein designated alliumin, with a molecular mass of 13kDa and an N-terminal sequence similar to a partial sequence of glucanase, and demonstrating antifungal activity against Mycosphaerella arachidicola, but not against Fusarium oxysporum, was isolated from multiple-cloved garlic (Allium sativum) bulbs. The protein, designated as alliumin, was purified using ion exchange chromatography on DEAE-cellulose, CM-cellulose and Mono S, affinity chromatography on Affi-gel blue gel, and gel filtration on Superdex 75. Alliumin was unadsorbed on DEAE-cellulose, but was adsorbed on Affi-gel blue gel, CM-cellulose and Mono S. Its antifungal activity was retained after boiling for 1h and also after treatment with trypsin or chymotrypsin (1:1, w/w) for 30min at room temperature. Alliumin was inhibitory to the bacterium Pseudomonas fluorescens and exerted antiproliferative activity toward leukemia L1210 cells. However, it was devoid of ribonuclease activity, protease activity, mitogenic activity toward mouse splenocytes, and antiproliferative activity toward hepatoma Hep G2 cells. [Copyright &y& Elsevier]

Analyzes the temporal and spatial dynamics of mycosphaerella blight from a central inoculum source in a pea field. Quantitative description of the temporal and spatial dynamics of mycosphaerella blight in field pea with mathematical models in combination with geostatistical analysis; Characterization of the disease progress over time at various distances and in various directions from the inoculum source using the logistic model; Quantification of the disease gradients using the exponential model.

Native forests in Chile have been replaced by exotic plantations, generating a mosaic of forest fragments immersed in a matrix of plantations and farms. This landscape change could affect habitat availability for native carnivores such as Oncifelis guigna (Felidae) and Pseudalopex culpaeus (Canidae). We determine the potential impact of native forest fragmentation on these species, assessing habitat use by these carnivores. The study was carried out in continuous forest (150 ha), native forest fragments (<10 ha) and surrounding pine plantations in central Chile (35°59' S, 72°41' W). We placed scent-stations (SSs) in three types of habitat from January to August 2000, setting a total of 620 SSs to determine habitat selection. We characterized structure and composition of 100 m2 of vegetation around every SS, and measured its distance to nearest native forest patch, road and bottom creek. O. guigna preferred habitats with dense bush cover, far from roads and close to large patches of native forest, being almost exclusively restricted to this type of habitat. On the other hand, P. culpaeus preferred open habitats, close to roads, relying extensively on pine plantations but scarcely using forest and forest fragments. Our results suggest that native forest fragmentation, considering habitat use only, would have a negative effect on O. guigna populations. Thus, forest size reduction and isolation may reduce O. guigna survival in a pine dominated landscape. In contrast, P. culpaeus, a generalist species that would use habitat depending on its abundance, may adapt to changes in this landscape. [ABSTRACT FROM AUTHOR]

Three Botryosphaeria spp. were grown on autoclaved apple and peach stems in Cotton-plugged tubes with constant moisture at 6, 12, 18, 24, and 30°C to determine the effect of temperature on sporulation. Number of conidia per pycnidium was determined weekly from 4 to 10 weeks after inoculation. The experiment was repeated three times. Maximum sporulation occurred at 24°C with B. dothidea and at 18 and 24°C with B. obtusa. Spore production of both fungi showed a quadratic curvilinear response to temperature Pycnidia were erumpent, typical of their habit in nature. Maximum sporulation of B. rhodina occurred at 12, 24, and 30°C instead of at a distinctive peak. Of the three fungi, B. rhodina produced the greatest number of conidia per pycnidium at all temperatures. Mycelia and pycnidia of B. rhodina grew on top of the bark, which is atypical of their habit in nature. For spore production by B. dothidea, there was a significant interaction between temperature and time. Maximum sporulation over the 10-week period occurred in week 4 and/or 6 for B. dothidea at 12, 18, and 24°C, with a linear response at 12 and 24°C (P ≤ 0.05). Conidial maturation of B. obtusa and B. rhodina had a quadratic curvilinear response due to temperature, with a maximum maturation at 12, 18, and 24°C with B. obtusa and at 24°C with B. rhodina. Spore maturation would affect longevity of conidial viability. Maximum spore production over time and percent pigmented spores over time by B. obtusa, and spore maturation over time by B. rhodina occurred in weeks 8, 9, and 10 with a significant linear response (P ≤ 0.05). All three Botryosphaeria spp. produced conidia over the 6 to 30°C range and over the 7- week period (weeks 4 to 10), with maximum sporulation or spore maturation at 18 to 24°C. [ABSTRACT FROM AUTHOR]

Recently, we observed that expression of a pea gene ( S64) encoding an oxophytodienoic acid reductase (OPR) was induced by a suppressor of pea defense responses, secreted by the pea pathogen Mycosphaerella pinodes. Because it is known that OPRs are usually encoded by families of homologous genes, we screened for genomic and cDNA clones encoding members of this putative OPR family in pea. We isolated five members of the OPR gene family from a pea genomic DNA library, and amplified six cDNA clones, including S64, by RT-PCR (reverse transcriptase-PCR). Sequencing analysis revealed that S64 corresponds to PsOPR2, and the amino acid sequences of the predicted products of the six OPR-like genes shared more than 80% identity with each other. Based on their sequence similarity, all these OPR-like genes code for OPRs of subgroup I, i.e., enzymes which are not required for jasmonic acid biosynthesis. However, the genes varied in their exon/intron organization and in their promoter sequences. To investigate the expression of each individual OPR-like gene, RT-PCR was performed using gene-specific primers. The results indicated that the OPR-like gene most strongly induced by the inoculation of pea plants with a compatible pathogen and by treatment with the suppressor from M. pinodes was PsOPR2. Furthermore, the ability of the six recombinant OPR-like proteins to reduce a model substrate, 2-cyclohexen-1-one (2-CyHE), was investigated. The results indicated that PsOPR1, 4 and 6 display robust activity, and PsOPR2 has a most remarkable ability to reduce 2-CyHE, whereas PsOPR3 has little and PsOPR5 does not reduce this compound. Thus, the six OPR-like proteins can be classified into four types. Interestingly, the gene structures, expression profiles, and enzymatic activities used to classify each member of the pea OPR-like gene family are clearly correlated, indicating that each member of this OPR-like family has a distinct function. [ABSTRACT FROM AUTHOR]

Phenotypic and genotypic variability of 18 endophytic Guignardia strains from different host plants (Anacardiaceae: Anacardium giganteum, Myracrodruon urundeuva, Spondias mombin; Apocynaceae: Aspidosperma polyneuron; Ericaceae: Rhododendron sp.; Fabaceae: Bowdichia nitida; Leguminosae: Cassia occidentalis; Rutaceae: Citrus aurantium) growing in different sites in Brazil was assessed by means of morphometric measurements and inter-single-sequence-repeat-anchored polymerase chain reaction (ISSR-PCR) amplifications of the DNA. Morphology of conidia and ascospores and growth rates of the Brazilian isolates corresponded well with those of G. mangiferae. Multiple correspondence analysis (MCA) of the ISSR-PCR data yielded three groups of strains, which did, however, not correspond either to the host or to the geographic origin. The same individual tree hosted genotypically different strains indicating multiple infections. Phylogeny based on ITS1-5.8S-ITS2 sequence analyses confirmed conspecificity of the Brazilian isolates with G. mangiferae (syn. G. endophyllicola). [ABSTRACT FROM AUTHOR]

Two nucleoside triphosphatase (NTPase) cDNA clones were isolated from a cDNA library of Pisum sativum L., cv. Midoriusui. The genes encoding the cDNAs were designated PsAPY1 and PsAPY2. PsAPY1 included the N-terminal amino acid sequence of an NTPase bound to pea cell wall. The phylogenic analysis indicated that PsAPY1 belongs to an NTPase subfamily responsive to environmental stimuli and that PsAPY2 belongs to a discrete subfamily, the physiological role of which is almost unknown. The adenosine triphosphatase activity of recombinant PsAPY1 was regulated by an elicitor and a suppressor from the pea pathogen Mycosphaerella pinodes. Based on these findings, we discuss the role of NTPases in response to biological stresses. [ABSTRACT FROM AUTHOR]

A strain of Guignardia citricarpa Kiely was isolated from infected mango (Mangifera indica L.) leaves. The morphological and physiological characteristics of perithecia and ascospores were identical with those described for G. citricarpa. Inoculated leaves developed lesions 7 to 10 days after ascospore germination. Young lesions appeared as minute, sunken, blackish depressions on upper and lower leaf surfaces. Mature lesions were roughly circular ranging from 1 to 2 mm in diameter. The fungus was consistently reisolated from the lesions which appeared on the leaves, arising from inoculation. Benomyl at 1.7 g/1 provided control of black spot. [ABSTRACT FROM AUTHOR]

The article investigates the hispathology of green Pinus taeda needles infected with Mycosphaerella dearnessi. Mature, fascicled needles exhibiting symptoms considered typcial of M. dearnessi were collected from forest-grown individual Pinus taeda, which were approximately twenty years of age. The tissue abnormalities observed normally occurred within the terminal limits and external to the endodermis of the symptom lesions. Collapsed mesophyll cells typified the pathological lesion tissue. Hypodermal and epidermal cells within the lesions were not affected, other than when associated with stroma development. Abnormalities of resin duct cells were exhibited in host tissue distal from the lesion limits, as was an intercellular interface. Non-stromatic hyphae were not observed in the distal tissue from the lesion limits, as was an intercellular interface.

The polymerase chain reaction (PCR)-based technique of random amplification of polymorphic DNA (RAPD) was used to differentiate DNA from species of the genus Mycosphaerella. DNA from two pathogens which cause Sigatoka leafspot diseases of banana, M. fijiensis and M. musicola, and two other Mycosphaerella species which are commonly found on banana, M. musae and M. minima, gave distinct RAPD banding patterns with all PCR primers tested. PCR, using primer RC07, amplified a 1250 bp RAPD fragment from all isolates of M. fijiensis obtained from II geographical origins. This fragment was absent from the other species of Mycosphaerella. In Southern blots of genomic DNA, this band hybridized exclusively to DNA from M. fijiensis, and the pattern of hybridization suggested that it was binding to repeated DNA. A RAPD band amplified with primer PM06 obtained from M. musicola was also found to be species-specific. Southern analysis suggested that the fragment hybridized to a single-copy sequence in the M. musicola genome. Total genomic DNA from M. musicola was found to be a species-specific hybridization probe. Dot—blots confirmed the specificity of these probes, and could be used to identify isolates of Mycosphacrella which cause Sigatoka disease of banana in south-east Asia. [ABSTRACT FROM AUTHOR]

Epidemics of disease caused by Septoria tritici were studied in detail in 11 crops of winter wheat cv. Longbow over 4 years. Serious damage to the uppermost two leaf layers was caused by splash-borne infection from lower in the crop early in the life of the leaves, followed by one or rarely two cycles of multiplication within a leaf layer. Infection conditions rarely limited damage, even in a dry year; the timing and, to a lesser extent, amount of initial inoculum movement to an upper leaf layer was of greater importance. Timing of initial infection was determined by when rain splash occurred in relation to emergence of a leaf layer. Occurrence of infections soon after a leaf layer started to emerge allowed more time for multiplication of disease within that layer. These infections tended to be more severe because the leaves were closer to inoculum sources within the crop. Slight differences in phenology between locations explain why initially random disease distributions sometimes become aggregated. Early-sown crops are at greater risk because they mature more slowly, allowing more disease multiplication and better transfer between leaf layers. [ABSTRACT FROM AUTHOR]

After inoculation of winter wheat cv. Longbow at a single time, lesions of M. graminicola were produced over a long interval starting 15–35 days after inoculation, dependent on temperature. There was no evidence that a single infection gave rise to more than one lesion. After the initial infection period at 100% relative humidity (r.h.), keeping leaves wet for c. 10 h per day did not shorten latent period on seedlings. Experiments in controlled-environment chambers demonstrated a minimum latent period at approximately 17° C. Variation in the latent period of individual lesions was also minimum at this temperature. The latent period varied among the cultivars tested, cv. Longbow having the shortest, cv. Avalon having almost the longest. Field observations broadly confirmed the results of experiments in constant-environment chambers. [ABSTRACT FROM AUTHOR]

Methods of cucumber seed production in the Lea Valley district of England, where Mycosphaerella melonis widespread, were examined in 1967. No evidence that this fungus is seed-borne on cucumber was obtained. An illustrated description of the pathogen is given, and diagnosis by inoculating test plants described. [ABSTRACT FROM AUTHOR]

Presents the proposal to conserve the name Dothidea. Inclusion of six species and one subordinate taxon; Foundation ofthe family Dothideaceae; Lectotypification of Dothidea by D.moriformis.

is realized in eight steps starting from (R)-phenyllactic acid and 3-phenylprop-2-ynol [ABSTRACT FROM AUTHOR]