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Background: Pseudomonas syringae can cause stem necrosis and canker in a wide range of woody species including cherry, plum, peach, horse chestnut and ash. The detection and quantification of lesion progression over time in woody tissues is a key trait for breeders to select upon for resistance. Results: In this study a general, rapid and reliable approach to lesion quantification using image recognition and an artificial neural network model was developed. This was applied to screen both the virulence of a range of P. syringae pathovars and the resistance of a set of cherry and plum accessions to bacterial canker. The method developed was more objective than scoring by eye and allowed the detection of putatively resistant plant material for further study. Conclusions: Automated image analysis will facilitate rapid screening of material for resistance to bacterial and other phytopathogens, allowing more efficient selection and quantification of resistance responses.

Stem canker (blackleg) is economically the most important disease of oilseed rape world­wide. This disease is caused by two species of pathogenic fungi of the genus Leptosphaeria: Leptosphaeria maculans (Desm.) ces. and de Not anamorf Phoma lingam (Tode. Fr.) Desmas, that causes stem canker and blackleg root and Leptospaeria biglobosa Shoem and Brun, that causes symptoms such as cancers of the upper part of the stem usually causing less damage, and can cause serious damage in countries with higher summer temperatures. Pathogenic fungi from one area to another are transmitted by ascospores and contaminated (infected) seed. In order to prove the modes of transmission of parasites, the test is done transmitting the parasite by seeds. Disinfected seeds of oilseed rape cultivars Quinta were submerged in the suspension of pycnospores. Submerged seeds were kept at 20 º C ± 1 º C and 12 h photoperiod for 48 h. After planting in plastic containers seeds were kept at 25 º C ± 1 º C and 12h photoperiod. In this experiment the following isolates were used: C-5, L-5, K-7, LJ-3, S-11, St-1, GS-3 and Lm as a reference isolate (L. maculans) fol­lowed by K-113, K-115 and Lb as a reference isolate (L. biglobosa). The symptoms were as­sessed after 7 and 14 days after emergence. Ratings were made with + which meant visible symptoms on cotyledons or hypocotyl and - what referred to healthy plants. After 7 days, the isolates (Lm, C-5, L-5, K-7, LJ-3, S-11, St-1, GS-3) were caused disease symptoms on plants of oilseed rape. This pathogenicity is reflected in the number of seedlings, leaf spots and stalk lodging cotyledons. At izolate Lb (reference isolate L. biglobosa) K-113 and K-115 after 7 and 14 days was not observed pathogenicity on rapeseed plants. The control variety seeds were soaked in distilled water. The trial was set in 6 reps, and pathogenicity of fungal isolates in relation to the control was tested using Dunette's test. After 14 days re-isolation of pathogen was done., Rak stabla (crna noga) je najznačajnije oboljenje uljane repice širom sveta. Bolest mogu prouzrokovati dve vrste patogenih gljiva iz roda Leptosphaeria: Leptosphaeria maculans (Desm.) ces. i de Not, anamorf Phoma lingam (Tode. Fr.) Desmas, koja prouzrokuje rak stabla i crnu nogu na korenu i Leptospaeria biglobosa Shoem and Brun, koja prouzrokuje simptome slične raku ali na gornjim delovima stabla obično prouzrokujući manje štete. Ozbiljnije štete mogu nastati u zemljama sa višim letnjim temperaturama. Patogene gljive se iz jedne oblasti u drugu prenose askosporama i zaraženim semenom. Da bi se utvrdili načini prenošenja parazita testirana je mogućnost prenošenja semenom. Dezinfikovano seme uljane repice, kultivara Quinta je potopljeno u suspenziju piknospora. Ovakvo seme je držano na 20ºC ± 1ºC i 12h fotoperiodu tokom 48 sati. Posle setve seme je preneto u plastične posude a temperatura čuvanja je bila 25ºC ± 1º C i fotoperiod od 12h. U ovom eksperimentu korišćeni su sledeći izolati: C-5, L-5, K-7, LJ-3, S-11, St-1, GS-3 i Lm kao referentni izolat (L. maculans) kao i K-113, K-115 i Lb kao referentni izolat (L. biglobosa). Ocena prisustva simptoma je rađena posle 7 i 14 dana od nicanja. Sa znakom + su se obeležavale biljke sa vidljivim simptomima na kotiledonima ili hipokotilu a znakom - biljke bez pojave simptoma. Posle 7 dana izolati Lm, C-5, L-5, K-7, LJ-3, S-11, St-1 i GS-3 su izazvali simptome bolesti na biljkama uljane repice. Patogenost se ogledala kroz broj oštećenih klijanaca, lisnih pega i povijenih kotiledona. Kod izolata Lb (referentni izolat L. biglobosa) K-113 i K-115 posle 7 i 14 dana nije primećena patogenost na biljkama uljane repice. Kontrolna varijanta semena je potapana u destilovanu vodu. Ogled je postavljen u 6 ponavljanja, i patogenost izolata gljive u odnosu na kontrolu je izražena Danetovim testom. Posle 14 dana izvedena je ponovna izolacija patogena.

The anamorphic genus Phoma was subdivided into nine sections based on morphological characters, and included teleomorphs in Didymella, Leptosphaeria, Pleospora and Mycosphaerella, suggesting the polyphyly of the genus. Recent molecular, phylogenetic studies led to the conclusion that Phoma should be restricted to Didymellaceae. The present study focuses on the taxonomy of excluded Phoma species, currently classified in Phoma sections Plenodomus, Heterospora and Pilosa. Species of Leptosphaeria and Phoma section Plenodomus are reclassified in Plenodomus, Subplenodomus gen. nov., Leptosphaeria and Paraleptosphaeria gen. nov., based on the phylogeny determined by analysis of sequence data of the large subunit 28S nrDNA (LSU) and Internal Transcribed Spacer regions 1 & 2 and 5.8S nrDNA (ITS). Phoma heteromorphospora, type species of Phoma section Heterospora, and its allied species Phoma dimorphospora, are transferred to the genus Heterospora stat. nov. The Phoma acuta complex (teleomorph Leptosphaeria doliolum), is revised based on a multilocus sequence analysis of the LSU, ITS, small subunit 18S nrDNA (SSU), ß-tubulin (TUB), and chitin synthase 1 (CHS-1) regions. Species of Phoma section Pilosa and allied Ascochyta species were determined to belong to Pleosporaceae based on analysis of actin (ACT) sequence data. Anamorphs that are similar morphologically to Phoma and described in Ascochyta, Asteromella, Coniothyrium, Plectophomella, Pleurophoma and Pyrenochaeta are included in this study. Phoma-like species, which grouped outside the Pleosporineae based on a LSU sequence analysis, are transferred to the genera Aposphaeria, Paraconiothyrium and Westerdykella. The genera Medicopsis gen. nov. and Nigrograna gen. nov. are introduced to accommodate the medically important species formerly known as Pyrenochaeta romeroi and Pyrenochaeta mackinnonii, respectively.

Stem canker in blueberries (Vaccinium corymbosum L.) is a disease which is widely distributed around the world and of growing importance in Chile, associated with Neofusicoccum species. The purpose of the present work was to study the effects of water activity (a w) and temperature on mycelial growth in vitro of N. arbuti, N. australe and N. parvum, obtained from blueberries with symptoms of stem canker. According to the results obtained, 25 °C was the optimum temperature for mycelial growth of N. arbuti, N. australe and N. parvum. These species presented minimal growth at 35 °C and none at 0 and 5 °C. The effect of a w on mycelial growth was significant (P≤0.001) and varied with the species of Neofusicoccum and the temperature. At 25 °C, the optimum temperature, the three species of Neofusicoccum presented minimum growth with a w of 0.900 and 0.920, while optimum mycelial growth was found with a w equal to 0.990. Independent of the Neofusicoccum species, the effect of temperature (T) and a w on mycelial growth was best explained by y = -721.62 + 0.24T + 788.92a w. (R²adj = 0.77, P<0.001), suggesting that T and a w jointly explained 77% of the total variation on mycelial growth of Neofusicoccum spp. The results obtained provide important information for a better understanding of the biology of these plant pathogenic fungi, and suggest that temperature and a w could be important parameters for understanding factors that affect the inoculum production, colonization and infection by Neofusicoccum spp. in blueberry plantations., La cancrosis de la madera en arándanos (Vaccinium corymbosum L.) es una enfermedad de amplia distribución en el mundo y de creciente importancia en Chile, asociada a la acción de especies de Neofusicoccum. Este trabajo tuvo como objetivo estudiar el efecto de la actividad de agua (a w) y de la temperatura sobre el crecimiento micelial in vitro de N. arbuti, N. australe y N. parvum, obtenidos de arándanos con síntomas de cancrosis de la madera. Según los resultados obtenidos, 25 °C fue la temperatura óptima para el crecimiento micelial de N. arbuti, N. australe y N.parvum. Estas especies crecieron mínimamente a 35 °C y no crecieron a 0 y 5 °C. La a w afectó significativamente (P≤0.001) el crecimiento micelial y su efecto varió en función de la especie de Neofusicoccum y de la temperatura. A 25 °C, temperatura óptima, las tres especies de Neofusicoccum crecieron mínimamente con a w de 0,900 y 0,920, siendo óptimo el crecimiento micelial con a w igual a 0,990. Independientemente de Neofusicoccum spp., el crecimiento micelial (y) entre 20 y 30 °C se explicó a través de y = -721,62 + 0,24T + 788,92a w. (R² = 0,77, P<0,001). Los resultados obtenidos aporta información para la mejor compresión de la biología de estos hongos fitopatógenos y sugieren que la a w es un importante factor que podría afectar la producción de inóculo, colonización y la infección por Neofusicoccum spp., en arándanos.

Stem canker in blueberries (Vaccinium corymbosum L.) is a disease which is widely distributed around the world and of growing importance in Chile, associated with Neofusicoccum species. The purpose of the present work was to study the effects of water activity (a w) and temperature on mycelial growth in vitro of N. arbuti, N. australe and N. parvum, obtained from blueberries with symptoms of stem canker. According to the results obtained, 25 °C was the optimum temperature for mycelial growth of N. arbuti, N. australe and N. parvum. These species presented minimal growth at 35 °C and none at 0 and 5 °C. The effect of a w on mycelial growth was significant (P≤0.001) and varied with the species of Neofusicoccum and the temperature. At 25 °C, the optimum temperature, the three species of Neofusicoccum presented minimum growth with a w of 0.900 and 0.920, while optimum mycelial growth was found with a w equal to 0.990. Independent of the Neofusicoccum species, the effect of temperature (T) and a w on mycelial growth was best explained by y = -721.62 + 0.24T + 788.92a w. (R²adj = 0.77, P<0.001), suggesting that T and a w jointly explained 77% of the total variation on mycelial growth of Neofusicoccum spp. The results obtained provide important information for a better understanding of the biology of these plant pathogenic fungi, and suggest that temperature and a w could be important parameters for understanding factors that affect the inoculum production, colonization and infection by Neofusicoccum spp. in blueberry plantations., La cancrosis de la madera en arándanos (Vaccinium corymbosum L.) es una enfermedad de amplia distribución en el mundo y de creciente importancia en Chile, asociada a la acción de especies de Neofusicoccum. Este trabajo tuvo como objetivo estudiar el efecto de la actividad de agua (a w) y de la temperatura sobre el crecimiento micelial in vitro de N. arbuti, N. australe y N. parvum, obtenidos de arándanos con síntomas de cancrosis de la madera. Según los resultados obtenidos, 25 °C fue la temperatura óptima para el crecimiento micelial de N. arbuti, N. australe y N.parvum. Estas especies crecieron mínimamente a 35 °C y no crecieron a 0 y 5 °C. La a w afectó significativamente (P≤0.001) el crecimiento micelial y su efecto varió en función de la especie de Neofusicoccum y de la temperatura. A 25 °C, temperatura óptima, las tres especies de Neofusicoccum crecieron mínimamente con a w de 0,900 y 0,920, siendo óptimo el crecimiento micelial con a w igual a 0,990. Independientemente de Neofusicoccum spp., el crecimiento micelial (y) entre 20 y 30 °C se explicó a través de y = -721,62 + 0,24T + 788,92a w. (R² = 0,77, P<0,001). Los resultados obtenidos aporta información para la mejor compresión de la biología de estos hongos fitopatógenos y sugieren que la a w es un importante factor que podría afectar la producción de inóculo, colonización y la infección por Neofusicoccum spp., en arándanos.

A complex of soybean diseases is caused by species from the genus Diaporthe /Phomopsis. Diaporthe phaseolorum (anamorph Phomopsis phaseoli) and Phomopsis longicolla (teleomorph unknown) are described as soybean pathogens. The first species includes three varieties: D. phaseolorum var. sojae, anamorph Phomopsis sojae, the causal agent of pod and stem blight, and D. phaseolorum var. caulivora and D. phaseolorum var. meridionalis, agents of northern and southern stem canker. The species P. longicolla is the most common and most damaging agent of soybean seed decay. The diseases caused by parasites from this genus were first observed and described on soybean in the USA. Presently they are widespread in most soybean-growing regions around the world. Soybean in Serbia is attacked by all pathogens mentioned above, except for D. phaseolorum var. meridionalis, the causal agent of the southern stem canker. D. phaseolorum var. caulivora (northern stem canker) has the greatest economic importance because it causes wilt and drying of plants during pod development and grain filling. Most intensive outbreaks of the disease occurred in the 1980s in southern and southeastern Banat, southern Bačka and Srem. Prematurely wilted plants yielded 50% to 62% (depending on variety) less than healthy plants. Such heavy losses raised the question of the profitability of soybean growing. P. sojae and P. longicolla are less important in Serbia at the moment. Intensive infections of soybean seed break out occasionally. It was found that P. longicolla is the primary agent of seed decay and latent infections of seed in our country, although the other members of this genus may cause identical symptoms. Sexual cycle of development (teleomorph stage) of the fungi of the genus Diaporthe /Phomopsis form perithecia with asci and ascospores, while in the asexual cycle (anamorph stage) various types of conidia (α and β) are formed in pycnidia. The species P. longicolla has no teleomorph stage. Infected har, Kompleks oboljenja na soji izazivaju gljive iz roda Diaporthe/Phomopsis. Kao paraziti soje opisana su tri varijeteta vrste Diaporthe phaseolorum (anamorf Phomopsis phaseoli), i to: D. phaseolorum var. sojae (syn. P. sojae), prouzrokovač paleži mahuna i stabla (pod and stem blight), zatim D. phaseolorum var. caulivora i D. phaseolorum var. meridionalis prouzrokovači 'severnog' i 'južnog' tipa raka stabla (soybean stem canker). Phomopsis longicolla (teleomorf nepoznat) je najčešći prouzrokovač truleži semena (soybean seed decay), mada ovo oboljenje izazivaju i sva tri varijeteta gljive D. phaseolorum. Svi pomenuti pripadnici roda, izuzev D. phaseolorum var. meridionalis, prisutni su na soji u Srbiji, a najveći značaj ima D. phaseolorum var. caulivora, prouzrokovač raka stabla. Poslednjih nekoliko decenija sprovedena su brojna, sveobuhvatna proučavanja parazita roda Diaporthe/ Phomopsis na soji u našoj zemlji. Nedavno započeta istraživanja na molekularnom nivou ukazuju da su pored pomenutih na soji prisutne i druge vrste ovog roda. U ovom radu su analizirani rezultati višegodišnjih istraživanja u svetu i kod nas.

Fungi are of primary ecological, biotechnological and economic importance. Many fundamental biological processes that are shared by animals and fungi are studied in fungi due to their experimental tractability. Many fungi are pathogens or mutualists and are model systems to analyse effector genes and their mechanisms of diversification. In this study, we report the genome sequence of the phytopathogenic ascomycete Leptosphaeria maculans and characterize its repertoire of protein effectors. The L. maculans genome has an unusual bipartite structure with alternating distinct guanine and cytosine-equilibrated and adenine and thymine (AT)-rich blocks of homogenous nucleotide composition. The AT-rich blocks comprise one-third of the genome and contain effector genes and families of transposable elements, both of which are affected by repeat-induced point mutation, a fungal-specific genome defence mechanism. This genomic environment for effectors promotes rapid sequence diversification and underpins the evolutionary potential of the fungus to adapt rapidly to novel host-derived constraints

Species of the coelomycetous genus Phoma are ubiquitously present in the environment, and occupy numerous ecological niches. More than 220 species are currently recognised, but the actual number of taxa within this genus is probably much higher, as only a fraction of the thousands of species described in literature have been verified in vitro. For as long as the genus exists, identification has posed problems to taxonomists due to the asexual nature of most species, the high morphological variability in vivo, and the vague generic circumscription according to the Saccardoan system. In recent years the genus was revised in a series of papers by Gerhard Boerema and co-workers, using culturing techniques and morphological data. This resulted in an extensive handbook, the ¿Phoma Identification Manual¿ which was published in 2004. The present review discusses the taxonomic revision of Phoma and its teleomorphs, with a special focus on its molecular biology and papers published in the post-Boerema era.