Ocena ryzyka porazenia pszenicy przez Tapesia yallundae

The objective of the study was to design a prediction model for eyespot (Tapesia yallundae) infection based on climatic factors (temperature, precipitation, air humidity). Data from experiment years 1994-2002 were used to study correlations between the eyespot infection index and individual weather characteristics. The model of prediction was constructed using multiple regression when a separate parameter is assigned to each factor, i.e. the frequency of days with optimum temperatures, humidity, and precipitation. The correlation between relative air humidity and precipitation and the infection index is significant.Celem podjętych badań było opracowanie modelu opisującego ryzyko porażenia roślin przez T.yallundae. W przeprowadzonej analizie uwzględnianymi parametrami były liczba dni: z temperaturą 4 - 10°C, opadami powyżej 3 mm oraz wilgotnością powietrza powyżej 80%. Stwierdzono występowanie istotnej korelacji pomiędzy indeksem porażenia roślin a wspomnianymi parametrami

Colonization of winter wheat stem bases by communities of pathogenic fungi

The current study was focused on fungi colonizing the stem bases of wheat. Particularly, fungal species with significant harmful effect on wheat were studied. The dynamics of the stem base colonization by these fungi over the growing season were observed, and the association between individual pathogenic fungi was also evaluated. In addition, the fungal leaf sheaths penetration, which can cause physical disturbance, was assessed. The asymptomatic presence of fungal DNA in wheat tissue was confirmed. Microdochium nivale was found on the stem bases most frequently. Other fungi, such as Oculimacula spp., Rhizoctonia cerealis and Fusarium spp., were presented considerable less frequently. The statistical significant association was confirmed only between M. nivale var. nivale and M. nivale var. majus . Out of these, M. nivale tended to decrease in summer season, the frequency of occurrence of Oculimacula spp. and R. cerealis increased at later growth stages. Along with this, these species infected only plants previously colonized by M. nivale . Asignificant relationship between visual symptoms and presence of M. nivale DNA in the host tissue was confirmed

Novel Multiplex and Loop-Mediated Isothermal Amplification (LAMP) Assays for Rapid Species and Mating-Type Identification of Oculimacula acuformis and O. yallundae (Causal Agents of Cereal Eyespot), and Application for Detection of Ascospore Dispersal and in planta Use

Eyespot, caused by the related fungal pathogens Oculimacula acuformis (OA) and O. yallundae (OY), is an important cereal stem-base disease in temperate parts of the world. Both species are dispersed mainly by splash-dispersed conidia but are also known to undergo sexual reproduction yielding apothecia containing ascospores. Field diagnosis of eyespot can be challenging with other pathogens causing similar symptoms, which complicates eyespot management strategies. Differences between OA and OY (e.g. host pathogenicity and fungicide sensitivity) require that both be targeted for effective disease management. Here, we develop and apply two molecular methods for species-specific and mating-type (MAT1-1 or MAT1-2) discrimination of OA and OY isolates. First, a multiplex PCR-based diagnostic assay targeting the MAT idiomorph region was developed allowing simultaneous determination of both species and mating type. This multiplex-PCR assay was successfully applied to type a global collection of isolates. Second, the development of loop-mediated isothermal amplification (LAMP) assays targeting beta-tubulin sequences is described, which allow fast (<9 min) species-specific discrimination of global OA and OY isolates. The LAMP assay can detect very small amounts of target DNA (1 pg) and was successfully applied in planta. In addition, mating-type specific LAMP assays were also developed for rapid (<12 min) genotyping of OA and OY isolates. Finally, the multiplex PCR-based diagnostic was applied, in conjunction with spore trapping in field experiments, to provide evidence of the wind dispersal of ascospores from a diseased crop. The results indicate an important role of the sexual cycle in the dispersal of eyespo

Ramularia collo-cygni: an emerging pathogen of barley crops.

AbstractRamularia collo-cygni is the biotic factor responsible for the disease Ramularia leaf spot (RLS) of barley (Hordeum vulgare). Despite having been described over 100 years ago and being considered a minor disease in some countries, the fungus is attracting interest in the scientific community as a result of the increasing number of recorded economically damaging disease epidemics. New reports of disease spread and fungal identification using molecular diagnostics have helped redefine RLS as a global disease. This review describes recent developments in our understanding of the biology and epidemiology of the fungus, outlines advances made in the field of the genetics of both the fungus and host, and summarizes the control strategies currently available

R<i>amularia collo-cygni</i> - an emerging pathogen of barley crops

Ramularia collo-cygni is the biotic factor responsible for the disease Ramularia leaf spot (RLS) of barley (Hordeum vulgare). Despite having been described over 100 years ago and being considered a minor disease in some countries, the fungus is attracting interest in the scientific community as a result of the increasing number of recorded economically damaging disease epidemics. New reports of disease spread and fungal identification using molecular diagnostics have helped redefine RLS as a global disease. This review describes recent developments in our understanding of the biology and epidemiology of the fungus, outlines advances made in the field of the genetics of both the fungus and host, and summarizes the control strategies currently available. </jats:p