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The purpose of the current study was to estimate immunity of the winter grain varieties sown in the south of Russia to the pink snow mold pathogen (Microdochium nivale (Fr.) Samuels & I.C. Hallett) in the sprouting phase. For resistance to M. nivale there have been studied 35 winter wheat varieties sown in the south of the Russian Federation, 19 winter barley varieties and 4 variety samples and 13 winter triticale varieties developed in the LLC “Agrostandart”, FSBSI RCG named after P.P. Lukyanenko, FSBSI FRC Kabardino-Balkarian Research Center of the RAS, FSBSI “ARC Donskoy”, FSBSI “North Caucasian FRSC”, FSBSI “FRAC”, NPO “KUBANZERNO”, FSBEI HE “KubSAU”. There has been substantiated a methodological approach to conducting research on immunological estimation of winter grain varieties in the laboratory conditions. The optimal temperature for the cultivation of the pathogen was +10/+15 °C (with a photoperiod of 12 hours). There was found that the required temperature to stimulate sporulation was +5 °C. The optimum temperature for the incubation period was +5 °C at 85% humidity. There has been established that the only winter wheat variety ‘Dolya’ had a very high resistance degree to pink snow mold; the varieties ‘Antonina’ and ‘Brigada’ had a high resistance degree; 21 varieties were classified as resistant. M. nivale resistance was demonstrated by 9 winter barley varieties and 3 variety samples (‘Versal’, ‘Iosif’, ‘KA-12’, ‘KA-5/KA-3’, ‘KA-5/KA-1’, ‘Karrera’, ‘Kondrat’, ‘Kubagro-1’, ‘Lazar’, ‘Master’, ‘Romans’, ‘Sarmat’). Among the studied winter triticale varieties, 4 varieties had a very high resistance degree (‘Argus’, ‘Slon’, ‘Tikhon’, ‘Ullubiy’) and 9 varieties had a high resistance degree to pink snow mold pathogen (‘Aznavur’, ‘Argo’, ‘Arioso’, ‘Valentin 90’, ‘Iliya’, ‘Sotnik’,’ Styuard’, ‘Forte’, ‘Khleborob’).

The current trend of winter rye breeding for the conditions of northern agriculture is development of aluminum and acid-tolerant cultivars. Studies were carried out in the central zone of the Kirov region in 1991-2019. The complex natural provocative background was used (aluminum ion content 25.5-26.7 mg/100 g of soil at a pH of salt extract 3.6-3.8; annual epiphytotic development of pink snow mold Microdochium nivale (Fr.). Winter-resistant and adaptive cv. Kirovskaya 89 served as the initial material. A rigid natural provocative background made it possible to select the best plants (500 pieces) that were transplanted in spring to an isolated area. Subsequent negative selections, field and laboratory assessments made it possible to create the Kiprez population. During the period of 1995-2013 population reproduction was carried out on a provocative background and 5 cycles of negative selection with simultaneous study in competitive varietal testing on two soil backgrounds. The first selection cycle contributed to an increase in the yield of the new population under conditions of edaphic stress over the original cv. Kirovskaya 89 by 12.6%; the second and third by 19.5 and 29.3%, respectively. Further selection did not show a significant effect. Since 2010, the further improvement of the cv. Kiprez has been carried out using individual-family selection and paired crosses. A multi-year competitive test (2014-2019) showed the advantage of the cv. Kiprez over the standard and the initial cultivar. The average yield increase to the Kirovskaya 89 variety under conditions of slightly acidic soils (pH − 5.3-5.7; Al3+ − 5.0-6.5) was 0.50 t / ha (Kirov) and 0.75 t/ha (Falenki); in the conditions of edaphic stress − 1.91 t / ha (Falenki). A combination of aluminum- and acid tolerance of the cultivar with drought resistance was revealed. In 2014, with a moisture deficit (31% of the norm) in the grain filling and ripening phase, cv. Kiprez exceeded significantly the cv. Falenskaya 4 (standard) by 0.82 tons/ha (19.1%) in a acidic background; initial cv. Kirovskaya 89 - by 1.97 tons/ha (62.7%). Cv. Kiprez is recommended for cultivation on low-fertile soils in harsh hydrothermal conditions of northern agriculture.

The state, selection achievements of triticale culture from Poland, its distribution, acreage, and yield are analyzed. In 2007 – 2009, 52 varieties of winter triticale were studied, in 2013 – 2016 — 17 varieties, and in 2018 – 2019 — 20 new varieties from Poland were tested in the Moscow oblast’. Polish short-stemmed varieties Grenado Argento and Korvetto under the conditions of Moscow and other regions have a complex of economically valuable features and properties, so they are used in the selection programs of scientific centers in Russia. In the 2017 – 2019, the study of the gene pool in the Moscow oblast’ identified Polish varieties Felo (k-4010), Hortense (k-4012), Preco/Kill/Rex/Aos/Rex, having a moderately short stem (95 – 110 cm), increased resistance to winter stress (7 – 9 points), snow mold (5 – 7 points) and brown rust (9 points), as well as a large, well-watered ear (56 – 59 achenes) with a grain weight of 2.8 – 3.1 g, 1000 grains — 50 – 52 g, and grains/m2 — 860 – 890 g. In 2007 – 2018 more than 100 Polish cultivars were studied using a set of indicators. The most valuable of them were used in the development of new, more advanced lines and varieties of triticale. Created with the introduction in the State register of highly productive (more than 10 tons/ha of grain) winter variety triticale Kapella. The source material for its production by the method of ecological mutagenesis was a variety of spring triticale from Poland (k-2045), which has a set of valuable indicators.

The article considers the results of experiments on the study and selection of sources of valuable features from the world collection. The aim of the research is to create new varieties of winter triticale with high features of productivity (over 12 t/ha) and grain quality in comparison with the Victor and Hermes standards. Special attention in the experiments is paid to the search for genotypes that are promising for use in breeding programs for different types of crossing, obtaining hybrid populations, identifying forms, lines with a complex of economically useful features. Breeders of Federal Research Center “Nemchinovka” for a number of years received varieties of winter triticale, competitive in Russia and abroad, able to form a crop of more than 10 t\ha of quality grain. However, their disadvantages are tallness, susceptibility to dangerous diseases (snow mold, septoriosis), and significant variability in grain harvest over the years (2.9). The authors have identified sources of economic and valuable features from the collection of N. I. Vavilov All-Russian Institute of Plant Genetic Resources. This includes the winter-hardy variety Tsekad 90, drought-resistant Doctrina 110, short-stemmed Legion, Kentavr, yielding large-grain Efremovskaya, etc., successfully used in breeding. Highly productive lines have been created (No.6 408-19-71, No.618-176, No.878-1-25, No.690-1-19) and varieties (Gera, Kapella, Arktur) with a fixed grain harvest of more than 10t\ ha, adaptive to the natural conditions of the non-Chernozem zone and the middle Volga region.

Due to increasing demands to reduce chemical plant protection products, including prophylactic chemical seed treatments, there is a renewed interest in thermal seed treatments for cereal crops. We carried out contemporary evaluations of various alternative seed treatments for economically relevant cereal diseases in Switzerland. Thermal seed treatments were evaluated for effectiveness against two seed-borne diseases, snow mold (Microdochium spp.) and loose smut of barley (Ustilago nuda), commonly found in Swiss cereal production. Field trials testing seed treatments against Microdochium spp., including M. majus and M. nivale, on wheat were conducted across four growing seasons from 2016/17 to 2019/20 and against U. nuda on barley across three growing seasons from 2016/17 to 2018/19. The foci of these trials were primarily on thermal seed treatments, including steam, hot air, and warm water. Additionally, a Cerall® treatment, based on the microorganism Pseudomonas chlororaphis strain MA 342, was included in two of the trials focusing on Microdochium spp. Steam, warm water, and hot air showed high efficacy against Microdochium spp., while Cerall® showed no disease reduction. In the Microdochium spp. 2018/19 trial, a combination of poor field conditions, low quality seed, and high disease pressure reduced seed germination. The 2019/20 Microdochium spp. field trial, which occurred during less challenging field conditions than those in 2018/19 and included the same seed lot from 2018/19 and a less diseased second lot, showed an improved efficacy of the steam treatments. The warm water treatments were found to be the only effective thermal treatment against U. nuda. Our results demonstrate that the steam treatments more readily affected germination rate in a highly diseased seed lot, while warm water treatments showed limited damage to the seed. Warm water was found to be the most consistently effective thermal treatment against both diseases, and constraints in implementing such a treatment are discussed. If the steam treatment parameters are correctly set to minimize damage to the plant, it offers effective protection against some seed-borne diseases. Overall, the results from this study give more information about effectiveness of alternative seed treatments under various field conditions.

Speckled snow mold caused by Typhula ishikariensis is one of the most devastating diseases of winter wheat in Hokkaido, Japan and parts of the Pacific Northwest region of USA. Munstertaler is a winter wheat landrace from Switzerland that has very high resistance to snow mold and superior freezing tolerance. Quantitative trait loci (QTL) for resistance to speckled snow mold were identified in a doubled haploid population derived from a cross between Munstertaler and susceptible variety Ibis, both under field conditions and controlled environment tests. Composite interval mapping analysis revealed a major QTL on chromosome 5D from Munstertaler, and on chromosome 6B from Ibis. Flanking microsatellite marker cfd 29 for the QTL on chromosome 5D was about 5 cM distant from vernalization requirement gene Vrn-D1, suggesting that the QTL on chromosome 5D is located on a cold-stress-related gene cluster along with Vrn-D1 and freezing tolerance gene Fr-D1. The QTL on chromosome 6B from Ibis was located on the centromere region flanking QTn.mst-6B, which is reported to increase plant tiller number.

The aim of the study was to establishdistribution of pink snow mold on turfgrass and to improve the measures for disease control. The crop survey was carried out in the Polissya, Forest-Steppe and Steppe areas. For the identification of pathogens, a selection of plant samples was carried out with further analysis in laboratory conditions. Experiments were carried out during 2015-2018 on the lawn mixture "Universalna". The effect of fungicides of various chemical groups and their mixtures was investigated. Treatment was carried out prophylactically in the fall before installing the snow cover. The assessments were performed according to generally accepted methods; disease spread, disease severity and technical efficiency of pesticides were determined. Symptoms of pink snow mold were fixed annually with a large variation in the spread and severity of disease. Its highest development was recorded in the Zhytomyr region during the vegetative period 2017/2018 , which is associated with a longer period of snow cover. The use of fungicides and their mixtures significantly reduced the number of infected plants, but the protective fungicidal action varied. The most effective was the use of a tank mixture of fungicides Maxim 025 FS (0.4-0.75 l/ha) with Horus 75 WG (0.3-0.6 kg/ha). The average level of fungicidal action was demonstrated by Horus 75 WG, Amistar Gold 250 SE and Amistar Extra 280 SC - 51.4-60.5%. In addition, due to the decrease in the disease development, positive effect on the formation of the quality of the lawn was achieved, projective coverage increased from 62 to 86%. During 2015-2018, the results of the monitoring of the emergence and development of diseases showed that turfgrass was annually affected by snow mold. Development of the disease reached 14,7-26,4%. Preventive spraying of grass in the autumn period protects plants against pink snow mold in the spring. Under application of a mixture of fungicides Maxim 025 FS + Horus 75 WG high level protection was obtained. Depending on the flow rates it varied from 85.3 to 91.5%. Projective coverage thus increased from 62% to 80-86%.

In the conditions of the Kirov region, the major factor reducing the productivity of winter crops is infestation with snow mold (Microdochium nivale (Fr.) Samuels et. Hallet. - synonym Fusarium nivale (Fr.) Ces.), which annually grows by 80-100%. Therefore, the main direction of breeding is receiving winter rye varieties having maximum resistance to this disease. During the period of 2003-2017 there was carried out the assessment of zoned and perspective cultivars of domestic breeding of various ecological-and-geographical origin for snow mold infestation in natural provocative conditions. Weather conditions differed greatly in all periods of rye development. It has been established that plant resistance to M. nivale pathogen is influenced greatly by the condition of plants before wintering regulated by the sowing time. Well-developed plants of Falenskaya 4 variety formed the optimum density of an agro-phytocenosis, accumulated bigger amount of sugars (more than 7%), regenerated during spring re-growth by more than 90%, and produced stable high yield (more than 4.9 t/ha). In order to realize the biological potential of the variety, there was a need to shift the previously established sowing time to 5-10 days later period. The productivity was influenced greatly by April conditions, namely, by the period of total clearing of sowings from snow, which took only several days (3-6). Warm and dry weather favored an active re-growth of rye and prevented disease development. Cold and damp weather provoked fungus development, which affected quickly the plants weakened after rewintering. It was revealed that winter rye varieties of different ecological-and-geographical groups responded to this disease differently. The variability in productivity of each cultivar by years was high (CV = 25.8…65.4%). The greatest stability was characteristic for varieties bred in FARC North-East. The main methods of breeding for the resistance to snow mold are crossing and selection in the conditions of a provocative background. The efficiency of a selection method is confirmed with creation from Falenskaya 4 a highly winter-hardy variety Flora with active regeneration after snow mold infestation (100%) and stable productivity by years – 4.62 t/ha (addition yield to an initial cultivar was 0.27 t/ha). The distinctive feature of Flora variety is active formation of powerful green mass in spring that is important for the early use for green forage for cattle and poultry. Since 2012 the variety is included in the State Register of breeding achievements in Volga-Vyatka and North-West regions of the Russian Federation.

Results 10 years' (2008-2017) comparative studying of varieties of winter rye with recessive-polygenic (the first group) and dominant- monogenic (the second group) short-stem type are presented. In each group tested 5 varieties which estimated on 6 traits: productivity, winter hardiness, plant height, weight is 1000 grains, number of falling and viscosity of water extract of grain meal. Determined by each trait: stability of a phenotype (SF), ecological variation (CV), ecological plasticity (bi), general (GAА) and specific (SAА) adaptive ability, selection value of a genotype (SVG). Average productivity on groups of varieties was identical (respectively 6,69 and 6,62 t/ha), however varieties with dominant-monogenic type of a short-stem differed authentically in the best winter hardiness of plants (for 6,3%) and had shorter stalk (on 9,3 cm). On the ecological variation of traits was influenced significantly by all three factors: weather conditions of year (75,5-95,0%), variety genotype (1,1-2,5%) and interaction variety x years (2,9-22,3%). The most strongly weather conditions of year influenced a productivity variation (86,3% for the first group and 95,0% for the second). On the trait of winter hardiness force of influence of a factor a variety x years was higher, than on other traits, and made respectively 9,3 and 22,3%. Ecological stability at varieties of the second group was twice higher (CV=12,4%), than at varieties of the first group (CV=24,3%). The conclusion is made that varieties of winter rye with a dominant-monogenic short-stem have lower norm of reaction to the adverse conditions of a rewintering developing in years with a high snow cover. Therefore regions where the main limiting factor is the low rewintering because of strong defeat of plants a snow mold have to be the main area of cultivation of such varieties of winter rye. The opinion is expressed that in the main winter rye regions of Russia it is expedient to cultivate varieties of winter rye with different types of a short-stem, but taking into account their agroecological specifics.

Winter rye is a versatile crop widely used for food and industry. Although rye is resistant to abiotic stressors and many phytopathogens, it is severely damaged by pink snow mold (SM)—a progressive disease caused by the psychrotolerant fungus Microdochium nivale under the snow cover or during prolonged periods of wet and cool conditions. Due to little use of the SM resistance sources in contemporary breeding, varieties with at least moderate resistance to SM are limited. Our study aimed to integrate field assessment under natural conditions and an artificially enriched infection background with laboratory techniques for testing rye accessions and selecting SM resistant sources for applied breeding programs and genetic research. We revealed valuable sources of SM resistance and split rye accessions, according to the level of the genetic divergence of the SM resistance phenotype. This allowed us to select the most distinct donors of the SM resistance, for their use as parental forms, to include novel variability sources in the breeding program for achieving high genetic variability, as well as enhanced and durable SM resistance, in progeny. The rye accessions analyzed here, and the suggested options for their use in breeding, are valuable tools for rye breeding.

Snow mold fungi cause serious damage to the seedlings of some coniferous species in the boreal region where deep snow covers the seedlings in winter. Racodium therryanum is one of the fungi causing such damage in Japan. Neither sexual nor asexual spores of R. therryanum have been found in the field, and thus, the taxonomy and life cycle of this fungus is unclear. In this study, we developed seven microsatellite markers for population studies such as population structure, recombination and genetic diversity of R. therryanum through de novo genome assembly. Seven microsatellite markers were developed and applied for 133 R. therryanum isolates from Picea glehnii, P. jezoensis and Abies sachalinensis in a nursery and two planted sites in forests (forest sites) situating 10–20 km apart. Little genetic differentiation between the two forest sites suggests that gene flow had occurred between the forest sites. The nursery population was characterized by low genetic diversity compared to the two forest sites. Discriminant analysis of principal components (DAPC) indicated three genetically differentiated clusters of R. therryanum which occurred sympatrically in each site. No dominant clusters were observed in the three host species, and no genetic differentiation was observed among the host species. The observed not significant linkage disequilibrium suggested the genetic recombination of R. therryanum. Microsatellite markers developed in this study can be useful for the further population studies of R. therryanum.

Propiconazole is often used to remove fungal endophytes from turfgrass to study the effects of Epichloë endophytes. However, besides a fungicidal effect, propiconazole can bind to the genes in the cytochrome P450 family and affect the biosynthesis of brassinosteroids. For this reason, outside of fungicidal application, propiconazole has also been used as plant growth regulator. In this study, we used a combination of RNA sequencing and liquid chromatography–mass spectrometry (LC-MS) to study how hard fescue (Festuca brevipila) responded to the high dose of propiconazole treatment. To test the long-term effect of the heavy use of propiconazole on plants, we inoculated with Microdochium nivale (causal agent of pink snow mold) half year post the last fungicide application. Propiconazole-treated plants showed enhanced pink snow mold resistance. This study suggested that the high dose use of propiconazole fungicide resulted in phenotypic and physiological changes in the plant such as slow growth and change in disease resistance. Genes and pathways affected by propiconazole identified in this study provide turfgrass breeders new information for genetic improvement of hard fescue and also provide turfgrass management new ways to control turfgrass diseases.

Snow mold is a severe plant disease caused by psychrophilic or psychrotolerant fungi, of which Microdochium species are the most harmful. A clear understanding of Microdochium biology has many gaps; the pathocomplex and its dynamic are poorly characterized, virulence factors are unknown, genome sequences are not available, and the criteria of plant snow mold resistance are not elucidated. Our study aimed to identify comprehensive characteristics of a local community of snow mold-causing Microdochium species colonizing a particular crop culture. By using the next-generation sequencing (NGS) technique, we characterized fungal and bacterial communities of pink snow mold-affected winter rye (Secale cereale) plants within a given geographical location shortly after snowmelt. Twenty-one strains of M. nivale were isolated, classified on the basis of internal transcribed spacer 2 (ITS2) region, and characterized by morphology, synthesis of extracellular enzymes, and virulence. Several types of extracellular enzymatic activities, the level of which had no correlations with the degree of virulence, were revealed for Microdochium species for the first time. Our study shows that genetically and phenotypically diverse M. nivale strains simultaneously colonize winter rye plants within a common area, and each strain is likely to utilize its own, unique strategy to cause the disease using “a personal” pattern of extracellular enzymes.

Key messageSnow mold resistance is a complex quantitative trait highly affected by environmental conditions during winter that must be addressed by resistance breeding.AbstractSnow mold resistance in winter cereals is an important trait for many countries in the Northern Hemisphere. The disease is caused by at least four complexes of soilborne fungi and oomycetes of whichMicrodochium nivaleandM. majusare among the most common pathogens. They have a broad host range covering all winter and spring cereals and can basically affect all plant growth stages and organs. Their attack leads to a low germination rate, and/or pre- and post-emergence death of seedlings after winter and, depending on largely unknown environmental conditions, also to foot rot, leaf blight, and head blight. Resistance in winter wheat and triticale is governed by a multitude of quantitative trait loci (QTL) with mainly additive effects highly affected by genotype × environment interaction. Snow mold resistance interacts with winter hardiness in a complex way leading to a co-localization of resistance QTLs with QTLs/genes for freezing tolerance. In practical breeding, a multistep procedure is necessary with (1) freezing tolerance tests, (2) climate chamber tests for snow mold resistance, and (3) field tests in locations with and without regularly occurring snow cover. In the future, resistance sources should be genetically characterized also in rye by QTL mapping or genome-wide association studies. The development of genomic selection procedures should be prioritized in breeding research.

Purpose. Analysis of winter rye varietal resources formation for Ukrainian producers. Results. Rye varieties (Secale cereale L.) were analyzed for a number of economically valuable traits and resistance to abiotic factors. Accor­ding to the yield data in the zones of Steppe, Forest-Steppe and Polissia, one can see that the variety of foreign selection occupies the leading place. The analyzed cultivars are early maturing, what allows to get crops in a shorter time. The State Register of Plant Varieties includes plants which were 100–140 cm in height. The mass of 1000 grains of all analyzed varieties was 32–34 g. The protein content in grains of varieties ranged from 9 to 12%. High rates of resistance to abiotic factors, such as droughts, and undesirable events like lodging and shedding, allow growing these varieties in all soil-climatic zones on the territory of Ukraine. It is worth noting that the varieties have a high resistance to powdery mildew and snow mold. The State Register of Plant Varieties includes 43 varieties of winter rye as of August 10, 2018. Varieties that are listed in the State Register of Plant Varieties suitable for distribution in Ukraine have high rates of resistance to abiotic factors, what is the basis for their inclusion in the Registry.Conclusions. A detailed study and analysis of the resistance of plant varieties to stress factors allows us to assess them thoroughly. In addition to the assessment of frost and winter resistance, drought and heat resistance of field crops, it is necessary to assess the cold resistance, resistance to winter thaws, asphyxiation, ice crust, rotting and other adverse factors. Such analysis will allow a better description of new varieties and the selection of those that in addition to high yields, are resistant to abiotic factors. In climate changes it will allow obtaining high yields of winter rye.

Insufficient yield capacity potential of varieties is one of the reasons for decrease in areas and production of winter rye grain. Creation of productive varieties adaptable to region conditions is possible with the use of modern sources of breeding-valuable traits that meet demands of growing conditions. The purpose of the research was to assess the yield capacity of 578 varieties of the world gene pool and 86 varieties of domestic selection in the conditions of the Kirov region and to select the sources of breeding-valuable traits. Studies were done in 1996-2015. During the study in collection nursery 9 varieties with yield capacity at the level of standard Falenskaya 4 (400 g/m 2 ) were selected: Zhatva, Nadezhda, Narymskaya 89 (Russian Federation); Feya (Belarus); Lira, Pallada (Ukraine); SСW 1662 (Germany); (k-11060) local (Finland); Suceava 317/76 (Romania). Nine sources of valuable traits on the density of productive plant stand (> 371 pcs./m 2 ) were selected; 15 - on ear productivity (> 19 g), 23 - on the grain size (weight of 1000 grains >36 g). The following varieties of domestic breeding have high potential of yield capacity: Purga, Tatyana, NVP-3, Pamyat' Kondratenko, Grafinya, Rushnik, Tatarskaya 1, Estafeta Tatarstana, Era, Volkhova, Roksana, Populyaciya BC, Chulpan 7, Pamyati Kunakbaeva. Heavy-productive varieties (variety Era had the maximum yield capacity - 8.28 t/ha) in some years suffer significantly or even completely die at overwintering during the period of snow mold (Microdochium nivale) epiphytoty. Varieties bred in Russia Pamyat Kondratenko, Chulpan 7, Populyaciya AC, Marusen'ka, Irina, Antares, Volna, Radon', Tatarskaya 1, Saratovskaya 6, Saratovskaya 7, Kirovskaya 89, Snezhana, and Krona can be recommended as a source of high ear productivity. Eight sources of large grains and 12 sources of grain number in an ear have been selected. Work collection of gene sources for use in modern winter rye breeding programs of the North-East breeding center has been formed.

There were studied the peculiarities of fungal diseases of triticale and spelt in the conditions of Ukrainian Polissia. It was found that Septoria leaf blotch and powdery mildew have a dominant role in the pathogenic complex of both cultures as their relative shares are 34.0 and 23.0% respectively in the complex of triticale leaf mycoses, and 52.0 and 36.0% respectively in the complex of spelt leaf mycoses. It was noted that such diseases as tan spot, brown leaf rust and snow mold rarely occurred on winter triticale plants, and such diseases as ascochyta leaf blight, spot blotch and Fusarium disease were episodic in nature. Development of tan spot and spot blotch on spelt plants had non-systematic character. It was established that on spelt wheat level of disease severity is lower and number of pathogens is less

Snow molds cause damage to plants under snow. While snow cover protects plants from freezing, it maintains darkness, humidity and low temperature. The habitat under snow characterizes the pathogens as opportunistic parasites. Plant photosynthesis is inhibited, and disease resistance decreases with time. Low temperature suppresses the activity of most microorganisms, and only low temperature-tolerant microorganisms can prevail. The most critical issue for snow molds is the duration of snow cover. They have evolved different survival strategies. Biological control is promising so far as low temperature-tolerant antagonists are introduced to the habitat under snow where diversity of active microorganisms is low and a vacant niche is available for the antagonists. Global warming certainly affects the incidence of snow molds but may not reduce snow mold damage since farmers choose to grow more productive but less winter hardy cultivars and crops. Snow molds are not only economically important but represent good materials for biological science due to their unique features.

Climate change is reducing the depth and duration of winter snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced snowpack might promote B. tectorum population growth by decreasing damage from snow molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early snowmelt and either fungicide addition or snow mold infection of B. tectorum. The greenhouse experiment confirmed that the snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and snow mold inoculation had no effect on survival. We did find interactive effects of snowmelt and fungal treatments on B. tectorum seed production: with ambient snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.

Climate change is reducing the depth and duration of winter snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced snowpack might promote B. tectorum population growth by decreasing damage from snow molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early snowmelt and either fungicide addition or snow mold infection of B. tectorum. The greenhouse experiment confirmed that the snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and snow mold inoculation had no effect on survival. We did find interactive effects of snowmelt and fungal treatments on B. tectorum seed production: with ambient snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.

Climate change is reducing the depth and duration of winter snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced snowpack might promote B. tectorum population growth by decreasing damage from snow molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early snowmelt and either fungicide addition or snow mold infection of B. tectorum. The greenhouse experiment confirmed that the snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and snow mold inoculation had no effect on survival. We did find interactive effects of snowmelt and fungal treatments on B. tectorum seed production: with ambient snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation., Climate change and biological invasions are two primary drivers of global change. They can also have interactive effects. We studied the potential for climate change to promote the growth of a destructive invasive annual grass, Bromus tectorum, by reducing snow pack and releasing the plant from snow mold infections. We found evidence that snow molds do limit seed production but not survival or overall population growth. The potential for climate change to reduce the impact of cold weather pathogens deserves further investigation.

In previous testing, we found that gray snow mold, caused by Typhula ishikariensis or T. incarnata, could be controlled by applying T. phacorrhiza onto turf grass prior to snowfall. To test for phytopathogenicity of this biocontrol agent, the five most disease-suppressive isolates were cultured on mixed grains and applied to 12 turfgrass cultivars and 2 winter wheat cultivars in December 1995 and 1996. After snow melt in April 1996 and 1997, significantly greater winter injury was visible on plots treated with the pathogens compared to T. phacorrhiza-treated plots or untreated plots. Except for one cultivar in 1996, there were no significant differences between T. phacorrhiza-treated plots and untreated plots. Pelletized alginate formulations of T. phacorrhiza containing kaolin clay with various nutritional amendments were tested for viability and efficacy. After 64 weeks of storage, viability remained >85% at -15°C and >70% at 4°C, but 2) was equivalent to using larger amounts of mixed grain inoculum (200 g/m2) or wheat bran inoculum (100 g/m2) in 2 years of field testing.

TAD1 (Triticum aestivum defensin 1) is a plant defensin specifically induced by low temperature in winter wheat. In this study, we demonstrated that TAD1 accumulated in the apoplast during cold acclimation and displayed antifungal activity against the pink snow mold fungi Microdochium nivale. When M. nivale was treated with TAD1, Congo red-stainable extracellular polysaccharides (EPS) were produced. The EPS were degradable by cellulase treatment, suggesting the involvement of β-1,4 glucans. Interestingly, when the fungus was treated with FITC-labeled TAD1, fluorescent signals were observed within the EPS layer. Taken together, these results support the hypothesis that the EPS plays a role as a physical barrier against antimicrobial proteins secreted by plants. We anticipate that the findings from our study will have broad impact and will increase our understanding of plant–snow mold interactions under snow.

Since 1995 the pathogens of genus Fusarium causing Root Rot, Snow Mold, Fusarium Head Blight of grain crops have been monitored in the Volga-Vyatka, Central, Central Chernozem and North Caucasian regions of the Russian Federation and in there were identified 15 Fusarium spp.: F. culmorum, F. heterosporum, F. sporotrichioides, F. oxysporum, F. nivale, F. graminearum, F. avenacеum, F. gibbosum, F. sambucinum, F. moniliforme, F. semitectum, F. poae, F. lateritium, F. solani, F. redolens. The high uniformity of Fusarium spp. has been revealed for the regions due to the susceptibility of crops to the soil-inhabiting micromycetes. Consistent long-term monitoring of the dynamics and frequency of occurrence of Fusarium spp. in a wide range of climatic areas has made it possible to characterize the state of the species of fungi in the regions and also to study their intraspecific and interspecific variability in toxicity and pathogenicity depended on biotic and abiotic factors. The prevalence of Fusarium spp. in t...

Snow mold fungus, Typhula ishikariensis , secretes seven antifreeze protein isoforms (denoted Tis AFPs) that assist in the survival of the mold under snow cover. Here, the X-ray crystal structure of a hyperactive isoform, Tis AFP8, at 1.0 A resolution is presented. Tis AFP8 folds into a right-handed β-helix accompanied with a long α-helix insertion. Tis AFP8 exhibited significantly high antifreeze activity that is comparable with other hyperactive AFPs, despite its close structural and sequence similarity with the moderately active isoform Tis AFP6. A series of mutations introduced into the putative ice-binding sites (IBSs) in the β-sheet and adjacent loop region reduced antifreeze activity. A double-mutant A20T/A212S, which comprises a hydrophobic patch between the β-sheet and loop region, caused the greatest depression of antifreeze activity of 75%, when compared with that of the wild-type protein. This shows that the loop region is involved in ice binding and hydrophobic residues play crucial functional roles. Additionally, bound waters around the β-sheet and loop region IBSs were organized into an ice-like network and can be divided into two groups that appear to mediate separately Tis AFP and ice. The docking model of Tis AFP8 with the basal plane via its loop region IBS reveals a better shape complementarity than that of Tis AFP6. In conclusion, we present new insights into the ice-binding mechanism of Tis AFP8 by showing that a higher hydrophobicity and better shape complementarity of its IBSs, especially the loop region, may render Tis AFP8 hyperactive to ice binding.

During May and June of 2006, ‘Lapins’ sweet cherry (Prunus avium) trees were observed with white fungal growth on blossoms and young fruit in two commercial orchards in central Oregon (Wasco County). Entire blossom clusters and 30% of fruit clusters were affected. Rot on the fruit was firm, light brown, and covered the entire fruit, extending halfway down the pedicel. Affected blossoms were light brown and stuck to adjacent fruit and blossoms. Six disease samples from fruit, four samples from pedicels, and four samples from blossoms were surface sterilized and plated on potato dextrose agar acidified with lactic acid ([APDA] 1.5%). A white fungus producing sclerotia measuring 4 to 8 mm in diameter was recovered from all the samples after 10 days on APDA at 25°C. Koch's postulates were satisfied by inoculating green, pea-sized ‘Lapins’ cherry fruit with mycelial plugs colonized by the white fungus. Symptoms and signs similar to those seen in the orchard were produced. The same sclerotium-producing fungus was recovered from all inoculated fruit. The pathogen was identified as Sclerotinia sclerotiorum (Lib.) de Bary on the basis of the size of sclerotia and nested PCR using fungal universal primer pair ITS4/ITS5 and S. sclerotiorum-specific primer pair SSFWD/SSREV (2). A negative control, devoid of DNA templates in the reaction mix, was included in the PCR assay. S. sclerotiorum is endemic on wheat in Wasco County. The affected orchards were surrounded by wheat fields in which snow mold disease that is caused by S. sclerotiorum was particularly serious in the spring of 2006 compared with previous years. Rot on cherries was first observed and very severe in May of 2005, with symptoms and signs mainly on leaves of all trees across 45 ha. New symptoms continued to appear on cherry until mid-June. During 2006, most symptoms and signs were on fruit with some leaf spotting. Both years had unusually wet springs with 12.2 cm of rainfall received from April to June 2005 and 12.4 cm from April to June 2006, which is well above the 6.81 cm average for the previous 5 years. S. sclerotiorum causes green fruit rot of stone fruits, including almond, apricot (3), nectarine, and peach (1). To our knowledge, this is the first report of S. sclerotiorum causing blossom blight and green fruit rot on sweet cherry in Oregon. References: (1) K. M. Flint. Green fruit rot. Page 15 in: Compendium of Stone Fruit Diseases. The American Phytopathological Society. St. Paul, MN, 1995. (2) J. Freeman et al. Eur. J. Plant Pathol. 108:877, 2002. (3) R. E. Smith. Phytopathology 31:407, 1931.

Typhula incarnata, the causal agent of gray snow mold, is an important winter pathogen of turfgrasses in the northern United States. The relative susceptibility of cultivars of three bent-grass species (creeping, colonial, and velvet bentgrass) to Typhula incarnata and the aggressiveness of 15 T. incarnata isolates obtained from infected turfgrasses on golf courses in Michigan, Minnesota, and Wisconsin were evaluated under controlled conditions. A hypersensitive type of resistance response to T. incarnata was not observed in any cultivar. Disease severity increased with higher inoculum concentration of T. incarnata. Colonization by gray snow mold gradually decreased with increasing plant age from 11 weeks after seeding in most cultivars tested, suggesting that age-related resistance was expressed over time. There were significant differences in disease severity among the three bentgrass species, particularly between tetraploid (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating varying levels of susceptibility to T. incarnata. All 15 isolates were pathogenic on bentgrass and were significantly different in aggressiveness, but aggressiveness was not related to geographic origin. Therefore, turfgrass breeders should be able to use one or a few virulent representative isolates of the pathogen to screen for resistance.

Speckled snow mold, caused by Typhula ishikariensis, is one of the most important Typhula snow molds in subarctic zones of the Northern Hemisphere. Nine isolates of three T. ishikariensis varieties (var. ishikariensis, var. canadensis, and var. idahoensis) isolated from infected turfgrasses on golf course fairways throughout Wisconsin were evaluated for their aggressiveness toward nine cultivars of three bentgrass species (three creeping, three colonial, and three velvet cultivars) under controlled environmental conditions. Speckled snow mold severity increased as inoculum concentration of T. ishikariensis was increased. In general, bentgrass susceptibility increased between 9 and 11 weeks after seeding but gradually decreased thereafter, suggesting expression of age-related resistance as plants matured. Significant differences in aggressiveness were detected within and among T. ishikariensis varieties. Significant interactions between T. ishikariensis varieties or isolates and bentgrass species were detected, but there was no interaction between pathogen isolates and bentgrass cultivars. Disease severity evaluations showed significant differences among bentgrass cultivars and species in their response to T. ishikariensis. Since bentgrass species exhibit differential responses to T. ishikariensis varieties, representative isolates of each variety should be employed for screening of bentgrass germplasm for resistance to speckled snow mold.

Nishio, Z., Iriki, N., Takata, K., Ito, M., Tabiki, T., and Murray, T. D. 2008. Influence of coldhardening and soil matric potential on resistance to speckled snow mold in wheat. Plant Dis. 92:1021-1025. The influence of soil matric potential, cold-hardening temperature, and duration on resistance to speckled snow mold caused by Typhula ishikariensis in wheat was investigated. Six winter wheat lines were subjected to cold-hardening temperatures of 2 or 4°C for 1, 2, 3, or 4 weeks with soil matric potential of –0.1 or –0.01 MPa. Plants were inoculated with T. ishikariensis after cold-hardening, incubated at 10°C for 25 days in the dark, and then evaluated for regrowth. Overall recovery from snow mold was least when plants were hardened at 2°C for 1 week at –0.01 MPa and greatest when hardened at 4°C for 4 weeks at –0.1 MPa. Survival of plants following snow mold was greater when plants were cold-hardened at 4 than at 2°C and at –0.1 than –0.01 MPa soil matric potential. The greatest difference in survival among lines and correlation with field observations occurred when plants were hardened at 4°C at –0.1 MPa matric potential for 3 weeks. Understanding the influence of temperature and soil matric potential during coldhardening on speckled snow mold resistance will be useful to breeding programs developing snow-mold-resistant cultivars under controlled environment conditions.

Creeping bentgrass (Agrostis stolonifera) is the primary species used on golf courses in temperate regions but requires prophylactic fungicide treatment to prevent snow mold diseases. We hypothesized that fine fescues (Festuca spp.) and colonial bentgrass (A. capillaris) have superior resistance to snow mold diseases compared with creeping bentgrass. Our objective was to compare the resistance of fine fescues, colonial bentgrass, and creeping bentgrass to snow mold diseases caused by Microdochium nivale and Typhula spp. Field plots were established in two separate years on fairways of three golf courses in Wisconsin to encompass the geographic distribution of snow mold pathogens. The experimental design was a split-split-split plot arrangement with three replications. Whole plots were pathogen species, host genus were subplots, host cultivars were sub-subplots, and inoculated versus noninoculated treatments were sub-sub-subplots. Plots were visually evaluated each spring for disease, turf quality, and Poa annua infestation. Data were analyzed using planned contrasts. Inoculation effects depended on pathogen type and location. Creeping bentgrass always had the most snow mold damage. Fine fescues had less snow mold damage than colonial bentgrass except for one year–location but did not provide acceptable year-long turf quality due to P. annua invasion.

Rye is a robust and stress-tolerant cereal, grown on 4.4 million hectares, mainly in Northeastern Europe. Grain yields range, on average, from 2.0 to 5.8 mt ha−1 on farm level depending on the country, but reached >10 mt ha−1 in multi-locational official trials in Germany. Rye grain is used for bread making, distilling, homegrown feed and bioenergy production. Hybrid breeding has gained much attention caused by higher grain yields and a higher gain from selection compared to open-pollinated cultivars. Prerequisites are self-fertility, cytoplasmic-male sterility (CMS) with effective nuclear encoded genes to restore fertility (Rf) and distinct heterotic pools. Elaborated breeding plans are available. Commercial rye hybrids are crosses between a CMS single cross as seed parent and a restorer synthetic as pollinator. Molecular breeding was promoted in the last decade by the availability of PCR-based markers and the production of medium- to high-density single nucleotide polymorphism (SNP) assays. Markers are used for introgressing monogenic traits, developing landscapes of quantitative trait loci (QTL), and genomic selection. In the future, disease resistances to snow mold, stem rust, and Fusarium head blight, resilience to drought and heat stress, optimized feeding quality and yield improvement by broadening the genetic basis of hybrid breeding are important goals.

In northern regions, winter wheat (Triticum aestivum L.) accumulates fructan during cold-acclimation in autumn and freeze-acclimation in early winter. The content of fructan in wheat crown tissues is associated with both freezing tolerance and snow mold resistance, and expression levels of fructan synthesis genes in leaf and crown tissue are correlated with both changes and varietal differences in fructan accumulation levels of wheat during cold- and freeze-acclimation. Fructan hydrolysis activity has also been thought be involved in wintering ability of wheat. Since several kinds of gene homologs encoding fructan exohydrolase (FEH: EC. 3.2.1.153, 154) with different substrate specificities have recently been cloned from wheat, changes in transcript levels of wheat FEH genes in field-grown wheat cultivars from autumn to spring were analyzed to investigate regulation of seasonal changes in fructan content. The seasonal expression patterns of five genes encoding 1-FEH, 6-FEH (and Wfh-sm3), 6&1-FEH and 6-KEH (kestose exohydrolase) varied. Among the five genes, only seasonal changes in the expression of wfh-sm3, which codes an enzyme that is able to hydrolyze almost all components of fructan that has accumulated in hardened wheat tissues, were correlated with those changes in fructan contents. Moreover, the transcript levels of wfh-sm3 were low in snow mold-resistant cultivars that accumulate high levels of fructan. The transcript levels of 6-FEH increased with decrease in ambient temperatures and the levels decreased under snow. The analysis indicated that cooperative expression of 6-FEH and 1-FEH genes might be related to the seasonal changes and varietal difference in mono- and disaccharide contents. This study showed that the coordinated expression of FEH genes in wheat was related to the regulation of water-soluble carbohydrate accumulation from autumn to early winter and fructan consumption under snow cover as well as energy supply and that wheat FEHs also play an important role in the varietal difference in freezing tolerance and snow mold resistance. In particular, the expression of wfh-sm3 may regulate fructan metabolism associated with tolerance for wintering stresses.

Typhula ishikariensis Imai is a causal agent of Typhula snow mold, one of the most important turfgrass diseases in northern regions of the United States. Within Wisconsin isolates, there are three district groups clustered with known isolates of T. ishikariensis var. ishikariensis, var. canadensis and var. idahoensis as identified by RAPD markers. To further investigate the genetic relationship among these groups (varieties), monokaryon-monokaryon and dikaryon-monokaryon mating experiments were conducted. Mating types from var. ishikariensis, var. canadensis and var. idahoensis isolates were paired in all possible combinations. Pairings between var. canadensis and var. idahoensis were highly compatible, while no compatibility was detected between var. ishikariensis and either var. canadensis or var. idahoensis. These results indicate that var. ishikariensis is genetically separated from var. canadensis and var. idahoensis, whereas var. canadensis and var. idahoensis appeared to be genetically related to each other as a taxonomic unit. In the genetic relationship with the known biological species, var. ishikariensis and var. canadensis were genetically related to biological species I and II, respectively. However, var. idahoensis was not compatible with any of the biological species, suggesting that the pathogen may be in the process of biological speciation from var. canadensis.

We examined three specimens of sclerotia from Tashkent Province, Uzbekistan collected in April 1957. Phylogenetic results suggested that the collected fungi were highest homology (98.0%) to snow mold, Typhula sp. in Iran. Rind cells of collected fungi were lobate and gently rough closely morphologically similar to Typhula subvariabilis.

It is a goal of the turf industry to reduce fungicide use, maximize fungicide efficacy, and minimize the risk of fungicide resistance. Based on these integrated pest management principles and curre...

Microdochium majus and Microdochium nivale are two of fungal pathogens that cause Fusarium head blight (FHB) in wheat, and have also caused pink snow mold in eastern Hokkaido, Japan. With the aim of assessing levels of genetic variation and population structure, 172 isolates of these Microdochium species obtained from five populations of infected wheat seeds were first classified into each species using polymerase chain reaction (PCR) amplification with specific primers. In total 165 (95.9 % of all isolates) and seven isolates (six of Tokachi populations and one of Abashiri populations) were identified as M. majus and M. nivale, respectively, indicating that M. majus was predominant and the main causal pathogen of FHB in this area. Inter-simple sequence repeat (ISSR) analysis showed that the total genetic diversity was 0.023 when estimated by Nei's gene diversity index within the five populations dominated by M. majus. An AMOVA analysis also showed that 86.74 % of the total genetic variation was within populations and 13.26 % among populations. These results indicated that little genetic differentiation occurred among the five populations of M. majus. Based on the unweighted pair group method of cluster analysis using the ISSR data, all isolates were identified as one of eight haplotypes in M. majus or six haplotypes in M. nivale, allowing the construction of a dendrogram with two clades corresponding to each species. There was no correlation between the clustering of isolates and their geographic distribution on the tree. These findings show that migration is likely playing an important role in the population biology of M. majus, providing some support for the prediction of epidemics of fungicide resistant strains within populations of the FHB pathogen.

Metabolism of fructans in temperate grasses dynamically fluctuates before and during winter and is involved in the overwintering activity of plants. We monitored three candidate factors that may be involved in seasonal fructan metabolism in timothy (Phleum pratense): transcription levels of two fructosyltransferase (PpFT1 and PpFT2) genes and one fructan exohydrolase (Pp6-FEH1) gene during fall and winter and under artificially cold conditions. Functional analysis using a recombinant enzyme for PpFT2, a novel fructosyltransferase cDNA, revealed that it encoded sucrose:fructan 6-fructosyltransferase, with enzymatic properties different from previously characterized PpFT1. PpFT1 transcripts decreased from September to December as the amount of fructans increased, whereas PpFT2 transcripts increased in timothy crowns. PpFT2 was transcriptionally more induced than PpFT1 in response to cold and sucrose in timothy seedlings. A rapid increase in Pp6-FEH1 transcripts and increased monosaccharide content were observed in timothy crowns when air temperature was continuously below 0°C and plants were not covered by snow. Transcriptional induction of Pp6-FEH1 by exposure to -3°C was also observed in seedlings. These findings suggest Pp6-FEH1 involvement in the second phase of hardening. PpFT1 and PpFT2 transcription levels decreased under snow cover, whereas Pp6-FEH1 transcription levels were constant, which corresponded with the fluctuation of fructosyltransferase and fructan exohydrolase activities. Inoculation with snow mold fungi (Typhula ishikariensis) increased Pp6-FEH1 transcription levels and accelerated hydrolysis of fructans. These results suggest that transcriptional regulation of genes coding fructan metabolizing enzymes is partially involved in the fluctuation of fructan metabolism during cold acclimation and overwintering.

Oomyceteous snow molds, Pythium species, were reported to be less tolerant to chilling and freezing temperatures than other snow mold taxa. However, Pythium species are often found to be pathogenic on mosses in Polar Regions. We investigated the frost resistance of Pythium species from Temperate (Hokkaido, Japan) and Subantarctic Regions. Free mycelia and hyphal swellings, structures for survival, of Pythium iwayamai and Pythium paddicum lost viability within freeze-thaw 3 cycles; however, mycelia in host plants survived the treatment. It was reported that fungi in permafrost are characterized both by the presence of natural cryoprotectants in these ecotopes and by the ability to utilize their inherent mechanisms of protection. It is conceivable that plant substrates or derivatives thereof are natural cryoprotectants, enabling them to provide advantageous conditions to microorganisms under freezing conditions. Our results are the first to experimentally support this hypothesis.

Plants grown through the winter are subject to selective pressures that vary with each year’s unique conditions, necessitating tolerance of numerous abiotic and biotic stress factors. The objective of this study was to identify molecular markers in winter wheat (Triticum aestivum L.) associated with tolerance of two of these stresses, freezing temperatures and snow mold—a fungal disease complex active under snow cover. A population of 155 F2:5 recombinant inbred lines from a cross between soft white wheat cultivars “Finch” and “Eltan” was evaluated for snow mold tolerance in the field, and for freezing tolerance under controlled conditions. A total of 663 molecular markers was used to construct a genetic linkage map and identify marker-trait associations. One quantitative trait locus (QTL) associated with both freezing and snow mold tolerance was identified on chromosome 5A. A second, distinct, QTL associated with freezing tolerance also was found on 5A, and a third on 4B. A second QTL associated with snow mold tolerance was identified on chromosome 6B. The QTL on 5A associated with both traits was closely linked with the Fr-A2 (Frost-Resistance A2) locus; its significant association with both traits may have resulted from pleiotropic effects, or from greater low temperature tolerance enabling the plants to better defend against snow mold pathogens. The QTL on 4B associated with freezing tolerance, and the QTL on 6B associated with snow mold tolerance have not been reported previously, and may be useful in the identification of sources of tolerance for these traits.

In response of fungicides for control of gray snow mold, isolates of Typhula incarnata were collected from three golf courses in 2012 Yongpyeong, Korea and tested for sensitivity to propiconazole, tebuconazole and azoxystrobin fungicides. Four discriminatory concentrations were used to detect in vitro sensitivity of 50 isolates. Mean 50% effective concentration inhibiting mycelial growth () values for tebuconazole was the lowest among the three fungicides. The value of tebuconazole ranged from 0.0005 to 0.014 with a mean of 0.0048 . The mean values of propiconazole in triazole family was 0.5825 (0.78-1.651) . value of azoxystrobin ranged from 0.0017 to 0.131 with a mean of 0.0278 . There was no correlation among values for propiconazole, azoxystrobin and tebuconazole indicating no cross-resistance relationships with each other. Results of this study were confirmed no resistance isolates in vitro sensitivity of T. incarnata of three fungicides in Yongpyeong.

Antifreeze proteins (AFPs) are found in organisms ranging from fish to bacteria, where they serve different functions to facilitate survival of their host. AFPs that protect freeze-intolerant fish and insects from internal ice growth bind to ice using a regular array of well-conserved residues/motifs. Less is known about the role of AFPs in freeze-tolerant species, which might be to beneficially alter the structure of ice in or around the host. Here we report the 0.95-Å high-resolution crystal structure of a 223-residue secreted AFP from the snow mold fungus Typhula ishikariensis . Its main structural element is an irregular β-helix with six loops of 18 or more residues that lies alongside an α-helix. β-Helices have independently evolved as AFPs on several occasions and seem ideally structured to bind to several planes of ice, including the basal plane. A novelty of the β-helical fold is the nonsequential arrangement of loops that places the N- and C termini inside the solenoid of β-helical coils. The ice-binding site (IBS), which could not be predicted from sequence or structure, was located by site-directed mutagenesis to the flattest surface of the protein. It is remarkable for its lack of regularity and its poor conservation in homologs from psychrophilic diatoms and bacteria and other fungi.

Creeping bentgrass (Agrostis stolonifera L.) is the most widely cultivated and high-value turfgrass species. Genetic linkage maps of creeping bentgrass were constructed for quantitative trait loci (QTL) analysis of gray snow mold (Typhula incarnata) resistance, recovery and leaf width. A segregating population of 188 pseudo-F2 progeny was developed by two-way pseudo-testcross mapping strategy. Amplified fragment length polymorphism, new developed Agrostis specific expressed sequence tag-single sequence repeat (SSR), random amplified polymorphic DNA and genomic SSR markers corresponding to DNA polymorphisms heterozygous in one parent and null in the other, were scored and placed on two separate genetic linkage maps, representing each parent. In the male parent map, 100 markers were mapped to 14 linkage groups covering a total length of 793 cM with an average interval of 8.2 cM. In the female parent map, 146 markers were clustered in another 14 linkage groups spanning 805 cM with an average distance of 5.9 cM between adjacent markers. We identified three putative QTL for leaf width and one QTL for snow mold disease resistance. The construction of a linkage map and QTL analysis are expected to facilitate the development of disease resistant creeping bentgrass cultivars by using molecular marker-assisted selection.

Pink snow mold, caused by Microdochium nivale, is a major disease on cool season turfgrasses in golf courses in northern Unites States. The relative susceptibility of 17 commercial cultivars of three bentgrass species (creeping, colonial and velvet bentgrass) to Microdochium nivale and the aggressiveness of M. nivale eight isolates obtained from infected turfgrasses on golf courses in Wisconsin were evaluated under controlled conditions. For the field trial, susceptibility of 2 year-old 12 commercial bentgrass cultivars was evaluated after inoculating three M. nivale isolates in the fields. There were significant differences in disease severities among the three bentgrass species, particularly between tetraploids (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating that there are varying levels of susceptibility in species and cultivars to M. nivale. Host resistance by days of cold hardening was confirmed, by detecting the resistance by 30 days of cold hardening treatments. In field trial, susceptibility of 12 bentgrass cultivars was highly correlated to the results obtained from growth chamber experiments. The positive correlation of the susceptibility between growth chamber experiments and field trials demonstrates that the growth chamber method is a useful technique for saving time, space and labor to evaluate efficiently pink snow mold susceptibility of bentgrass cultivars. This study could be applied to evaluating susceptibility of bentgrass to pink snow mold and also predicting a prospective evaluation of bentgrass cultivars to pink snow mold in fields in a breeding program.

In autumn, winter wheat and temperate forage grasses, such as orchardgrass, timothy, and perennial ryegrass, accumulate fructan, which is a kind of fructose-based oligo- and polysaccharide. The fructan content in their crown tissue reaches more than 30% of their dry weight before snow cover, and this increase in fructan content is associated with both the freezing tolerance and the snow mold resistance of winter crops in the northern region of Japan. These crops mainly accumulate the β(2,6)-linked levan type of fructan, and their structure and composition vary among wheat and grasses. We cloned several kinds of genes encoding fructosyltransferase and fructan exohydrolase from these plants, and analysis of the expression of fructosyltransferase revealed varietal differences in wheat under field conditions and low-temperature responses in grasses. Further investigation of the control of fructan metabolism through molecular biology and genetics should lead to the development of methods for improving the over-wintering ability of these crops.

Despite their close association with human activities, plant pathogenic fungi have rarely been found in archaeological excavations. We report here that a fungus was closely associated with human activities even in prehistoric times. Sclerotium-like objects were found at historical sites (4000 to 400 BP) on the island of Hokkaido, northern Japan. They were spherical, 0.3-1.0 mm in diameter, and had a medulla and rind. Some had leaf fragments on the surface or a protuberance that resembled emerging sporocarp primordia. These traits indicated that they were sclerotia of the snow mold fungus, Typhula ishikariensis biotype B.

The snow mold fungus, Sclerotinia borealis, shows optimal growth at 4°C on potato dextrose agar (PDA) and can grow even at subzero temperature. Its mycelial growth was improved on frozen PDA at −1°C and on PDA containing potassium chloride (KCl) (water potential, −4.27 to −0.85 MPa) or d(−) sorbitol (−3.48 to −0.92 MPa). Its optimal growth temperature shifted from 4 to 10°C on PDA amended with KCl or sorbitol, indicating that inherent optimal growth occurs at high temperatures. These results suggest that S. borealis uses concentrated nutrients in the frozen environment and that such physiologic characteristics are critical for the fungus to prevail at subzero temperatures.

To clarify relationships among factors associated with winter stress in orchardgrass (Dactylis glomerata L.), water-soluble carbohydrate (WSC) concentration, resistance to snow mold, and tolerance to prolonged snow cover were evaluated under both conditions of natural infection and chemical control of snow mold. A total of 18 cultivars from Japan, Europe, and the United States were transplanted into the field at Hokkaido in October 2003 and 2004. Crown samples were collected before the start of snow cover in fall and after melting of the snow in spring and were analyzed for WSC concentration. The total WSC concentration of cultivars originating in cold regions was higher in spring than that of cultivars originating in warm regions. The WSC concentration in fall was not correlated with tolerance to prolonged snow cover and resistance to snow mold. Otherwise, WSC concentration in spring was significantly correlated with spring regrowth and resistance to snow mold. Although dry wt. in the fall was negatively correlated with spring regrowth and snow mold resistance, it was not correlated with tolerance to prolonged snow cover. WSC concentration of crown tissues in spring should be an important selection criterion for a superior winter-hardy cultivar with rapid regrowth in spring. Cultivars that show both more fall growth and better tolerance to prolonged snow cover could be used in crosses with winter-hardy cultivars to increase forage yield in the fall.

Fungi have developed a variety of mechanisms for tolerating cold, including production of proteins that bind to ice, as shown by their ability to slightly lower the freezing point. At present, only one of these proteins, from the snow mold Typhula ishikariensis, and partial transcripts of a similar protein from shiitake mushroom, Lentinula edodes, have been identified. Here, we report the full sequences of ice-binding proteins from shiitake and another mushroom, the cold-adapted Flammulina populicola (enoki mushroom), and show that the recombinant proteins have ice-binding activity. The three proteins share 50-55% identities and are similar to other ice-binding proteins recently identified in ice bacteria and sea ice diatoms. The possibility that ice-binding protein genes have spread among these phyla by horizontal transfer is discussed.