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Background: Snow mold caused by different psychrophilic phytopathogenic fungi is a devastating disease of winter cereals. The variability of the snow mold pathocomplex (the quantitative composition of snow mold fungi) has not been evaluated across different crops or different agrocenoses, and no microbial taxa have been predicted at the whole-microbiome level as potential effective snow mold control agents. Our study aimed to assess the variability of the snow mold pathocomplex in different winter cereal crops (rye, wheat, and triticale) in different agrocenoses following the peak disease progression and to arrange a hierarchical list of microbial taxa predicted to be the main candidates to prevent or, conversely, stimulate the development of snow mold pathogens. Results: The variability of microbiomes between different crops within a particular agrocenosis was largely determined by fungal communities, whereas the variability of microbiomes of a particular crop in different agrocenoses was largely determined by bacterial communities. The snow mold pathocomplex was the most "constant" in rye, with the lowest level of between-replicate variability and between-agrocenoses variability and (similar to the triticale snow mold pathocomplex) strong dominance of Microdochium over other snow mold fungi. The wheat snow mold pathocomplex was represented by different snow mold fungi, including poorly investigated Phoma sclerotioides. To predict snow mold-control microorganisms, a conveyor of statistical methods was formed and applied; this conveyor enables considering not only the correlation between the abundance of target taxa and a phytopathogen but also the stability and fitness of taxa within plant-associated communities and the reproducibility of the predicted effect of taxa under different conditions. This conveyor can be widely used to search for biological agents against various plant infectious diseases. Conclusions: The top indicator microbial taxa for winter wheat and rye following the winter period were Ph. sclerotioides and Microdochium, respectively, both of which are causal agents of snow mold disease. Bacteria from the Cellulomonas, Lechevalieria, and Pseudoxanthomonas genera and fungi from the Cladosporium, Entimomentora, Pseudogymnoascus, and Cistella genera are prime candidates for testing their plant-protective properties against Microdochium-induced snow mold disease and for further use in agricultural practice. [ABSTRACT FROM AUTHOR]

The paper reveals the causes and consequences of unfavorable conditions for overwintering of winter grain crops on the example of the Moscow region. Unstable winter periods in the recent decades resulting from climate change have often led to the damage or loss of winter grain crops (winter wheat, winter rye, and triticale). Using the difference integral curve of average annual temperatures for the entire year, the growing season (May–September), and the period from September to April, including the winter season, it is shown that warm years and warm seasons have been generally observed since 1987. The sum of negative temperatures, snow depth, frost depth, the number of days with snow cover, the duration of cold periods with air temperatures below 0, –5, –10°C, etc. are analyzed for assessment of the changes in overwintering conditions. [ABSTRACT FROM AUTHOR]

Abstract Pink snow mold, caused by a phytopathogenic and psychrotolerant fungus, Microdochium nivale, is a severe disease of winter cereals and grasses that predominantly occurs under snow cover or shortly after its melt. Snow mold has significantly progressed during the past decade, often reaching epiphytotic levels in northern countries and resulting in dramatic yield losses. In addition, M. nivale gradually adapts to a warmer climate, spreading to less snowy territories and causing different types of plant diseases throughout the growing period. Despite its great economic importance, M. nivale is poorly investigated; its genome has not been sequenced and its crucial virulence determinants have not been identified or even predicted. In our study, we applied a hybrid assembly based on Oxford Nanopore and Illumina reads to obtain the first genome sequence of M. nivale. 11,973 genes (including 11,789 protein-encoding genes) have been revealed in the genome assembly. To better understand the genetic potential of M. nivale and to obtain a convenient reference for transcriptomic studies on this species, the identified genes were annotated and split into hierarchical three-level functional categories. A file with functionally classified M. nivale genes is presented in our study for general use. M. nivale gene products that best meet the criteria for virulence factors have been identified. The genetic potential to synthesize human-dangerous mycotoxins (fumonisin, ochratoxin B, aflatoxin, and gliotoxin) has been revealed for M. nivale. The transcriptome analysis combined with the assays for extracellular enzymatic activities (conventional virulence factors of many phytopathogens) was carried out to assess the effect of host plant (rye) metabolites on the M. nivale phenotype. In addition to disclosing plant-metabolite-upregulated M. nivale functional gene groups (including those related to host plant protein destruction and amino acid metabolism, xenobiotic detoxication (including phytoalexins benzoxazinoids), cellulose destruction (cellulose monooxygenases), iron transport, etc.), the performed analysis pointed to a crucial role of host plant lipid destruction and fungal lipid metabolism modulation in plant-M. nivale interactions.

Pink snow mold, caused by a phytopathogenic and psychrotolerant fungus, Microdochium nivale, is a severe disease of winter cereals and grasses that predominantly occurs under snow cover or shortly after its melt. Snow mold has significantly progressed during the past decade, often reaching epiphytotic levels in northern countries and resulting in dramatic yield losses. In addition, M. nivale gradually adapts to a warmer climate, spreading to less snowy territories and causing different types of plant diseases throughout the growing period. Despite its great economic importance, M. nivale is poorly investigated; its genome has not been sequenced and its crucial virulence determinants have not been identified or even predicted. In our study, we applied a hybrid assembly based on Oxford Nanopore and Illumina reads to obtain the first genome sequence of M. nivale. 11,973 genes (including 11,789 protein-encoding genes) have been revealed in the genome assembly. To better understand the genetic potential of M. nivale and to obtain a convenient reference for transcriptomic studies on this species, the identified genes were annotated and split into hierarchical three-level functional categories. A file with functionally classified M. nivale genes is presented in our study for general use. M. nivale gene products that best meet the criteria for virulence factors have been identified. The genetic potential to synthesize human-dangerous mycotoxins (fumonisin, ochratoxin B, aflatoxin, and gliotoxin) has been revealed for M. nivale. The transcriptome analysis combined with the assays for extracellular enzymatic activities (conventional virulence factors of many phytopathogens) was carried out to assess the effect of host plant (rye) metabolites on the M. nivale phenotype. In addition to disclosing plant-metabolite-upregulated M. nivale functional gene groups (including those related to host plant protein destruction and amino acid metabolism, xenobiotic detoxication (including phytoalexins benzoxazinoids), cellulose destruction (cellulose monooxygenases), iron transport, etc.), the performed analysis pointed to a crucial role of host plant lipid destruction and fungal lipid metabolism modulation in plant-M. nivale interactions. [ABSTRACT FROM AUTHOR]

Traditionally, the main strategic crop for the Russian Federation is winter cereals, therefore, the snow cover regime is of great importance for their cultivation. In the second decade of April 2021, after the snow cover disappeared on the experimental fields of Russian State Agrarian University, severe damage and partial death of winter triticale from the disease pink snow mold was noted. Measurements of the parameters of the snow cover in the period 2001–2021 showed that in the winter and spring of 2021 on the territory of Moscow the characteristics of the snow cover regime were close to agrometeorological Hazardous Phenomena standards on the territory of the Russian Federation. The risk of developing pink snow mold is directly related to the snow cover regime. Analysis of the dynamics of the characteristics of the snow cover according to the data of the Meteorological Observatory V.A. Michelson for 30 years has made it possible to propose a simple quantitative assessment of the risk of damping of winter crops. Over the past 20 years, the necessary conditions for the development of snow mold in winter cereals took place in 2010/11, 2012/13, 2017/18 and 2020/21. Analysis of the data on the early establishment of snow cover over the past 30 years shows that this factor is gradually losing its relevance due to the pronounced trend of its retardation. There is a noticeable tendency for an increase in the frequency of extremely late periods of formation of stable snow cover up to the second – third decade of January. During the study period, this phenomenon was observed in 2006 (January 20), 2013 (January 12) and 2019 (January 23). The proposed empirical function of the probability of snow cover formation, depending on the calendar date, can be recommended for assessing risks when making agronomic decisions (timing of sowing winter cereals and harvesting other crops). Freezing of crops has not been observed over the past 30 years.

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. [ABSTRACT FROM AUTHOR]

Typhula ishikariensis and the related fungi were separated into three biological species by morphological and physiological characteristics, as well as DNA sequences and mating reactions. We propose that the T. ishikariensis complex should be divided into three species (T. ishikariensis, T. canadensis and T. hyperborea) and two varieties (T. ishikariensis var. ishikariensis and var. idahoensis). Typhula hyperborea was reappraised to be recognized also as a separate species of the T. ishikariensis complex. [ABSTRACT FROM AUTHOR]

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.

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 molds are an important group of diseases of amenity turfgrass in temperate climates. Acceptable control is typically achieved through one or two fungicide applications prior to snow cover, though there is increasing interest in exploring alternative control products such as iron sulfate and/or potassium phosphite. Previous research has demonstrated that poor snow mold control is achieved when these alternative products are applied once prior to snow cover, so the objective of this study was to assess their efficacy when applied repeatedly throughout the fall. Iron sulfate heptahydrate, potassium phosphite, and the fungicide propiconazole were applied six times, every 2 weeks, throughout the fall of 2019 at three locations in Wisconsin that typically produce high, medium, and low snow mold pressure. No reduction in disease relative to the nontreated control was observed at any location in response to the iron sulfate and potassium phosphite treatments. Propiconazole did provide effective snow mold control at the low and moderate pressure locations but not at the high pressure location. Both iron sulfate and potassium phosphite have shown efficacy against select turfgrass diseases, but do not appear to provide control of snow mold in areas where snow cover persists during winter. Core Ideas: Demand is increasing for alternative, nonfungicidal snow mold control strategies.Repeated applications of iron sulfate and potassium phosphite during the fall failed to suppress snow mold at three locations in Wisconsin.Repeated applications of propiconazole did provide effective control in low and moderate disease pressure environments, providing a potential control strategy for locations with few fungicides available. [ABSTRACT FROM AUTHOR]

Turfgrass managers rely on fungicides to suppress snow mold diseases in areas with persistent snow cover, which are commonly applied once or twice in late fall prior to snow cover. Fungicide applications targeting snow mold are expected to control snow mold diseases for the duration of winter; however, climate change is increasing the frequency of winter rainfall and snowmelts and may alter the duration of snow mold control. A 3-year study was conducted in Madison, WI, to assess the impact of snow cover and antitranspirants on the persistence of the commonly used fungicides chlorothalonil and propiconazole. Snow cover, fungicide treatment, and the use of antitranspirants had minimal impacts on fungicide persistence and disease control. The most important factors influencing persistence of the fungicides were snowmelt and winter rainfall events, yet antitranspirants demonstrated modest evidence of extending chlorothalonil persistence in certain years. These results demonstrate that increasing snowmelt and winter rainfall events associated with climate change will increase dissipation of fungicides used for snow mold suppression, which will likely impact disease control.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.

Shoots of Calluna vulgaris, Erica carnea, Juniperus communis subsp. nana, Picea abies, and Pinus mugo subsp. mugo covered with felty, melanized epiphytic mycelia typical for brown felt blight caused by Herpotrichia pinetorum were collected at several locations in the Swiss Alps. Most cultures prepared from the mycelia on J. communis subsp. nana and P. abies were H. pinetorum, whereas the majority of cultures from P. mugo subsp. mugo and C. vulgaris were identified by internal transcribed spacer ITS1-5.8S-ITS2 sequencing and morphology as Allantophomopsis cytisporea. The fungus tolerates low temperatures, has an optimum between 16°C and 24°C, and ceases to grow at 28°C. 35°C is lethal. A. cytisporea is known as the causal agent of cranberry black rot on Vaccinium macrocarpon but has never been described as a snow mold. A. cytisporea is an endophyte in C. vulgaris but seems able to kill leaflets and whole shoots during winter. The epiphytic mycelium can expand from C. vulgaris to neighboring shoots of P. mugo subsp. mugo and J. communis subsp. nana below the snow where it forms epiphytic mycelial mats reminiscent of H. pinetorum. H. pinetorum has a strong antibiotic effect against A. cytisporea at 4°C and 20°C, whereas A. cytisporea grows faster at these temperatures. The effects of climate change on the interaction between the two snow mold fungi and their consequences on regeneration of woody plants at timberline are discussed.

Snowmold is a severe plant disease caused by psychrophilic or psychrotolerant fungi, ofwhich Microdochium species are the most harmful. A clear understanding ofMicrodochium 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 ofM. 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 diverseM. 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. [ABSTRACT FROM AUTHOR]

Snow mold is a fungal infection affecting all types of grasses after the melting of snow. This infection will result in a color change of the grass to pink or grey. Relatively pink snow mold is more severe than grey snow mold, and can even destroy the roots of the grass. The fungus causing snow mold is inactive in summer. This bibliometric analysis had been conducted to understand the active authors, organizations, journals, and countries involved in the research domain of “snow mold”. All published articles related to “snow mold” from “Scopus”, were analyzed using the VOS viewer to develop analysis tables and visualization maps. This article had set the objective to consolidate the literature regarding the snow mold and also to find out the trends related to the same. The most active authors are Tronsmo A.M. and Hoshino T. with the highest number of publications and co-authorship links respectively. Raymond J.A. is the author with the highest number of citations. Moriyama M. is the most productive author with the highest citation rate. Canadian Journal of Plant Pathology is the most active journal with the highest number of publications and Plant Phytopathology is the journal with the highest number of co-authorship links. Physiologia Plantarum is the journal with the highest citation. Journal of Phycology is the most productive journal in this research domain with the highest average citations. The most active country is the USA with the highest number of publications, Japan with the highest citations, and Norway with the highest co-authorship linkages. Bulgaria is the country with the highest average citations per publication. Institute of Plant Physiology, Polish Academy of Sciences is the most active organization with the highest publications and co-authorship links. The Medical University of South Carolina is the highly productive organization in this research domain, with the highest number of citations and Hokkaido Natl. Agric. Exp. Station is the organization with the highest average citation. [ABSTRACT FROM AUTHOR]

High winter hardiness is an advantage of winter rye over other cereals. This trait is determined by a number of parameters: biological and genetic properties, weather conditions and technological features. The main reasons of failure of winter rye sowings in North-East of European Russia are frost-killing and asphyxiation. Frost-killing is characteristic for beginning of winter with low snow cover and for cold spell in spring. The critical situation with frost damage in the region was recorded in 2009-2010 when soil temperature at the depth of tillering zone site continuously kept at -18 °С day and night. The depth of soil freezing was more than a meter. Winter wheat and triticale were almost completely winterkilled in Kirov region. The failure rate of winter rye Falenskaya 4 in Federal Agricultural Scientific Center of North-East was equal to 17%. Annual damage of rye production in the region is caused by asphyxiation and affection by snow mold (M nivale). On the average damage caused by this disease is 15-20% and in some years even more. Other unfavorable factors of overwintering are shell ice, damping-off and pushing-out of crops. Stability of winter rye production depends on observing the cultivation technology and breeding of highly winter-hardy varieties. Thus, winter resistance is one of the key priorities of breeding programs in North-East of European Russia. The development of such varieties depends on improvement the breeding methods and use of sources of winter hardiness corresponded to region conditions.

Shoots of Calluna vulgaris, Erica carnea, Juniperus communis subsp. nana, Picea abies, and Pinus mugo subsp. mugo covered with felty, melanized epiphytic mycelia typical for brown felt blight caused by Herpotrichia pinetorum were collected at several locations in the Swiss Alps. Most cultures prepared from the mycelia on J. communis subsp. nana and P. abies were H. pinetorum, whereas the majority of cultures from P. mugo subsp. mugo and C. vulgaris were identified by internal transcribed spacer ITS1-5.8S-ITS2 sequencing and morphology as Allantophomopsis cytisporea. The fungus tolerates low temperatures, has an optimum between 16°C and 24°C, and ceases to grow at 28°C. 35°C is lethal. A. cytisporea is known as the causal agent of cranberry black rot on Vaccinium macrocarpon but has never been described as a snow mold. A. cytisporea is an endophyte in C. vulgaris but seems able to kill leaflets and whole shoots during winter. The epiphytic mycelium can expand from C. vulgaris to neighboring shoots of P. mugo subsp. mugo and J. communis subsp. nana below the snow where it forms epiphytic mycelial mats reminiscent of H. pinetorum. H. pinetorum has a strong antibiotic effect against A. cytisporea at 4°C and 20°C, whereas A. cytisporea grows faster at these temperatures. The effects of climate change on the interaction between the two snow mold fungi and their consequences on regeneration of woody plants at timberline are discussed. [ABSTRACT FROM AUTHOR]

Synthetic covers are often used to protect high-value golf course putting greens throughout much of North America and Scandinavia from injury during harsh winter conditions. However, these covers may trap heat and moisture at the turf surface and provide optimal conditions for snow mold development. This study was conducted to determine the most effective fungicide application strategy under both permeable and impermeable synthetic covers. Three different fungicide timings (early, late, and early + late) were tested under no cover, a permeable Evergreen (Hinspergers Poly Industries, Mississauga, ON) cover, and an impermeable GreenJacket cover (GreenJacket, Genoa City, WI) during the winters of 2011-2012 and 2012-2013 in Antigo, WI. Snow mold pressure appeared highest under the impermeable cover, though under all three cover treatments both the late and early + late fungicide timings provided excellent snow mold suppression. These results suggest that despite the increased disease pressure that may be observed under winter covers, excellent snow mold suppression can still be achieved with just one application of a highly efficacious fungicide mixture shortly prior to cover installation. [ABSTRACT FROM AUTHOR]

Brachypodium distachyon is a C3 grass that is an attractive model host system for studying pathogenicity of major turfgrass pathogens due to its genetic similarity to many cool-season turfgrasses. Infection assays with two or more isolates of the casual agents of dollar spot, brown patch, and Microdochium patch resulted in compatible interactions with B. distachyon inbred line Bd21-3. The symptoms produced by these pathogens on Bd21-3 closely resembled those observed on the natural turfgrass host (creeping bentgrass), demonstrating that B. distachyon is susceptible to the fungal pathogens that cause dollar spot, brown patch, and Microdochium patch on turfgrasses. The interaction between Sclerotinia homoeocarpa isolates and Brachypodium ecotypes was also investigated. Interestingly, differential responses of these ecotypes to S. homoeocarpa isolates was found, particularly when comparing B. distachyon to B. hybridum ecotypes. Taken together, these findings demonstrate that B. distachyon can be used as a model host system for these turfgrass diseases and leveraged for studies of molecular mechanisms contributing to host resistance. [ABSTRACT FROM AUTHOR]

Plants grown through the winter are subject to selective pressures that vary with each year' 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. [ABSTRACT FROM AUTHOR]

I examined behavioral flexibility with respect to potentially conflicting demands of Bonasa umbellus L. (Ruffed Grouse) adapted to winter conditions in a mixed forest of western Maine. At the beginning of winter, during the first snow of 15 cm, the grouse roosted overnight 2-4 m above ground in dense stands of conifers. After 40 cm of snow depth, they dove into the snow in flight in open areas of deciduous forest and tunneled, at varying angles and distances from the entrance approach, to den at night and most of the day. With new snow on top of packed snow near the end of winter, they switched tactics again and rested and spent the overnight hours in snow molds on the ground under cover of conifer branches or against tree trunks. The 3 behaviors are discussed in the context of winter diet and anti-predation strategies. [ABSTRACT FROM AUTHOR]

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Snow mold fungus, Typhula ishikariensis, secretes seven antifreeze protein isoforms (denoted TisAFPs) that assist in the survival of the mold under snow cover. Here, the X-ray crystal structure of a hyperactive isoform, TisAFP8, at 1.0 Å resolution is presented. TisAFP8 folds into a right-handed β-helix accompanied with a long α-helix insertion. TisAFP8 exhibited significantly high antifreeze activity that is comparable with other hyperactive AFPs, despite its close structural and sequence similarity with the moderately active isoform TisAFP6. A series of mutations introduced into the putative ice-binding sites (IBSs) in the β-sheet and adjacent loop region reduced antifreeze activity. A doublemutant 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 TisAFP and ice. The docking model of TisAFP8 with the basal plane via its loop region IBS reveals a better shape complementarity than that of TisAFP6. In conclusion, we present new insights into the ice-binding mechanism of TisAFP8 by showing that a higher hydrophobicity and better shape complementarity of its IBSs, especially the loop region, may render TisAFP8 hyperactive to ice binding. [ABSTRACT FROM AUTHOR]

TAD1 ( Triticum aestivum defensin 1) is induced during cold acclimation in winter wheat and encodes a plant defensin with antimicrobial activity. In this study, we demonstrated that recombinant TAD1 protein inhibits hyphal growth of the snow mold fungus, Typhula ishikariensis in vitro . Transgenic wheat plants overexpressing TAD1 were created and tested for resistance against T. ishikariensis . Leaf inoculation assays revealed that overexpression of TAD1 confers resistance against the snow mold. In addition, the TAD1 —overexpressors showed resistance against Fusarium graminearum , which causes Fusarium head blight, a devastating disease in wheat and barley. These results indicate that TAD1 is a candidate gene to improve resistance against multiple fungal diseases in cereal crops. [ABSTRACT FROM AUTHOR]