Botanophila-Epichloë Interaction in a Wild Grass, Puccinellia distans, Lacks Dependence on the Fly Vector

In grass-infecting Epichloë (Ascomycetes: Clavicipitaceae) fungi, the transfer of spermatia for fungal fertilization depends on an insect vector: flies of the genus Botanophila (Diptera: Anthomyiidae). The flies use the fungal stroma, a spore-producing fungal structure surrounding the grass inflorescence, for laying eggs and as a food source for both adults and larvae. This fly-fungus interaction is generally regarded as obligatory and mutualistic. Two Botanophila taxa were noted among four populations of the nonagricultural grass Puccinellia distans (L.) Parl. that were infected with the fungus Epichloë typhina (Pers.) Tul. However, during the 7 yr of field observations, Botanophila flies were present every year in only one population of P. distans. The number of eggs per stroma ranged from zero to four and differed with year and site. Overall, eggs (or larvae) were observed on only 132 (19.2%) of the 687 stromata examined during the survey, with one (13.8%), two (4.5%), or more than two (0.9%) per stroma. However, 90.8% of the examined stromata were fertilized and produced perithecia, suggesting that other mechanisms or vectors of spermatia were responsible for fertilizatio

Change in abundance of three phytophagous mite species (Acari : Eriophyidae, Tetranychidae) on quackgrass in the presence of choke disease

Phytophagous mites and endophytic fungi may interact when sharing a host plant, potentially influencing one another’s growth or population dynamics; however, interactions between them are poorly known and remain largely unexplored. In this study, quantitative associations between three species of phytophagous mites and the endophytic fungus Epichloë bromicola Leuchtm. & Schardl (Clavicipitaceae, Ascomycotina) on quackgrass, Elymus repens (L.) Gould are reported. The mites’ abundance was assessed on field-collected grass shoots that were either exhibiting choke disease symptoms or without the fungus. Overall, the abundance of Tetranychus urticae and Aculodes mckenziei was significantly lower on quackgrass plants infected by E. bromicola compared to plants without the fungus. Conversely, populations of Abacarus hystrix were significantly larger on plants colonised by the fungus than on uninfected plants. Thus, the presence of this endophytic fungus may have divergent effects on different phytophagous mite species although the basis of these effects is not yet known

Botanophila–Epichloe Interaction in a Wild Grass, Puccinellia distans, Lacks Dependence on the Fly Vector

In grass-infecting Epichloe (Ascomycetes: Clavicipitaceae) fungi, the transfer of spermatia for fungal fertilization depends on an insect vector: flies of the genus Botanophila (Diptera: Anthomyiidae). The flies use the fungal stroma, a spore-producing fungal structure surrounding the grass inßorescence, for laying eggs and as a food source for both adults and larvae. This fly-fungus interaction is generally regarded as obligatory and mutualistic. Two Botanophila taxa were noted among four populations of the nonagricultural grass Puccinellia distans (L.) Parl. that were infected with the fungus Epichloe typhina (Pers.) Tul. However, during the 7 yr of field observations, Botanophila flies were present every year in only one population of P. distans. The number of eggs per stroma ranged from zero to four and differed with year and site. Overall, eggs (or larvae) were observed on only 132 (19.2%) of the 687 stromata examined during the survey, with one (13.8%), two (4.5%), or more than two (0.9%) per stroma. However, 90.8% of the examined stromata were fertilized and produced perithecia, suggesting that other mechanisms or vectors of spermatia were responsible for fertilization

The occurrence and preference of Botanophila flies (Diptera: Anthomyiidae) for particular species of Epichloë fungi infecting wild grasses

Specific associations between species frequently occur in ecological interactions. The aim of this study was to determine the preferences of anthomyiid flies of the genus Botanophila for particular species of fungi as sites for laying eggs and as food for both larvae and adults. The associations of their eggs, larvae and flies with the stromata of different species of Epichloë fungi infecting 7 species of grass in Poland were analyzed. Scanning electron microscopy of the surface of their eggs and an analysis of the genetic sequences of their mitochondrial cytochrome oxidase (COII) were used to identify the taxa of the flies studied. Three types of eggs were distinguished based on their shape, colour and the presence of dorsal folds and sculpturing on the shells. Tentatively,these eggs were assigned to the following species: B. laterella, B. phrenione, B. dissecta and B. lobata. COII sequences obtained from larvae that hatched from two of the types of eggs formed three distinct clades associated with the reference sequences for Botanophila phrenione, B. lobata (new to the fauna of Poland) and a putative species, “Taxon 1”. Only one of these flies (B. lobata) was restricted to a single species of Epichloë (E. bromicola on Elymus repens); B. phrenione was recorded mainly from E. typhina infecting three different species of grass. The results of this study confirm that there is not a close species specific association between this fungus and this insect

The fungal endophyte Epichloë typhina improves photosynthesis efficiency of its host orchard grass (Dactylis glomerata)

According to the results presented in this paper the fungal endophyteEpichloë typhinasignificantly improves the growth, PSII photochemistry and C assimilation efficiency of its hostDactylis glomerata. In this paper, we present a comprehensive study of the impact of the endophytic fungi Epichloë typhina on its plant hosts’ photosynthesis apparatus. Chlorophyll a fluorescence, gas exchange, immuno-blotting and spectrophotometric measurements were employed to assess photosynthetic performance, changes in pigment content and mechanisms associated with light harvesting, carbon assimilation and energy distribution in Dactylis glomerata colonized with Epichloë typhina. According to the results presented in this study, colonization of D. glomerata results in improved photosynthesis efficiency. Additionally, we propose a new mechanism allowing plants to cope with the withdrawal of a significant fraction of its energy resources by the endophytic fungi. The abundance of LHCI, LHCII proteins as well as chlorophyll b was significantly higher in E+ plants. Malate export out of the chloroplast was shown to be increased in colonized plants. To our knowledge, we are the first to report this phenomenon. Epichloë colonization improved PSII photochemistry and C assimilation efficiency. Elevated energy demands of E+ D. glomerata plants are met by increasing the rate of carbon assimilation and PSII photochemistry. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00425-015-2337-x) contains supplementary material, which is available to authorized users

Fungal networks - structure, function and use by humans

Grzyby to organizmy występujące we wszystkich strefach klimatycznych, zasiedlające głównie lądy. Dzięki dopasowującym się do warunków środowiska mechanizmom wzrostu, tworzą podziemne sieci, zajmujące znaczną powierzchnię. W obrębie sieci rosnącej w heterogenicznym środowisku zachodzi transport związków odżywczych przez translokację długodystansową. Translokacja ma kluczowe znaczenie dla przetrwania grzybni, ponieważ strzępki rosnące w rejonie ubogim w pokarm są wspierane przez znajdujące się w części zasobniejszej. Grzyby mogą wchodzić w interakcje z innymi organizmami. Wykorzystując czynniki Myc aktywują zespoły genów roślinnych, co umożliwia rozwój grzybni, kolonizację korzeni rośliny, a w efekcie prowadzi do zawiązania mikoryzy. Sieci mikoryzowe wykorzystywane są przez rośliny do komunikacji i ostrzegania się przed niebezpieczeństwem. Natomiast ludzie wykorzystują właściwości sieci grzybowych m.in. do planowania przebiegu sieci komunikacyjnych, mykoremediacji czy produkcji opakowań biodegradowalnych. Przyjmując, że na świecie występuje ok 1,5 miliona gatunków grzybów, z czego znanych jest jedynie ok. 10%, możemy przypuszczać, jak wiele ich niezwykłych właściwości pozostaje do odkrycia.Fungi are mostly terrestrial organisms occurring in all climatic zones. Thanks to the growth mechanisms that are adaptable to environmental conditions, they form underground networks covering large areas. Within a network that grows in heterogenic environment, nutrients are allocated through a long-distance translocation. Translocation is of a key importance for mycelium survival, because hyphae growing in a nutrient-poor place are supported by hyphae from a nutrient-rich area. Fungi may also enter into interactions with other organisms. Using Myc factors, they activate plant gene complexes, which enables the development of mycelium and colonization of plant roots leading to the development of mycorrhiza. Mycorrhizal networks are used by plants to communicate and warn each other of a danger. In turn, humans use the characteristics of fungal networks, among others, to design the flow of communication systems, for myco-remediation and production of biodegradable packing materials. Assuming that about 1.5 mln of fungal species occur in the world, out of which only some 10% are known, we can only presume how many unusual properties of fungi remain still undiscovered

The fungus Epichloë typhina in populations of a halophyte Puccinellia distans: salinity as a possible inhibitor of infection

Puccinellia distans is a non-agricultural halophytic grass that has become another host plant for Epichloe typhina, hitherto not reported from Poland. In 1992 we noticed the first symptoms of choke disease in a single population of P. distans in central Poland. Since then we have observed choke disease in 5 populations of P. distans only in man-made habitats. These habitats are strongly anthropogenically salinated but they exhibit the pattern of species composition characteristic of natural salines. In this paper we test the hypothesis that the level of salinity affects the infection of P. distans by the fungus E. typhina. Seven plots were established in the field and each plot was divided into 25 subplots. Within each plot the level of infection in a spring generation of shoots was negatively correlated with salinity (common regression within the plots, beta = -0.674, df = 117, p < 0.001). Negative correlation was also found in an autumn generation within the plots (beta = -0.682, df = 94, p < 0.001) after excluding plot P in which the frequency of infected individuals was the lowest and equal only to 0.05. The proportion of individuals infected by the endophytic stage of the fungus in the populations was assessed using diagnostic polymerase chain reaction. The greatest percentage (98.3%) of infected individuals was found in the population growing in the habitat of the lowest salinity. The high salinity reduces the chance of P. distans to become infected, but may promote the stroma formation of E. typhina twice in the season. Disease expression in autumn clearly represents a misadaptation which could be explained by the fact that the species interactions described here appeared relatively recently as a result of human activity. This hypothesis requires further experimental verification

Does the Degree of Mutualism between Epichloë Fungi and Botanophila Flies Depend upon the Reproductive Mode of the Fungi?

Epichloë (Ascomycota: Clavicipitaceae) fungi can form an intriguing interaction with Botanophila flies. The fungi live within above-ground shoots of grasses. Some species (type I) only reproduce sexually by forming stromata on all host culms (choke disease). Stromata produce haploid spores (spermatia) that fertilize stromata of opposite mating type to form dikaryotic cells. A second category of Epichloë species (type II) produces stromata on only some of the host culms; culms without choke produce flowers and seeds. These Epichloë can reproduce asexually by invading host seed, as well as sexually. Female Botanophila flies visit stromata for feeding and oviposition. Spermatia pass through the gut of Botanophila intact and viable. Flies can cross-fertilize the fungus during defecation after egg laying. Hence, we described the interaction as a mutualism similar to pollination. Yet, subsequent work by others and ourselves showed that visitation by Botanophila flies was not necessary for cross fertilization of Epichloë. We believe these contradictory results can be reconciled from an evolutionary perspective, if one takes into account the reproductive mode of the fungus. We explore a novel hypothesis to reconcile this contradiction, its predictions and discuss ways in which to test them.ISSN:2309-608

Does the Degree of Mutualism between Epichloë Fungi and Botanophila Flies Depend upon the Reproductive Mode of the Fungi?

Epichloë (Ascomycota: Clavicipitaceae) fungi can form an intriguing interaction with Botanophila flies. The fungi live within above-ground shoots of grasses. Some species (type I) only reproduce sexually by forming stromata on all host culms (choke disease). Stromata produce haploid spores (spermatia) that fertilize stromata of opposite mating type to form dikaryotic cells. A second category of Epichloë species (type II) produces stromata on only some of the host culms; culms without choke produce flowers and seeds. These Epichloë can reproduce asexually by invading host seed, as well as sexually. Female Botanophila flies visit stromata for feeding and oviposition. Spermatia pass through the gut of Botanophila intact and viable. Flies can cross-fertilize the fungus during defecation after egg laying. Hence, we described the interaction as a mutualism similar to pollination. Yet, subsequent work by others and ourselves showed that visitation by Botanophila flies was not necessary for cross fertilization of Epichloë. We believe these contradictory results can be reconciled from an evolutionary perspective, if one takes into account the reproductive mode of the fungus. We explore a novel hypothesis to reconcile this contradiction, its predictions and discuss ways in which to test them