Fungal Genotypes Research Articles

Differences in metabolites production using the Biolog FF Microplate™ system with an emphasis on some organic acids of Aspergillus niger wild type strains

This paper investigates the differences in some metabolites using Biolog FF Microplate™ system and the production of organic acids such as β-hydroxybutyric, p-hydroxyphenylacetic, and others. Another group of organic acids such as gluconic, oxalic and citric acid were studied during cultivation in a liquid medium. Four different Aspergillus niger (An) wild type strains were used as a model organism. Three strains, from the Banska Stiavnica – Sobov (An – S), Pezinok (An – P) and Slovinky (An – Sl) localities were isolated from contaminated old mining areas with soil with ultra acidic to strong alkaline reactions. The fourth strain isolated from the Gabcikovovo (An – G) locality was used for comparative purposes. According to the RAMP analysis, the strains are clustered into two groups, An – S and An – P (similarity 82%), An – G and An – Sl (similarity 64%) which correlates with the pH values of the original environment. However, significant differences were found in metabolic processes in the reaction with a wide range of organic acids. In general, the reactions with D-lactic acid and D-malic acid correlate with the results of the RAMP analysis of fungal genotype similarities, the An – S and An – P strains had an identical negative reaction, and an identical positive reaction was found in the An – Sl and An – G strains. During incubation the wild-type strains produced substantial amounts of gluconic acid, oxalic acid and small amounts of citric acid. The appearance and accumulation of organic acids was found to be highly pH dependent with the most active strain isolated from an ultra-acidic environment. The comparative strain differs entirely in the production of oxalic acid.

High diversity and low host-specificity of Termitomyces symbionts cultivated by Microtermes spp. indicate frequent symbiont exchange

Abstract Fungus-growing termites (subfamily Macrotermitinae) live in an obligate mutualistic symbiosis with species of the fungal genus Termitomyces (Basidiomycota). Although the species that build large mounds are the most conspicuous, termites of the genus Microtermes construct large underground networks of tunnels connecting many fungus gardens. They are also the only entire genus within the Macrotermitinae in which vertical transmission of the fungal symbiont has evolved. To study patterns of genetic diversity in species of the genus Microtermes and their Termitomyces symbionts, we sampled at three different locations in South Africa and sequenced COI for the termites and ITS for the fungi. We discovered high genetic diversity in both termites and fungal symbionts but very low interaction specificity. This implies that frequent horizontal exchange of fungal symbionts occurs between species, despite vertical transmission across generations. We also estimated colony size based on termite haplotype and fungal genotype combinations and found indications that colonies may extend over large areas.

Molecular Characterization of Coccidioides spp. Strains Isolated from Patients in the Argentine Republic

This review summarizes the analysis of the internal transcribed spacers (ITS) sequencing of Coccidioides spp. strains isolated in the endemic region of coccidioidomycosis in Argentina, to be able to associate the presence of a specific fungal genotype with a specific geographical region. Recent studies have focused on the identification and genetic variability between and intraspecies as a tool to contribute to the coccidioidomycosis epidemiology; these findings may contribute to the specific identification of circulating strains of Coccidioides spp. in Argentina. Coccidioides immitis and C. posadasii are causative agents of coccidioidomycosis, an endemic mycosis of arid and semiarid regions of America. The classic diagnosis based on microbiological methods only identifies up to the level of gender, being sufficient to initiate a treatment, since until now no specific clinical differences associated with one or another species have been described. It is likely that the number of strains analyzed here only represents a small portion of the circulating strains in our region; however, the ITSs sequencing from strains isolated in the Argentine territory has allowed us to conclude that the strains circulating in our country to date are C. posadasii.

Arbuscular Mycorrhizal Fungi and Associated Microbiota as Plant Biostimulants: Research Strategies for the Selection of the Best Performing Inocula

Arbuscular mycorrhizal fungi (AMF) are beneficial soil microorganisms establishing mutualistic symbioses with the roots of the most important food crops and playing key roles in the maintenance of long-term soil fertility and health. The great inter- and intra-specific AMF diversity can be fully exploited by selecting AMF inocula on the basis of their colonization ability and efficiency, which are affected by fungal and plant genotypes and diverse environmental variables. The multiple services provided by AMF are the result of the synergistic activities of the bacterial communities living in the mycorrhizosphere, encompassing nitrogen fixation, P solubilization, and the production of phytohormones, siderophores, and antibiotics. The tripartite association among host plants, mycorrhizal symbionts, and associated bacteria show beneficial emerging properties which could be efficiently exploited in sustainable agriculture. Further in-depth studies, both in microcosms and in the field, performed on different AMF species and isolates, should evaluate their colonization ability, efficiency, and resilience. Transcriptomic studies can reveal the expression levels of nutrient transporter genes in fungal absorbing hyphae in the presence of selected bacterial strains. Eventually, newly designed multifunctional microbial consortia can be utilized as biofertilizers and biostimulants in sustainable and innovative production systems.

Effects of endophyte fungal species and host plant genotype on the leaf shape and leaf area of endophyte-grass symbionts

Effects of endophyte fungal species and host plant genotype on the leaf shape and leaf area of endophyte-grass symbionts

Biodiversity of Pyricularia oryzae Cav. in rice-growing regions of the south of Russia using PCR method.

The purpose of this research by the way of investigating the molecular genetic structure of a highly variable fungal phytopathogen Pyricularia oryzae Cav., to determine effective genes for the development of a strategy for immunogenetic protection against rice blast in conditions of epiphytotic development of the disease in the south of Russia, which would combine high efficacy with both environmental friendliness and resource and energy saving, to ensure country's food security. The knowledge of local pathotype diversity of Pyricularia oryzae Cav. and the (a)virulence genes in rice-growing regions of Russia may allow the prediction of new races and its interaction in local agro-ecology. The identification of virulence gene may become an indispensable theoretical basis for the development of genetic sources with long-lasting resistance to rice blast. Based on molecular and genetic approaches, the genetic structure and biodiversity of the phytopathogenic fungus Pyricularia oryzae Cav. in the south of Russia were considered. The monitoring was studied and it isolated 57 strains of the pathogen from the damaged herbal material collected from the fields in eight agro-ecological rice-growing regions of the Krasnodar Region (Russian Federation): Krasnoarmeysky, Kalininsky, Krymsky, Abinsky, Temryuksky, Seversky, Slavyansky districts, Krasnodar, Rostov Region (Russian Federation)-Proletarsky district and the Republic of Adygea (Russian Federation). A multiplex PCR technique was applied on the basis of fragment analysis to identify the virulent fungal isolates. 33 fungal genotypes with unique genetic profiles were identified among the studied races of Pyricularia oryzae Cav. Their DNA profiles were created. The studied isolates of the pathogen of rice blast were classified using morphological and microbiology cultural features. Based on the phytopathological test using differentiation rice varieties, the quantitative and qualitative composition of (a)virulence genes in fungal races was established. Effective genes for pathogen resistance, which are recommended for breeding programs for the development of rice varieties resistant to rice blast, were identified in the south of Russia.

Genotype-specific effects of ericoid mycorrhizae on floral traits and reproduction in Vaccinium corymbosum.

PremiseMost plants interact with mycorrhizal fungi and animal pollinators simultaneously. Yet, whether mycorrhizae affect traits important to pollination remains poorly understood and may depend on the match between host and fungal genotypes. Here, we examined how ericoid mycorrhizal fungi affected flowering phenology, floral traits, and reproductive success, among eight genotypes of highbush blueberry, Vaccinium corymbosum (Ericaceae). We asked three overarching questions: (1) Do genotypes differ in response to inoculation? (2) How does inoculation affect floral and flowering traits? (3) Are inoculated plants more attractive to pollinators and less pollen limited than non‐inoculated plants of the same genotype?MethodsTo examine these questions, we experimentally inoculated plants with ericoid mycorrhizal fungi, grew the plants in the field, and measured flowering and floral traits over 2 years. In year 2, we conducted a hand‐pollination experiment to test whether plants differed in pollen limitation.ResultsInoculated plants had significantly higher levels of colonization for some genotypes, and there were significant floral trait changes in inoculated plants for some genotypes as well. On average, inoculated plants produced significantly larger floral displays, more fruits per inflorescence, and heavier fruits with lower sugar content, than non‐inoculated, control plants. Hand pollination enhanced the production of fruits, and fruit mass, for non‐inoculated plants but not for those that were inoculated.ConclusionsOur results demonstrate that inoculation with ericoid mycorrhizal fungi enhanced flowering and altered investment in reproduction in genotype‐specific ways. These findings underscore the importance of examining belowground symbionts and genotype‐specific responses in their hosts to fully understand the drivers of aboveground interactions.

Trichothecene Genotypes Analysis of Fusarium Isolates from di-, tetra- and Hexaploid Wheat

New sources of resistance to fungal diseases, including FHB (Fusarium head blight), need to be identified. The results of research investigating ancient wheat species with desirable traits appear promising. The aim of this study was to determine the presence of Fusarium culmorum (W. G. Sm.) Sacc., F. graminearum Schwabe, F. poae (Peck) Wollenw, F. avenaceum (Fr.) Sacc. and F. langsethiae Torp & Nirenberg in the grain and glumes of diploid Triticum monococcum ssp. monococcum, tetraploid T. turgidum ssp. dicoccum, T. turgidum ssp. polonicum and T. turgidum ssp. durum, and hexaploid T. aestivum ssp. spelta and T. aestivum ssp. aestivum grown in north-eastern and south-eastern Poland and to analyze the trichothecene genotypes of the isolated strains. The results of this study also point to shifts in the genotype of Polish F. culmorum and F. graminearum populations from 3-ADON to NIV and 15-ADON to 3-ADON genotypes, respectively. Our findings indicate that selected einkorn lines could potentially be used as sources of genetic material for breeding new varieties resistant to FHB. The fungal genotypes should be closely screened in Poland and the neighboring countries to assess the effects of potential genotypes profile change on fungal virulence, toxin loading and host specificity.

Multiple infections, relatedness and virulence in the anther-smut fungus castrating Saponaria plants.

Multiple infections (co-occurrence of multiple pathogen genotypes within an individual host) can have important impacts on diseases. Relatedness among pathogens can affect the likelihood of multiple infections and their consequences through kin selection. Previous studies on the castrating anther-smut fungus Microbotryum lychnidis-dioicae have shown that multiple infections occur in its host plant Silene latifolia. Relatedness was high among fungal genotypes within plants, which could result from competitive exclusion between unrelated fungal genotypes, from population structure or from interactions between plant and fungal genotypes for infection ability. Here, we aimed at disentangling these hypotheses using M.saponariae and its host Saponaria officinalis, both experimentally tractable for these questions. By analysing populations using microsatellite markers, we also found frequent occurrence of multiple infections and high relatedness among strains within host plants. Infections resulting from experimental inoculations in the greenhouse also revealed high relatedness among strains co-infecting host plants, even in clonally replicated plant genotypes, indicating that high relatedness within plants did not result merely from plant x fungus interactions or population structure. Furthermore, hyphal growth in vitro was affected by the presence of a competitor growing nearby and by its genetic similarity, although this latter effect was strain-dependent. Altogether, our results support the hypothesis that relatedness-dependent competitive exclusion occurs in Microbotryum fungi within plants. These microorganisms can thus respond to competitors and to their level of relatedness.

Little evidence that farmers should consider abundance or diversity of arbuscular mycorrhizal fungi when managing crops.

Contents Summary 1092 I. Introduction 1093 II. Investigating activity of AMF in agroecosystems 1093 III. Crop benefit from AMF: agronomic and mycorrhizal literature differ 1094 IV. Flawed methodology leads to benefits of mycorrhizas being overstated 1094 V. Rigorous methodology suggests low colonisation by AMF can sometimes reduce crop yield 1095 VI. Predicting when mycorrhizas matter for crop yield 1096 VII. Crop genotype 1099 VIII. Fungal genotype 1100 IX. Complex interactions between the mycorrhizal fungal and soil microbial communities 1102 X. Phosphorus-efficient agroecosystems 1102 XI. Conclusions 1103 Acknowledgements 1104 References 1104 SUMMARY: Arbuscular mycorrhizal fungi (AMF) are ubiquitous in agroecosystems and often stated to be critical for crop yield and agroecosystem sustainability. However, should farmers modify management to enhance the abundance and diversity of AMF? We address this question with a focus on field experiments that manipulated colonisation by indigenous AMF and report crop yield, or investigated community structure and diversity of AMF. We find that the literature presents an overly optimistic view of the importance of AMF in crop yield due, in part, to flawed methodology in field experiments. A small body of rigorous research only sometimes reports a positive impact of high colonisation on crop yield, even under phosphorus limitation. We suggest that studies vary due to the interaction of environment and genotype (crop and mycorrhizal fungal). We also find that the literature can be overly pessimistic about the impact of some common agricultural practices on mycorrhizal fungal communities and that interactions between AMF and soil microbes are complex and poorly understood. We provide a template for future field experiments and a list of research priorities, including phosphorus-efficient agroecosystems. However, we conclude that management of AMF by farmers will not be warranted until benefits are demonstrated at the field scale under prescribed agronomic management.

Partner communication and role of nutrients in the arbuscular mycorrhizal symbiosis.

Contents Summary 1031 I. Introduction 1031 II. Interkingdom communication enabling symbiosis 1032 III. Nutritional and regulatory roles for key metabolites in the AM symbiosis 1035 IV. The plant-fungus genotype combination determines the outcome of the symbiosis 1039 V. Perspectives 1039 Acknowledgements 1041 References 1041 SUMMARY: The evolutionary and ecological success of the arbuscular mycorrhizal (AM) symbiosis relies on an efficient and multifactorial communication system for partner recognition, and on a fine-tuned and reciprocal metabolic regulation of each symbiont to reach an optimal functional integration. Besides strigolactones, N-acetylglucosamine-derivatives released by the plant were recently suggested to trigger fungal reprogramming at the pre-contact stage. Remarkably, N-acetylglucosamine-based diffusible molecules also are symbiotic signals produced by AM fungi (AMF) and clues on the mechanisms of their perception by the plant are emerging. AMF genomes and transcriptomes contain a battery of putative effector genes that may have conserved and AMF- or host plant-specific functions. Nutrient exchange is the key feature of AM symbiosis. A mechanism of phosphate transport inside fungal hyphae has been suggested, and first insights into the regulatory mechanisms of root colonization in accordance with nutrient transfer and status were obtained. The recent discovery of the dependency of AMF on fatty acid transfer from the host has offered a convincing explanation for their obligate biotrophism. Novel studies highlighted the importance of plant and fungal genotypes for the outcome of the symbiosis. These findings open new perspectives for fundamental research and application of AMF in agriculture.

Screening of white-rot fungi for bioprocessing of wheat straw into ruminant feed.

In this study, the biological variation for improvement of the nutritive value of wheat straw by 12 Ceriporiopsis subvermispora, 10 Pleurotus eryngii and 10 Lentinula edodes strains was assessed. Screening of the best performing strains within each species was made based on the invitro degradability of fungal-treated wheat straw. Wheat straw was inoculated with each strain for 7weeks of solid state fermentation. Weekly samples were evaluated for invitro gas production (IVGP) in buffered rumen fluid for 72h. Out of the 32 fungal strains studied, 17 strains showed a significantly higher (P<0·05) IVGP compared to the control after 7weeks (227·7ml g-1 OM). The three best Ceriporiopsis subvermispora strains showed a mean IVGP of 297·0mlg-1 OM, while the three best P. eryngii and L. edodes strains showed a mean IVGP of 257·8 and 291·5mlg-1 OM, respectively. Ceriporiopsis subvermispora strains show an overall high potential to improve the ruminal degradability of wheat straw, followed by L. edodes and P. eryngii strains. Large variation exists within and among different fungal species in the valorization of wheat straw, which offers opportunities to improve the fungal genotype by breeding.

Resistance to Cypress Canker Disease in Italian cypress has desirable effects on disease epidemiology, but may fail against novel genotypes of the pathogen Seiridium cardinale

Prevention is hailed as the only successful and cost-effective approach to control the introduction of exotic forest pathogens, and several international policies are in place to avoid such introductions. However, once a pathogen has been introduced and is widely spread in a novel range, regulations are relaxed. Concerns have been voiced about the detrimental consequences of the introduction of multiple genotypes of a pathogen, but evidence about such consequences has rarely been documented. Cypress Canker Disease (CCD) is a pandemic lethal disease of plants in the family Cupressaceae caused by the fungal pathogen Seiridium cardinale (W.W. Wagener) B. Sutton & I.A.S. Gibson (Sc). Sc is native to California, where populations are genetically diversified, while widely spread CCD outbreaks in the Mediterranean basin have been caused by the introduction of a single genotype. Resistant plant clones have been selected in Italy based on long-term field tests using a representative Mediterranean Sc genotype. Here we use a 90-day greenhouse trial on 419 21-month old grafts to test the response of four putatively resistant and three putatively susceptible clones of Italian cypress (Cupressus sempervirens L.) against one Mediterranean and five Californian fungal genotypes. By measuring mortality, size of the lesion caused by the fungus on the stem, and fungal sporulation, we ask the following questions: (1) Does the fast greenhouse assay confirm results of the extended field trials; (2) Is resistance confirmed for all putatively resistant clones when using a broad representation of the pathogen; and, (3) Does resistance have the potential to reduce transmission rates of the pathogen, thus potentially slowing down the CCD epidemic? Results indicated that: (1) Lesion size, but not seedlings’ survival, can be used as metric to measure resistance in small grafted ramets; (2) One of four putatively resistant plant clones was considered susceptible at the end of the trial; and, (3) Sporulation was significantly lower in resistant than in susceptible plant clones. Based on these results, we conclude that resistance may be a viable disease control approach in this pathosystem due to the effect it has on both plant survival and fungal sporulation. However, we also conclude that resistance can be considered robust and effective against the pathogen species in its entirety, only if tested using several fungal genotypes. This study is one of the first to show that multiple introductions of a pathogen could break down host resistance and have a measurable detrimental effect on native ecosystems, suggesting that international policies should be revised accordingly.

Does genotypic and species diversity of mycorrhizal plants and fungi affect ecosystem function?

Contents Summary 1122 I. Introduction 1122 II. Are there consistent patterns in diversity of mycorrhizal fungal genotypes and species across space? 1125 III. What is the variation in functional traits and genes of mycorrhizal fungi at different taxonomic scales? 1125 IV. How will environmental change impact the relationships between genotypic and species diversity of mycorrhizal fungi and ecosystem function? 1126 V. Conclusions: considerations for future MEF research 1127 Acknowledgements 1127 References 1127 SUMMARY: Both genotypes and species of mycorrhizal fungi exhibit considerable variation in traits, and this variation can result in their diversity regulating ecosystem function. Yet, the nature of mycorrhizal fungal diversity-ecosystem function (MEF) relationships for both genotypes and species is currently poorly defined. New experiments should reflect the richness of genotypes and species in nature, but we still lack information about the extent to which fungal populations in particular are structured. Sampling designs should quantify the diversity of mycorrhizal fungal genotypes and species at three key broad spatial scales (root fragment, root system and interacting root systems) in order to inform manipulation experiments and to test how mycorrhizal fungal diversity both responds, and confers resilience to, environmental drivers.

Local epidemiology of the wood decay agent Laetiporus sulphureus in carob stands in Sicily

SummaryThe basidiomycete Laetiporus sulphureus (Bull) Murrill is a forest pathogen causing brown cubical heart rot in a broad range of host trees. Despite its wide distribution and importance, studies aimed at understanding the epidemiology of the fungus in specific areas or hosts are lacking. In this study, an incidence of L. sulphureus as high as 34% was determined through molecular analysis of wood samples collected from 70 carob (Ceratonia siliqua L.) trees in the South‐west of Sicily, Italy. A phylogenetic analysis of Internal Transcribed Spacer (ITS) sequences indicated that all carob isolates belonged to the cluster E of Laetiporus taxonomy. Ten molecular markers based on Single Sequence Repeats (SSRs) designed on the L. sulphureus genome were developed, and isolates were genotyped through High‐resolution Melting (HRM) analysis. High gene diversity (0.581), no correlation between fungal genotype and host tree species and significant correlation between spatial and genetic distance were observed, suggesting an important role of basidiospores in the epidemiology of the fungus and a risk of transmission from a host tree species to the others. Finally, from a prognostic perspective, significant differences among isolates in terms of mycelial growth suggest that in addition to an accurate identification, a phenotypic characterization of isolates affecting trees may also be important.

Fungal genotype determines survival of Drosophila melanogaster when competing with Aspergillus nidulans.

Fungi produce an astonishing variety of secondary metabolites, some of which belong to the most toxic compounds in the living world. Several fungal metabolites have anti-insecticidal properties which may yield advantages to the fungus in competition with insects for exploitation of environmental resources. Using the Drosophila melanogaster/Aspergillus nidulans ecological model system to assess secondary metabolite mutant genotypes, we find a major role for the veA allele in insect/fungal confrontations that exceeds the influence of other factors such as LaeA. VeA along with LaeA is a member of a transcriptional complex governing secondary metabolism in A. nidulans. However, historically a mutant veA allele, veA1 reduced in secondary metabolite output, has been used in many studies of this model organism. To test the significance of this allele in our system, Aspergillus nidulans veA wild type, veA1, ΔveA and ΔlaeA were evaluated in confrontation assays to analyze egg laying activity, and the survival rate of larvae. The veA1 genetic background led to a significant increase of larval survival. Adult flies were observed almost exclusively on veA1, ΔveA or ΔlaeA genetic backgrounds, suggesting a role for the velvet complex in insect/fungal interactions. This effect was most profound using the veA1 mutant. Hence, larval survival in confrontations is highly affected by the fungal genotype.

Strain Identity of the Ectomycorrhizal Fungus Laccaria bicolor Is More Important than Richness in Regulating Plant and Fungal Performance under Nutrient Rich Conditions.

Effects of biodiversity on productivity are more likely to be expressed when there is greater potential for niche complementarity. In soil, chemically complex pools of nutrient resources should provide more opportunities for niche complementarity than chemically simple pools. Ectomycorrhizal (ECM) fungal genotypes can exhibit substantial variation in nutrient acquisition traits and are key components of soil biodiversity. Here, we tested the hypothesis that increasing the chemical complexity and forms of soil nutrients would enhance the effects of intraspecific ECM diversity on host plant and fungal productivity. In pure culture, we found substantial variation in growth of strains of the ECM fungus Laccaria bicolor on a range of inorganic and organic forms of nutrients. Subsequent experiments examined the effects of intraspecific identity and richness using Scots pine (Pinus sylvestris) seedlings colonized with different strains of L. bicolor growing on substrates supplemented with either inorganic or organic forms of nitrogen and phosphorus. Intraspecific identity effects on plant productivity were only found under the inorganic nutrient amendment, whereas intraspecific identity affected fungal productivity to a similar extent under both nutrient treatments. Overall, there were no significant effects of intraspecific richness on plant and fungal productivity. Our findings suggest soil nutrient composition does not interact strongly with ECM intraspecific richness, at least under experimental conditions where mineral nutrients were not limiting. Under these conditions, intraspecific identity of ECM fungi becomes more important than richness in modulating plant and fungal performance.

Bifiguratus adelaidae, gen. et sp. nov., a new member of Mucoromycotina in endophytic and soil-dwelling habitats

ABSTRACTIllumina amplicon sequencing of soil in a temperate pine forest in the southeastern United States detected an abundant, nitrogen (N)-responsive fungal genotype of unknown phylogenetic affiliation. Two isolates with ribosomal sequences consistent with that genotype were subsequently obtained. Examination of records in GenBank revealed that a genetically similar fungus had been isolated previously as an endophyte of moss in a pine forest in the southwestern United States. The three isolates were characterized using morphological, genomic, and multilocus molecular data (18S, internal transcribed spacer [ITS], and 28S rRNA sequences). Phylogenetic and maximum likelihood phylogenomic reconstructions revealed that the taxon represents a novel lineage in Mucoromycotina, only preceded by Calcarisporiella, the earliest diverging lineage in the subphylum. Sequences for the novel taxon are frequently detected in environmental sequencing studies, and it is currently part of UNITE’s dynamic list of most wanted fungi. The fungus is dimorphic, grows best at room temperature, and is associated with a wide variety of bacteria. Here, a new monotypic genus, Bifiguratus, is proposed, typified by Bifiguratus adelaidae.

Early molecular signatures of responses of wheat to Zymoseptoria tritici in compatible and incompatible interactions.

Zymoseptoria tritici, the causal agent of septoria tritici blotch, a serious foliar disease of wheat, is a necrotrophic pathogen that undergoes a long latent period. Emergence of insensitivity to fungicides, and pesticide reduction policies, mean there is a pressing need to understand septoria and control it through greater varietal resistance. Stb6 and Stb15, the most common qualitative resistance genes in modern wheat cultivars, determine specific resistance to avirulent fungal genotypes following a gene‐for‐gene relationship. This study investigated compatible and incompatible interactions of wheat with Z. tritici using eight combinations of cultivars and isolates, with the aim of identifying molecular responses that could be used as markers for disease resistance during the early, symptomless phase of colonization. The accumulation of TaMPK3 was estimated using western blotting, and the expression of genes implicated in gene‐for‐gene interactions of plants with a wide range of other pathogens was measured by qRT‐PCR during the presymptomatic stages of infection. Production of TaMPK3 and expression of most of the genes responded to inoculation with Z. tritici but varied considerably between experimental replicates. However, there was no significant difference between compatible and incompatible interactions in any of the responses tested. These results demonstrate that the molecular biology of the gene‐for‐gene interaction between wheat and Zymoseptoria is unlike that in many other plant diseases, indicate that environmental conditions may strongly influence early responses of wheat to infection by Z. tritici, and emphasize the importance of including both compatible and incompatible interactions when investigating the biology of this complex pathosystem.

New aspects of the biology of Mortierella alliacea

A fungal genotype related to Mortierella alliacea was detected by environmental PCR in samples of the mite species Leptogamasus obesus and Oppiella subpectinata, as well as in the soil body. The association may be epi- or endozoic. A genotypically corresponding strain was newly isolated from mites and examined to gain deeper insight into the biology of the scarcely known fungal species. Morphological and physiological traits, as well as molecular data confirmed an affiliation to Mortierella alliacea Linnemann. However, the strain showed minor morphological differences to the original description of M. alliacea (selected here as lectotype) and to the isolate CBS 894.68 (selected here as epitype) with regard to sporocystospore and chlamydospore morphology. Therefore, an emended species description is provided. The psychrotolerant fungus is able to grow at temperatures between 0 and 25 °C. Chitin degradation was not observed, and it lacked the capability to degrade starch, cellulose, lignin, and lipids. Proteolytic activity was only exhibited at 4 °C. Co-incubated mites were not affected by the fungus, indicating that the mites predominantly serve as vectors. The fungus’ limited degradation capabilities suggest that it predominantly lives on readily accessible carbohydrates in soil.