Plant-fungal Interactions Research Articles

Symbiotic fungi alter plant resource allocation independent of water availability.

The ability of plants to adapt or acclimate to climate change is inherently linked to their interactions with symbiotic microbes, notably fungi. However, it is unclear whether fungal symbionts from different climates have different impacts on the outcome of plant-fungal interactions, especially under environmental stress. We tested three provenances of fungal inoculum (originating from dry, moderate or wet environments) with one host plant genotype exposed to three soil moisture regimes (low, moderate and high). Inoculated and uninoculated plants were grown in controlled conditions for 151 days, then shoot and root biomass were weighed and fungal diversity and community composition determined via amplicon sequencing. The source of inoculum and water regime elicited significant changes in plant resource allocation to shoots versus roots, but only specific inocula affected total plant biomass. Shoot biomass increased in the high water treatment but was negatively impacted by all inoculum treatments relative to the controls. The opposite was true for roots, where the low water treatment led to greater proportional root biomass, and plants inoculated with wet site fungi allocated significantly more resources to root growth than dry- or moderate-site inoculated plants and the controls. Fungal communities of shoots and roots partitioned by inoculum source, water treatment, and the interaction of the two. The provenance of fungi can significantly affect total plant biomass and resource allocation above- and belowground, with fungi derived from more extreme environments eliciting the strongest plant responses.

Effector proteins of Funneliformis mosseae BR221: unravelling plant-fungal interactions through reference-based transcriptome analysis, in vitro validation, and protein‒protein docking studies

BackgroundArbuscular mycorrhizal (AM) fungi form a highly adaptable and versatile group of fungi found in natural and man-managed ecosystems. Effector secreted by AM fungi influence symbiotic relationship by modifying host cells, suppressing host defense and promoting infection to derive nutrients from the host. Here, we conducted a reference-based transcriptome sequencing of Funneliformis mosseae BR221 to enhance understanding on the molecular machinery involved in the establishment of interaction between host and AM fungi.ResultsA total of 163 effector proteins were identified in F. mosseae isolate BR221, of these, 79.14% are extracellular effectors and 5.5% are predicted cytoplasmic effectors. In silico prediction using a pathogen-host interaction database suggested four of the 163 effectors could be crucial in establishing AM fungi-host interactions. Protein–protein docking analysis revealed interactions between these potential effectors and plant proteins known to be differentially expressed during mycorrhizal association, such as defensins, aquaporins, and PTO proteins. These interactions are multifaceted in modulating host physiological and defense mechanisms, including immune suppression, hydration, nutrient uptake, and oxidative stress modulation.ConclusionsThese findings of the current study provide a foundational understanding of fungal-host molecular interactions and open avenues for exploring pathways influenced by these effectors. By deepening our knowledge of these mechanisms, the use of AM fungi in biofertilizer formulations can be refined by selecting strains with specific effectors that enhance nutrient uptake, improve drought and disease resistance, and tailor the fungi’s symbiotic efficiency to different crops or environmental conditions, thus contributing to more targeted and sustainable agricultural practices.

Contrasting effects of arsenic on mycorrhizal-mediated silicon and phosphorus uptake by rice.

Silicon (Si) and arbuscular mycorrhizal fungi (AMF) increase plant resistance to various environmental stresses, including heavy metal (and metalloid) toxicity. Although Si and AMF each independently enhance plant tolerance, the nature of their interactions and their combined impacts on nutrient uptake, especially in the context of toxic elements such as arsenic (As), remains to be elucidated. This study investigated AMF-mediated regulation of plant nutrient uptake under As stress using rice, a model Si-accumulating plant. Experiments were conducted under As-free and As stress conditions, incorporating AMF inoculation and silicic acid application, with a focus on nutrient uptake and transporter expression. Without As, AMF inoculation increased shoot Si content by 44%, while invariance was common under As toxicity stress (10μM of As(III)). Despite As presence, AMF increased Lsi1 expression with Si application, elevating As content in roots and shoots by 38% and 55%, respectively. Introduction of As stress amplified AMF role in phosphorus (P) uptake from 13% to 38%, correlating with up-regulated P transporter expression. Three-way ANOVA of interactions among As, Si, and AMF on P and As uptake by rice revealed that As amplified AMF potential to increase P uptake while weakening promotive effect on Si uptake. Silicon reduced As absorption, while AMF increased As uptake, but the elevated As were potentially retained within fungal hyphae, limiting transfer to rice plants. Overall, As toxicity stress had contrasting effects on P- and Si-promoting roles of AMF. These findings contribute to our understanding of plant-fungal interactions under heavy metal stress.

Assembly and Evaluation of a Confocal Microscopy Image Analysis Pipeline Useful in Revealing the Secrets of Plant-Fungal Interactions.

The ability of laser scanning confocal microscopy to generate high-contrast 2D and 3D images has become essential in studying plant-fungal interactions. Techniques such as visualization of native fluorescence, fluorescent protein tagging of microbes, green fluorescent protein (GFP)/red fluorescent protein (RFP)-fusion proteins, and fluorescent labeling of plant and fungal proteins have been widely used to aid in these investigations. Use of fluorescent proteins has several pitfalls, including variability of expression in planta and the requirement of gene transformation. Here, we used the unlabeled pathogens Parastagonospora nodorum, Pyrenophora teres f. teres, and Cercospora beticola infecting wheat, barley, and sugar beet, respectively, to show the utility of a staining and imaging pipeline that uses propidium iodide (PI), which stains RNA and DNA, and wheat germ agglutinin labeled with fluorescein isothiocyanate (WGA-FITC), which stains chitin, to visualize fungal colonization of plants. This pipeline relies on the use of KOH to remove the cutin layer of the leaf, increasing its permeability, allowing the different stains to penetrate and effectively bind to their targets, resulting in a consistent visualization of cellular structures. To expand the utility of this pipeline, we used the staining techniques in conjunction with machine learning to analyze fungal biomass through volume analysis, as well as quantifying nuclear breakdown, an early indicator of programmed cell death (PCD). This pipeline is simple to use, robust, consistent across host and fungal species, and can be applied to most plant-fungal interactions. Therefore, this pipeline can be used to characterize model systems as well as nonmodel interactions where transformation is not routine. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Impact of Urban Xenobiotics on Mycorrhizal Associations in Urban Plants

Urban xenobiotics are a vital contamination phenomenon of urban plants in the overall country. They are a result of human activity due to growing urbanization and population growth. There are extensive sources of both natural (soil or rock erosion, fires, biodegradation, and volcanic eruptions) and anthropogenic (soil pollution, air, and herbicides). Currently, the demand for pharmaceuticals, compared to the growing population, has placed a risk on the urban plant. Additionally, the production of illegal drugs has caused the release of dangerous carcinogens into fungal activities, which will have an impact on plant health, microbial structure, and fungal interaction. Because of the harsh environment, higher temperatures, heavy metals, and higher N deposition, most urban trees suffer from stress conditions, and mycorrhiza is negatively impacted by plant conditions. Some mycorrhiza fungi are unable to sporulate and hyphal at higher xenobiotic concentrations in urban areas. This chapter takes a look at the sources and compounds of xenobiotics and their harmful impact on mycorrhiza; and its association with the urban plants.

Arctic plant-fungus interaction networks show major rewiring with environmental variation

Global environmental change may lead to changes in community structure and in species interactions, ultimately changing ecosystem functioning. Focusing on spatial variation in fungus–plant interactions across the rapidly changing Arctic, we quantified variation in the identity of interaction partners. We then related interaction turnover to variation in the bioclimatic environment by combining network analyses with general dissimilarity modelling. Overall, we found species associations to be highly plastic, with major rewiring among interaction partners across variable environmental conditions. Of this turnover, a major part was attributed to specific environmental properties which are likely to change with progressing climate change. Our findings suggest that the current structure of plant-root associated interactions may be severely altered by rapidly advancing global warming. Nonetheless, flexibility in partner choice may contribute to the resilience of the system.

Blumeria hordei affects volatile emission of susceptible and resistant barley plants and modifies the defense response of recipient plants.

The barley powdery mildew disease caused by the biotrophic fungus Blumeria hordei (Bh) poses enormous risks to crop production due to yield and quality losses. Plants and fungi can produce and release volatile organic compounds (VOCs) that serve as signals in plant communication and defense response to protect themselves. The present study aims to identify VOCs released by barley (Hordeum vulgare) during Bh-infection and to decipher VOC-induced disease resistance in receiver plants. VOC profiles of susceptible MLO wild type (MLO WT) and a resistant near-isogenic backcross line (mlo5) were characterized over time (one day or three days after Bh inoculation) using TD-GC/MS. Comparative analysis revealed genotype-dependent VOC profiles and significant differences in emission rates for β-caryophyllene, linalool, (Z)-3-hexenol, and methyl salicylate. Furthermore, susceptible barley plants were exposed to the complex VOC bouquet of MLO WT or mlo5 sender plants in plant-to-plant communication. We found that VOC-induced resistance in receiver plants depended on the sender genotype in a Bh susceptibility assay. Additionally, untargeted metabolomics and gene expression studies provide evidence toward an SA-dependent pathway mediating VOC-induced resistance against powdery mildew. The exogenous application of methyl salicylate resulted in the enhanced expression of the BARLEY CHEMICALLY INDUCED-4 marker gene and induced resistance in receiver plants. The findings suggest genotype-dependent alterations in barley VOC profiles during biotrophic plant-fungus interactions and show a VOC-mediated resistance that shares components with salicylic acid-related pathways. The VOC signals identified here could serve as non-invasive markers for disease progression in barley-powdery mildew interactions and as signals for resistance induction in recipient plants.

Growth Promotion of Rice and Arabidopsis thaliana by Volatile Organic Compounds Produced by Endophytic Clonostachys Species.

Plant-endophytic fungi are widely distributed and highly diverse, with many of them capable of influencing plant growth and development, which is related to the production of volatile organic compounds (VOCs). While certain fungal VOCs have been found to stimulate plant growth, others exhibit inhibitory effects. Importantly, the impact of fungal VOCs extends beyond host plants to affect non-host plants as well. In this study, we isolated two plant-endophytic fungi, Clonostachys sp. CC1 and Clonostachys sp. CC2, from healthy rice roots. These strains were co-cultured with both rice and Arabidopsis thaliana. Our results demonstrated that both strains significantly enhanced the growth of both rice and A. thaliana. Specifically, they increased the length and biomass of rice and A. thaliana seedlings, as well as the chlorophyll content, while decreasing the H2O2 content in the leaves of both plants. The VOCs produced by these strains were analyzed using gas chromatography-mass spectrometry (GC-MS), which identified a total of 10 main ingredients. Among these compounds, 1-pentanol, ethylbenzene, and dimethyl phthalate inhibited the growth of rice while promoting the growth of A. thaliana, highlighting the variability in the effects of these compounds on different plant species and the complexity of plant-fungal interactions.

Natural and Nature-Inspired Catechol Siderophores: A Promising Strategy for Rice Blast Management.

The rice-blast fungus Pyricularia oryzae poses a significant threat to rice production worldwide. Ferroptosis, an iron-dependent form of regulated cell death, has recently been reported to be involved in P. oryzae pathogenicity during plant-fungal interactions. Ferroptosis regulates the developmental cell death of conidia necessary for appressorium maturation. In this study, we have established that a series of benzamides containing a chelating catechol moiety suppresses the formation/maturation of appressoria, which are essential for host infection by the rice blast fungus. Moreover, for the most active compounds we have shown that their activity can be at least partially reversed by adding exogenous Fe3+. These results highlight the close association between iron availability and appressorium maturation, opening new avenues for the development of targeted strategies for P. oryzae management.

Modulation of fungal phosphate homeostasis by the plant hormone strigolactone

Inter-kingdom communication through small molecules is essential to the coexistence of organisms in an ecosystem. In soil communities, the plant root is a nexus of interactions for a remarkable number of fungi and is a source of small-molecule plant hormones that shape fungal compositions. Although hormone signaling pathways are established in plants, how fungi perceive and respond to molecules is unclear because many plant-associated fungi are recalcitrant to experimentation. Here, we develop an approach using the model fungus, Saccharomyces cerevisiae, to elucidate mechanisms of fungal response to plant hormones. Two plant hormones, strigolactone and methyl jasmonate, produce unique transcript profiles in yeast, affecting phosphate and sugar metabolism, respectively. Genetic analysis in combination with structural studies suggests that SLs require the high-affinity transporter Pho84 to modulate phosphate homeostasis. The ability to study small-molecule plant hormones in a tractable genetic system should have utility in understanding fungal-plant interactions.

RNA silencing is a key regulatory mechanism in the biocontrol fungus Clonostachys rosea-wheat interactions

BackgroundSmall RNA (sRNAs)- mediated RNA silencing is emerging as a key player in host-microbe interactions. However, its role in fungus-plant interactions relevant to biocontrol of plant diseases is yet to be explored. This study aimed to investigate Dicer (DCL)-mediated endogenous and cross-kingdom gene expression regulation in the biocontrol fungus Clonostachys rosea and wheat roots during interactions.ResultsC. rosea Δdcl2 strain exhibited significantly higher root colonization than the WT, whereas no significant differences were observed for Δdcl1 strains. Dual RNA-seq revealed the upregulation of CAZymes, membrane transporters, and effector coding genes in C. rosea, whereas wheat roots responded with the upregulation of stress-related genes and the downregulation of growth-related genes. The expression of many of these genes was downregulated in wheat during the interaction with DCL deletion strains, underscoring the influence of fungal DCL genes on wheat defense response. sRNA sequencing identified 18 wheat miRNAs responsive to C. rosea, and three were predicted to target the C. rosea polyketide synthase gene pks29. Two of these miRNAs (mir_17532_x1 and mir_12061_x13) were observed to enter C. rosea from wheat roots with fluorescence analyses and to downregulate the expression of pks29, showing plausible cross-kingdom RNA silencing of the C. rosea gene by wheat miRNAs.ConclusionsWe provide insights into the mechanisms underlying the interaction between biocontrol fungi and plant roots. Moreover, the study sheds light on the role of sRNA-mediated gene expression regulation in C. rosea-wheat interactions and provides preliminary evidence of cross-kingdom RNA silencing between plants and biocontrol fungi.

The role of Aspergillus flavus in modulating the physiological adjustments of sunflower to elevated CO2 and temperature

Exploring the interactions between plants and foliar endophytic fungi under varying climatic conditions is crucial for harnessing endophytes that enhance plant resilience to environmental stressors. This study examines the role of a specific strain of Aspergillus flavus as an endophyte in sunflowers under standard and altered CO2 and temperature regimes. We assessed the impact of this fungus on physiological traits such as chlorophyll and flavonoid content, gas exchange, and Chlorophyll a fluorescence using open-top chambers simulating ambient (∼420 µmol mol−1) and elevated (∼880 µmol mol−1) CO2 levels, along with a temperature increase of 3°C. The findings indicate that A. flavus promotes nitrogen assimilation and chlorophyll production under ambient conditions, potentially enhancing sunflower growth and photosynthetic performance. However, under elevated temperatures (eT), inoculation with A. flavus resulted in decreased biomass and reduced Photosystem II efficiency. Elevated CO2 (eCO2) conditions also led to unexpected negative effects, with reductions in foliar nitrogen, leaf area, and light capture efficiency, culminating in diminished biomass. When both elevated CO2 and temperature conditions were combined (eCO2eT), the interaction further impaired Photosystem II efficiency, suggesting exacerbated physiological stress. These results demonstrate that environmental modifications can transform A. flavus from a beneficial endophyte to a potential pathogen, highlighting the dual nature of plant-fungal interactions. This study underscores the complexity of these relationships under changing climatic conditions and suggests a cautious approach to the agricultural use of endophytes to ensure plant health and productivity.

Comparative transcriptome profiling of resistant and susceptible groundnut (Arachis hypogaea) genotypes in response to stem rot infection caused by Sclerotium rolfsii

AbstractThis study aimed to explore transcriptomic distinctions between resistant (CS‐319) and susceptible (JAL‐42) groundnut (Arachis hypogaea) genotypes exposed to Sclerotium rolfsii infection across different developmental stages. Employing a de novo assembly‐based approach, we analysed the transcriptomic response in these groundnut plants under control and infected conditions at 24, 72 and 120 hours post‐inoculation (hpi). Our RNA‐Seq data yielded a total of 133,900,261 reads, revealing 7796 differentially expressed genes (DEGs). We constructed a gene regulatory network with 59 hub genes, identified 6783 transcription factors and uncovered 88,424 putative markers, including 17,236 simple‐sequence repeats (SSRs), 10,099 single‐nucleotide polymorphisms (SNPs) and 78,332 indels. Notably, the majority of DEGs were upregulated at 24 hpi in the resistant genotype, encompassing diverse functional categories such as pathogenesis‐related genes, defence‐related (R) genes, genes involved in plant–fungus interactions, oxidation–reduction‐related genes, transport, metabolism and proteolysis genes, along with transcription factors (FAR1, B3, GATA, NAC, WRKY, MYBC1 and bHLH), secondary metabolic pathway‐related genes and photosynthesis‐related genes. The up‐regulation of WRKY transcripts, associated with the activation of the jasmonic acid defence signalling pathway, potentially induced systemic acquired resistance (SAR). Conversely, these DEGs exhibited down‐regulation in the susceptible genotype. Furthermore, a total of 17,236 expressed sequence tag (EST)‐SSRs were identified from the unigenes, holding significant potential for advancing plant breeding through marker‐assisted methods, facilitating quantitative trait locus (QTL) mapping and evaluating genetic diversity among genotypes. This study's approach contributes to a more profound understanding of the molecular‐level defence mechanisms involved in the interaction between groundnuts and S. rolfsii.

New insights into decoding the lifestyle of endophytic Fusarium lateritium Fl617 via comparing genomes

Fungal-plant interactions have persisted for 460 million years, and almost all terrestrial plants on Earth have endophytic fungi. However, the mechanism of symbiosis between endophytic fungi and host plants has been inconclusive. In this dissertation, we used a strain of endophytic Fusarium lateritium (Fl617), which was found in the previous stage to promote disease resistance in tomato, and selected the pathogenic Fusarium oxysporum Fo4287 and endophytic Fusarium oxysporum Fo47, which are in the same host and the closest relatives of Fl617, to carry out a comparative genomics analysis of the three systems and to provide a new perspective for the elucidation of the special lifestyle of the fungal endophytes. We found that endophytic F. lateritium has a smaller genome, fewer clusters and genes associated with pathogenicity, and fewer plant cell wall degrading enzymes (PCWDEs). There were also relatively fewer secondary metabolisms and typical Fusarium spp. toxins, and a lack of the key Fusarium spp. pathogenicity factor, secreted in xylem (SIX), but the endophytic fungi may be more sophisticated in their regulation of the colonization process. It is hypothesized that the endophytic fungi may have maintained their symbiosis with plants due to the relatively homogeneous microenvironment in plants for a long period of time, considering only plant interactions and discarding the relevant pathogenicity factors, and that their endophytic evolutionary tendency may tend to be genome streamlining and to enhance the fineness of the regulation of plant interactions, thus maintaining their symbiotic status with plants.

Unravelling transcriptional responses of the willow to Fusarium kuroshium infection

Fusarium kuroshium and the ambrosia beetle Euwallacea kuroshio attack several tree species, including the arroyo willow (Salix lasiolepis). Despite the importance of this pest, there is no molecular information about this plant-fungus interaction. Using an in vitro pathosystem of S. lasiolepis leaves – F. kurosihum and the RNA-seq approach, this study analyzed for the first time the transcriptome of both organisms at 4-, 8-, and 12-days post-inoculation. De novo assembly was done to generate the willow transcriptome, and a total of 361,2151 unique transcripts (UniGenes) were found. 4,583 UniGenes responded to the infection, and the posterior analysis showed that it contains the molecular elements to develop both pattern- and effector-triggered immunity responses (PTI and ETI, respectively). Significant expression changes of genes involved in an oxidative burst, Ca2+ signaling, and mutually antagonistic interaction between salicylic acid- and jasmonic acid/ethylene-dependent signaling suggest that the willow recognized the fungus and triggered downstream responses. Additionally, chromatin remodelers and non-coding RNA play a significant role in plant defense. Concerning F. kuroshium, 178 induced genes that show homology with genes involved in the pathogenicity in other ascomycetes fungi plus transport proteins, ribosomal proteins, and uncharacterized proteins with specific domains were identified. Collectively these data provide a basis for future research on the molecular response of this transcendental tree during biotic stress, specifically during Fusarium dieback disease.

Sugar Transporter HmSWEET8 Cooperates with HmSTP1 to Enhance Powdery Mildew Susceptibility in Heracleum moellendorffii Hance.

The powdery mildew caused by Eeysiphe heraclei is a serious concern in Heracleum moellendorffii Hance. Therefore, exploring the mechanisms underlying sugar efflux from host cells to the fungus during the plant-fungus interaction showed great significance. The study successfully cloned HmSWEET8 and HmSTP1 genes based on RNA-seq technology. The complementation assays in yeast EBY.VW4000 found HmSWEET8 and HmSTP1 transporting hexose. Over-expressing or silencing HmSWEET8 in H. moellendorffii leaves increased or decreased powdery mildew susceptibility by changing glucose concentration in infective sites. Meanwhile, over-expressing HmSTP1 in H. moellendorffii leaves also increased powdery mildew susceptibility by elevating the glucose content of infective areas. Additionally, HmSTP1 expression was up-regulated obviously in HmSWEET8 over-expressed plants and inhibited significantly in HmSWEET8 silenced plants. Co-expressing HmSWEET8 and HmSTP1 genes significantly increased powdery mildew susceptibility compared with over-expressed HmSWEET8 or HmSTP1 plants alone. The results demonstrated that HmSTP1 may assist with HmSWEET8 to promote E. heraclei infection. Consequently, the infection caused by E. heraclei resulted in the activation of HmSWEET8, leading to an increased transfer of glucose to the apoplasmic spaces at the sites of infection, then, HmSTP1 facilitated the transport of glucose into host cells, promoting powdery mildew infection.

Botrytis cinerea causes different plant responses in grape (Vitis vinifera) berries during noble and grey rot: diverse metabolism versus simple defence.

The complexity of the interaction between the necrotrophic pathogen Botrytis cinerea and grape berries (Vitis vinifera spp.) can result in the formation of either the preferred noble rot (NR) or the loss-making grey rot (GR), depending on the prevailing climatic conditions. In this study, we focus on the functional gene set of V. vinifera by performing multidimensional scaling followed by differential expression and enrichment analyses. The aim of this study is to identify the differences in gene expression between grape berries in the phases of grey rot, noble rot, and developing rot (DR, in its early stages) phases. The grapevine transcriptome at the NR phase was found to exhibit significant differences from that at the DR and GR stages, which displayed strong similarities. Similarly, several plant defence-related pathways, including plant-pathogen interactions as hypersensitive plant responses were found to be enriched. The results of the analyses identified a potential plant stress response pathway (SGT1 activated hypersensitive response) that was found to be upregulated in the GR berry but downregulated in the NR berry. The study revealed a decrease in defence-related in V. vinifera genes during the NR stages, with a high degree of variability in functions, particularly in enriched pathways. This indicates that the plant is not actively defending itself against Botrytis cinerea, which is otherwise present on its surface with high biomass. This discrepancy underscores the notion that during the NR phase, the grapevine and the pathogenic fungi interact in a state of equilibrium. Conversely the initial stages of botrytis infection manifest as a virulent fungus-plant interaction, irrespective of whether the outcome is grey or noble rot.

Fungal–Plant Interactions: Latest Advances and Prospects

During the evolution of higher plants, many microorganisms evolve alongside them, creating a synergistic plant–microbe world [...]

The Contribution of Trichoderma viride and Metallothioneins in Enhancing the Seed Quality of Avena sativa L. in Cd-Contaminated Soil.

Pollution of arable land with heavy metals is a worldwide problem. Cadmium (Cd) is a toxic metal that poses a severe threat to humans' and animals' health and lives. Plants can easily absorb Cd from the soil, and plant-based food is the main means of exposure to this hazardous element for humans and animals. Phytoremediation is a promising plant-based approach to removing heavy metals from the soil, and plant growth-promoting micro-organisms such as the fungi Trichoderma can enhance the ability of plants to accumulate metals. Inoculation of Avena sativa L. (oat) with Trichoderma viride enhances germination and seedling growth in the presence of Cd and, in this study, the growth of 6-month-old oat plants in Cd-contaminated soil was not increased by inoculation with T. viride, but a 1.7-fold increase in yield was observed. The content of Cd in oat shoots depended on the Cd content in the soil. Still, it was unaffected by the inoculation with T. viride. A. sativa metallothioneins (AsMTs) participate in plant-fungi interaction, however, their role in this study depended on MT type and Cd concentration. The inoculation of A. sativa with T. viride could be a promising approach to obtaining a high yield in Cd-contaminated soil without increasing the Cd content in the plant.

Establishment of an Infection System for Gentian (Gentiana spp.) Sclerotial Flower Blight Disease.

Gentians (Gentiana spp.) as floriculture crops are constantly exposed to several fungal and viral pathogens in the field. Among the fungal diseases afflicting gentian production, gentian sclerotial flower blight caused by Ciborinia gentianae incurs economic losses, as it affects flowers before and after harvest. Currently, preventive measures for this disease are limited, and no resistant cultivars have been reported. This is partly because of the lack of a reliable infection system that could promote research on this plant-fungus interaction. In this study, Gentiana plant tissue culture material was inoculated with C. gentianae culture filtrate. We successfully demonstrated non-ascospore-mediated infection of C. gentianae. Inoculation of individual hyphal structures present in the culture filtrate suggested that sclerotial primordia are the main agents of this infection. Interestingly, our results indicated that primary infection of C. gentianae occurs in petals rather than leaves, which enables systemic infection and therefore mirrors the fungus's infection strategy observed in the field. Moreover, we showed that (i) non-ascospore hyphal structures can also cause disease in flowers grown in the field, and (ii) ascosporic infection can also be observed using the in vitro system, opening possibilities for both practical and basic research aimed to combat gentian sclerotial flower blight disease.