Biology subjects

Eichmeier, A.

Publications and source records attributed to Eichmeier, A..

4 recordsLinked to original sources

bioRxiv2026

Sodium nitrophenolates as a potential tool for the management of grapevine trunk diseases

Fungal trunk diseases represent a major constraint on the production of grapevine and other perennial crops, while effective curative control methods remain limited. This study evaluated the antifungal and defence-modulating effects of the sodium nitrophenolate based product Atonik against selected fungi associated with trunk diseases. In vitro efficacy was tested against ten fungal pathogens, and its effect against Eutypa lata was further evaluated in grapevine under in planta conditions. Atonik inhibited mycelial growth in a pathogen and concentration dependent manner, with the strongest effects at the highest tested concentration observed against Cadophora luteo-olivacea, E. lata, and Phaeoacremonium minimum. In grapevine, E. lata caused a mean lesion length of 48.38 mm, whereas Atonik treatment reduced it to 12.29 mm. Absolute qPCR indicated higher VvSOD transcript abundance in treated plants. RNA-seq analysis identified 168 genes associated with infection and 43 genes associated with treatment. The results suggest that sodium nitrophenolates may reduce wood necrosis caused by E. lata through a combination of direct antifungal activity and modulation of grapevine defence responses.

plant biology↗

bioRxiv2026

Comparative genomics of Cadophora luteo-olivacea reveals a divergent lineage, conserved functional repertoires, and strain-level variation in pathogenicity

Cadophora luteo-olivacea is an ecologically versatile fungus associated with grapevine trunk diseases, yet the extent to which strains from different hosts and environments differ in genome composition, functional potential, and pathogenicity remains poorly understood. Here, we performed a comparative genomic analysis of 12 C. luteo-olivacea isolates recovered from grapevine, almond, apple, Crocus bulbs, soil, air, wastewater, and deep-sea sediment. Genome assemblies were highly complete (BUSCO >99%) and ranged from 46.94 to 50.70 Mbp. Pairwise average nucleotide identity (ANI) revealed a cohesive 11-strain group and one markedly divergent strain, CBS 266.93. Phylogenomic analysis based on 2,645 single-copy orthologs further showed that CBS 266.93 lies outside the main C. luteo-olivacea clade and forms a sister relationship with Cadophora malorum, indicating that its taxonomic placement warrants reassessment. Across the remaining strains, broad functional conservation was observed, including similar KOG profiles, extensive carbohydrate-active enzyme repertoires (798-849 genes per genome), and abundant biosynthetic gene clusters (26-35 per genome). Transposable element content varied substantially among strains (0.67-4.45% of genome), but this variation did not parallel overall functional profiles. All isolates colonized grapevine leaves in vitro, although lesion severity differed significantly among strains, indicating conserved plant-colonizing capacity with quantitative variation in aggressiveness. Small RNA profiling of inoculated grapevine leaves further revealed isolate-associated differences in host miRNA family expression, particularly for miR398, miR827, and miR156. Together, these results show that most C. luteo-olivacea strains share a conserved genomic framework compatible with plant colonization, while retaining lineage-and strain-level phenotypic and host-associated variation.

genomics↗

bioRxiv2024

Drought influences the fungal community structure, diversity, and functionality inhabiting the grapevine xylem and enhances the abundance of Phaeomoniella chlamydospora

The productivity of grapevines in Mediterranean regions faces significant threats from global warming, which may intensify competition for water resources. Recent research highlights the impact of water deficit on the root-associated microbiota of grapevines, particularly organisms capable of mitigating abiotic and biotic stressors. This study explores the influence of drought on the structure, diversity, and functionality of xylem- inhabiting fungal communities of grapevine, with a focus on the fungal pathogen Phaeomoniella chlamydospora associated with esca and Petri diseases. One-year-old grapevine rootlings grown under greenhouse conditions were subjected to three water regimes: severe water deficit (SWD) at 25% of field capacity, moderate water deficit (MWD) at 50% of field capacity, and no water deficit (AWD) at 100% of field capacity. Wood samples were non-destructively collected before planting (t0) and one (t1) and two (t2) growing seasons after planting from the bottom, medium, and apical parts of the rootstock. Fungal composition and P. chlamydospora abundance were assessed using ITS high-throughput amplicon sequencing (HTAS) and droplet-digital PCR (ddPCR), respectively. The induced water stress not only altered the diversity and composition of the fungal microbiome in the xylem vessels but also affected co- occurrence networks, resulting in less complex networks with fewer correlations between taxa, potentially increasing grapevine vulnerability to various biotic and abiotic stresses. SWD significantly reduced microbial diversity, leading to a shift in the abundance of pathotrophs such as P. chlamydospora in the xylem. This underscores the interconnectedness between water stress, microbiome dynamics, and plant health. The combination of compromised plant defenses, altered physiological conditions, and shifts in the surrounding microbial community may create conditions conducive to increased P. chlamydospora abundance in the xylem vessels of young vines following water stress.

microbiology↗

bioRxiv2020

Grapevine pruning time affects natural wound colonization by wood-invading fungi

Grapevine pruning wounds made during the dormant season are a port of entry of wood-invading fungi. Timing of pruning may affect the wound susceptibility to these fungi, such as those associated with grapevine trunk diseases (GTDs). This study aimed to determine the effect of pruning time on natural fungal infection in six vineyards in Galicia, Spain, belonging to three Denominations of Origin (D.O) over two growing seasons. Pruning wounds were left unprotected physically and chemically during two periods of three months each, from November to February and from February to May. The diversity and composition of the fungal microbiome that colonized the pruning wounds was identified by ITS2 high-throughput amplicon sequencing (HTAS). A broad range of fungi was able to colonize grapevine pruning wounds at both infection periods. Fungal microbiome composition did not shift as year of sampling. Fungal communities were affected in their diversity and composition by the D.O., whereas the spatial variation (i.e. vineyard within each region) was low. Pruned canes harboured a core community of fungal species, which appeared to be independent of the infection period. Accumulated rainfall over 8 and 11 weeks after pruning positively correlated with the total fungal microbiome and in particular with the GTD fungal genus Diaporthe abundances. A strong seasonal effect on GTD fungal infection was detected for most genera, with higher percentages of abundance detected after pruning in February (winter) as compared with that of pruning in November (mid-autumn). In light of the GTD colonization results and given the environmental conditions and the geographical location of this study, early pruning is recommended to reduce the infections caused by GTD fungi during the pruning season in Galicia.

microbiology↗