Biology subjects

Bujanda, R.

Publications and source records attributed to Bujanda, R..

5 recordsLinked to original sources

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↗

bioRxiv2024

Evaluating treatments for the protection of grapevine pruning wounds from natural infection by trunk disease fungi

Infection of grapevines by fungal pathogens causing grapevine trunk diseases (GTDs) primarily arises from annual pruning wounds made during the dormant season. While various studies have showcased the efficacy of products in shielding pruning wounds against GTDs infections, most of these investigations hinge on artificial pathogen inoculations, which may not faithfully mirror real field conditions. This study aimed to evaluate and compare the efficacy of various liquid formulation fungicides (pyraclostrobin + boscalid) and paste treatments, as well as biological control agents (BCA: Trichoderma atroviride SC1, T. atroviride I-1237, and T. asperellum ICC012 + T. gamsii ICC080), for their potential to prevent natural infection of grapevine pruning wounds by trunk disease fungi in two field trials located in Samaniego (Northern Spain) and Madiran (Southern France) over three growing seasons. Wound treatments were applied immediately after pruning in February. One year after pruning, canes were harvested from vines and brought to the laboratory for assessment of Trichoderma spp. and fungal trunk pathogens. More than 1,200 fungal isolates associated with five GTDs (esca, Botryophaeria, Diaporthe and Eutypa diebacks, and Cytospora canker) were collected from the two vineyards each growing season. Our findings reveal that none of the products under investigation exhibited complete effectiveness against all the GTDs. The efficacy of these products was particularly influenced by the specific year of study. A notable exception was observed with the biocontrol agent T. atroviride I-1237, which consistently demonstrated effectiveness against Botryosphaeria dieback infections throughout each year of the study, irrespective of the location. The remaining products exhibited efficacy in specific years or locations against particular diseases, with the physical barrier (paste) showing the least overall effectiveness. The recovery rates of Trichoderma spp. in treated plants were highly variable, ranging from 17% to 100%, with both strains of T. atroviride yielding the highest isolation rates. This study underscores the importance of customizing treatments for specific diseases, taking into account the influence of environmental factors for BCA applications.

microbiology↗

bioRxiv2020

Field evaluation of biocontrol agents against black-foot and Petri diseases of grapevine

BACKGROUNDBlack-foot and Petri diseases are the main fungal diseases associated with young grapevine decline. Two field experiments were established to evaluate the preventive effect of two potential biocontrol agents (BCAs), i.e. Streptomyces sp. E1 + R4 and Pythium oligandrum Po37, and three BCA-commercial products containing Trichoderma atroviride SC1, Trichoderma koningii TK7 and Pseudomonas fluorescens+Bacillus atrophaeus on fungal infection in grafted plants and plant growth parameters. RESULTSThe effectiveness of some BCA in reducing the incidence and severity of both diseases was dependent on the plant part analyzed and the plant age. No single BCA application was able to control both diseases. Streptomyces sp. E1+R4 were able to reduce significantly black-foot disease infection while P. oligandrum Po37 and Trichoderma spp. were able to reduce significantly Petri disease infection. BCA treatments had no effect on the shoot weight, and root weight was significantly lower in all BCA treatments with respect to the control. CONCLUSIONSThe combination of the disease-suppressive activity of two or more beneficial microbes in a biocontrol preparation is required to prevent infection by black-foot and Petri disease fungi in vineyards.

plant biology↗

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↗