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During a study of Botryosphaeriaceae species associated with grapevine trunk diseases in the Czech Republic, a collection of 22 Botryosphaeriaceae-like strains were isolated from four cultivars (Blaufränkisch, Pálava, Pinot Noir, and Welschriesling) in four distinct vineyards. Based on morphology and DNA sequence data (ITS, tub2, and tef), four species were identified: Botryosphaeria dothidea, Diplodia mutila, D. seriata, and Neofusicoccum parvum. These species are reported for the first time from grapevine in the Czech Republic. Relationships between vascular lesions and particular species were highlighted in this study. Diplodia seriata was the most frequently isolated species, present in all four sampled cultivars, while D. mutila was the least frequent, present only in 'Pálava'. The cultivar Pinot Noir was the most tolerant host for Botryosphaeriaceae fungi. [ABSTRACT FROM AUTHOR]

Diaporthe species are important pathogens, saprobes, and endophytes on grapevines. Several species are known, either as agents of pre- or post-harvest infections, as causal agents of many relevant diseases, including swelling arm, trunk cankers, leaf spots, root and fruit rots, wilts, and cane bleaching. A growing body of evidence exists that a class of small non-coding endogenous RNAs, known as microRNAs (miRNAs), play an important role in post-transcriptional gene regulation, during plant development and responses to biotic and abiotic stresses. In this study, we explored differentially expressed miRNAs in response to Diaporthe eres and Diaporthe bohemiae infection in Vitis vinifera cv. Chardonnay under in vitro conditions. We used computational methods to predict putative miRNA targets in order to explore the involvement of possible pathogen response pathways. We identified 136 known and 41 new miRNA sequence variants, likely generated through post-transcriptional modifications. In the Diaporthe eres treatment, 61 known and 17 new miRNAs were identified while in the Diaporthe bohemiae treatment, 101 known and 21 new miRNAs were revealed. Our results contribute to further understanding the role miRNAs play during plant pathogenesis, which is possibly crucial in understanding disease symptom development in grapevines infected by D. eres and D. bohemiae. [ABSTRACT FROM AUTHOR]

Fungal trunk diseases (FTDs) have been a significant threat to the global stone fruit industry. FTDs are caused by a consortium of wood-decaying fungi. These fungi colonize woody tissues, causing cankers, dieback, and other decline-related symptoms in host plants. In this study, a detailed screening of the fungal microbiota associated with the decline of stone fruit trees in the Czech Republic was performed. The wood fragments of plum and apricot trees showing symptoms of FTDs were subjected to fungal isolation. The partial internal transcribed spacer region, partial beta-tubulin, and translation elongation factor 1-α genes were amplified from genomic DNA extracted from fungal cultures. All isolates were classified, and the taxonomic placement of pathogenic strains was illustrated in phylogenetic trees. The most abundant pathogenic genus was Dactylonectria (31%), followed by Biscogniauxia (13%), Thelonectria (10%), Eutypa (9%), Dothiorella (7%), Diplodia (6%), and Diaporthe (6%). The most frequent endophytic genus was Aposphaeria (17%). The pathogenicity of six fungal species ( Cadophora daguensis , Collophorina africana , Cytospora sorbicola , Dothiorella sarmentorum , Eutypa lata , and E. petrakii var. petrakii ) to four Prunus spp. was evaluated, and Koch's postulates were fulfilled. All tested isolates caused lesions on at least one Prunus sp. The most aggressive species was E. lata , which caused the largest lesions on all four tested Prunus spp., followed by E. petrakii var. petrakii and D. sarmentorum . Japanese plum ( Prunus salicina ) and almond ( P. amygdalus ) were the most susceptible hosts, while apricot ( P. armeniaca ) was the least susceptible host in the pathogenicity trial., Competing Interests: The author(s) declare no conflict of interest.