Alternaria alternata – the main causal agent of disease symptoms in juniper, rose, yew and highbush blueberry in nurseries in southern Poland

Abstract

Symptoms of discoloration and necrosis of the leaves/needles and shoots of plants are an increasingly common phenomenon in nurseries. They necessitate the withdrawal of the affected plants from sale, which has significant economic consequences. In 2010-2011, observations were conducted of the health of shrubs in nurseries of the Małopolska province. Disease symptoms were mostly found in juniper (Juniperus horizontalis 'Wiltonii'), rose (ground-cover rose 'Star Profusion'), yew (Taxus × media 'Hillii') and highbush blueberry (Vaccinium corymbosum 'Patriot'). These species were selected for further study. The affected shrubs represented more than 46% of the population of a given species. Fragments of the diseased organs: the leaves or needles, the base of the shoots, and the roots, were collected from the borderline between healthy and diseased tissue, and used to isolate and identify the microorganisms colonizing the diseased parts. The affected organs were found to be inhabited to the largest extent by the fungus Alternaria alternata (Fr.) Keissl., which accounted for 19.7 to 47.5% of the isolates from the tested species of shrubs. There were also large populations of fungi of the genera: Botrytis (up to 9.82%), Cladosporium (up to 5.66%), Colletotrichum (up to 5.13%), Fusarium (up to 18.38%), Mortierella (up to 7.26%), Pestalotia (up to 5.36%), Rhizoctonia (up to 5.36%), Sclerotinia (up to 6.99%), and Trichoderma (up to 17.09%). The fungus A. alternata, being by far the dominant pathogen, was tested for its pathogenicity for the shoots of the chosen species of shrubs. The test was conducted for 14 days in a chamber with parameters so programmed that they reflected the natural conditions at the height of the growing season. The fungus A. alternata exhibited pathogenicity for all of the tested species of shrubs. Necrosis developed on all the inoculated fragments of shoots. The surface area of necrotic lesions was larger on the shoots of juniper and blueberry.

Mycobiota of juniper Juniperus x media with symptoms of dieback in sewage plant facilities area in Poznań

“…Among 200 other Septoria species occurring in Poland, many cause spotting and necrosis of the herbaceous parts of plants. The infection of juniper by a fungal community similar to that found at the sewage treatment facility in Poznań was previously observed by Nadziakiewicz et al (2018).…”

Tomato Cultivars With Variable Tolerances to Water Deficit Differentially Modulate the Composition and Interaction Patterns of Their Rhizosphere Microbial Communities

“…Thus, these specific microorganisms from the TRz under DI that belong to taxa with known beneficial characteristics for plants, could be contributing to the tolerant phenotype, highlighting the metabolic bidirectionality of the holobiont system. Remarkably, some other fungal over-represented OTUs in the TRz under DI have also been associated with plant pathogenesis ( Zhang et al, 2005 ; Nadziakiewicz et al, 2018 ; Campos-Rivero et al, 2019 ; Jastrzêbska et al, 2020 ). Notwithstanding, since none of the plants in this study showed signs of any disease, these results emphasize that the development of an infectious disease depends on particular environmental factors and host-microbe interactions ( Bass et al, 2019 ), being some potential pathogens even plausibly relevant for the adaptation of plants to water deficit.…”

Endophytic mycobiota associated to plants of Vaccinium corymbosum L. in Cañete valley- Perú

“…(Citrus, 2005). In addition, in V. corymbosum, species of Lasiodiplodia (Rodríguez-Gálvez et al, 2020), Nigrospora sphaerica (Wright et al, 2007), Alternaria alternata (Nadziakiewicz et al, 2018), Cladosporium tenuiussimum were identified as pathogens. (Lei et al, 2019), Stemphylium sp.…”