Field study on changes in viability of airborne fungal propagules exposed to UV radiation

Abstract

The responses of airborne fungi to UV-B under natural conditions were investigated at the coastal station in Preila, Lithuania. Results of this investigation demonstrated that solar radiation has a marked lethal effect on outdoor airborne fungi. Sensitivity to solar radiation was the highest for the fungal propagules collected late in the evening (relative recovery 6.2%) and early morning (25.3%). The lowest sensitivity to solar radiation was observed for fungal propagules collected at midday (50.0%) and in the afternoon (53.0%). The reason for the lethal effect is thought to be elimination of the sensitive fraction of the night-time fungal populations as solar radiation gradually increases beginning at dawn. Among 356 fungus strains isolated during the investigations, 128 can be characterized as potential pathogens, and 21 strains among those most common in fungal populations belonging to plant, animal, and human pathogen groups. The collected fungal populations were exposed to solar UV-B irradiation for 2 h (from 12 p.m. to 2 p.m.). Fungal communities in the air samples were composed of saprotrophs, some of which are regarded as potential phytopathogens (Alternaria, Cladosporium, and Fusarium) or as entomopathogens (Beauveria, Paecilomyces, and Metarhizium). The airborne fungal species identified after exposure to solar radiation were predominantly: Aspergillus niger, Alternaria alternata, Cladosporium cladosporioides, Arthrinium phaerosporum, and dematiaceous sterile mycelium.

Epidemiology and Population Biology of Pseudoperonospora cubensis: A Model System for Management of Downy Mildews

“…These results are similar to those reported for potato late blight, where solar radiation is the most important variable in survival of Phytophthora infestans sporangia (64). Deleterious effects of solar radiation on spores are primarily due to the UV-B spectrum (112). Total solar radiation has been found to explain the same degree of variation in survival of P. cubensis sporangia as does UV radiation (54).…”

Conidia survival of Aspergillus section Nigri, Flavi and Circumdati under UV‐A and UV‐B radiation with cycling temperature/light regime

“…Some authors have suggested that conidia pigmentation could represent an important protection against UV radiation . Three differently coloured conidia of Aspergillus were tested in our experiment: yellow, green and black, belonging to sections Circumdati , Flavi and Nigri , respectively.…”

“…Although information concerning the effects of UV‐B on fungi and bacteria is scarce, studies on microfungal communities in soils of extreme habitats, such as desert (very high solar radiation, drought, and extreme temperatures), suggest the dominance of dark‐coloured microfungi with large multicelled conidia . Likewise, the main airborne fungal species identified at a coastal station after exposure to solar radiation were predominantly Aspergillus niger , Alternaria alternata , Cladosporium cladosporoides and Arthrinium phaerosporum . Therefore, Aspergillus species could prevail over other species under high‐UV‐radiation environments.…”

Effects of enhanced UV-B radiation on the diversity and activity of soil microorganism of alpine meadow ecosystem in Qinghai–Tibet Plateau

“…Some bacteria (e.g., QT4, QT6) presented in the enhanced UV-B treatment, not in CK. This may because species diversity was affected by solar UV-B radiation because of species-specific sensitivity to the radiation and another studies reported that UV-B radiation could alter the plant and its root exudates, so some of the soil bacteria were stimulated or inhibited (Kashimada et al 1996;Piccini et al 2009;Ulevičius et al 2004). …”