UV-B Resistant Yeast Inhabit the Phyllosphere of Strawberry
Ana Gabriele Barbosa Casteliani *
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Vanessa Nessner Kavamura
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Tiago Domingues Zucchi
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Mírian Lobo Sáber
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Rosely Santos do Nascimento
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Rosa Toyoko Shiraishi Frighetto
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Rodrigo Gouvêa Taketani
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
Itamar Soares de Melo
Laboratory of Environmental Microbiology, Embrapa Environment. Jaguariúna, SP, Brazil
*Author to whom correspondence should be addressed.
Abstract
The increase on the worldwide influx of solar ultraviolet radiation (UV-B) has inflicted a considerable challenge, due to its deleterious effects to live beings and pose a special threat to phyllosphere communities. However, UV-B influence on epiphytic yeasts associated with agricultural crops remains limited. Main aim of the present study was to determine the effect of ultraviolet-B radiation on the epiphytic yeast populations associated with strawberry under field conditions. Thus, strawberries (Fragaria x ananassa Duchesne cv. Oso Grande) were grown under three different treatments: a) environmental UV-B, b) enhanced UV-B and c) decreased UV-B; thereafter, their yeast epiphytic populations were analyzed by T-RFLP prior to yeast isolation, identification and in vitro test for the sensitivity against UV-B. Our results demonstrated that UV-B radiation did not significantly affect the strawberry epiphytic yeast populations. However, isolates directly exposed to radiation, generally revealed morphological abnormalities and a diminishing value in the percentage of survival, although they remained constant after 240 min of exposure. The increase in UV-B radiation was not sufficient to affect the dynamics and composition of epiphytic yeast communities from strawberry, there was a clear morphotype shift towards the selection of pigmented isolates.
Keywords: Global warming, field conditions, T-RFLP, leaf surface, phyllosphere