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Você está aqui: Página Inicial English Version Impacts of UV-B

Impacts of UV-B

UV-B radiation (280 - 320 nm) may increase as a result of ozone depletion in the Earth’s stratosphere. The environmental effects of this increase on plants appear to be a function of photomorphogenetic responses, while plant pathogens may have both photomorphogenetic and harmful responses. Reductions in the plant foliage and accumulation of biomass have been detected in several species in response to high levels of solar UV-B. Growth reductions may result from direct photochemical damage to macromolecules such as proteins and nucleic acids, or be an indirect consequence of increased production of reactive oxygen species in plants exposed to UV-B.


The effects of increased UV-B on plant-pathogen interactions have been studied in only a few pathosystems with experiments using many different techniques. Increased UV-B after inoculation tends to reduce the incidence of diseases, perhaps due to direct damage to the pathogen, but the answers have varied between and within pathogen species. There are considerable reports about the effects of UV light on the germination of fungal spores, hyphal growth, and sporulation. However, few studies in the literature report the effects of UV-B radiation on the occurrence and severity of plant diseases. Likewise, relatively little research exists about the effects on beneficial microbiota, especially on biocontrol agents, symbiotic microorganisms, and non-cultivable microbes.


Answers to these questions will be explored through field and laboratory experiments which simulate the decrease of the ozone layer by approximately 30% using special lamps that emit UV-B and UV-A. Some of the models (host plant-pathogens) studied may guide future research on genetic improvements. 

 

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 Incubation chamber (Figure: Wagner Bettiol – Embrapa Environment)

 

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Soybean experiment at Jaguariúna – SP – Brazil (Photo: Rosa Toyoko Shiraishi Frighetto – Embrapa Environment)

 

 

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Overview of UVB experiment at Jaguariúna – SP – Brazil (Figure: Wagner Bettiol – Embrapa Environment)

General objective

Assess the impact of ultraviolet B (UV-B) in the microbiota associated with plants and the physiological responses of plants to increased UV-B radiation.

Specific Objectives

- Evaluate the impacts of increased UV-B radiation on the physiological responses of soybean that involve induced resistance and changes in enzyme activity;
- Evaluate the resistance or susceptibility of soybean varieties to UV-B and possible mechanisms of DNA repair;
- Evaluate the effects of UV-B on the biological fixation of N2;
- Evaluate the effects of UV-B on cultivatable and non-cultivatable microorganisms of soybeans and coffee using molecular techniques;
- Evaluate the effects of UV-B on the community of yeasts from the phyllosphere;
- Evaluate the effects of UV-B on biological control agents (Metarhizium anisopliae, Beauveria bassiana, Bacillus thuringiensis, Clonostachys rosea and Trichoderma spp.);
- Evaluate the effects of UV-B on coffee leaf rust and bacterial diseases of soybean.