Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation.

AUTOR(ES)

Harlow, G R

RESUMO

A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage.

Documentos Relacionados

• An Arabidopsis photolyase mutant is hypersensitive to ultraviolet-B radiation
• Sensitivity of aflatoxin b1 to ionizing radiation.
• An Arabidopsis mutant hypersensitive to red and far-red light signals.
• p53 mutations increase resistance to ionizing radiation.
• Inactivation of carotenoid-producing and albino strains of Neurospora crassa by visible light, blacklight, and ultraviolet radiation.