Two Photolyases Repair Distinct DNA Lesions and Reactivate UVB-Inactivated Conidia of an Insect Mycopathogen under Visible Light
| Autor: | Sheng-Hua Ying, Ding-Yi Wang, Bo Fu, Sen-Miao Tong, Ming-Guang Feng |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Insecta
DNA Repair Light DNA damage Ultraviolet Rays Mutant Conidiation Beauveria bassiana Pyrimidine dimer Applied Microbiology and Biotechnology Radiation Tolerance Microbiology 03 medical and health sciences chemistry.chemical_compound Gene Expression Regulation Fungal Invertebrate Microbiology Animals Photolyase skin and connective tissue diseases 030304 developmental biology Cell Nucleus 0303 health sciences Ecology biology integumentary system 030306 microbiology DNA Spores Fungal biology.organism_classification chemistry Pyrimidine Dimers Photoprotection Deoxyribodipyrimidine Photo-Lyase Food Science Biotechnology DNA Damage |
| Popis: | Fungal conidia serve as active ingredients of fungal insecticides but are sensitive to solar UV irradiation, which impairs double-stranded DNA (dsDNA) by inducing the production of cytotoxic cyclobutane pyrimidine dimers (CPDs) and (6-4)-pyrimidine-pyrimidine photoproducts (6-4PPs). This study aims to elucidate how CPD photolyase (Phr1) and 6-4PP photolyase (Phr2) repair DNA damage and photoreactivate UVB-inactivated cells in Beauveria bassiana, a main source of fungal insecticides. Both Phr1 and Phr2 are proven to exclusively localize in the fungal nuclei. Despite little influence on growth, conidiation, and virulence, singular deletions of phr1 and phr2 resulted in respective reductions of 38% and 19% in conidial tolerance to UVB irradiation, a sunlight component most harmful to formulated conidia. CPDs and 6-4PPs accumulated significantly more in the cells of Δphr1 and Δphr2 mutants than in those of a wild-type strain under lethal UVB irradiation and were largely or completely repaired by Phr1 in the Δphr2 mutant and Phr2 in the Δphr1 mutant after optimal 5-h exposure to visible light. Consequently, UVB-inactivated conidia of the Δphr1 and Δphr2 mutants were much less efficiently photoreactivated than were the wild-type counterparts. In contrast, overexpression of either phr1 or phr2 in the wild-type strain resulted in marked increases in both conidial UVB resistance and photoreactivation efficiency. These findings indicate essential roles of Phr1 and Phr2 in photoprotection of B. bassiana from UVB damage and unveil exploitable values of both photolyase genes for improved UVB resistance and application strategy of fungal insecticides. IMPORTANCE Protecting fungal cells from damage from solar UVB irradiation is critical for development and application of fungal insecticides but is mechanistically not understood in Beauveria bassiana, a classic insect pathogen. We unveil that two intranuclear photolyases, Phr1 and Phr2, play essential roles in repairing UVB-induced dsDNA lesions through respective decomposition of cytotoxic cyclobutane pyrimidine dimers and (6-4)-pyrimidine-pyrimidine photoproducts, hence reactivating UVB-inactivated cells effectively under visible light. Our findings shed light on the high potential of both photolyase genes for use in improving UVB resistance and application strategy of fungal insecticides. |
| Databáze: | OpenAIRE |
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