RESUMO
Resistance to benzimidazole fungicides in many phytopathogenic fungi is caused by specific point mutations in the ß-tubulin gene (ß-tubulin). However, the mutated locus and genotype of ß-tubulin differ among phytopathogenic fungi. To validate the point mutation in Fusarium asiaticum ß2-tubulin that confers resistance to carbendazim and to analyze the molecular interaction between carbendazim and F. asiaticum ß2-tubulin. In this study, a new point mutation (GAGâGCG, E198A) at codon 198 of ß2-tubulin in a wild-type F. asiaticum strain was constructed by site-directed mutagenesis followed by a split marker strategy. The site-directed mutants were verified and exhibited a high level of resistance to carbendazim. In the absence of fungicide treatment, the biological characteristics did not differ between the site-directed mutants and the wild-type strain. Molecular docking between carbendazim and ß2-tubulin was carried out using the Surflex-Dock program in Sybyl X-2.0 version and the results indicated that the E198A mutation altered the configuration of ß2-tubulin, resulting in the change of the bonding sites and docking scores. We concluded that the point mutation of F. asiaticum ß2-tubulin conferring carbendazim resistance may not always be the bonding site for carbendazim.
Assuntos
Benzimidazóis/farmacologia , Carbamatos/farmacologia , Farmacorresistência Fúngica/genética , Fungicidas Industriais/farmacologia , Fusarium/efeitos dos fármacos , Mutação Puntual , Tubulina (Proteína)/genética , Sítios de Ligação , Fusarium/genética , Genes de Plantas , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Mutagênese Sítio-Dirigida , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Bemisia tabaci, a pest insect with stronger capabilities of flying and host plant-exploitation, is capable of flying 150 m high and over a distance as far as 7 km, but hardly flies higher than 0. 5 m and long distance in food-abundant areas. B. tabaci has the characteristics of both searching-and migrating flying, which enable it to exploit and locate on suitable hosts. Up to now, no oogenesis-flight syndrome of B. tabaci has been detected. Visual spectrum, air temperature and relative humidity, host quality, and wind speed are the main factors affecting the flight behavior of B. tabaci. In this paper, the flying capability of B. tabaci and the factors affecting its flight behavior were summarized, and the corresponding IPM strategies in the areas where B. tabaci could not overwintering in open field were discussed.
