Evaluation and development of mango explant decontamination protocol for micropropagation.
Andrade S. R. M. de, Pinto A. C. de Q., Faleiro F. G., Cordeiro M. C. R., Ramos V. H. V., Teixeira J. B.
Author Affiliation: Embrapa Cerrados, BR 020, Km 18, Rod. Brasília/Fortaleza, Caixa Postal 08223, CEP 73310-970, Planaltina, DF, Brazil.
Boletim de Pesquisa e Desenvolvimento - Embrapa Cerrados : 24 pp.
Abstract : A protocol was developed for the decontamination of internodal segments to establish methods for micropropagation of mango lateral buds. The first step was to develop a superficial decontamination of the explants followed by a control of microorganism growth into the medium. The results demonstrate that explants need to be pretreated with neutral detergent in tap water, a mixture with hypochlorite and Tween, and 15 seconds of sonication in 500 mg benomyl/litre before incubation in the solution. Treatment with 70% ethanol followed by 1% hypochlorite and 30 minutes of 500 mg benomyl/litre immersion was the most efficient for superficial decontamination. In general, the treatments were efficient for decontamination of superficial fungi, however, they did not eliminate contamination of endogenous bacteria and fungi. Inclusion of copper sulfate (25 and 50 mg/litre) into the nutrient medium controlled the endogenous fungi although it failed to control the endogenous bacteria. The evaluation demonstrated that the bacteria are Gram positive and resistant to rifampicin (300 mg/litre), kanamycin (150 mg/litre), ampicillin (150 mg/litre), tetracycline (150 mg/litre), chloramphenicol (150 mg/litre), carbenicillin (150 mg/litre) and streptomycin (300 mg/litre). However, the combination of 80 mg sulfamethoxazole + 16 mg trimetroprim/litre or 80 mg sulfamethoxazole/litre alone showed satisfactory results on the control of endogenous bacteria, while 16 mg trimethoprim/litre did not work alone.