Assessing the Efficacy of Broad-Spectrum Antibiotics in Controlling Bacterial Contamination in the In Vitro Micropropagation of Ginger (Zingiber officinale Rosc)

Abstract

Ginger (Zingiber officinale Rosc) (Zingiberaceae) is a livelihood and commercial crop in Ethiopia. But, the availability of clean and healthy planting materials has become a problem due to wilt disease, caused by Ralstonia solanacearum Biovar 3 Race 4. This problem obliged growers to seek for tens of millions of vigorous and disease-free planting materials very quickly via in vitro micropropagation of shoot tip explants. For this purpose, protocols of sterilizing shoot tip explants and controlling bacterial contamination of one Ethiopian ginger cultivar called Deribo were tested. Hence, this article reports the finding of a study that aimed at testing the (a) effectiveness of three sterilization agents, namely, 0.25% w/v RBK (composed of ridomile, bayleton, and kocide at 1 : 1 : 1 ratio), 0.50% v/v NaOCl, and 70% v/v ethanol at three different treatment times in combination with 0.25% HgCl2; (b) efficacy of four broad-spectrum antibiotics and their combinations in controlling bacterial contaminants of ginger shoot tip explants and in vitro micropropagation media; and (c) effects of the antibiotics on the shooting performances of the explants of the cultivar. A 0.50% v/v NaOCl at exposure time of 20 min followed by 0.25% HgCl2 has resulted in 80% contamination-free and 70% live explants after three weeks of incubation. Likewise, cefotaxime at 50, 100, and 200 mg/L and cefotaxime plus streptomycin at 25, 50, and 100 mg/L yielded 87 to 93% contamination-free microshoots after three weeks of culturing. The number of explants killed by the antibiotics increased with increasing the concentration of the antibiotics. Cefotaxime at 50 mg/L and cefotaxime plus streptomycin at 25 mg/L yielded significantly highest mean microshoots per explant (7.10 ± 0.36 and 7.51 ± 0.27, respectively) and mean shoot length (4.2 ± 0.26 and 3.56 ± 0.17 cm, respectively). Some of the microshoots showed some yellowing. But, they turned green and grew normal after subcultured into fresh, antibiotics-free culture media. These findings are important foundations towards developing more optimized protocols of sterilizing explants and controlling bacterial contaminants for large-scale in vitro micropropagation of the Deribo ginger cultivar.

OPTIMISATION OF CULTURE CONDITION FOR SACHA INCHI (Plukenetia Volubilis) CALLUS INDUCTION

“…Generally, 70% ethanol is used as pre-treatment with other sterilizing agent and aid well in sterilization, but it is also known for its phototoxic effects and dehydration ability towards plant tissue (Mahmoud and Al-Ani, 2016). The effectiveness of ethanol is dependent on the exposure time, where overexposure can reduce the rate of success (Tewelde et al, 2020). For fragile and thin immature leaves and flower buds, both were optimized to be soaked in 70% ethanol for only 30 seconds as longer exposure was not effective in removing contaminants and might damage the explant tissues due to the phytotoxicity of the alcohol (Rodrigues et al, 2013).…”

Enhanced Carbonylation of Photosynthetic and Glycolytic Proteins in Antibiotic Timentin-Treated Tobacco In Vitro Shoot Culture

“…To eliminate microbial contamination in the plant tissue culture, a variety of antibiotics and application strategies have been adapted, including medium supplementation with a microbial growth-inhibiting concentration [19] or pretreatment with a high dose of antibiotics [20]. Although the treatment is often reported to improve the propagation or regenerative properties of the tissues [21][22][23][24][25], antibiotics could be toxic to plant cells, especially at the higher concentration that is required for effective decontamination, and even short-term exposure to antibiotics can affect plant growth and development, resulting in reduced plant tissue propagation capacity [26,27]. The negative effect of antibiotics depends on the concentration and duration of exposure, which varies for different plant species [28,29].…”