M Elena Díaz, Andrea N Peña Malavera, M Francisca Perera and Aldo S Noguera
Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), Estación Experimental Agroindustrial Obispo Colombres (EEAOC) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CCT NOA Sur, Av. William Cross 3150, Las Talitas, Tucumán, R. Argentina, T4101XAC; franciscaperera@yahoo.com.ar
A significant problem in in vitro culture is endogenous contamination (viruses, viroids, bacteria, fungi or yeasts inside cells, in intercellular spaces or vascular bundles) since they cannot be eliminated by chemical disinfection before micropropagation. Those causing in vitro damage (but not necessarily in in vivo conditions) are termed vitropathogens. Bacteria were the main problem in EEAOC’s sugarcane micropropagation, causing loses of 14% of the total production, representing almost 55% of the total production losses. Bacteria not only cause plant death but also decrease multiplication rates, and even cause failures in rooting stage. Two antibiotics (cefotaxime and gentamicin) were evaluated and contaminant bacteria identified by sequencing the 16S region. Cefotaxime was more effective in controlling bacterial growth in in vitro sugarcane cultures without decreasing the multiplication rates. Gentamicin did not control bacterial infection effectively and 2.7% of plants showed phenotypic alterations (chimeras, albinism). Identified bacteria belong to the genera Bacillus and Microbacterium. Given that 73% of the sugarcane area in Tucumán is planted with high-quality seed cane produced by this project, the incorporation of control strategies will positively affect production and profitability.