Project description:Sugarcane plantlets from a variety with high inputs of N obtained from BNF (genotype SP70-1143, CTC, Brazil) free of microorganisms were obtained by sterile meristem culture and micropropagation according to the method of Hendre et al. (1983). In vitro-grown SP70-1143 rooted sugarcane plantlets were inoculated as described by James et al. (1994) with 0.1 ml of 106–107 bacterial suspension. Controls were inoculated with medium only. Endophytic diazotrophic bacteria used were Gluconacetobacter diazotrophicus (PAL5 strain) or a mixture of Herbaspirillum seropedicae (HRC54 strain) and H. rubrisubalbicans (HCC103 strain). All plants were maintained at 30°C with an irradiance of 60 µmol photons m–2 s–1 for 12 h d–1. One day after the inoculation, plant tissues were examined for bacterial colonization by the Most Probable Number (MPN) estimation, according to the methods of Reis et al. (1994) and plantlets were collected and immediately frozen in liquid nitrogen. Five plantlets were polled for each treatment. Extraction of total RNA was performed separately on each sample pool. Keywords: comparison of associations with different endophytic bacterias
