OCCURRENCE, PHYSIOLOGICAL AND MOLECULAR ANALYSIS OF ENDOPHYTIC DIAZOTROPHIC BACTERIA IN GRAMINEOUS ENERGY PLANTS

Endophytic diazotrophic bacteria could be isolated from the energy pla nts Pennisetum purpureum, Miscanthus sinensis, Miscanthus sacchariflor us and Spartina pectinata using semisolid nitrogen free media. Higher levels of diazotrophic bacteria were found if no nitrogen fertilizer w as applied. The bacteria were characterized on the basis of typical mo rphology, physiological tests, and the use of phylogenetic oligonucleo tide probes. They belong partially to the species Azospirillum lipofer um and Herbaspirillum seropedicae while others supposedly represent a new species of Herbaspirillum. Using PCR-fingerprinting techniques a l imited genetic diversity of these isolates was found which may indicat e an adaptation to the specific conditions of the interior of these pl ants.