Detection ofnifHSequences in Sugarcane (Saccharum officinarumL.) and Pineapple (Ananas comosus[L.] Merr.)

To detect N,-Axing bacteria in a plant without using culture methods, n@H gene segments were amplified with degenerate primers from DNA extracted from stems of sugarcane (Succhurum omcinurum L.) and leaves of pineapple (Ananas comosus [L.] Merr.).Sequences of the n@H clones were homologous to those of bacteria in the genera Brudyrhizobium, Serrutiu, and KZebsieZZu.The bacteria with n@H sequences homologous to those of the three genera may be promising candidates for predominant endophytic diazotrophs in sugarcane and pineapple, because these sequences were commonly detected in samples from different host plants, which were collected at difperent locations.On the other hand, no n@H sequence related to GZuconucetobucter diazotrophicus, which is an endophytic N,-Axing bacterium and had been previously isolated from sugarcane, was detected in sugarcane.This indicates the absence or the presence of few G. diuzotrophicus in the stems of the sugarcane plants used in the current study.