One bacteria endophyte were isolated from the root nodules of Podocarpus macrophyllus(Thunb.)D.Don.The bacteria has the ordinary characteristics of Rhizobium of leguminous plants after indentification.It made nodulation on its host after inoculation strains.So did on Podocarpus nagi(Thunb.)zoll.et Mor.ex Zoll. seedling which is of the same family and genus with Podocarpus macrophyllus(Thunb.)D.Don.Both strain and host seeding have C 2H 4 reduction activity.But it can not made nodulation on 11 kind of offering tests of leguminous plants after inoculation strains.According to its characteristics the bacteria thus appears to be a member of a disinct Rhizobium lineage.Its phylogenetic relationship position remain to be research.
Symbiotic nitrogen fixation of rhizobia and leguminous plants is considered as the most important biologic nitrogen fixation system on earth. Symbiotic nodulation of gymnosperm Podocarpus macro-phyllus and rhizobia has never been reported. In this study, 11 endophytic bacteria strains were isolated from root nodules of P. macrophyllus and its variation P. macrophyllus var. maki. The plant infection tests on these strains indicated that the isolated strains could be nodulated on P. macrophyllus plants, and weak nitrogenase activity of nodules was found in acetylene reduction method. According to the physiological and biochemical characteristics of the 11 strains, GXLO 02 was selected as the representative strain. 16S rDNA full-length sequence analysis of GXLO 02 confirmed that the representative strain GXLO 02 belongs to Rhizobium sp.
HUANG BaoLing, LU ChengQun, WU Bo & FAN LiQin 1 Forestry College, Guangxi University, Nanning 530004, China
