Studying On Endotrophic Bacteria In The Root Nodule Of Podocarpus

20 strains of endotrophic bacteria in the root nodule of Podocarpus were idetified phylogenetic relationship in the first time which had been isolated from different Podocarpus growing different stands.Firstly,the result of the morphological character shows that all strains are short bacillus and gram-negative bacteria except DL7 strain;40%strains have gemma,and the strains which isolated from the root nodule of Podocarpus macrophyllus (Thunb.) have more similar morphological character with Rhizobium than the others.Secondly,in the result of the physiology and biochemical character,we know that 25%strains can produce 3-keto-lactose;45%strains can utilize amylum;40%strains can grow better on the substrade of peptone-laction medium than on the YMA medium;50%strains can hydrolysis gelatin;55%strains can use citrate;and in B.T.B experiment,L7,DL7 strains show negative,the other strains produce acid and make the indicater yellow;L3,L5,DL5 strains are oxidisability type,the others strains are zymolysis type in glucose zymolysis test;in ethanooysis test,25%strains show positive,and only DL8 strain can hydrolyze L-arginine in argininase test;the greater part of strains can utilize carbon and inorganic nitrogen better than do the amino-acid.In the stress tolerance experiment,20 strains not only have strong stress tolerance to acid-base,NaCl,but also to high temperature.such as in 39℃ temperature,all strains grow well;even in 60℃ water bath culturing 30min,thereare 45%strains can still live on the YMA medium.Greater part of strains nodulate after inoculanting back to the host or to the Robinia Pseudoacacia linn;and there are 40%strains can nodulate and cross-nodulate at the same time.Based on the former researches of morphological character,physiological and biochemical character,Ll,L2,L7,L8 strains are defined Rhizobium;L3,L4, L5,DL2,DL3,DL7,JM3,JM4 strains are defined Bacillus;L6, DL1,DL5,DL6, DL8,DL9 strains can not be defined, because these strains not only display some character of Rhizobium,but also do some other character.they have to do further study.Account on the resust of former research,full-length 16S rDNA sequences of representative strains L2,L7,DL7 were sequenced.The result indicated that L2,L7 strains are Rhizobium,and L2 strain has 99% similarity values with Rhizobium lusitanum strain P1-7,L7 strain has 99% similarity values with Candidatus Rhizobium massibiae; DL7 strain is Bacillus and has 98% similarity value with Bacillus megaterium KL-197.