Identification of novel spp. of rice and wheat endophytic diazotrophs by 16S rDNA gene and FTIR analysis

In this research، six isolates، including three from three rice roots (PxR1، PxR2 and StR1) and three from three wheat roots (PxW1، PxW2 and PxW3) were isolated as endophytic bacteria and except for StR1، all the isolates were identified as Pseudoxanthomonas based on phenotypic analysis including FTIR and PCR amplification of 16S rDNA. The results showed that PxR1، PxR2، PxW1 and PxW2 were all similar and belonged to a novel species of Pseudoxanthomonas، but PxW3 was from different species. StR1 belonged to a novel species of Stenotrophomonas. Two strains including Azospirillum brasiliense Sp7 (S1) and Azospirillum lipoferum (S2) were selected as standard strains and compared with those isolates; however، phenotypic and genotypic analysis verified that those isolates were not Azospirillum. For the first time، it was indicated that Pseudoxanthomonas existed as an endophytic bacterium in rice root.