Isolation of an endophytic diazotroph,Klebsiella oxytoca,from sweet potato stems in Japan |
| |
| Authors: | Katsuki Adachi Makoto Nakatani Hideyuki Mochida |
| |
| Institution: | Department of Upland Farming Research , National Agricultural Research Center for Kyushu Okinawa Region , Miyakonojo, Miyazaki, 885-0091, Japan |
| |
| Abstract: | Abstract The population density of endophytic bacteria in the stem of field-grown sweet potato cultivars (Beniotome BO], Koganesengan KS], and Shiroyutaka SYD in Miyakonojo, Miyazaki, Japan, ranged from 102 to 104 cells g?1 fresh weight sample using a semi-solid nitrogen-free medium. Eleven strains were isolated from the stems and two isolates, BO-1 and BO-5, showed a positive reaction in the acetylene reduction activity (ARA) test. BO-1 and BO-5 were isolated from cv. Beniotome in September 1999 and 2000, respectively. Morpho-physiological characterization of these isolates revealed that BO-1 and BO-5 showed a similar colony color in potato sucrose agar slants, produced bubbles in a modified semi-solid medium, acidified the medium, and displayed similar characteristics using the API 20NE rapid diagnostic kit. Partial sequence analysis of 16S rRNA from BO-1 revealed a 100% similarity (491 bp) to that of Klebsiella oxytoca. The other 9 isolates showed a negative reaction in the ARA test, slightly acidified or did not acidify the medium. Partial sequence analysis of the 16S rRNA revealed that the isolate SY-2 corresponded to Methylobacterium sp. (99.3% similarity for 1,241 bp), BO-3 to Pantoea agglomerans (99.1% similarity for 469 bp), and BO-8 to Sphingomonas sanguinis (98.8% similarity for 419 bp). |
| |
| Keywords: | endophytic diazotrophs Klebsiella oxytoca N2-fixation non-leguminous crops sweet potato |
|
|
