The phylogenetic diversity of cowpea root-nodulating bacteria in the South-West of Japan was investigated using 60 isolates. Seeds of cowpea were aseptically sown in vermiculite and inoculated with a suspension of Cowpea Soil (CS) or Bean Soil (BS) or without a soil suspension as a control. CS and BS were collected from the Kyushu University's farm (Japan) at sites where cowpea and bean, respectively, have been cultivated previously. Based on an analysis of the 16S rRNA gene and the Internal Transcribed Spacer (ITS) sequence between the 16S and 23S rRNA genes, 56 isolates were assigned to the genus Bradyrhizobium, while one isolate was found to be closely related to the genus Ralstonia. The ITS-based phylogeny showed 53 isolates, 2 isolates, and 1 isolate, to be closely related to B. yuanmingense, B. elkanii and B. japonicum, respectively, suggesting that B. yuanmingense strains predominated in the soils. Among the isolates tested, B. yuanmingense TSC10 and TTC9 exhibited a greater symbiotic activity and could be considered efficient inoculants for cowpea.

In Table3, TSC1 isolate was shown nodulating the four cowpea cultivars with an acetylene-reducing activity. However, by further purification of the TSC1 culture on AIE agar plates, it is likely that it was contaminated with compatible bradyrhizobia which certainly had caused the nodulation when TSC1 was inoculated to cowpea. In addition, repetitive inoculations tests of this purified isolate (TSC1) to cowpea have indicated that Ralstonia sp. TSC1 has no nodulation and no nitrogen fixation capability. As a result, we decide to delete the previous Table 3, and edited the text as follows:Page 110, line 13 to 19 of left column (Cross-inoculation with TSC1………..Dan IIa, Tv-7778): Cross-inoculation with TSC1 (data not shown) indicated that this strain didn't react with any of the four host cultivars and had no nodulation and no nitrogen fixation capability.Page 111, line 17 to 19 of left column (Further molecular analysis……..symbiotic characteristic): Further analysis should be carried out on the novel species isolated from cowpea (Ralstonia sp. TSC1) to better understand its features.The paper has scientific significance in that it provides valuable information on the diversity and phylogeny of cowpea nodulating-bacteria in the West-South area of Japan. Furthermore, among the isolates described in the paper, strains with high nitrogen-fixing potential were identified.