Table 3. Glycine max cv. Osumi root attachment.

Inoculant	CFU/cm of proximal root	CFU/cm of lateral root
None	0±0*	0±0*
SMH12	1.68±0.18×105	1.22±0.29×104
SVQ648	1.10±0.42×105	3.83±0.5×103*
SMH12 (pME6863)	5.00±0.10×104*	8.45±0.46×102*
SMH12 (pME6000)	1.55±0.27×105	1.20±0.39×104

Soybean plants were inoculated with the test strains, one centimetre of the proximal root and of the lateral roots of each plant were collected after 7 days, and the bacteria present were resuspended and plated. Data are the mean ± SD of at least three independent experiments performed in triplicate. Mutant nodD1 and the lactonase strain attachment were individually compared with the parental strain SMH12 attachment by using the Mann-Whitney non-parametric test. Values tagged by * are significantly different at the level α = 5%.