Table 3.

Relative expression of fatty acid degradation genes in S. meliloti cultures of two strains at exponential and stationary phases of growth

Gene	Relative expression ratio, 1021 vs. 1021FDC5a
	Microarrays (OD, 1.2)b	RT-qPCR (OD, 1.2)c	RT-qPCR (OD, 0.8)c
smc02229	11.96	80.64 ± 28.93	−1.65 ± 0.22
fadA	3.5	ND	ND
fadB	2.8	11.68 ± 4.9	1.18 ± 0.1

^aData correspond to results obtained from cultures of the two strains grown in Robertsen medium. Similar results were obtained from cultures grown in Sherwood medium (data not shown). Cultures in stationary phase (OD, 1.2) were used for the microarray experiments; cultures in either the stationary or exponential (OD, 0.8) growth phase were used in the RT-qPCRs. ND, not determined.

^bFold changes in gene expression obtained in the microarray experiments were calculated as 2^M (see text).

^cFold changes in gene expression obtained from RT-qPCR were calculated from C_T values obtained from real-time PCR experiments using the comparative ΔΔC_T method (37). The smc03224 gene coding for 16S rRNA was used as an internal control. Data are averages from two independent biological experiments with three technical replicates. The minus sign indicates a decreased fold change in 1021. The standard errors of the means from the RT-qPCRs are shown.