Table 1.
qRT-PCR primer sets used in this study.
Figure 1.
Specificity of qRT-PCR amplification.
A: Melt curves for candidate reference genes. B: Agarose gel (2%) showing amplification of a single product of expected size for each candidate reference gene.
Figure 2.
Expression levels of reference gene candidates.
A: Expression of reference genes across A. brasilense strains. B: Expression of reference genes across different culture conditions. Gene expression levels are represented by average Ct values. NB: nutrient broth; Flocc: Flocculation medium; N-free: Nitrogen free medium. Each bar represents the mean Ct values from three independent experiments. Error bars indicate standard error.
Table 2.
Descriptive statistics of reference gene expression by BestKeeper.
Figure 3.
Analysis of reference gene stability by NormFinder.
Low standard deviation (SD) values indicate stable gene expression. Genes are ordered left to right in order of decreasing stability.
Figure 4.
NormFinder estimation of the optimum number of reference genes.
Lowest accumulated standard deviation (Acc. SD) values indicate the optimal number of reference genes. The recommended upper limit for Acc. SD is set at 0.15.
Figure 5.
Analysis of reference gene stability by GeNorm.
Low stability values (M-values) indicate stable gene expression. Genes are ordered left to right in order of decreasing stability.
Table 3.
Summary of reference gene ranking by BestKeeper, NormFinder and GeNorm analysis.