Identification of new reference genes for colony counting by reverse-transcription quantitative PCR in Bifidobacterium animalis

Bifidobacterium animalis, one of the predominant bacteria in intestines humans and other mammals, is widely added to dairy products. We employed RNA sequencing analyze gene expression variance on a genome-wide scale found stable reference genes (RG) B. animalis. A total 1,665 were identified by analyzing data from transcriptome under 4 different conditions, 13 probable candidate RG with variation coefficient values <0.1 validated using reverse-transcription quantitative PCR (RT-qPCR). The amplification efficiency ranging 94.16% 126.25%. integrated analysis results BestKeeper, geNorm, NormFinder, RefFinder algorithms revealed that rplD atpA comprehensive ranked 1.68 2.82, respectively, which more than traditional RG. Compared plate count (1.58 × 106 cfu/mL), concentrations animalis AR668 RT-qPCR rplD, atpA, 16S rRNA as 2.27 106, 2.24 6.66 cfu/mL, after 10 h fermentation fermented skim milk. It suggested can be accurate for colony counting Our study provides foundation foods.