16S
rRNA gene was used as internal standard, which was obtained
based on the following RT-PCR primers P1 50 ACGATCCGTAACTGGTCTGA
30 and P2 50 TTCGCACCTCAGTGTCAGTA 30 . All
the RNA purification, cDNA reverse transcription of P. putida
KTMQ01, P. putida KTMQ01 (pBBR1MCS-2) and P. putida KT2442
were adjusted to the same concentration based on the absorbance
value.