Expression analysis by semi-quantitative RT-PCR
Total RNA was extracted from young leaves
of 2-week-old rice seedlings using the TRIzol
method (Life Technologies, USA). The extracted
RNA was treated with DNase I (New England
Biolabs, UK) at 37 oC for 10 min to remove
contaminated DNA. The DNase I – treated RNA
samples were reverse transcribed by Superscript III
first-strand synthesis system (Life Technologies,
USA) according to the manufacturer’s instructions.
For the template, 1 g of total RNA was used in a
10 l Reverse Transcription (RT) reaction. The RT
profile was as follows: denaturation and annealing of oligo
(dT) at 65 oC for 5 min, reverse transcription at 50 oC for
50 min, and reaction termination at 85 oC for 5 min.
Gene-specific primers were designed from
coding regions of different rice anthocyanin structural
genes. A list of primers was shown in Table 1.
Amplification of target cDNA was performed with
GoTaq® Green Master Mix. The PCR profile was 95
oC for 3 min, 27 cycles at 95 oC for 1 min, 52-56 oC
for 1 min and 72 oC for 1 min, and 5 min at 72 oC
for the final extension. Aliquots of PCR products
were analyzed on a 1 % (w/v) agarose gel by
electrophoresis. For semi-quantitative RT-PCR
assays, the total amount of cDNA in samples was
standardized after the amount of actin mRNA was
evaluated with an OsActin primer pair (Table 1).