Fig. 3. Levels of transcripts, enzyme activities, and MdFRK2 protein in leaves from transgenic lines.

a Schematic diagram of vector construct. b Semiquantitative RT-PCR. WT, wild-type; L1, L4, and L9, MdFRK2-OE lines. c Western blotting using the specific monoclonal antibody generated from rabbit. Amount of protein extract loading was referenced by immunoblot analysis with anti-Actin antibody. M: protein marker. d, e Quantitative RT-PCR of MdFRKs expression and MdFRK activity in mature leaves from wild-type (WT) and transgenic lines (L1, L4, and L9), respectively. f Phenotype of wild-type (WT) and transgenic lines (L1, L4, and L9). In (b, d), the MdActin gene was used as internal control. Error bars represent SD based on 3 independent replicates. Statistically significant differences among values (at P < 0.05) were detected with independent t-tests and SPSS software. Scale bar = 2 cm