To confirm the expression of human Lf in alfalfa
plants, RT-PCR, ELISA, and Western blot analyses were
performed. Accumulation of human Lf mRNAs was
detected only in the clone 53 using gene-specific primers,
amplifying a fragment corresponding to the expected
356 bp PCR product when positive control was used as a
template (Fig. 3B). Although presence of human Lf
transcripts was not detected in the other clones, they were
included in further experiments
RT-PCR analysis confirming presence of human Lf
mRNA in plant cells
high quality recombinant protein as well as for quality
improvement of this important forage crop. As the
production of recombinant protein with high authenticity
is of significant importance for its application as
therapeutic agent as well as for achieving crop quality
improvement, we aimed obtaining full length Lf in alfalfa
plants. Our results have shown that transformation of
alfalfa with human Lf cDNA under control of the
35S CaMV promoter using Agrobacterium tumefciensmediated
gene transfer leads to production of recombinant
human Lf with molecular mass of approximately 80
kDa in leaf alfalfa extracts which corresponds to the size
of the native protein. Maximum expression level of the
recombinant human Lf, determined by ELISA assay, was
0.0047 % of TSP (clone 53). It is comparable to
previously reported expression levels in transgenic alfalfa
plants bearing a gene encoding the avian reovirus σC
protein under control of the 35S CaMV promoter (Huang
et al. 2006) and could be explained with the relative low
efficiency of this constitutive promoter in alfalfa
compared to other dicotyledoneus species (D’Aoust et al.
2004). Different expression of recombinant human Lf in
leaf tissue are reported in other systems – tobacco (0.1 -
0.8 % of TSP) (Zhang et al. 1998, Salmon et al. 1998)
and potato (0.01 - 0.1 % of TSP) (Chong and Langridge