|KANOBE, MILLY - Iowa State University|
|RODERMEL, STEVE - Iowa State University|
|BAILEY, THEODORE - Iowa State University|
Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2013
Publication Date: 6/14/2013
Citation: Kanobe, M.N., Rodermel, S.R., Bailey, T., Scott, M.P. 2013. Changes in endogenous gene transcript and protein levels in maize plants expressing the soybean ferritin transgene. Frontiers in Plant Science. 4:196 DOI: 10.3389/fpls.2013.00196.
Interpretive Summary: Iron deficiency anemia is one of the most important nutrition problems in the world. One proposed soloution is called biofortification and this solution involves developing transgenic crops engineered to contain more nutritionally available iron. Several groups have developed biofortified maize by adding a gene from soybean called ferritin. It has been shown that this approach is effective at increasing levels of iron in the seeds, but relatively little is known about the effects of the transgene on expression of other genes in the seed, especially on the seed storage proteins. We compared transgenic and non-transgenic lines and identified effects on gene expression, but overall they were minor. These data will be valuable to researchers intersted in fine-tuning expression of soybean ferritin in maize and may facilitate production of maize varieties with imporoved iron nutrition.
Technical Abstract: Transgenic agricultural crops with increased nutritive value present prospects for contributing to public health. However, their acceptance is poor in many countries due to the perception that genetic modification may cause unintended effects on expression of native genes in the host plant. Here, we tested effects of soybean ferritin transgene (SoyFer1, M64337) on transcript and protein levels of endogenous genes in maize. Results showed that the transgene was successfully introduced and expressed in the maize seed endosperm. mRNA abundance of seven tested iron homeostasis genes and seed storage protein genes differed significantly between seed samples positive and negative for the transgene. The PCR negative samples had higher zein and total protein content compared to the positive samples. However, PCR positive samples had significantly higher concentrations of calcium, magnesium and iron. We have shown that the soybean ferritin transgene affected the expression of native iron homeostasis genes in the maize plant. These results underscore the importance of taking a holistic approach to the evaluation of transgenic events in target plants, comparing the transgenic plant to the untransformed controls.