|IVIC-HAYMES, SNEZANA - Walter Reed Army Medical Center|
|SAVIC, JELENA - University Of Belgrade|
Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2013
Publication Date: 2/26/2013
Citation: Smigocki, A.C., Ivic-Haymes, S., Li, H., Savic, J. 2013. Pest protection conferred by A Beta vulgaris serine proteinase inhibitor gene. PLoS One. 8(2):e57303.
Interpretive Summary: A genetic trait (BvSTI gene) that has potential to increase insect and disease resistance in plants was isolated from sugar beet. To study the effect of this gene on insect resistance, the gene was re-designed so that its product can be synthesized in genetically modified tobacco plants (Nicotiana benthamiana). We demonstrate that the growth and development of five insects that fed on these modified plants were impaired. These results suggest that the sugar beet gene may be useful for control of insect pests on plants other than sugar beet. Scientists will use this information to identify new genetic traits that will lead to new approaches for increasing pest and disease resistance in crop plants.
Technical Abstract: Proteinase inhibitors provide a means of engineering plant resistance to insect pests. A Beta vulgaris serine proteinase inhibitor gene (BvSTI) was fused to the constitutive CaMV35S promoter for over-expression in Nicotiana benthamiana plants to study its effect on lepidopteran insect pests. Independently derived BvSTI transgenic Nicotiana T2 homozygous progeny were shown to have relatively high BvSTI gene transcript levels. BvSTI-specific polyclonal antibodies cross-reacted with the expected 30 kDA recombinant BvSTI protein on Western blots. In gel trypsin inhibitor activity assays revealed a major clear zone that corresponded to the BvSTI proteinase inhibitor that was not detected in the untransformed control plants. BvSTI-transgenic plants were bioassayed for resistance to five lepidopteran insect pests. Spodoptera frugiperda, S. exigua and Manduca sexta larvae fed BvSTI leaves had significant reductions in larval weights as compared to larvae fed on untransformed leaves. In contrast, larval weights increased relative to the controls when Heliothis virescens and Agrotis ipsilon larvae were fed on BvSTI leaves. As the larvae entered the pupal stage, pupal sizes reflected the overall larval weights. Some developmental abnormalities of the pupae and emerging moths were noted. These findings suggest that the sugar beet BvSTI gene may prove useful for effective control of several different lepidopteran insect pests in genetically modified Nicotiana. The sugar beet serine proteinase inhibitor may be more effective for insect control because sugar beet is cropped in restricted geographical areas thus limiting the exposure of the insects to sugar beet proteinase inhibitors and build up of non-sensitive midgut proteases.