|Rajasekaran, Kanniah - Rajah|
Submitted to: Aflatoxin Elimination Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/1/2002
Publication Date: 10/15/2002
Citation: Weissinger, A., Wu, M., Liu, Y., Ingram, K., Rajasekaran, K., Cleveland, T.E. 2002. Development of transgenic peanut with enhanced resistance against preharvest aflatoxin contamination. Proceedings of the 14th Aflatoxin Elimination Workshop, October 23-26, 2001, Phoenix, Arizona. p. 140. Interpretive Summary:
Technical Abstract: Transformation of plants with genes encoding various toxic peptides has been proposed as a means of combating fungal pathogens. An interesting approach involves the use of wholly synthetic Peptidyl Membrane Interactive Molecules (MIM®), small peptides which were developed by Demegen, Inc., some of which closely mimic naturally occurring molecules such as cecropins. Previously, we attempted to make transgenic peanut plants using a gene encoding Peptidyl MIM® "D5C", an alpha-helical peptide (MW 4000) that is highly active against A. flavus. Of 128 putative transgenic plant lines recovered, fifteen carried the D5C transgene, but none contained D5C mRNA, nor was the D5C peptide detected by western blots capable of detecting the peptide at a level of 1 ng, or about 0.3% of total soluble protein. Primary transgenic peanut plants yielded significantly fewer pods than control plants. Bioassays for antifungal activity of leaf extracts against A. flavus and Verticillium dahiliae failed to detect any significant difference between transgenic and control plants. These, and subsequent experimental results, indicate that D5C exhibits marked phytotoxicity at levels known to be required to kill A. flavus. Further, these results suggest that the phytotoxicity of D5C makes it unsuitable for antifungal applications in peanut.