Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 17, 2004
Publication Date: August 11, 2004
Citation: Johnson, E.T., Dowd, P.F. Differentially enhanced insect resistance, at a cost, in Arabidopsis thaliana constitutively expressing a transcription factor of defensive metabolites. Journal of Agricultural and Food Chemistry. 52(16):5135-5138. Interpretive Summary: Insect damage to crops causes billions of dollars of losses each year and indirect losses due to contamination with mold toxins. Resistant plants produced by biotechnology have significantly reduced insect damage and mold toxins, but the best method of deploying resistance genes is unclear. In a model plant system, we found triggering multiple defensive chemical pathways with a single gene change could increase resistance to one insect species, but not another; and production of seed was also reduced compared to wild type plants. This study indicates strategies to enhance plant insect resistance involving biotechnology need to be carefully regulated to avoid yield losses.
Technical Abstract: A transgenic line of Arabidopsis thaliana that constitutively expresses a conserved MYB transcription factor of phenylpropanoid biosynthesis resulting in solid-purple leaves had relatively strong resistance to leaf feeding by first instar fall armyworms (Spodoptera frugiperda), but no resistance to cabbage looper (Trichoplusia ni larvae), when compared to wild-type plants. However, flower stalk and silique production were significantly reduced (by 22% and nearly twofold, respectively) in the transgenic line compared to wild-type plants. Reduction in feeding by Spodopetera frugiperda was significantly positively correlated with reduction in weights of survivors, but both were negatively correlated with the concentration of anthocyanins. These results indicate that a single gene regulator can activate a defensive pathway sufficient to produce increased resistance to insects, but that this activation confers a cost in plant productivity.