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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 5/17/2017 Publication Date: 11/5/2017 Citation: Dowd, P.F., Johnson, E.T. 2017. A maize defensin active against maize ear insect and fungal pests. Meeting Abstract. Interpretive Summary: Technical Abstract: Identification of genes responsible for pest resistance in maize will assist with breeding attempts to reduced crop losses, and hazards due to toxins produced by molds infecting ears. The same genes may be responsible for producing proteins active against both insects and plant pathogens. A gene coding for a defensin-like protein was cloned from an inbred reported to be resistant to Fusarium proliferatum and Fusarium verticillioides ear rot, based on its location in a QTL associated with resistance to those and other species of ear rot molds that produce mycotoxins. The gene was expressed transgenically in maize callus and the construct presence confirmed in transformants by PCR analysis. The protein was detected with antibody made to a portion of the protein. Positive transformants were more resistant to corn earworms (Helicoverpa zea) and fall armyworms (Spodoptera fruigperda) as indicated by significantly lower weights of larvae fed on callus expressing the defensin gene compared to those fed on control callus expressing a GUS gene. Positive transformant callus also had significantly less visible growth of F. proliferatum and F. verticillioides, but not F. graminearum, than controls. This indicates for the first time a defensin that is active against both insects and fungi, thereby allowing for more effective breeding for resistance to both major classes of pests attacking maize. |
