A maizewin protein confers enhanced antiinsect and antifungal resistance when the gene is transgenically expressed in maize callus

Authors: Dowd, Patrick; Naumann, Todd; Johnson, Eric; Price, Neil

Submitted to: Plant Gene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2020
Publication Date: 10/17/2020
Citation: Dowd, P.F., Naumann, T.A., Johnson, E.T., Price, N.P. 2020. A maizewin protein confers enhanced antiinsect and antifungal resistance when the gene is transgenically expressed in maize callus. Plant Gene. 24. Article 100259. https://doi.org/10.1016/j.plgene.2020.100259.
DOI: https://doi.org/10.1016/j.plgene.2020.100259

Interpretive Summary: Insects and diseases greatly reduce corn yields. Corn ear molds can produce toxins harmful to people and animals, causing hundreds of millions of dollars in losses in the U.S. alone. Plant resistance is an economical means to reduce corn ear damage caused by insects and corn ear molds, but there continues to be a need to determine what genes are involved in producing resistance. A gene isolated from a chromosome region that was previously associated with ear rot resistance was evaluated for its resistance role. The gene had a postulated role as an enzyme that degrades components of the fungal cell wall. When introduced into corn cells, cell clumps that had the gene reduced growth of maize pest caterpillars and representative ear rot fungi compared to cell clumps that did not contain the gene. Analysis of the cell clumps that were active against insects and fungi for enzymatic activity supported a role in degrading the fungal cell wall. This knowledge can be used to guide breeding for insect and ear rot resistance in crop plants, thereby enhancing yield, quality and safety.

Technical Abstract: Maize in a crop of worldwide importance, but insects and plant pathogens limit sustainable production. The development of maize varieties with improved resistance will be facilitated by identification of relevant resistance alleles through appropriate biological assays. A barwin-like gene (which we call maizewin) located in a QTL for Fusarium resistance annotated such that potential glucanase and chitinase activity could occur in the translated protein, was cloned from an ear rot resistant inbred and transgenically expressed in maize callus. Although limited increases in insect resistance occurred in the transgenic callus material containing the maizewin gene compared to a GUS control gene, resistance to Fusarium pathogens was common and associated with increased glucanase activity. The gene appeared to produce a protein with glucanase and chitosanase activity, consistent with an antifungal role. The allele that produces the functional resistant protein may be relatively uncommon in maize germplasm. Incorporation of a functional maizewin allele into susceptible germplasm should help increase production by contributing to control of both insect pests and plant pathogens.