Higher expression of induced defenses in teosintes (Zea spp.) is correlated with greater resistance to fall armyworm, Spodoptera frugiperda. Issue 2 (4th December 2012)

• Record Type: Journal Article
• Authors: Szczepaniec, Adrianna; Widney, Sarah E.; Bernal, Julio S.; Eubanks, Micky D.
• Is Part Of: Entomologia experimentalis et applicata. Volume 146:Issue 2(2013:Feb.)
• Page Start: 242
• Page End: 251
• Publication Date: 2012-12-04
• Subjects: Entomology -- Periodicals; 595.7
• DOI: 10.1111/eea.12014
• Languages: English
• ISSNs: 0013-8703

Abstract

<abstract abstract-type="main" id="eea12014-abs-0001"> <title>Abstract</title> <p>Selection for plant traits important for agriculture can come at a high cost to plant defenses. While selecting for increased growth rate and yield, domestication and subsequent breeding may lead to weakened defenses and greater susceptibility of plants to herbivores. We tested whether expression of defense genes differed among maize, <italic>Zea mays</italic> ssp. <italic>mays </italic>L. (Poaceae), and its wild relatives <italic>Zea mays</italic> ssp. <italic>parviglumis </italic>Iltis & Doebley and <italic>Zea diploperennis </italic>Iltis et al. We used two populations of <italic>Z. mays</italic> ssp. <italic>parviglumis</italic>: one expected to express high levels of an herbivore resistance gene, wound‐inducible protein (<italic>wip1</italic>), and another expected to have low expression of <italic>wip1</italic>. To test whether maize and wild <italic>Zea</italic> differed in induction of defenses against <italic>Spodoptera frugiperda</italic> (Smith) (Lepidoptera: Noctuidae), we quantified expression of several genes involved in plant defense: <italic>wip1</italic>, maize protease inhibitor (<italic>mpi</italic>), pathogenesis‐related protein (<italic>PR‐1</italic>), and <italic>chitinase</italic>. Moreover, we compared growth, development, and survival of caterpillars on maize and wild <italic>Zea</italic> plants. We found that maize expressed low levels of all but one of the genes when attacked by caterpillars, whereas the wild relatives of maize expressed induced defense genes at high levels. Expression of <italic>wip1</italic>, in particular, was much greater in the <italic>Z. mays</italic> ssp. <italic>parviglumis</italic> population that we expected to naturally express high levels of <italic>wip1</italic>, with expression levels 29‐fold higher than in herbivore‐free plants. Elevated expression of defenses in wild plants was correlated with higher resistance to caterpillars. Larvae were 15–20% smaller on wild <italic>Zea</italic> compared with maize, developed 20% slower, and only 22% of them survived to pupation on <italic>Z. mays</italic> ssp. <italic>parviglumis</italic> with high levels of <italic>wip1</italic>. Our results suggest that domestication has inadvertently reduced the resistance of maize, and it is likely that expression of <italic>wip1</italic> and other genes associated with defenses play an important role in this reduction in resistance.</p> </abstract>