Plant Pathology and Microbiology Publications Plant Pathology and Microbiology 2021 A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores Seung Ho Chung Boyce Thompson Institute for Plant Research Mahdiyeh Bigham Boyce Thompson Institute for Plant Research Ryan R. Lappe Iowa State University, [email protected] Barry Chan University of California, Davis Ugrappa Nagalakshmi University of California, Davis See next page for additional authors Follow this and additional works at: https://lib.dr.iastate.edu/plantpath_pubs Part of the Agricultural Science Commons, Agriculture Commons, Plant Breeding and Genetics Commons, and the Plant Pathology Commons The complete bibliographic information for this item can be found at https://lib.dr.iastate.edu/ plantpath_pubs/306. For information on how to cite this item, please visit http://lib.dr.iastate.edu/howtocite.html. This Article is brought to you for free and open access by the Plant Pathology and Microbiology at Iowa State University Digital Repository. It has been accepted for inclusion in Plant Pathology and Microbiology Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores Abstract Spodoptera frugiperda (fall armyworm) is a notorious pest that threatens maize production worldwide. Current control measures involve the use of chemical insecticides and transgenic maize expressing Bacillus thuringiensis (Bt) toxins. Although additional transgenes have confirmed insecticidal activity, limited research has been conducted in maize, at least partially due to the technical difficulty of maize transformation. Here, we describe implementation of a sugarcane mosaic virus (SCMV) vector for rapidly testing the efficacy of both endogenous maize genes and heterologous genes from other organisms for the control of S. frugiperda in maize. Four categories of proteins were tested using the SCMV vector: (i) maize defence signalling proteins: peptide elicitors (Pep1 and Pep3) and jasmonate acid conjugating enzymes (JAR1a and JAR1b); (ii) maize defensive proteins: the previously identified ribosome‐inactivating protein (RIP2) and maize proteinase inhibitor (MPI), and two proteins with predicted but unconfirmed anti‐insect activities, an antimicrobial peptide (AMP) and a lectin (JAC1); (iii) lectins from other plant species: Allium cepa agglutinin (ACA) and Galanthus nivalis agglutinin (GNA); and (iv) scorpion and spider toxins: peptides from Urodacus yaschenkoi (UyCT3 and UyCT5) and Hadronyche versuta (Hvt). In most cases, S. frugiperda larval growth was reduced by transient SCMV‐mediated overexpression of genes encoding these proteins. Additionally, experiments with a subset of the SCMV‐expressed genes showed effectiveness against two aphid species, Rhopalosiphum maidis (corn leaf aphid) and Myzus persicae (green peach aphid). Together, these results demonstrate that SCMV vectors are a rapid screening method for testing the efficacy and insecticidal activity of candidate genes in maize. Keywords maize, Zea mays, Spodoptera frugiperda, fall armyworm, Rhopalosiphum maidis, Myzus persicae, sugarcane mosaic virus, peptide elicitors, venom toxins, lectins Disciplines Agricultural Science | Agriculture | Plant Breeding and Genetics | Plant Pathology Comments This article is published as Chung, Seung Ho, Mahdiyeh Bigham, Ryan R. Lappe, Barry Chan, Ugrappa Nagalakshmi, Steven A. Whitham, Savithramma P. Dinesh‐Kumar, and Georg Jander. "A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores." Plant Biotechnology Journal (2021). doi:10.1111/pbi.13585. Creative Commons License This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License Authors Seung Ho Chung, Mahdiyeh Bigham, Ryan R. Lappe, Barry Chan, Ugrappa Nagalakshmi, Steven A. Whitham, Savithramma P. Dinesh-Kumar, and Georg Jander This article is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/plantpath_pubs/306 Plant Biotechnology Journal (2021), pp. 1–12 doi: 10.1111/pbi.13585 A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores Seung Ho Chung1 , Mahdiyeh Bigham1, Ryan R. Lappe2, Barry Chan3, Ugrappa Nagalakshmi3, Steven A. Whitham2, Savithramma P. Dinesh-Kumar3 and Georg Jander1,* 1Boyce Thompson Institute for Plant Research, Ithaca, NY, USA 2Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, USA 3Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, CA, USA Received 6 January 2021; Summary revised 7 March 2021; Spodoptera frugiperda (fall armyworm) is a notorious pest that threatens maize production accepted 16 March 2021. worldwide. Current control measures involve the use of chemical insecticides and transgenic *Correspondence (Tel 1 607 254 1365; maize expressing Bacillus thuringiensis (Bt) toxins. Although additional transgenes have email [email protected]) confirmed insecticidal activity, limited research has been conducted in maize, at least partially due to the technical difficulty of maize transformation. Here, we describe implementation of a sugarcane mosaic virus (SCMV) vector for rapidly testing the efficacy of both endogenous maize genes and heterologous genes from other organisms for the control of S. frugiperda in maize. Four categories of proteins were tested using the SCMV vector: (i) maize defence signalling proteins: peptide elicitors (Pep1 and Pep3) and jasmonate acid conjugating enzymes (JAR1a and JAR1b); (ii) maize defensive proteins: the previously identified ribosome-inactivating protein (RIP2) and maize proteinase inhibitor (MPI), and two proteins with predicted but unconfirmed anti-insect activities, an antimicrobial peptide (AMP) and a lectin (JAC1); (iii) lectins from other plant species: Allium cepa agglutinin (ACA) and Galanthus nivalis agglutinin (GNA); and (iv) scorpion and spider toxins: peptides from Urodacus yaschenkoi (UyCT3 and UyCT5) and Hadronyche versuta (Hvt). In most cases, S. frugiperda larval growth was reduced by transient Keywords: maize, Zea mays, SCMV-mediated overexpression of genes encoding these proteins. Additionally, experiments Spodoptera frugiperda, fall armyworm, with a subset of the SCMV-expressed genes showed effectiveness against two aphid species, Rhopalosiphum maidis, Myzus Rhopalosiphum maidis (corn leaf aphid) and Myzus persicae (green peach aphid). Together, persicae, sugarcane mosaic virus, these results demonstrate that SCMV vectors are a rapid screening method for testing the peptide elicitors, venom toxins, lectins. efficacy and insecticidal activity of candidate genes in maize. Introduction ground plant parts, S. frugiperda larvae reduce photosynthetic area, cause developmental delays and decrease yield. Maize (Zea mays) is one of the world’s most important cereal Currently available S. frugiperda control methods, both appli- crops, serving not only as a food source for humans and livestock, cation of chemical insecticides (Togola et al., 2018) and but also as a raw material for the production of ethanol and other transgenic maize producing Bacillus thuringiensis (Bt) toxins industrial products (Ai and Jane, 2016; Chaudhary et al., 2014). (Huang et al., 2014; Tabashnik and Carriere, 2017), are becoming The needs of an ever-expanding population will lead to increasing less effective as the insects develop resistance. Therefore, there is demands on maize production in the coming years. Therefore, a need to screen for additional transgenes that can be used to maintaining adequate maize yields will require reducing not only enhance maize resistance to S. frugiperda feeding. Broadly, such the cost of agricultural inputs, but also the negative impacts of approaches can include upregulation of maize defence signalling, biotic and abiotic stresses that limit maize productivity. overexpression of individual maize defensive proteins and expres- More than 100 species of insect pests feed on maize plants in sion of heterologous insecticidal proteins. agricultural fields (McMullen et al., 2009; Meihls et al., 2012). Plant elicitor peptides (Peps) trigger anti-herbivore defence Among these pests, one of the most damaging is Spodoptera responses (Huffaker, 2015; Huffaker et al., 2013; Poretsky et al., frugiperda (fall armyworm; Figure 1a), a lepidopteran species that 2020). In maize, ZmPep1 and ZmPep3 up-regulate defences, at is indigenous to the Americas but recently has become invasive in least in part by induction of the jasmonic acid (JA) signalling Africa and Asia (Food and Agriculture Organization of the United pathway (Huffaker et al., 2011, 2013). A key step in the JA Nations, 2018; Goergen et al., 2016). By consuming all above- pathway is the conjugation of JA with isoleucine by JAR1 Please cite this article as: Chung, S. H., Bigham, M., Lappe, R. R., Chan, B., Nagalakshmi, U., Whitham, S. A., Dinesh-Kumar, S. P. and Jander, G. (2021) A sugarcane mosaic virus vector for rapid in planta screening of proteins that inhibit the growth of insect herbivores. Plant Biotechnol. J., https://doi.org/10.1111/ pbi.13585 ª 2021 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and