Arginine depletion as a defense mechanism in maize against the larval pests Spodoptera frugiperda and S. littoralis

• Grant number: 16/10469-4
• Support Opportunities: Scholarships abroad - Research
• Start date: July 17, 2016
• End date: December 20, 2016
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Massuo Jorge Kato
• Grantee: Massuo Jorge Kato
• Host Investigator: Jonathan Gershenzon
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Max Planck Society, Jena, Germany
• Associated research grant: 14/50316-7 - Dimensions US-Biota São Paulo: Chemically mediated multi-trophic interaction diversity across tropical gradients, AP.BTA.TEM

Abstract

Some plant proteins have been detected in frass of caterpillars (i.e. post-digestion), suggesting that they are particularly resistant to digestive proteases and can play a role in continuous post-ingestion defense. Some of them are JA-responsive, some of them clearly implicated in plant defense. Depletion of specific amino acids has been proposed as a plant defense mechanism, in tomato by threonine deaminase and arginase, respectively, leading to nutrient imbalances.In maize, two particular proteins found in frass suggest that depletion of the semi-essential amino acid Arg may be important in this plant too: Arg decarboxylase (forming agmatine + CO2) and agmatine deiminase. Agmatine has also some reported bioactivities, and especially can inhibit Arg decarboxylase, justifying why both enzymes are present and could be active.