RT Journal Article T1 Inhibitory Properties of Cysteine Protease Pro-Peptides from Barley Confer Resistance to Spider Mite Feeding A1 Santamaria, Estrella A1 Arnaiz, Ana A1 Díaz Mendoza, María Mercedes A1 Martinez, Manuel A1 Diaz, Isabel AB C1A plant cysteine proteases are synthesized as pre-pro-enzymes that need to be processed to become active by the pro-peptide claves off from its cognate enzyme. These pro-sequences play multifunctional roles including the capacity to specifically inhibit their own as well as other C1A protease activities from diverse origin. In this study, it is analysed the potential role of C1A pro-regions from barley as regulators of cysteine proteases in target phytophagous arthropods (coleopteran and acari). The in vitro inhibitory action of these pro-sequences, purified as recombinant proteins, is demonstrated. Moreover, transgenic Arabidopsis plants expressing different fragments of HvPap-1 barley gene containing the pro-peptide sequence were generated and the acaricide function was confirmed by bioassays conducted with the two-spotted spider mite Tetranychus urticae. Feeding trials resulted in a significant reduction of leaf damage in the transgenic lines expressing the pro-peptide in comparison to non-transformed control and strongly correlated with an increase in mite mortality. Additionally, the analysis of the expression levels of a selection of potential mite targets (proteases and protease inhibitors) revealed a mite strategy to counteract the inhibitory activity produced by the C1A barley pro-prodomain. These findings demonstrate that pro-peptides can control mite pests and could be applied as defence proteins in biotechnological systems. PB Public Library of Science YR 2015 FD 2015 LK https://hdl.handle.net/20.500.14352/95876 UL https://hdl.handle.net/20.500.14352/95876 LA eng NO Santamaria ME, Arnaiz A, Diaz-Mendoza M, Martinez M, Diaz I (2015) Inhibitory Properties of Cysteine Protease Pro-Peptides from Barley Confer Resistance to Spider Mite Feeding. PLoS ONE 10(6): e0128323. https://doi.org/10.1371/journal.pone.0128323 NO Ministerio de Economía y Competitividad (España) DS Docta Complutense RD 6 abr 2025