Multifunctional amaranth cystatin inhibits endogenous and digestive insect cysteine endopeptidases: A potential tool to prevent proteolysis and for the control of insect pests

Abstract

In a previous study, the amaranth cystatin was characterized. This cystatin is believed to provide protection from abiotic stress because its transcription is induced in response to heat, drought, and salinity. It has also been shown that recombinant amaranth cystatin inhibits bromelain, ficin, and cysteine endopeptidases from fungal sources and also inhibits the growth of phytopathogenic fungi. In the present study, evidence is presented regarding the potential function of amaranth cystatin as a regulator of endogenous proteinases and insect digestive proteinases. During amaranth germination and seedling growth, different proteolytic profiles were observed at different pH levels in gelatin-containing SDS-PAGE. Most of the proteolytic enzymes detected at pH 4.5 were mainly inhibited by trans-epoxysuccinyl-leucyl amido(4-guanidino)butane (E-64) and the purified recombinant amaranth cystatin. Furthermore, the recombinant amaranth cystatin was active against insect proteinases. In particular, the E-64-sensitive proteolytic digestive enzymes from Callosobruchus maculatus, Zabrotes subfasciatus, and Acanthoscelides obtectus were inhibited by the amaranth cystatin. Taken together, these results suggest multiple roles for cystatin in amaranth, specifically during germination and seedling growth and in the protection of A. hypochondriacus against insect predation. Amaranth cystatin represents a promising tool for diverse applications in the control of insect pest and for preventing undesirable proteolytic activity.

The role of gibberellin synthase geneGhGA2ox1in upland cotton (Gossypium hirsutumL.) responses to drought and salt stress

“…and Valdés‐Rodríguez et al. . A constant electric current of 40 mA was used to run two gels for 6 H.…”

Expression of cysteine proteinases and cystatins in parasites and use of cysteine proteinase inhibitors in parasitic diseases. Part II: Arthropods

“…Concerning the use of CPIs of natural herbs, amaranth CYS proved to have effective proteolytic activity against a wide range of CPs detected in ticks infestation of plants, suggesting its role in control of insect pests (34) . The present review will only focus on the role and function(s) of CPs and CYSs, of medically important ticks which transmit or potentially transmit human diseases.…”

Phytocystatins: Defense Proteins against Phytophagous Insects and Acari

“…Mostly, recombinant cystatins have been used to perform in vitro inhibitory assays using specific protease substrates and protein extracts or purified digestive proteases from arthropods. This approach generates rapid and useful information about the proteolytic profiles and cystatin binding affinities [37,38,76,77] and is particularly used for the tailoring and selection of PhyCys for pest control (see Section 4). …”