Abstract

Carbohydrate-active enzymes including glycosidases, transglycosidases, glycosyltransferases, polysaccharide lyases and carbohydrate esterases are responsible for the enzymatic processing of carbohydrates in plants. A number of carbohydrate-active enzymes are produced by microbial pathogens and insects responsible of severe crop losses. Plants have evolved proteinaceous inhibitors to modulate the activity of several of these enzymes. The continuing discovery of new inhibitors indicates that this research area is still unexplored and may lead to new exciting developments. To date, the role of the inhibitors is not completely understood. Here we review recent results obtained on the best characterised inhibitors, pointing to their possible biological role in vivo. Results recently obtained with plant transformation technology indicate that this class of inhibitors has potential biotechnological applications.

Author Keywords: Glycosidase proteinaceous inhibitor; Plant defense; Plant development

Abbreviations: α-AIs, α-amylase inhibitors; AMY1 and AMY2, α-amylases isozyme 1 and 2 from barley seeds; ATBI, alkalo-thermophilic Bacillus sp. inhibitor; BASI, barley α-amylase/subtilisin inhibitor; EDGPs, extracellular dermal glycoproteins; GIP, endoglucanase inhibiting protein; LRR; leucine-rich repeat; PME, pectin methylesterases; PMEI, Pectin methylesterase inhibitors; PL, pectin lyase; PNLIP, pectin lyase inhibitor; PHA, phytohemagglutinin; PG, polygalacturonase; PGIP, polygalacturonase inhibiting protein; RASI, rice α-amylase/subtilisin inhibitor; RG, rhamnogalacturonase; TAXI-I and TAXI-II, Triticum aestivum xylanase inhibitors; WASI, Wheat α-amylase/subtilisin inhibitor; XIP-I, xylanase inhibitor protein I; XEGIP, xyloglucan-specific endoglucanase inhibitor

Article Outline

1. Introduction

2. Inhibitors of pectic enzymes

2.1. PGIPs

2.2. PMEI

3. Xylanase inhibitors

3.1. Taxi-type xylanase inhibitors

3.2. XIP-I type xylanase inhibitor

3.2.1. Potential role of xylanase inhibitors

4. α-Amylase inhibitors

4.1. BASI

4.2. Lectin-like α-amylase inhibitors

5. Conclusions

Acknowledgements

References

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