Plant chitinases

Abstract

Within the last 10 years, much attention has been focused on the role chitinases play within the plant. Evidence is strong that they are antifungal proteins, yet they may also play a part in a nonspecific stress response and can be developmentally regulated. They consist of several enzyme classes and are produced in many plants by small gene families. This review discusses the nature of these enzymes and the genes that encode them, developmental- and tissue-specific expression, and the classes of organic and inorganic molecules which induce chitinase gene expression and accumulation. Prospects for the development of fungus-resistant varieties of plants using "foreign" chitinase genes are also analyzed. Key words: pathogenesis-related protein, antifungal protein, gene regulation, induction, hydrolase.

Expression of pathogenesis-related (PR) genes in avocados fumigated with thyme oil vapours and control of anthracnose

“…Both β-1,3-glucanase and chitinase genes are known to be regulated in a development-and organ-specific pattern, but stress conditions such as challenge infection by fungi and elicitor treatment also induces their expression (Graham and Sticklen, 1994). Significantly early and higher β-1,3-glucanase and chitinase mRNA levels and enzyme activities were shown in avocado cv.…”

Purification, cDNA cloning, and characterization of LysM-containing plant chitinase from horsetail (Equisetum arvense)

“…The major hydrolysis products from (GlcNAc) 6 were (GlcNAc) 4 , (GlcNAc) 3 , and (GlcNAc) 2 , and those from (GlcNAc) 5 were mainly (GlcNAc) 3 and (GlcNAc) 2 . A small amount of (GlcNAc) 3 , (GlcNAc) 2 , and GlcNAc were detected during (GlcNAc) 4 hydrolysis by EaChiA. In this condition, (GlcNAc) 3 and (GlcNAc) 2 were not degraded by EaChiA (data not shown).…”

“…GH-18 chitinases are widely distributed in a variety of organisms such as bacteria, fungi, animals, and higher plants. However, GH-19 chitinases have been found mainly in seed plants 1,2) and rarely in bacteria. 3) Independent of the CAZy classification, plant chitinases are divided into five classes 1,4,5) and two subclasses 6,7) based on their amino acid sequences and domain architectures: class I chitinases, consisting of an N-terminal chitin-binding domain and a catalytic domain; class II chitinases, which have only a catalytic domain homologous to that of class I chitinases; class IV chitinases, which share homology with class I chitinases, but are smaller as a result of one deletion in the chitin-binding domain and four deletions of loop regions in the catalytic domain; and class II-L chitinases, which are a low molecular weight subclass of class II due to some deletion(s) of the loop region(s).…”

Temporal and spatial expression of mRNAs encoding pathogenesis‐related proteins during ethylene‐promoted leaflet abscission in Sambucus nigra*

“…It is therefore possible that chitinases may have a role in the processes involved in cell wall breakdown that occur during the process of abscission. However, chitinase activity can be dramatically induced by wounding, by pathogen infection, by elicitor treatment with extracts from fungal and plant cell walls and lastly by ethylene (Graham & Stricklen 1994). It is possible, then, that ,IET15 and JETI9 may encode proteins that have a dual function that may have a role in cell wall hydrolysis of plant tissues leading to abscission while protecting those tissues from pathogen invasion.…”