Chitinases of fungi and plants: their involvement in morphogenesis and host-parasite interaction

Abstract

There has been a considerable amount of recent research aimed at elucidating the roles of chitinase in fungi and plants. In filamentous fungi and yeasts, chitinase is involved integrally in cell wall morphogenesis. Chitinase is also involved in the early events of host‐parasite interactions of biotrophic and necrotrophic mycoparasites, entomopathogenic fungi and vesicular arbuscular mycorrhizal fungi. In plants, induction of chitinase and other hydrolytic enzymes is one of a coordinated, often complex and multifaceted defense mechanism triggered in response to phytopathogen attack. Chitinase induction in plants is not considered solely as an antifungal resistance mechanism. Plant chitinases can be induced by various abiotic factors as well and there is some circumstantial evidence to suggest a morphogenetic role despite the apparent absence of the substrate in plant cells. Finally, some chitinases and other chitin‐binding proteins including some plant lectins share chitin‐binding domains as part of their molecular structure and provide fuel for the so‐called ‘lectin‐chitinase’ debate and speculation for the origin of chitinase in plants.

Purification and Characterization of Human Chitotriosidase, a Novel Member of the Chitinase Family of Proteins

“…Interestingly, in plants, chitinases are believed to be involved in defense against pathogens as well as morphogenetic processes that involve remodeling (see Ref. 21, and references therein). The role of the chitinases in morphogenesis is poorly understood since plants do not contain endogenous chitin.…”

Purification and characterization of chitinases from Paecilomyces variotii DG-3 parasitizing on Meloidogyne incognita eggs

“…Some extracellular chitinases from entomopathogenic fungi have been considered to be important for pathogenicity. The 33,43.5,45, and 60 kDa chitinases from Metarhizium anisopliae, and 45.0 kDa endochitinase from Beauveria bassiana have been puriWed and characterized [14,19]. Compared with extracellular chitinases of mycoparasitic and entomopathogenic fungi, only a few from nematophagous fungi including 52 kDa chitinase from Paecilomyces lilacinus [15] and 43 kDa from Pochonia chlamydosporium (syn.…”

“…Fungi produce various isoforms of chitinase with diVerent biophysical functions including lysis of the cell walls (separation of cells after division, hyphal autolysis), nutritional requirements, morphogenetic formation (sporulation, spore germination, and hyphal growth), antagonistic, and parasitic actions against other organisms [31,33]. On the basis of their amino acid sequences and three-dimensional structures, fungal chitinases belong to glycoside hydrolase family 18, class III with a catalytic ( / ) 8 barrel domain [6,7,9].…”

Produção, purificação, clonagem e aplicação de enzimas líticas

“…Estudos de difração de raio-X demonstraram que se refere a uma estrutura cristalina altamente ordenada e insolúvel em água 27 . Na maioria dos fungos a quitina é o maior componente estrutural da parede celular, sendo, portanto, susceptível a inúmeras espé-cies de bactérias, actinomicetos e fungos que podem agir como antagonistas devido à produção de enzimas quitinolíticas 28 . É o segundo biopolímero mais abundante depois da celulose e está geralmente ligada a outros polissacarídeos e proteínas 26 .…”