Plant protection is a major challenge to agriculture worldwide. Yield losses due to fungal attack reach 10-20% on average, and can be more severe in local epidemic infections. The control of fungal diseases in modern agriculture is achieved by integrated pest management, in part based on breeding plant cultivars with resistance to specific fungal races. Alternative strategies are being tested which aim to develop information with broad range fungal resistance by genetic engineering. Monocot and dicot plants respond naturally to fungal attack by a complex network of defence mechanisms. These include enzymes such as ß-1, 3-glucanase and chitinase, which degrade fungal cell wall structural polysaccharides.

Chitinase catalyze the hydrolysis of chitin, a biopolymer of N-acetyl-D-glucosamine. In vitro studies of fungal growth inhibition by chitinases and enhanced resistance of transgenic plants to fungal pathogens are consistent with the hypothesis that chitinases are an important component of plant defence systems. Plant chitinases are the subject of intense research that may ultimately lead to disease resistant crops and decreased use of ecologically harmful pesticides.

Several of these enzymes have been shown to inhibit fungal growth in vitro, and they are therefore candidate anti fungal genes for engineered expression in transgenic plants. Studies have shown that over expression of chitinases in transgenic plants can mediate increased protection against the soil-borne fungi. The introduction of chitinase genes into plants under the control of a constitutive promoter increased plant fungal resistance in greenhouse and field studies.