Biofuels provide a potential route to avoiding the global political instability and environmental issues that arise from reliance on petroleum. Currently, most biofuel is in the form of ethanol generated from starch or sugar, but this can meet only a limited fraction of global fuel requirements. Conversion of cellulosic biomass, which is both abundant and renewable, is a promising alternative. However, the cellulases and pretreatment processes involved are very expensive. Genetically engineering plants to produce cellulases and hemicellulases, and to reduce the need for pretreatment processes through lignin modification, are promising paths to solving this problem, together with other strategies, such as increasing plant polysaccharide content and overall biomass.

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.

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The catalytic domain of Acidothermus cellulolyticus thermostable endoglucanase gene (encoding for endo-1,4-beta-glucanase enzyme or E1) was constitutively expressed in rice. Molecular analyses of T1 plants confirmed presence and expression of the transgene. The amount of E1 enzyme accounted for up to 4.9% of the plant total soluble proteins, and its accumulation had no apparent deleterious effects on plant growth and development. Approximately 22 and 30% of the cellulose of the Ammonia Fiber Explosion (AFEX)-pretreated rice and maize biomass respectively was converted into glucose using rice E1 heterologous enzyme. As rice is the major food crop of the world with minimal use for its straw, our results suggest a successful strategy for producing biologically active hydrolysis enzymes in rice to help generate alcohol fuel, by substituting the wasteful and polluting practice of rice straw burning with an environmentally friendly technology.

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