Response of Transgenic Cucumber and Carrot Plants Expressing Different Chitinase Enzymes to Inoculation with Fungal Pathogens

Genes from mycoparasitic fungi as a source for improving plant resistance to fungal pathogens

“…Plant genes encoding cell wall degrading enzymes, especially chitinases, have been used to alter plant resistance to fungal pathogens, but no single genes have produced an adequate level of resistance (11)(12)(13)(14), and almost no papers report resistance to multiple pathogens. Reasons for this may be that plant chitinases: (i) usually affect only the hyphal tip and are unable to effectively degrade harder chitin structures, (ii) have weak antifungal activity alone, (iii) are inhibitory only to a limited number of fungal species, and (iv) have no effect on several important pathogens (15)(16)(17).…”

Engineering disease resistance in plants

“…And although all plants studied so far seem to have defence systems induced by salicylic acid, jasmonic acid and ethylene, the effector antipathogenic proteins and compounds differ considerably. In an elegant demonstration of the difficulty of this strategy, Punja and Raharjo (1996) showed that transfer of a chitinase gene, which encodes a protein that degrades the cell wall of many fungi, to two different crops resulted in a resistance-elevating effect in carrot, but not in cucumber, even when the same pathogen was used to challenge the crops. But with the ongoing genome sequencing of key agricultural crops, and advances in the study of antimicrobial gene expression , it will probably be possible to identify the 'gaps' in pathogen defence of certain plant species, and so complement these systems more effectively.…”

Cloning and Characterization of a Balsam Pear Class I Chitinase Gene (Mcchit1) and Its Ectopic Expression Enhances Fungal Resistance in Transgenic Plants

“…1) With chitinolytic and antifungal activities, chitinases have been used to counter fungi directly and by expressing them in vivo in a wide scope. [2][3][4][5][6][7][8] Many chitinases have been expressed in various plants to enhance resistance against fungal disease, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and also resistance to spiders and insects. [20][21][22] When a powerful fungal endochitinase from a mycoparasitic fungus, Trichoderma, was expressed, the transgenic plants showed high resistance to a broad spectrum of fungal pathogens.…”

“…[20][21][22] When a powerful fungal endochitinase from a mycoparasitic fungus, Trichoderma, was expressed, the transgenic plants showed high resistance to a broad spectrum of fungal pathogens. [10][11][12]14,15) However, it was frequently found that expressing a single chitinase gene enhanced resistance only against a limited number of pathogens and/or to an inadequate level in transgenic plants, [3][4][5][6][7] which is probably to be attributed to the low chitinolytic and antifungal activities of the chitinases in question. 10) Therefore, it is important to clone new genes encoding chitinases with high chitinolytic and antifungal activities for use in plant engineering against fungal diseases.…”