ISHS Acta Horticulturae 560: IV International Symposium on In Vitro Culture and Horticultural Breeding
GENETIC ENGINEERING FOR DISEASE RESISTANCE: ANTIFUNGAL PROTEINS/PEPTIDES TO THE RESCUE |
| Authors: | K. Rajasekaran, J.W. Cary, T.J. Jacks, T.E. Cleveland |
| Keywords: | Antifungal, Antimicrobial, Disease Resistance, Food and Feed Safety, Peptides |
| Abstract:
Plants do not possess a complex immunoglobulin-based protection system that is found in higher vertebrates to defend against attacking microbial pathogens; however, they do have a wide variety of innate host defense mechanisms at their disposal. These include the production of antimicrobial reactive oxygen species (ROS), secondary metabolites, hydrolytic enzymes, and a wide array of antimicrobial proteins and peptides. However, these defense mechanisms are not adequate and often compromised by the invading microbial pathogens. We have utilized several gene constructs coding for antimicrobial proteins/peptides from diverse sources to boost the existing disease resistance mechanisms or introduce novel traits. For example, we have demonstrated increased fungal and bacterial resistance in transgenic tobacco and cotton plants transformed with a haloperoxidase gene from Pseudomonas pyrrocinia. Haloperoxidases generate deadly antimicrobial compounds in planta such as hypohalite and peracetic acid and in addition, protect the plants through hypersensitive response upon microbial invasion. Recently we have utilized a synthetic gene coding for a lytic, antimicrobial peptide to introduce disease resistance trait into tobacco and cotton. These antifungal proteins and peptides are excellent candidates to augment disease resistance mechanisms in plants due to their nontoxic nature with respect to mammalian cells, ability to kill target microbes rapidly and their activity against a wide spectrum of phytopathogens. Discussion on other potential antifungal proteins and their possible modes of action are presented in this report. | |
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