C-TERMINAL DOMAIN OF HEL PROTEIN FROM ARABIDOPSIS HAS POTENT ANTIMICROBIAL AND RIBONUCLEASE ACTIVITIES

• Published in: Journal of plant pathology Vol. 91; no. 4; pp. S4.37 - S4.38
• Main Authors: Proietti, S, Aleandri, M P, Bertini, L, Chilosi, G, Caporale, C, Caruso, C
• Format: Journal Article
• Language: English
• Published: 01.12.2009
• Subjects: Amino acids; Arabidopsis thaliana
• ISSN: 1125-4653

The ability of plants to cope with abiotic and biotic stresses is essential for their survival. During millions of years, plant evolved defensive strategies to protect themselves against invading pathogens. Disease resistance often depends on whether the plant is able to recognize the pathogen early in the infection process. Recognition of pathogen triggers a coordinate activation of a specific set of genes encoding pathogenesis-related proteins (PRs), the final shot in the plant's arsenal against the invader. At present, a large number of PR proteins have been characterized and grouped into 17 families but, although the key role of PR proteins on plant defence responses is clear, more intriguing is the elucidation of their mechanism of action. We have focussed our attention on the functional characterization of a PR4 protein in wheat (Triticum aestivum) and in Arabidopsis thaliana. In wheat, we isolated a PR4 protein of class II (wheatwinl) and recently we correlated its antifungal properties with ribonuclease activity producing mutants affecting specific amino acids of the active site. We also isolated the ortholog gene in Arabidopsis thaliana, coding a PR4 protein of class I named HEL that is overexpressed after biotic and abiotic stresses. The recombinant C-terminal domain, expressed in E. coli showed stronger antifungal and ribonuclease activity than wheatwinl. Functional proteomic studies are in progress to identify putative partners of HEL protein whose involvement in a protein complex would be strongly suggestive of its biological function.