A novel broad spectrum resistance gene (RPW8) controls powdery mildews

Bitki dayanıklılık (R) genleri spesifik patojenlere karşı dayanıklılığı kontrol ederek onlara karşı aktif savunma oluştururlar. Son zamanlarda klonlanan RPW8 geni kütleme etmeni patojenlere karşı dayanıklılığı sağlamaktadır. RPW8 genini karakterize edebilmek için flfWS-transgenini içeren Arabidopsis thaliana bitkileri külleme patojenleri ile test edilmiştir. Test edilen tüm Erysiphe patojenleri RPW8 geni içeren bitkilerde hastalık oluşturmadığı için (avirulent), RPW8 geninin geniş spektrumlu bir gen olduğu ortaya konmuştur. RPWS tarafından ortaya konan dayanıklılık hypersensitif response (HR) ile ilgilidir. Bu olay bitki hücrelerinde hidrojen peroksit $(H_O_2)$ oluşumunun patojenin penetrasyonu ile eş zamanda gerçekleşmesi ile ortaya konmuştur. Külleme etmeni tarafından saldırıya uğrayan hücrelerde $H_2O_2$ birikimi artmış ve hızlı hücre ölümleri gerçekleşmiştir ki bu da patojenin bitki hücrelerinde gelişimini sınırlandırmıştır.

Anahtar Kelimeler:

hastalığa dayanıklılık, genler, bitki patojenleri, aşırı duyarlık, hidrojen peroksit, Arabidopsis thaliana, Erysiphe, bitki hastalıkları

Geniş spektrumlu yeni bir gen (RPW8) külleme hastalıklarını kontrol ediyor

Plant disease resistance (R) genes govern the recognition of specific pathogens and activate subsequent defense responses. The recently cloned RPWS gene controls resistance to powdery mildew pathogens. To characterise RPWS specificity, a range of powdery mildew pathogens was examined for virulence on Arabidopsis thaliana Col-0 containing the RPWS transgene. All the tested Erysiphe pathogens were avirulent on the RPWS containing plants showing the RPWS gene was a broad-spectrum powdery mildew resistance gene. The resistance conferred by RPWS gene was associated with a hypersensitive response (HR). This was characterized by timing of hydrogen peroxide $(H_2O_2)$ accumulation in plant epidermal cells penetrated by the pathogen. The powdery mildew attacked cells accumulated $H_2O_2$ producing rapid cell death that restricts growth of the pathogen in the plant cells.

Keywords:

disease resistance, genes, plant pathogens, hypersensitivity, hydrogen peroxide, Arabidopsis thaliana, Erysiphe, plant diseases,

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Adam, L. and Somerville, S. C, 1996. Genetic characterization of five powdery mildew disease resistance loci in Arabidopsis thaliana. The Plant Journal 9: 341-356.
Agrios, G. N. (1997). Plant Pathology. Academic Press, San Diego.
Baschges, R., Hollricher, K., Panstruga, R., Simons, G., Wolter, M., Frijters, A., Van Daelen, R., Van der Lee, T. et al„ (1997). The barley Mlo gene: a novel control element of plant pathogen resistance. Cell 88: 695-705.
Cao, H., Li, X. and Dong, X. (1998). Generation of broad-spectrum disease resistance by overexpression of an essential regulatory gene in systemic acquired resistance. Proceeding of the National Academy of Sciences of the U.S.A. 95: 6531-6536.
Dangl, J. L. and Jones, J. D. G. (2001). Plant pathogens and integrated defence responses to infection. Nature 411: 826-833.
De Wit, P. J. G. M. (1992). Molecular characterisation of gene-for-gene systems in plant-fungus interactions and the application of avirulence genes in control of plant pathogens. Annual Reviews of Phytopathology 30:391-418.
Del Pozo, O. and Lam, E., 1998. Caspases and programmed cell death in the hypersensitive response of plants to pathogens. Current Biology 8:1129-1132
Duckett, J. G. and Read, D. J. (1991). The use of the fluorescent dye 3,3'dihexyloxacarbocyanin iodide, for selective staining of ascomycete fungi associated with liverworth rhizoids and ericoid mycorrhizal roots. New Phytologist 118:250-272.
Flor, H. H. (1971). Current status of the gene-for-gene concept. Annual Reviews of Phytopathology 9: 275-296.
Frye, C. A. and Innes, R. W., 1998. An Arabidopsis mutant with enhanced resistance to powdery mildew. The Plant Cell 10:947-956.
Greenberg, J. T. (1996). Programmed cell death: a way of life for plants. Proceeding of the National Academy of Sciences of the U.S.A. 93: 12094-12097.
Hammond-Kosack, K. E. and Jones J. D. G., 1996. Resistance gene-dependent plant defense responses. The Plant Cell 8: 1773-1791.
Hammond-Kosack, K. E. and Jones, J. D. G. (1997). Plant Disease resistance genes. Annual Reviews of Plant Physiology and Plant Molecular Biology 48: 575-607.
Hengartner, M. O. and Bryant, J. A. (2000). Apoptic cell death: from worms to wombats... but what about the weeds? In Programmed Cell Death in Animals and Plants (Bryant, J.A., Highes, S. G. and Garland, J. M. eds.) pp. 1-12 Bios Scientific Publishers Oxford.
Levine, A., Tenhaken, R., Dixon, R. and Lamb, C, 1994. H2O2 from the oxidative burst orchestrates the plant hypersensitive disease resistance response. Cell 79: 583-593.
Rajasekhar, V. K., Lamb, C. and Dixon, R. A., 1999. Early events in the signal pathway for the oxidative burst in soybean cells exposed to avirulent Pseudomonas syringae pv glycinea. Plant Physiology 120: 1137-1146.
Rommens, C. M. and Kishore, G. M., 2000. Exploiting the ftill potential of disease-resistance genes for agricultural use. Current Opinion in Biotechnology 11: 120-125.
Thordal-Christensen, H., Zhang, Z., Wei, Y. and Collinge, D. B., 1997. Subcellular localization of H202 in plants: H202 accumulation in papillae and hypersensitive response during the barley powdery mildew interaction. Plant Journal 11: 1187-1194.
Yun, B-W. and Loake, G. (2002). Plant defence responses: current status and future exploitation. Journal of Plant Biotechnology 4:1-6
Xiao, S., Ellwood, S., Calis, O., Patrick, E., Li, T., Coleman, M. and Turner, J. G. (2001). Broad-spectrum mildew resistance in Arabidopsis thaliana mediated by RPW8. Science 291: 118-120
Vandenabeele, S., Van Der Kelen, K., Dat, J., Gadjev, I., Booneferaes, T., Morsa, S., Rottiers, P., Slooten, L., Van Mantagu, M., Zabeau, M., Inze, D. and Van Breusegem, F. (2003). A comprehensive analysis of hydrogen peroxide-induced gene expression in tobacco. Proceeding of the National Academy of Sciences of the U.S.A. 100:16113-16118.