A Novel Broad Spectrum Resistance Gene (RPW8) Controls Powdery Mildews

Yıl 2004, Cilt: 17 Sayı: 1, 9 - 17, 01.06.2004

Ö. Çalış

Öz

Plant disease resistance (R) genes govern the recognition of specific pathogens and activate subsequent defense responses. The recently cloned RPW8 gene controls resistance to powdery mildew pathogens. To characterise RPW8 specificity, a range of powdery mildew pathogens was examined for virulence on Arabidopsis thaliana Col-0 containing the RPW8 transgene. All the tested Erysiphe pathogens were avirulent on the RPW8 containing plants showing the RPW8 gene was a broad-spectrum powdery mildew resistance gene. The resistance conferred by RPW8 gene was associated with a hypersensitive response (HR). This was characterized by timing of hydrogen peroxide (H2O2) accumulation in plant epidermal cells penetrated by the pathogen. The powdery mildew attacked cells accumulated H2O2 producing rapid cell death that restricts growth of the pathogen in the plant cells.

Anahtar Kelimeler

Plant disease resistance, RPW8 gene, powdery mildew pathogens, hypersensitive response, hydrogen peroxide accumulation

Geniş Spektrumlu Yeni Bir Gen ( RPW8) Külleme Hastalıklarını Kontrol Ediyor

Öz

Bitki dayanıklılık (R) genleri spesifik patojenlere karşı dayanıklılığı kontrol ederek onlara karşı aktif savunma oluştururlar. Son zamanlarda klonlanan RPW8 geni külleme etmeni patojenlere karşı dayanıklılığı sağlamaktadır. RPW8 genini karakterize edebilmek için RPW8-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. RPW8 tarafından ortaya konan dayanıklılık hypersensitif response (HR) ile ilgilidir. Bu olay bitki hücrelerinde hidrojen peroksit (H2O2) oluşumunun patojenin penetrasyonu ile eş zamanda gerçekleşmesi ile ortaya konmuştur. Külleme etmeni tarafından saldırıya uğrayan hücrelerde H2O2 birikimi artmış ve hızlı hücre ölümleri gerçekleşmiştir ki bu da patojenin bitki hücrelerinde gelişimini sınırlandırmıştır.

Anahtar Kelimeler

Bitki dayanıklılık geni, RPW8 geni, külleme patojenleri, hypersensitif tepki, hidrojen peroksit oluşumu

Kaynakça

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