Full Journal - Journal of Cell and Molecular Biology - Haliç Üniversitesi

Journal of Cell and Molecular Biology 1: 93-99, 2002.
Golden Horn University, Printed in Turkey.
Camalexin is not required for the function of RRPPPP11 and RRPPPP1133 resistance
genes in AArraabbiiddooppssiiss tthhaalliiaannaa inoculated with PPeerroonnoossppoorraa ppaarraassiittiiccaa
Figen Mert-Türk 1 *, and Eric B. Holub 2
1 University of Çanakkale Onsekiz Mart, Faculty of Agriculture, Department of Plant Protection, 17100,
Çanakkale, Turkey; 2 Department of Plant Genetics and Biotechnology, Horticulture Research
International, Wellesbourne, Warwickshire, CV35 9EF, England (* author for correspondence)
Received 24 April 2002; Accepted 26 June 2002
Abstract
Peronospora parasitica is an obligate biotrophic pathogen and causes downy mildew in Arabidopsis thaliana. The
Col-pad3 mutant of A. thaliana accession Col-0 was previosly selected in a screen for phytoalexin deficiency
following inoculation by the strains of Pseudomonas syringae. The mutant does not accumulate detectable levels
of camalexin (the phytoalexin of A. thaliana) following inoculation with P. parasitica or abiotic inducer AgNO3.
RPP1 and RPP13 resistance genes lie at the bottom arm of chromosome three of accession Nd-1. Inoculation of
Nd-1 plants with RPP1- and RPP13-avirulent isolates of P. parasitica result pitting necrosis on the cotyledons and
flecking chlorosis of the seedlings with no pathogen sporulation. In this research, this only known possible
phytoalexin biosynthetic mutant was employed to investigate whether the mutation in PAD3 locus would have any
effect on the recognition of certain isolates of P. parasitica by RPP1 and RPP13 disease resistance genes in
A. thaliana accession Nd-1. According to the results camalexin is not required for the function of these two disease
resistance genes.
KKeeyy wwoorrddss:: Arabidopsis thaliana, Peronospora parasitica, pad mutants, resistance, phytoalexins, camalexin
Kamaleksin PPeerroonnoossppoorraa ppaarraassiittiiccaa ile inokulasyonundan sonra AArraabbiiddooppssiiss
tthhaalliiaannaa’n›n RRPPPP11 ve RRPPPP1133 dayan›kl›l›k genlerinin ifllevleri için gerekli de¤ildir
Özet
Peronospora parasitica bir zorunlu biyotrof patojen olup Arabidopsis thaliana’da mildiyöye sebep olur. A.
thaliana ’n›n bir ekotipi olan Col-0’dan izole edilen Col-pad3 mutant bitkisinin, daha önce Pseudomonas
syringae’nin ›rklar›yla inokulasyonundan sonra kamaleksin üretmedi¤i bulunmufltur. Bu mutant bitki P. parasitica
ve AgNO3 ile inokulasyondan sonra da tespit edilebilir miktarda kamaleksin üretmemektedir. Hastal›klara
dayan›kl›l›k genleri olan RPP1 ve RPP13 genleri ekotip Nd-1’de üçüncü kromozomun alt kolunda yer almaktad›r
ve bu genleri tan›yan P. parasitica’n›n avirulent ›rklar› ile inokulasyonu takiben, fidelerde nekrotik lekeler
oluflmakta ve patojenin sporulasyonuna rastlanmamaktad›r. Bu çal›flmada bilinen tek fitoaleksin biyosentetik
mutant› olan Col-pad3’ü kullanarak, PAD3 lokusunda meydana gelen mutasyonun, A. thaliana ekotip Nd-1’de
bulunan RPP1 ve RPP13 dayan›kl›l›k genleri üzerindeki etkisini araflt›rmak hedeflenmifltir. Elde edilen sonuçlara
göre, kamaleksinin bu iki dayan›kl›l›k geninin ifllevleri için gerekli olmad›¤› bulunmufltur. Pad3 mutasyonunun
Nd-1’de bulunmas› sonucu bu genotiplerde belli izolatlara karfl› duyarl›l›k gözlenmedi¤inden, yani hastal›k
oluflumu meydana gelmedi¤inden dolay›, kamaleksinin bu iki dayan›kl›l›k geninin ifllevleri için gerekli olmad›¤›
bulunmufltur.
AAnnaahhttaarr ssöözzccüükklleerr:: Arabidopsis thaliana, Peronospora parasitica, pad mutantlar›, dayan›kl›l›k, fitoaleksinler,
kamaleksin
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