TY - JOUR
T1 - Indole glucosinolates and camalexin do not influence the development of the clubroot disease in Arabidopsis thaliana
AU - Siemens, J.
AU - Glawischnig, E.
AU - Ludwig-Müller, J.
PY - 2008/6
Y1 - 2008/6
N2 - Root galls of Brassicaceae caused by Plasmodiophora brassicae are dependent on increased auxin and cytokinin formation. In this study we investigated whether indole glucosinolates are involved in indole-3-acetic acid (IAA) biosynthesis in root galls, by using a genetic approach. The cytochrome P450 enzymes, CYP79B2 and CYP79B3, convert tryptophan to indole-3-acetaldoxime (IAOx), which is a precursor for indole glucosinolates and the phytoalexin camalexin in Arabidopsis thaliana. Root galls of the Arabidopsis ecotypes Wassilewskija (WS) and Columbia (Col) accumulated camalexin, WS at levels up to 320 μg/g dry weight. By contrast, camalexin was absent in root galls of cyp79b2/b3 double mutants. Infection rate and disease index as a measure of club development in mutant and wild-type plants of the two ecotypes were investigated and no differences were found in gall formation. This demonstrates that camalexin is an ineffective inhibitor of P. brassicae and indole glucosinolates are not the source of elevated levels of IAA in galls, because free IAA levels in mutant galls were comparable with those in wild type.
AB - Root galls of Brassicaceae caused by Plasmodiophora brassicae are dependent on increased auxin and cytokinin formation. In this study we investigated whether indole glucosinolates are involved in indole-3-acetic acid (IAA) biosynthesis in root galls, by using a genetic approach. The cytochrome P450 enzymes, CYP79B2 and CYP79B3, convert tryptophan to indole-3-acetaldoxime (IAOx), which is a precursor for indole glucosinolates and the phytoalexin camalexin in Arabidopsis thaliana. Root galls of the Arabidopsis ecotypes Wassilewskija (WS) and Columbia (Col) accumulated camalexin, WS at levels up to 320 μg/g dry weight. By contrast, camalexin was absent in root galls of cyp79b2/b3 double mutants. Infection rate and disease index as a measure of club development in mutant and wild-type plants of the two ecotypes were investigated and no differences were found in gall formation. This demonstrates that camalexin is an ineffective inhibitor of P. brassicae and indole glucosinolates are not the source of elevated levels of IAA in galls, because free IAA levels in mutant galls were comparable with those in wild type.
KW - Arabidopsis thaliana
KW - Auxin biosynthesis
KW - Camalexin
KW - Clubroot
KW - Indole glucosinolates
KW - Plasmodiophora brassicae
UR - http://www.scopus.com/inward/record.url?scp=42649129711&partnerID=8YFLogxK
U2 - 10.1111/j.1439-0434.2007.01359.x
DO - 10.1111/j.1439-0434.2007.01359.x
M3 - Article
AN - SCOPUS:42649129711
SN - 0931-1785
VL - 156
SP - 332
EP - 337
JO - Journal of Phytopathology
JF - Journal of Phytopathology
IS - 6
ER -