Concentrations of indole‐3‐acetic acid in plants of tolerant and susceptible varieties of Chinese cabbage infected with Plasmodiophora brassicae Woron.

Abstract

SUMMARYA convenient method for infecting Brassica seedlings in liquid medium with the phytopathogenic fungus Plasmodiophora brassicae was developed. The infection rates of two susceptible and two tolerant Chinese cabbage varieties with wild type P. brassicae were investigated. The content of free indole-3-acetic acid (IAA) was determined using combined gas chromatography-mass spectronnetry (GC-MS) with [^^Cg]-I-AA as internal standard during the first period of infection with the fungus (5-14 d) and compared with the indole glucosinolate content of two Chinese cabbage varieties (one tolerant, one susceptible) in tbe same developmental stages. The results showed that the mean of the IAA content in the infected plants was approximately 66-5 °(, bigber tban that of the non-infected controls. In botb the susceptible and tolerant varieties bigber levels of IAA were found in tbe infected plants 10 d after tbe beginning of incubation. After 14 d of incubation IAA levels decreased in tbe susceptible, infected plants and increased in tbe tolerant, infected piants.

Glucosinolates and the clubroot disease: defense compounds or auxin precursors?

“…The availability of hormone-responsive reporter genes in Arabidopsis enabled the localization of enhanced auxin and cytokinin responsiveness to the part of the root where gall formation occurs ). An increase in free and conjugated IAA levels was reported for Arabidopsis and Brassica, although at different time points during infection, making comparisons difficult (Ludwig-Müller et al 1993, 1999aGrsic et al 1999;Grsic-Rausch et al 2000, Devos et al 2005. However, it is not entirely clear whether the pathogen or the host plant produces the hormones.…”

Indole glucosinolate breakdown and its biological effects

“…Roots Local NS to 2.2 NS to 2.9 --NS to 2 Ludwig- Müller et al (1993Müller et al ( , 1997 Brassica napus…”

Alternative transcription initiation of the nitrilase gene (BrNIT2) caused by infection with Plasmodiophora brassicae Woron. in Chinese cabbage (Brassica rapa L.)

“…Several studies have indicated that auxin levels increase in clubbed roots (Raa 1971;Butcher et al 1974;Ludwig-Müller et al 1993, 1999Ugajin et al 2003;Devos et al 2005), although most of these studies have indicated complicated changes in the time course. Contrastingly, lower levels of auxin have been reported in infected B. napus than in the corresponding control plants (Mousdale 1981).…”