The host range of Plasmodiophora brassicae and its relationship to endogenous glucosinolate content

Abstract

The host range of the soilborne obligate biotroph, Plasmodiophora brassicae was investigated. Evidence is presented that infection by P. brassicae might occur in non-Brassica species, leading to the potential formation of resting spores. Structures resembling P. brassicae were found in the root cortex of Tropaeolum majus, Carica papaya, Reseda alba and Beta vulgaris as demonstrated by scanning electron microscopy. Inoculation of Brassica rapa roots with spores extracted from either T. majus or B. vulgaris roots which had been previously inoculated with P. brassicae led to development of clubroot in the roots of B. rapa. It was also shown that the development of the symptom might be correlated with glucosinolate content, although other host factors are implicated in the B. vulgaris interaction with P. brassicae. In the glucosinolate-containing non-Brassicas, T. majus and C. papaya, the concentrations of benzylglucosinolate increased markedly in roots inoculated with P. brassicae, compared with the controls. There were also increases in concentrations of benzylglucosinolate in leaves of T. majus after P. brassicae infection. However, in R. alba roots, the total glucosinolate content decreased after inoculation with P. brassicae compared with the controls. High root concentrations of 2-OH-2-phenylethylglucosinolate (glucobarbarin) compared with low root indole glucosinolates in this species might limit P. brassicae infection and development. The importance of our investigations in relation to cultivation of non-Brassica species on fields infested with P. brassicae is discussed.

What can we learn from clubroots: alterations in host roots and hormone homeostasis caused by Plasmodiophora brassicae

“…However, conflicting results on this topic have been presented in Brassica species, not allowing any definite conclusion (Butcher et al 1974;Ockendon and Buczacki 1979;Chong et al 1981Chong et al , 1984Mullin et al 1980;LudwigMüller et al 1997;summarized in Ludwig-Müller 1999). On the other hand, the glucosinolate content of non-Brassica plants including Caricaceae, Resedaceae and Tropaeolaceae, which were inoculated with P. brassicae, also increased compared to control plants and small galls were occasionally detected in Tropaeolum majus (Ludwig-Müller et al 1999b) and Lepidium sativum (Butcher et al 1976). It was therefore speculated that these GSL (mainly benzyl GSL) could serve as precursors for phenylacetic acid, a naturally occurring auxin in T. majus (Ludwig- Müller and Cohen 2002).…”

“…Clubroot disease development is restricted mainly to members of the mustard family and to a few other plants (Ludwig-Müller et al 1999b), although P. brassicae is capable of infecting the root hairs of several noncruciferous hosts in Gramineae, Rosaceae, Papaveraceae, Polygonaceae, Resedaceae, and Leguminosae (Webb 1949;MacFarlane 1952). In addition to crop plants, it is known that also wild crucifer species like Capsella bursa-pastoris , Cardamine sp.…”

Root and shoot glucosinolates: a comparison of their diversity, function and interactions in natural and managed ecosystems

“…Carica papaya L. 1 Ludwig- Müller et al (1999) Diplotaxis tenuifolia (L.) DC. 1 Kirkegaard and Sarwar (1998) Eruca sativa Mill.…”

Differences in glucosinolate patterns and arbuscular mycorrhizal status of glucosinolate‐containing plant species

“…Some of these compounds have been shown to be fungitoxic\fungistatic (Greenhalgh & Mitchell, 1976 ;Bennett & Wallsgrove, 1994 ;Wallsgrove et al, 1998). Others such as the indolylglucosinolates play a role in the biosynthesis of indole-3-acetic acid (IAA) in the Brassicaceae and in the formation of clubroot disease (Plasmodiophora brassicae ; LudwigMu$ ller & Hilgenberg, 1988 ;Ludwig-Mu$ ller et al, 1990, 1997, 1999a. Non-Brassica plants such as Tropaeolum majus and Carica papaya have benzylglucosinolate as their major glucosinolate (Bennett et al, 1996(Bennett et al, , 1997.…”