Pathogenicity of Plasmodiophora brassicae populations from small, spheroid, resistant-type clubroot galls on roots of clubroot-resistant cultivars of Chinese cabbage (Brassica rapa L. subsp. pekinensis)

Abstract

A resistant type of small, spheroid clubroot galls (SSGs) containing resting spores formed on the root surface of clubroot-resistant (CR) cultivars of Chinese cabbage (Brassica rapa L. subsp. pekinensis) inoculated with an avirulent population of Plasmodiophora brassicae. Populations isolated from the SSGs severely affected a common (susceptible) cultivar but did not have the typical pathogenicity on CR cultivars, indicating similarity in pathogenicity between SSG and original spore populaions. Populations pathogenic on CR cultivars were not detected from SSGs. Therefore, the ability of the avirulent population among the SSGs to form resting spores may need to be considered to achieve clubroot control in common cultivars of crucifers.

Diversity and Active Mechanism of Fengycin-Type Cyclopeptides from Bacillus subtilis XF-1 Against Plasmodiophora brassicae

“…Until recently, there has been a lack of effective options for control of clubroot [51]. Several measures or studies have illustrated the potential for reducing this disease, such as soil pH and nutrient management [29,41,42,50,57], whereas agricultural practice based on better understanding of pathogen biology [17,36], such as crop rotation [55], nonhost plants or bait crops [1,14,58], resistant cultivars [30,44,47], integrated control [10,12], fungicides [25,35,46], or biofungicides were also applied [31,45]. Microbial control of clubroot is attractive because certain soil microbes can colonize roots and/or the rhizosphere [22,39,40,53], produce antifungal metabolites against P. brassicae [2,27], induce resistance to the disease [37], and so potentially provide durable protection.…”

Boron reduces development of clubroot in canola

“…Almost all of the canola cultivars in Canada are highly susceptible to this pathotype. Adapted cultivars with good resistance are now available, but how durable this resistance will be is unclear; clubroot resistance has been overcome quickly in commercial production in other regions (Osaki et al, 2008). No pesticides are registered for clubroot management on canola (Howard et al, 2010).…”

Pathogenic and genetic diversity in Plasmodiophora brassicae (clubroot) from Japan.

“…) ．なお，ハクサイ CR 品種の SSGs 内には根こぶ病菌 の成熟休眠胞子が発達するが，これらはもとの非親和性個 体群と同一の病原性を保持している (Osaki et al, 2008b (Fähling et al, 2003;Jones et al, 1982;Manzanares-Dauleux et al, 2001;Somé et al, 1996) et al, 2004;Kuginuki et al, 1999;田中ら，1998;Yano et al, 1996Yano et al, , 1997 et al, 1996, 1997 (田中ら， 1990, 1997Tanaka et al, 1991 (Tanaka et al, 1991 1958;Karling, 1968;Nowicki, 1973;Reyes et al, 1974 2008; 梅 原・ 田 村，1968) ， タ ネ ツ ケ バ ナ (Tanaka et al, 1993(Tanaka et al, , 2006b) ， お よ び オ オ バ タ ネ ツ ケ バ ナ (Tanaka et al, 1993 et al, 2003;Ito et al, 1997Ito et al, , 1999Manzanares-Dauleux et al, 2001;Osaki et al, 2008b;Yano et al, 1996, 1997) ．この内，Yano et al(1996, 1997 は (Osaki et al, 2008a;Yano et al, 1997 (Tanaka et al, 1991;田中ら，1997, 1998 (1975). Study of physiologic specialization in Plasmodiophora brassicae: proposals for attempted rationalization through an international approach.…”