The role of cytokinins in clubroot formation

Dekhuijzen, H. M.; Overeem, J. C.

doi:10.1016/0048-4059(71)90024-5

Cited by 91 publications

(29 citation statements)

References 15 publications

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“…Auxins stimulate cell division (Daly and Inman 1958), thus explaining the increase in root mass and accelerated formation of root hairs, while cytokinins induce root elongation (Daly and Inman 1958), thereby also increasing root mass. Cytokinins are also reportedly responsible for enhancing nutrient accumulation and transportation (Kiraly et al 1967;Dekhuijzen and Overeem, 1971;Sziraki et al 1975;Vizarova 1979), contributing to overall improved plant growth.…”

Section: Discussionmentioning

confidence: 97%

Endophytic microorganisms as potential growth promoters of banana

et al. 2007

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The potential of endophytic microorganisms in promoting the growth of their host plant was determined by artificially introducing five isolates (bacterial and fungal strains: UPM31F4, UPM31P1, UPM14B1, UPM13B8, UPM39B3) isolated from the roots of wild bananas into both healthy and diseased banana plantlets (Berangan cv. Intan). The response of the host plants to endophytic infection was assessed by measuring the change in four growth parameters: plant height, pseudostem diameter, root mass and total number of leaves. The endophytes tested as growth promoters were found to have a significant effect in both healthy and Fusarium-infected (diseased) plantlets. In both experimental systems, the bacterial isolate UPM39B3 (Serratia) and fungal isolate UPM31P1 (Fusarium oxysporum) showed promising growth-promoting properties. Isolate UPM39B3 (Serratia) induced the largest increases in all four growth parameters in healthy plantlets -3.14 cm (height), 1.12 cm (pseudostem diameter), 2.12 g (root mass) and 1.12 (total number of leaves plant À1 ) -followed by isolate UPM31P1 (Fusarium oxysporum). The beneficial effect of UPM39B3 (Serratia) and UPM31P1 (Fusarium oxysporum) was also reflected in the diseased plantlets, where pre-treatments with the isolates either singly (T6: UPM31P1; T8: UPM39B3) or in a mixture (T7: UPM31P1 + UPM39B3; T9: UPM14B1 + UPM13B8 + UPM39B3) were able to sustain the growth of plantlets, with significantly higher growth values than those in diseased plantlets that were not infected with endophytes (T10: FocR4). These results demonstrate the economic significance of these endophytic isolates, particularly UPM39B3 (Serratia) and UPM31P1 (Fusarium oxysporum), both as potential growth promoters of banana and as agents rendering tolerance towards Fusarium wilt as a strategy in the management of Fusarium wilt of banana via improved vegetative growth.

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Section: Discussionmentioning

confidence: 97%

Endophytic microorganisms as potential growth promoters of banana

et al. 2007

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“…Host cytoplasm (hc), cell wall (cw) and tonoplast (T) are intact. siological race c according to the method described by Dekhuijzen and Overeem (1971). Callus with multinucleate secondary plasmodia of physiological race c was transplanted every 3 weeks to a fresh medium supplemented with only 0.3 rag/1 ~-napthylene acetic acid.…”

Section: Methodsmentioning

confidence: 99%

Electron microscopic studies on the root hairs and cortex of a susceptible and a resistant variety of Brassica campestris infected with Plasmodiophora brassicae

Dekhuijzen¹

1979

Netherlands Journal of Plant Pathology

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The cortex of the roots of a susceptible and a resistant variety of Brassica campestris var. rapa infected with sterile resting spores of Plasmodiophora brassicae from senescent callus was studied at a stage prior to disease symptom development. Electron micrographs show the presence of amoeboid structures within the cortical cells of the susceptible variety 10 days after inoculation. Cell wall perforations, hypertrophied host cell nuclei, nucleoli and broken tonoplasts were frequently found in the susceptible variety. It has been concluded that amoeboid structures of the parasite penetrate the cell wall and disrupt the cortical cells.Electron micrographs of the resistant variety show the presence of zoosporangia with secondary zoospores in the root hairs nine days after inoculation. Two to four days later a large number of dead host cells can be observed in the outer cortical layer of the resistant variety, whereas no apparent changes are found in the inner cortex. The results suggest the occurrence of a hypersensitive host reaction which terminates further growth ofPlasmodiophora brassicae.

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“…Elevated levels of cytokinins have been observed in the clubbed tissues of turnips (Brassica rapa var. rapa; Dekhuijzen and Overeem 1971;Dekhuijzen 1980). Moreover, the plasmodia have been suggested to produce cytokinins and release them into the host cytoplasm, thereby inducing host cell division (Dekhuijzen 1981;Müller and Hilgenberg 1986).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2008

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In clubroot disease, gall formation is induced by infection with the obligate biotroph Plasmodiophora brassicae, and cell hypertrophy is dependent on increased auxin levels. The enzyme nitrilase is suggested to play an important role in auxin biosynthesis in plants. Here, we investigated the expression of nitrilase genes in clubroot disease in Chinese cabbage (Brassica rapa L.). We isolated four isogenes of nitrilase (BrNIT1, BrNIT2, BrNIT3, and BrNIT4) from Chinese cabbage. When a BrNIT2-specific probe was used for Northern blot hybridization, enhanced accumulation of a 1.4 kb mRNA and additional shorter transcripts (1.1 kb) were only detected in clubbed roots 25 days postinoculation (dpi) onward. The expression of BrNIT1 was not strongly affected by infection with P. brassicae. BrNIT3 expression was detected in the roots at 10 and 20 dpi, and the expression was less in clubbed roots than in healthy roots at 20 dpi. Analysis of the transcription initiation point of the BrNIT2 gene suggests that 1.1 kb transcripts were generated by alternative transcription initiation between the second intron and the third exon. The sequence from the second intron to half of the third exon (+415 to +1037, 623 bp) had promoter activity in Arabidopsis during clubroot formation. Therefore, our results suggest that transcriptional regulation of BrNIT2 might be involved in auxin overproduction during clubroot development.

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The role of cytokinins in clubroot formation

Cited by 91 publications

References 15 publications

Endophytic microorganisms as potential growth promoters of banana

Endophytic microorganisms as potential growth promoters of banana

Electron microscopic studies on the root hairs and cortex of a susceptible and a resistant variety of Brassica campestris infected with Plasmodiophora brassicae

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

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