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Suppression of clubroot disease under neutral pH caused by inhibition of spore germination of Plasmodiophora brassicae in the rhizosphere
Title: | Suppression of clubroot disease under neutral pH caused by inhibition of spore germination of Plasmodiophora brassicae in the rhizosphere |
Authors: | Niwa, Reiko Browse this author | Nomura, Yoshinobu Browse this author | Osaki, Mitsuru Browse this author | Ezawa, Tatsuhiro Browse this author →KAKEN DB |
Keywords: | Brassica rapa | nuclear/cell-wall double staining | rhizosphere | soil pH | soilborne disease | spore germination |
Issue Date: | Jun-2008 |
Publisher: | British Society for Plant Pathology |
Journal Title: | Plant Pathology |
Volume: | 57 |
Issue: | 3 |
Start Page: | 445 |
End Page: | 452 |
Publisher DOI: | 10.1111/j.1365-3059.2007.01817.x |
Abstract: | To elucidate the mechanism of clubroot suppression under neutral soil pH, a highly reproducible germination assay system under soil culture conditions was designed based on the hypothesis that germinated spores of Plasmodiophora brassicae could be identified by the absence of a nucleus (i.e. having released a zoospore to infect a root hair of the host plant). Brassica rapa var. perviridis seedlings were inoculated with a spore suspension of P. brassicae at a rate of 2.0 ×106 spores g-1 soil and grown in a growth chamber for 7 days. The spores were recovered from rhizosphere and non-rhizosphere soils and stained with both Fluorescent Brightener 28 (cell-wall-specific) and SYTO 82 orange fluorescent nucleic-acid stain (nucleus-specific stain). Total numbers of spores were counted under UV-excitation, and spores with a nucleus that fluoresced orange under G-excitation were counted. The significant increase in the percentage of spores without a nucleus (germinated spores) in the rhizosphere after 7 days’ cultivation and the correlation with root-hair infections validated the assay system. Applications of calcium-rich compost or calcium carbonate to neutralize the soil significantly reduced the percentage of germinated spores in the rhizosphere, as well as the number of root-hair infections. The present study provides direct evidence that the inhibition of spore germination is the primary cause of disease suppression under neutral soil pH. |
Rights: | The definitive version is available at www.blackwell-synergy.com |
Relation: | http://www3.interscience.wiley.com/journal/118484796/home |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/38186 |
Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 江澤 辰広
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