Effect of nitrate supply and mycorrhizal inoculation on characteristics of tobacco root plasma membrane vesiclesReportar como inadecuado




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Planta

, 231:425

First Online: 25 November 2009Received: 28 July 2009Accepted: 04 November 2009

Abstract

Plant plasma membrane pm vesicles from mycorrhizal tobacco Nicotiana tabacum cv. Samsun roots were isolated with negligible fungal contamination by the aqueous two-phase partitioning technique as proven by fatty acid analysis. Palmitvaccenic acid became apparent as an appropriate indicator for fungal membranes in root pm preparations. The pm vesicles had a low specific activity of the vanadate-sensitive ATPase and probably originated from non-infected root cells. In a phosphate-limited tobacco culture system, root colonisation by the vesicular arbuscular mycorrhizal fungus, Glomus mosseae, is inhibited by external nitrate in a dose-dependent way. However, detrimental high concentrations of 25 mM nitrate lead to the highest colonisation rate observed, indicating that the defence system of the plant is impaired. Nitric oxide formation by the pm-bound nitrite:NO reductase increased in parallel with external nitrate supply in mycorrhizal roots in comparison to the control plants, but decreased under excess nitrate. Mycorrhizal pm vesicles had roughly a twofold higher specific activity as the non-infected control plants when supplied with 10–15 mM nitrate.

KeywordsMycorrhiza Nitric oxide Nitrite:NO reductase Palmitvaccenic acid Plasma membrane Root AbbreviationsAMArbuscular mycorrhiza

NI-NORNitrite:NO reductase

pmPlasma membrane

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Autor: Martin Moche - Stefanie Stremlau - Lars Hecht - Cornelia Göbel - Ivo Feussner - Christine Stöhr

Fuente: https://link.springer.com/







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