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First published online September 28, 2007; 10.1104/pp.107.107599 Plant Physiology 145:919-924 (2007) © 2007 American Society of Plant Biologists Genotypic Difference in Silicon Uptake and Expression of Silicon Transporter Genes in Rice1Research Institute for Bioresources, Okayama University, Kurashiki 710–0046, Japan
Rice (Oryza sativa) is a highly silicon (Si)-accumulating species that shows genotypic differences in Si accumulation. We investigated the physiological and molecular mechanisms involved in the genotypic difference in Si uptake between the japonica var. Nipponbare and the indica var. Kasalath. Both the Si concentration in the shoot and the Si uptake per root dry weight were higher in Nipponbare than in Kasalath grown in either soil or nutrient solution. The Si uptake by a single root was also higher in Nipponbare than in Kasalath. A kinetics study showed that Nipponbare and Kasalath had a similar Km value, whereas the Vmax was higher in Nipponbare. The expression of two Si transporter genes (Low silicon rice 1 [Lsi1] and Lsi2) investigated using real-time reverse transcription polymerase chain reaction revealed higher expression of both genes in Nipponbare than in Kasalath. Immunostaining with Lsi1 and Lsi2 antibodies revealed a similar pattern of subcellular localization of these two Si transporters in both varieties; Lsi1 and Lsi2 were localized at the distal and proximal sides, respectively, of both exodermis and endodermis of the roots. These results revealed that the genotypic difference in the Si accumulation results from the difference in abundance of Si transporters in rice roots.
1 This work was supported by a Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan (grant nos. 15380053 and 17078008 to J.F.M.) and a grant from the Ministry of Agriculture, Forestry and Fisheries of Japan (Rice Genome Project IP–5003 to J.F.M.). The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Jian Feng Ma (maj{at}rib.okayama-u.ac.jp). www.plantphysiol.org/cgi/doi/10.1104/pp.107.107599 * Corresponding author; e-mail maj{at}rib.okayama-u.ac.jp. Received August 20, 2007; accepted September 17, 2007; published September 28, 2007. This article has been cited by other articles:
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