Characterization of the silicon uptake system and molecular mapping of the silicon transporter gene in rice.

Faculty of Agriculture, Kagawa University, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
Plant physiology (Impact Factor: 6.84). 11/2004; 136(2):3284-9. DOI: 10.1104/pp.104.047365
Source: PubMed


Rice (Oryza sativa L. cv Oochikara) is a typical silicon-accumulating plant, but the mechanism responsible for the high silicon uptake by the roots is poorly understood. We characterized the silicon uptake system in rice roots by using a low-silicon rice mutant (lsi1) and wild-type rice. A kinetic study showed that the concentration of silicon in the root symplastic solution increased with increasing silicon concentrations in the external solution but saturated at a higher concentration in both lines. There were no differences in the silicon concentration of the symplastic solution between the wild-type rice and the mutant. The form of soluble silicon in the root, xylem, and leaf identified by (29)Si-NMR was also the same in the two lines. However, the concentration of silicon in the xylem sap was much higher in the wild type than in the mutant. These results indicate that at least two transporters are involved in silicon transport from the external solution to the xylem and that the low-silicon rice mutant is defective in loading silicon into xylem rather than silicon uptake from external solution to cortical cells. To map the responsible gene, we performed a bulked segregant analysis by using both microsatellite and expressed sequence tag-based PCR markers. As a result, the gene was mapped to chromosome 2, flanked by microsatellite marker RM5303 and expressed sequence tag-based PCR marker E60168.

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    • "Its major role is to increase the plant resistance to pathogens, pests and diseases, especially to fungal diseases, thereby contributing to plant health and yield improvement (Bowen et al. 1992; Raven 2003; Henriet et al. 2006). One of the most important beneficial effects of silicon on plant growth is related to increased resistance under water stress conditions (Ma et al. 2004; Sacała 2009). This element can also positively affect plant metabolism under environmental stress conditions. "
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    ABSTRACT: In this study we investigated the effect of calcium and silicon foliar fertilization on the sugar beet root yield and quality parameters. Study was conducted in 2010-2012 in the southeastern region of Poland, in Sahryń (50°41′N and 23°46′E). In the experiment two treatments of foliar fertilization were used: (1) in the stage of 4-6 sugar beet leaf-262.0 g Ca/ha, 79.9 g Si/ha, and 3 weeks later-524.0 g Ca/ha, 159.8 g Si/ha; and (2) in the stage of 4-6 sugar beet leaf-524.0 g Ca/ha, 1598 g Si/ha, 3 weeks later-524.0 g Ca/ha, 159.8 g Si/ha. Calcium and silicon foliar fertilization resulted in increase of: (1) the root yield (average for both treatments about 21.8 %); (2) the biological sugar yield (about 24.4 %); and (3) the technological yield of sugar (about 24.8 %) compared with the control treatment. The difference between treatments of fertilization was not significant. Foliar application of calcium and silicon had no significant effect on such sugar beet roots quality parameters features as content of sucrose, alpha-amino-nitrogen, potassium and sodium.
    Sugar Tech 02/2015; DOI:10.1007/s12355-015-0371-4 · 0.58 Impact Factor
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    • "But incorporation of Si with POP can reduce the pest-disease infestation and can increase yield of rice significantly. Ma et al., 2004 reported that application of silicon decrease the pest and disease infestation of rice. In Si deficient soils it has been shown that Si reduces the severity of rice blast (Seebold et al., 2000). "
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    ABSTRACT: A study was undertaken to determine the effect of diatomaceous earth (DE a source of Silicon) on yield and disease infestation of rice. The experiments were carried out in old alluvial zone of West Bengal during 2012-2013. All the treatments were performed in a completely randomized block design. Results showed a significant increase in grain yield with Si application. Highest grain yield was found in the treatment of DE @ 600 kg ha-1 along with POP (package of practice). The POP contained FYM @ 5 t ha-1 , ZnSO 4. 7H 2 O @ 25 kg ha-1 and N: P: K :: 100:50:50 kg ha-1. All the treatments of Si were found to have a significant effect in promoting and disease resistance while higher doses of DE had a better effect than lower one. The investigation concludes that application of diatomaceous earth @ 600 kg ha-1 along with POP was effective to increase the grain yield of rice. Whereas, regarding reduction of pest and disease infestation DE application (@600 kg ha-1) showed significant effect when amalgamated with half the package of practice.
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    • "Like plants, diatoms contain several silicon transporters, often arranged in gene families, but these transporters are different in both their structures and functions from their plant counterparts (Hildebrand et al., 1998; Ma et al., 2004). Most tellingly, ectopic expression of a silicon transporter gene from diatoms in transgenic tobacco had no significant impact on silicon uptake, indicating fundamental differences in silicon absorption between plants and diatoms (Ma et al., 2004). These differences notwithstanding, insights into the significance and regulation of silicon-mediated processes in diatoms may potentially shed new light on the poorly understood role of silicon in plant stress responses. "
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    ABSTRACT: Plants are constantly threatened by a wide array of microbial pathogens. Pathogen invasion can lead to vast yield losses and the demand for sustainable plant-protection strategies has never been greater. Chemical plant activators and selected strains of rhizobacteria can increase resistance against specific types of pathogens but these treatments are often ineffective or even cause susceptibility against others. Silicon application is one of the scarce examples of a treatment that effectively induces broad-spectrum disease resistance. The prophylactic effect of silicon is considered to be the result of both passive and active defences. Although the phenomenon has been known for decades, very little is known about the molecular basis of silicon-afforded disease control. By combining knowledge on how silicon interacts with cell metabolism in diatoms and plants, this review describes silicon-induced regulatory mechanisms that might account for broad-spectrum plant disease resistance. Priming of plant immune responses, alterations in phytohormone homeostasis, regulation of iron homeostasis, silicon-driven photorespiration and interaction with defence signalling components all are potential mechanisms involved in regulating silicon-triggered resistance responses. Further elucidating how silicon exerts its beneficial properties may create new avenues for developing plants that are better able to withstand multiple attackers.
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