Up-Regulation of a Magnesium Transporter Gene<i>OsMGT1</i>Is Required for Conferring Aluminum Tolerance in Rice

Chen, Zhi Chang; Yamaji, Naoki; Motoyama, Ritsuko; Nagamura, Yoshiaki; Feng, Jian

doi:10.1104/pp.112.199778

Cited by 167 publications

(130 citation statements)

References 58 publications

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“…There are 10 MGT homologs in the Arabidopsis genome and nine homologs in rice (Schock et al, 2000;Gebert et al, 2009). Among them, AtMGT6 in Arabidopsis and OsMGT1 in rice mediate root Mg uptake, respectively, although they differ in their gene expression patterns (Mao et al, 2014;Chen et al, 2012). In this study, we found that OsMGT1 is involved in enhancing OsHKT1;5 transport activity at least in rice.…”

mentioning

confidence: 53%

“…The expression of OsMGT1 in the root mature zone was up-regulated by salt stress, although the induction was not as large as that by Al 3+ stress ( Fig. 5; Chen et al, 2012). Furthermore, different from the root tips, OsMGT1 in the root mature zone was highly expressed in the stellar tissues, especially in the root pericycle, which connects to the xylem and phloem (Fig.…”

Section: Discussion Different Roles Of Osmgt1 In Al Tolerance and Salmentioning

confidence: 93%

“…The homozygous insertion lines were isolated by PCR according to Chen et al (2012). The oshkt1;5 mutant was a T-DNA insertion line (Supplemental Fig.…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

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A Magnesium Transporter OsMGT1 Plays a Critical Role in Salt Tolerance in Rice

et al. 2017

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Salt stress is one of the major factors limiting rice (Oryza sativa) production globally. Although several transporters involved in salt tolerance have been identified in rice, the mechanisms regulating their transport activity are still poorly understood. Here, we show evidence that a rice Mg transporter OsMGT1 is required for salt tolerance probably by regulating transport activity of OsHKT1;5, a key transporter for the removal of Na + from the xylem sap at the root mature zone. Knockout of OsMGT1 did not affect total Na uptake, but increased Na concentration in the shoots and xylem sap, resulting in a significant increase in salt sensitivity at low external Mg 2+ concentration (20-200 mM). However, such differences were abolished at a higher Mg 2+ concentration (2 mM), although the total Na uptake was not altered. OsMGT1 was expressed in both the roots and shoots, but only that in the roots was moderately up-regulated by salt stress. Spatial expression analysis revealed that OsMGT1 was expressed in all root cells of the root tips but was highly expressed in the pericycle of root mature zone. OsMGT1 was also expressed in the phloem region of basal node, leaf blade, and sheath. When expressed in Xenopus laevis oocytes, the transport activity of OsHKT1;5 was enhanced by elevating external Mg 2+ concentration. Furthermore, knockout of OsHKT1;5 in osmgt1 mutant background did not further increase its salt sensitivity. Taken together, our results suggest that Mg 2+ transported by OsMGT1 in the root mature zone is required for enhancing OsHKT1;5 activity, thereby restricting Na accumulation to the shoots.

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confidence: 53%

Section: Discussion Different Roles Of Osmgt1 In Al Tolerance and Salmentioning

confidence: 93%

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A Magnesium Transporter OsMGT1 Plays a Critical Role in Salt Tolerance in Rice

et al. 2017

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“…NRAT1 transports trivalent Al into the cells (Xia et al, 2010) for subsequent sequestration of Al into the vacuoles by OsALS1 (Huang et al, 2012a). In addition, the magnesium transporter gene OsMGT1 for magnesium uptake (Chen et al, 2012), a gene encoding the small Cys-rich peptide OsCDT3 (Xia et al, 2013), and the citrate transporter gene OsFRDL4 involved in Al-induced secretion of citrate (Yokosho et al, 2011) also were demonstrated to contribute to high Al tolerance in rice. Recently, two other ART1-regulated genes, OsFRDL2 encoding a citrate transporter and OsEXPA10 encoding an expansin for cell elongation in the root tips, were found to be specifically induced by Al, but their contribution to Al tolerance in rice is minor (Che et al, 2016;Yokosho et al, 2016).…”

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Retrotransposon-Mediated Aluminum Tolerance through Enhanced Expression of the Citrate Transporter OsFRDL4

et al. 2016

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ORCID IDs: 0000-0003-3935-268X (K.Y.); 0000-0003-3411-827X (J.F.M.).High aluminum (Al) tolerance of rice (Oryza sativa) is controlled by multiple tolerance genes, but the regulatory mechanisms underlying the differential expression of these genes are poorly understood. Here, we investigated the factors regulating the expression of OsFRDL4, a gene encoding a citrate efflux transporter involved in Al-induced citrate secretion from the roots. Analysis with chromosome segment substitution lines derived from cv Nipponbare (high OsFRDL4 expression) and cv Kasalath (low OsFRDL4 expression) revealed that the differential expression of OsFRDL4 is responsible for the quantitative trait locus for Al tolerance detected previously on chromosome 1. Comparison of the OsFRDL4 gene structure in cv Nipponbare and cv Kasalath showed that there was no difference in the position of the transcriptional start site, but a 1.2-kb insertion showing high similarity to the solo long terminal repeat of the retrotransposon was found in the promoter region of OsFRDL4 in cv Nipponbare. This insertion showed higher promoter activity and contained nine cis-acting elements for ALUMINUM RESISTANCE TRANSCRIPTION FACTOR1 (ART1). However, this insertion did not alter the spatial expression or cellular localization of OsFRDL4. Furthermore, this insertion was found in most japonica varieties but was largely absent from indica varieties or wild rice species. These results indicate that the 1.2-kb insertion in the OsFRDL4 promoter region in japonica subspecies is responsible for their higher expression level of OsFRDL4 due to the increased number of cis-acting elements of ART1. Our results also suggest that this insertion event happened at the initial stage of domestication of japonica subspecies.

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“…Although the expression and localization of ART1 is not induced by Al, the expression of downstream genes is up-regulated by Al within hours ). All the proteins encoded are localized at all root cells Xia et al 2010Xia et al , 2013Yokosho et al 2011;Chen et al 2012), but play different roles in Al detoxification (Fig. 4).…”

Section: Art1-mediated High Al Tolerance In Ricementioning

confidence: 99%

Molecular mechanisms of Al tolerance in gramineous plants

2014

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Background Aluminum (Al) toxicity has limited the productivity and expansion of cereal crops on acid soils; however, a number of plant species or cultivars have developed different strategies for detoxifying aluminum both internally and externally. Scope This review focuses on recent progress on molecular mechanisms of Al tolerance in gramineous plants.Conclusions A common mechanism in all gramineous plants is the secretion of organic acid anions (citrate and malate) from the roots. Genes belonging to ALMT (for Aluminum-activated malate transporter) and MATE (Multidrug and toxic compound extrusion) family involved in the secretion have been identified in several plant species; however, different plant species show different gene expression patterns including Alinduction, spatial and temporal expression, and tissue localization. Furthermore, the mechanisms regulating the gene expression also differ with plant species, which are achieved by increased tandem repeated element, increase of copy number, insertion of transposon, or alteration of cis-acting element. In addition to these common Al exclusion mechanisms, rice as a highly Al-tolerant species has developed a number of other mechanisms for detoxification of Al. A transcription factor for Al tolerance ART1 identified in rice regulates at least 30 genes implicated in internal and external detoxification of Al. These multiple genes may contribute to the high Al tolerance of rice. In the future, regulation mechanisms of Al-tolerance genes need to be further investigated.

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Up-Regulation of a Magnesium Transporter GeneOsMGT1Is Required for Conferring Aluminum Tolerance in Rice

Cited by 167 publications

References 58 publications

A Magnesium Transporter OsMGT1 Plays a Critical Role in Salt Tolerance in Rice

A Magnesium Transporter OsMGT1 Plays a Critical Role in Salt Tolerance in Rice

Retrotransposon-Mediated Aluminum Tolerance through Enhanced Expression of the Citrate Transporter OsFRDL4

Molecular mechanisms of Al tolerance in gramineous plants

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