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Transceptors at the boundary of nutrient transporters and receptors: a new role for Arabidopsis SULTR1;2 in sulfur sensing.

Zheng ZL, Zhang B, Leustek T - Front Plant Sci (2014)

Bottom Line: Genetic, biochemical, and molecular studies in Arabidopsis over the past 10 years have started to shed some light on the regulatory mechanism of the S response.Key advances in transcriptional regulation (SLIM1, MYB, and miR395), involvement of hormones (auxin, cytokinin, and abscisic acid) and identification of putative sensors (OASTL and SULTR1;2) are highlighted here.Although our current view of S nutrient sensing and signaling remains fragmented, it is anticipated that through further studies a sensing and signaling network will be revealed in the near future.

View Article: PubMed Central - PubMed

Affiliation: Plant Nutrient Signaling and Fruit Quality Improvement Laboratory, Citrus Research Institute, Southwest University , Chongqing, China ; Department of Biological Sciences, Lehman College, City University of New York , Bronx, NY, USA.

ABSTRACT
Plants have evolved a sophisticated mechanism to sense the extracellular sulfur (S) status so that sulfate transport and S assimilation/metabolism can be coordinated. Genetic, biochemical, and molecular studies in Arabidopsis over the past 10 years have started to shed some light on the regulatory mechanism of the S response. Key advances in transcriptional regulation (SLIM1, MYB, and miR395), involvement of hormones (auxin, cytokinin, and abscisic acid) and identification of putative sensors (OASTL and SULTR1;2) are highlighted here. Although our current view of S nutrient sensing and signaling remains fragmented, it is anticipated that through further studies a sensing and signaling network will be revealed in the near future.

No MeSH data available.


A hypothetical model for the dual function transceptor SULTR1;2.(A) The normal (wild-type) transceptor functions both in SO42– transport and signaling; (B) the transceptor is defective both in transport and signaling due to the mutations of D108N or G208D.
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Figure 1: A hypothetical model for the dual function transceptor SULTR1;2.(A) The normal (wild-type) transceptor functions both in SO42– transport and signaling; (B) the transceptor is defective both in transport and signaling due to the mutations of D108N or G208D.

Mentions: In the case of SULTR1;2, the mutations in TM1 (sel1-15) or TM5 (sel1-16) could abolish both SO42– transport and signaling (as measured by expression of S response genes), but the defect in signaling could be independent of SO42– transport and accumulation (Zhang et al., 2014). Because of this, we propose that SULTR1;2 can function as a putative SO42– transceptor (Figure 1). Although SULTR1;2 cannot be the only S-sensor since the sel1-15/16 mutants show reduced sensitivity to S but does not entirely abolish the S-limitation response, this finding provides a first intriguing insight into S-sensing in plants given its PM location where extracellular SO42– is first in contact with the PM-localized sensors. Note that a dual-affinity nitrate transporter called NRT1.1 has been demonstrated to act as a nitrate sensor (Ho et al., 2009; Bouguyon et al., 2012), and thus using nutrient transporters to sense the external nutrient status may be evolutionally conserved and advantageous to plants. Indeed, a phosphate transceptor (Pho84) has been reported in yeast (Popova et al., 2010). More encouraging is that in yeast SO42– transporters Sul1/2 have also been described as being transceptors (Conrad et al., 2014). To gain further insights into the evolutionarily conserved mechanism of using sulfate transporters as sensors, we performed a sequence alignment using transporters from Arabidopsis, rice, Chlamydomonas, yeast, Drosophila and humans that are most closely related to Arabidopsis SULR1;2. The result (Figure 2) shows that while D108 is only specific to SULTR1 group in Arabidopsis and rice, G208 is highly conserved in all transporters. It will be interesting to determine whether G208 is critical for SO42– transport and signaling in many eukaryotes.


Transceptors at the boundary of nutrient transporters and receptors: a new role for Arabidopsis SULTR1;2 in sulfur sensing.

Zheng ZL, Zhang B, Leustek T - Front Plant Sci (2014)

A hypothetical model for the dual function transceptor SULTR1;2.(A) The normal (wild-type) transceptor functions both in SO42– transport and signaling; (B) the transceptor is defective both in transport and signaling due to the mutations of D108N or G208D.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263312&req=5

Figure 1: A hypothetical model for the dual function transceptor SULTR1;2.(A) The normal (wild-type) transceptor functions both in SO42– transport and signaling; (B) the transceptor is defective both in transport and signaling due to the mutations of D108N or G208D.
Mentions: In the case of SULTR1;2, the mutations in TM1 (sel1-15) or TM5 (sel1-16) could abolish both SO42– transport and signaling (as measured by expression of S response genes), but the defect in signaling could be independent of SO42– transport and accumulation (Zhang et al., 2014). Because of this, we propose that SULTR1;2 can function as a putative SO42– transceptor (Figure 1). Although SULTR1;2 cannot be the only S-sensor since the sel1-15/16 mutants show reduced sensitivity to S but does not entirely abolish the S-limitation response, this finding provides a first intriguing insight into S-sensing in plants given its PM location where extracellular SO42– is first in contact with the PM-localized sensors. Note that a dual-affinity nitrate transporter called NRT1.1 has been demonstrated to act as a nitrate sensor (Ho et al., 2009; Bouguyon et al., 2012), and thus using nutrient transporters to sense the external nutrient status may be evolutionally conserved and advantageous to plants. Indeed, a phosphate transceptor (Pho84) has been reported in yeast (Popova et al., 2010). More encouraging is that in yeast SO42– transporters Sul1/2 have also been described as being transceptors (Conrad et al., 2014). To gain further insights into the evolutionarily conserved mechanism of using sulfate transporters as sensors, we performed a sequence alignment using transporters from Arabidopsis, rice, Chlamydomonas, yeast, Drosophila and humans that are most closely related to Arabidopsis SULR1;2. The result (Figure 2) shows that while D108 is only specific to SULTR1 group in Arabidopsis and rice, G208 is highly conserved in all transporters. It will be interesting to determine whether G208 is critical for SO42– transport and signaling in many eukaryotes.

Bottom Line: Genetic, biochemical, and molecular studies in Arabidopsis over the past 10 years have started to shed some light on the regulatory mechanism of the S response.Key advances in transcriptional regulation (SLIM1, MYB, and miR395), involvement of hormones (auxin, cytokinin, and abscisic acid) and identification of putative sensors (OASTL and SULTR1;2) are highlighted here.Although our current view of S nutrient sensing and signaling remains fragmented, it is anticipated that through further studies a sensing and signaling network will be revealed in the near future.

View Article: PubMed Central - PubMed

Affiliation: Plant Nutrient Signaling and Fruit Quality Improvement Laboratory, Citrus Research Institute, Southwest University , Chongqing, China ; Department of Biological Sciences, Lehman College, City University of New York , Bronx, NY, USA.

ABSTRACT
Plants have evolved a sophisticated mechanism to sense the extracellular sulfur (S) status so that sulfate transport and S assimilation/metabolism can be coordinated. Genetic, biochemical, and molecular studies in Arabidopsis over the past 10 years have started to shed some light on the regulatory mechanism of the S response. Key advances in transcriptional regulation (SLIM1, MYB, and miR395), involvement of hormones (auxin, cytokinin, and abscisic acid) and identification of putative sensors (OASTL and SULTR1;2) are highlighted here. Although our current view of S nutrient sensing and signaling remains fragmented, it is anticipated that through further studies a sensing and signaling network will be revealed in the near future.

No MeSH data available.