Limits...
Differentially expressed membrane transporters in rice roots may contribute to cultivar dependent salt tolerance.

Senadheera P, Singh RK, Maathuis FJ - J. Exp. Bot. (2009)

Bottom Line: Physiological studies indicate that FL478 shows a lower Na(+) influx, a reduced Na(+) translocation to the shoot, and maintains a lower Na(+):K(+) ratio.However, transcripts for cation transport proteins including OsCHX11, OsCNGC1, OsCAX, and OsTPC1 showed differential regulation between the cultivars.The encoded proteins are likely to participate in reducing Na(+) influx, lowering the tissue Na(+):K(+) ratio and limiting the apoplastic bypass flow in roots of FL478 and are therefore important new targets to improve salt tolerance in rice.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Science, University of Colombo, Colombo, Sri Lanka.

ABSTRACT
Salinity tolerance in rice, like in other glycophytes, is a function of cellular ion homeostasis. The large divergence in ion homeostasis between the salt-tolerant FL478 and salt-sensitive IR29 rice varieties can be exploited to understand mechanisms of salinity tolerance. Physiological studies indicate that FL478 shows a lower Na(+) influx, a reduced Na(+) translocation to the shoot, and maintains a lower Na(+):K(+) ratio. To understand the basis of these differences, a comparative investigation of transcript regulation in roots of the two cultivars was undertaken. This analysis revealed that genes encoding aquaporins, a silicon transporter, and N transporters are induced in both cultivars. However, transcripts for cation transport proteins including OsCHX11, OsCNGC1, OsCAX, and OsTPC1 showed differential regulation between the cultivars. The encoded proteins are likely to participate in reducing Na(+) influx, lowering the tissue Na(+):K(+) ratio and limiting the apoplastic bypass flow in roots of FL478 and are therefore important new targets to improve salt tolerance in rice.

Show MeSH

Related in: MedlinePlus

Short-term Na+ uptake into different tissues of FL478 and IR29 at different time intervals after exposure to salinity treatment. At 15 DAS, seedlings were exposed to salt (50 mM NaCl). Plants were withdrawn from the growth medium after different time intervals and analysed for Na+ levels in different tissues. Data show the mean ±SD of three replicates and asterisks indicate significant differences at P <0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC2692005&req=5

fig3: Short-term Na+ uptake into different tissues of FL478 and IR29 at different time intervals after exposure to salinity treatment. At 15 DAS, seedlings were exposed to salt (50 mM NaCl). Plants were withdrawn from the growth medium after different time intervals and analysed for Na+ levels in different tissues. Data show the mean ±SD of three replicates and asterisks indicate significant differences at P <0.05.

Mentions: Short-term Na+ uptake experiments (3 h) were carried out to see if the trends discussed above also pertain to shorter periods. Figure 3 shows that a 3 h exposure to 50 mM NaCl resulted in a different pattern of tissue Na+ in the two cultivars, indicating that FL and IR may also employ varying strategies to maintain Na+ homeostasis during relatively short periods of exposure to salt. Na+ accumulation increased in both cultivars but a clear difference was already apparent after 50 min uptake with higher Na+ concentrations in IR leaf and culm tissues. More importantly, the leaf [Na+] in FL quickly stabilizes and even reduces slightly after 3 h, whereas that of IR leaves continues to increase. Thus, after 3 h, IR actually contained higher [Na+] in its leaf tissue than in its roots.


Differentially expressed membrane transporters in rice roots may contribute to cultivar dependent salt tolerance.

Senadheera P, Singh RK, Maathuis FJ - J. Exp. Bot. (2009)

Short-term Na+ uptake into different tissues of FL478 and IR29 at different time intervals after exposure to salinity treatment. At 15 DAS, seedlings were exposed to salt (50 mM NaCl). Plants were withdrawn from the growth medium after different time intervals and analysed for Na+ levels in different tissues. Data show the mean ±SD of three replicates and asterisks indicate significant differences at P <0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2692005&req=5

fig3: Short-term Na+ uptake into different tissues of FL478 and IR29 at different time intervals after exposure to salinity treatment. At 15 DAS, seedlings were exposed to salt (50 mM NaCl). Plants were withdrawn from the growth medium after different time intervals and analysed for Na+ levels in different tissues. Data show the mean ±SD of three replicates and asterisks indicate significant differences at P <0.05.
Mentions: Short-term Na+ uptake experiments (3 h) were carried out to see if the trends discussed above also pertain to shorter periods. Figure 3 shows that a 3 h exposure to 50 mM NaCl resulted in a different pattern of tissue Na+ in the two cultivars, indicating that FL and IR may also employ varying strategies to maintain Na+ homeostasis during relatively short periods of exposure to salt. Na+ accumulation increased in both cultivars but a clear difference was already apparent after 50 min uptake with higher Na+ concentrations in IR leaf and culm tissues. More importantly, the leaf [Na+] in FL quickly stabilizes and even reduces slightly after 3 h, whereas that of IR leaves continues to increase. Thus, after 3 h, IR actually contained higher [Na+] in its leaf tissue than in its roots.

Bottom Line: Physiological studies indicate that FL478 shows a lower Na(+) influx, a reduced Na(+) translocation to the shoot, and maintains a lower Na(+):K(+) ratio.However, transcripts for cation transport proteins including OsCHX11, OsCNGC1, OsCAX, and OsTPC1 showed differential regulation between the cultivars.The encoded proteins are likely to participate in reducing Na(+) influx, lowering the tissue Na(+):K(+) ratio and limiting the apoplastic bypass flow in roots of FL478 and are therefore important new targets to improve salt tolerance in rice.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Science, University of Colombo, Colombo, Sri Lanka.

ABSTRACT
Salinity tolerance in rice, like in other glycophytes, is a function of cellular ion homeostasis. The large divergence in ion homeostasis between the salt-tolerant FL478 and salt-sensitive IR29 rice varieties can be exploited to understand mechanisms of salinity tolerance. Physiological studies indicate that FL478 shows a lower Na(+) influx, a reduced Na(+) translocation to the shoot, and maintains a lower Na(+):K(+) ratio. To understand the basis of these differences, a comparative investigation of transcript regulation in roots of the two cultivars was undertaken. This analysis revealed that genes encoding aquaporins, a silicon transporter, and N transporters are induced in both cultivars. However, transcripts for cation transport proteins including OsCHX11, OsCNGC1, OsCAX, and OsTPC1 showed differential regulation between the cultivars. The encoded proteins are likely to participate in reducing Na(+) influx, lowering the tissue Na(+):K(+) ratio and limiting the apoplastic bypass flow in roots of FL478 and are therefore important new targets to improve salt tolerance in rice.

Show MeSH
Related in: MedlinePlus