Plants pass the salt

Genetic engineering of glycine betaine biosynthesis to enhance abiotic stress tolerance in plants

“…High salinity causes ion imbalance, toxic levels of cytoplasmic sodium, and osmotic stress (Ward et al 2003). Plants have evolved two different types of mechanisms to respond to salinity stress.…”

The SOS3 Family of Calcium Sensors and SOS2 Family of Protein Kinases in Arabidopsis

“…A recent study of the three-dimensional structure of SCaBP1/ CBL2 has shown that this protein contains two pairs of EF-hand motifs; one pair (the first and fourth) binds two Ca 2ϩ ions, whereas the other pair (the second and third) remains in an open conformation (Nagae et al, 2003a(Nagae et al, , 2003b. Although there is currently no experimental evidence for SOS3 binding to Na ϩ , the possibility cannot be excluded that SOS3 might serve as a Na ϩ sensor based on the ability of Na ϩ to bind within the EF-hand motifs of other proteins (Henzl et al, 2000;Ward et al, 2003).…”

Putative UDP-galactose Epimerase and Metallothioneine of <i>Paspalum vaginatum</i> Enhanced the Salt Tolerance of Rice, <i>Oryza sativa</i> L. from Transplanting to Harvest Stages

“…This comparison focused on the genes involved in long-term survival within the range of critical salinity. Up to now, the genes effective for salt tolerance in plants had been investigated mostly from the viewpoints of physiological aspects and defense mechanisms such as osmotic protection within the cell (Mohanty et al 2002, Abebe et al 2003 or compartmentation of NaCl in the cell-vacuoles (Ohta et al 2002), exclusion of toxic salts from cells through SOS signaling system (Ward et al 2003) or reduction of oxidative stresses (Asada 1999) as well as downward gene regulation by transcription factors (Dubouzet et al 2003). On the other hand, the regulation of NaCl in the uptake or exclusion from the individual plants has not been fully elucidated (Endo et al 1999).…”

“…Although rice has been growing in lowland deltas near the sea, its salt tolerance is extremely low. Recently in many reports, gene sources for potential enhancement of salt tolerance in plants have been identified: glycine betaine as an osmoprotectant (Sakamoto et al 1998, Mohanty et al 2002, Holmstorm et al 2000, MtlD (mannitol-1-phosphate dehydrogenase) in wheat (Abebe et al 2003); transcription factor: DREB1 (Kasuga et al 1999, Dubouzet et al 2003, HVA1 (late embryogenesis abundant protein gene) in rice (Xu et al 1996); vacuolar Na+/H+ antiporter (Rubio et al 1995, Apse et al 1999, Zhang et al 2001, Ohta et al 2002, mitogen-activated protein kinase (Kovtun et al 2000), hydroxyl radical scavenging catalases (Smirnoff andCumbes 1989, Asada 1999) and plasma membrane Na+/H+ exchanger regulated in the SOS signaling system (Liu and Zhu 1998, Qiu et al 2002, Shi et al 2003, Ward et al 2003. However, few studies have focused on the long-term survival or growth: in many cases, salt tolerance was evaluated on the basis of recovery after strong salinity stress regardless of the critical lethality of the plants.…”