TY - JOUR
T1 - Salt stress sensing and early signalling events in plant roots : current knowledge and hypothesis
AU - Shabala, Sergey
AU - Wu, Honghong
AU - Bose, Jayakumar
PY - 2015
Y1 - 2015
N2 - Soil salinity is a major environmental constraint to crop production. While the molecular identity and functional expression of Na+ transport systems mediating Na+ exclusion from the cytosol has been studied in detail, far less is known about the mechanisms by which plants sense high Na+ levels in the soil and the rapid signalling events that optimise plant performance under saline conditions. This review aims to fill this gap. We first discuss the nature of putative salt stress sensors, candidates which include Na+ transport systems, mechanosensory proteins, proteins with regulatory Na+ binding sites, sensing mediated by cyclic nucleotide-gated channels, purine receptors, annexin and voltage gating. We suggest that several transport proteins may be clustered together to form a microdomain in a lipid raft, allowing rapid changes in the activity of an individual protein to be translated into stress-induced Ca2+ and H2O2 signatures. The pathways of stress signalling to downstream targets are discussed, and the kinetics and specificity of salt stress signalling between glycophytes and halophytes is compared. We argue that these sensing mechanisms operate in parallel, providing plants with a robust system for decoding information about the specific nature and severity of the imposed salt stress.
AB - Soil salinity is a major environmental constraint to crop production. While the molecular identity and functional expression of Na+ transport systems mediating Na+ exclusion from the cytosol has been studied in detail, far less is known about the mechanisms by which plants sense high Na+ levels in the soil and the rapid signalling events that optimise plant performance under saline conditions. This review aims to fill this gap. We first discuss the nature of putative salt stress sensors, candidates which include Na+ transport systems, mechanosensory proteins, proteins with regulatory Na+ binding sites, sensing mediated by cyclic nucleotide-gated channels, purine receptors, annexin and voltage gating. We suggest that several transport proteins may be clustered together to form a microdomain in a lipid raft, allowing rapid changes in the activity of an individual protein to be translated into stress-induced Ca2+ and H2O2 signatures. The pathways of stress signalling to downstream targets are discussed, and the kinetics and specificity of salt stress signalling between glycophytes and halophytes is compared. We argue that these sensing mechanisms operate in parallel, providing plants with a robust system for decoding information about the specific nature and severity of the imposed salt stress.
UR - https://hdl.handle.net/1959.7/uws:60806
U2 - 10.1016/j.plantsci.2015.10.003
DO - 10.1016/j.plantsci.2015.10.003
M3 - Article
SN - 1873-2259
SN - 0168-9452
VL - 241
SP - 109
EP - 119
JO - Plant Science
JF - Plant Science
ER -