The role of monovalent cation transporters in plant responses to salinity

Exposure to high ambient levels of NaCl affects plant water relations and creates ionic stress in the form of the cellular accumulation of Cl- and, in particular, Na+ ions. However, salt stress also impacts heavily on the homeostasis of other ions such as Ca2+, K+, and NO3- and therefore requires insights into how transport and compartmentation of these nutrients is altered during salinity stress. A genomics approach can greatly help with the identification of genes, and therefore potentially gene products, that are involved in plant salinity. Both the literature and public databases contain the results of many genomics studies and, in this report, those data are collated in the context of cation membrane transport and salinity. The efficacy of genomics approaches in isolation is low due to large inherent variability and the exclusion of gene products that are predominantly regulated post-transcriptionally. In conjunction with complementary approaches, however, transcriptomics can help identify important transcripts and relevant associations between physiological processes. This analysis identified (i) vascular K+ circulation, (ii) root shoot translocation of Ca2+, and (iii) transition metal homeostasis as potentially important aspects of the plant response to salt stress.