COLD SHOCK DOMAIN PROTEIN 3 is involved in salt and drought stress tolerance in Arabidopsis.

Cold shock proteins (CSPs) of bacteria are produced in response to cold and function as RNA chaperones that are essential for cold adaptation. Arabidopsis thaliana COLD SHOCK DOMAIN PROTEIN 3 (AtCSP3) shares a domain with bacterial CSPs and is involved in acquisition of freezing tolerance. Our previous study revealed that many of the genes that are down regulated in an AtCSP3 knockout mutant (atcsp3-2) are functionally associated with responses to salt and drought as well as cold. Here, we examined the involvement of AtCSP3 in salt and drought stress tolerance. We found that AtCSP3 is induced during salt and drought stresses, and is regulated by ABA. A knockout mutant of AtCSP3 (atcsp3-2) showed lower survival rates after salt and drought stress treatments. Conversely, the AtCSP3-overexpressing plants displayed higher survival rates after treatment with these stresses. Most of the genes that were down regulated in the atcsp3-2 mutant were found to be inducible upon salt and drought stresses, and upregulated in the AtCSP3-overexpressors. Together, our data demonstrates that AtCSP3 is involved in the regulation of salt and drought stress tolerance in Arabidopsis.