A tobacco calmodulin-binding protein kinase (NtCBK2) induced by high-salt/GA treatment and its expression during floral development and embryogenesis

Calcium/calmodulin (CaM) plays vital roles in the regulation of many physiological and metabolic processes through its target proteins including calcium/CaM-modulated protein kinases. Here, we report our studies on the expression of a CaM-binding protein kinase gene (NtCBK2) during plant development and under some stimuli. Our results indicated that the expression of NtCBK2 was greatly enhanced after 10 min with high-salt or GA treatment, and reached the maximal at 30 min, while other stimuli, such as ABA, NAA, PEG-6000, cold (4degreesC) or high temperature (42degreesC) treatment had no effect on the expression of NtCBK2, suggesting possible involvement of NtCBK2 in salt and GA stress responses of plants. Using digoxigenin-labeled anti-sense RNA probe, the expression of NtCBK2 was detected in developing tobacco anther, pistil and embryo, revealing that the mRNA of NtCBK2 distributed mainly in actively dividing and vigorously metabolizing cells in a temporal and spatial manner during these developmental events. These data suggest that NtCBK2 may play a key role in the calcium/CaM-mediated signal pathway associated with floral development and embryogenesis in tobacco. (C) 2004 Elsevier Ireland Ltd. All rights reserved.