In recent years a slow-type anion channel (SLAC) family composing five members, including slow anion channel associated 1 (SLAC1) and four SLAC1 homologs (SLAHs), has been identified in Arabidopsis thaliana. | Turkish Journal of Botany Turk J Bot (2017) 41: 543-551 © TÜBİTAK doi: Research Article Investigation of the regulation mechanism of Arabidopsis thaliana anion channel SLAH2 1,2 1 1,3, Fen-Yong YAO , Guo-Ning QI , Jamshaid HUSSAIN * National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, . China 2 University of the Chinese Academy of Sciences, Shanghai, . China 3 Biotechnology Program, Department of Environmental Sciences, COMSATS Institute of Information Technology, Abbottabad, Pakistan 1 Received: Accepted/Published Online: Final Version: Abstract: In recent years a slow-type anion channel (SLAC) family composing five members, including slow anion channel associated 1 (SLAC1) and four SLAC1 homologs (SLAHs), has been identified in Arabidopsis thaliana. The anion channels are activated by calciumdependent protein kinases (CPKs) and play crucial roles in mediating anion fluxes across plasma membranes. SLAH2 is specifically expressed in root stele cells and has been characterized as a nitrate-selective anion channel activated by CPK21 and CBL-interacting protein kinase 23 (CIPK23). However, the interaction between CPKs and SLAH2 and how it is regulated remains to be elucidated. In this study we found that SLAH2 could be activated by a few CPKs from three subgroups of the CPK family. Out of those CPKs, the constitutively active form of CPK2 from subgroup 1 activates SLAH2, whereas the native as well as constitutively active form of CPK3 from subgroup 2 and CPK7, CPK10, and CPK32 from subgroup 3 activate SLAH2. We also explored the role of SLAH2 in root-toshoot nitrate transport by measuring the nitrate contents in xylem sap, but no significant differences were observed between the slah2-1 T-DNA insertion mutant and SLAH2 overexpression .
