Investigation of the regulation mechanism of Arabidopsis thaliana anion channel SLAH2

Authors : FEN-YONG YAO, GUO-NING QI, JAMSHAID HUSSSAIN

Pages : 543-551

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :In recent years a slow-type anion channel insert ignore into journalissuearticles values(SLAC); family composing five members, including slow anion channel associated 1 insert ignore into journalissuearticles values(SLAC1); and four SLAC1 homologs insert ignore into journalissuearticles values(SLAHs);, has been identified in Arabidopsis thaliana. The anion channels are activated by calcium-dependent protein kinases insert ignore into journalissuearticles values(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 insert ignore into journalissuearticles values(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-to-shoot 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 lines. Together, these data demonstrate that SLAH2 is regulated by multiple CPKs with variable Ca2+ sensitivities. Further research is required to understand the role of SLAH2 in nitrate transport.
Keywords : Arabidopsis, anion channel, SLAH2, CPKs, nitrate, calcium