关键词: 甜橙, 钾, 钾转运蛋白, CsKT1, AKT1, CBL/CIPK

Abstract:

Potassium transporters play important roles in the transmembrane transport of potassium ions. In this study，it was found that CsKT1 had the characteristics of Shaker potassium channel，and displayed the highest homologous to AKT1 in Shaker family members of Arabidopsis thaliana. The experiments showed that the K+-uptake deficient yeast containing CsKT1 can grow under the conditions with K+ concentration of 10，1 and 0.1 mmol · L-1. qRT-PCR assays showed that the expression of CsKT1 in root was higher than that in shoot，and the transcription level was not changed after 24 h low potassium treatment（0.1 mmol · L-1）in Citrus sinensis plants. CsKT1 exhibited plasma membrane localization specifically. The yeast two hybrid experiments showed that the C-terminal cytosolic region of CsKT1 protein not only interacted with AtCIPK23，but also interacted with CsCIPK7 protein，which displayed the highest homology with AtCIPK23. CsCIPK7 could also interact with AtCBL1. There were 8 members in citrus CBL family，in which CsCBL1 displayed the highest similarity with AtCBL1/AtCBL9. These results suggested that CsKT1 function as an AKT1-like potassium transporter.

Key words: Citrus sinensis, potassium, potassium transporter, CsKT1, AKT1, CBL/CIPK