Venus Flytrap HKT1-Type Channel Provides for Prey Sodium Uptake into Carnivorous Plant Without Conflicting with Electrical Excitability

被引：44

作者：

Boehm, J. ^{[1
]}

Scherzer, S. ^{[1
]}

Shabala, S. ^{[2
]}

Krol, E. ^{[1
]}

Neher, E. ^{[3
,4
]}

Mueller, T. D. ^{[1
]}

Hedrich, R. ^{[1
]}

机构：

[1] Univ Wurzburg, Dept Mol Plant Physiol & Biophys, Julius von Sachs Inst, Julius von Sachs Pl 2, D-97082 Wurzburg, Germany

[2] Univ Tasmania, Sch Land & Food, Hobart, Tas 7001, Australia

[3] King Saud Univ, Coll Sci, Dept Zool, POB 2455, Riyadh 11451, Saudi Arabia

[4] Max Planck Inst Biophys Chem, Dept Membrane Biophys, D-37077 Gottingen, Germany

来源：

MOLECULAR PLANT | 2016年 / 9卷 / 03期

基金：

欧洲研究理事会; 澳大利亚研究理事会;

关键词：

sodium channel; HKT1; Dionaea muscipula; action potential; glands; sodium uptake; HIGH-AFFINITY; HKT TRANSPORTERS; POTASSIUM UPTAKE; MEMBRANE TRANSPORTERS; SELECTIVITY FILTER; SALT TOLERANCE; K+; CA2+; NA+; FLUXES;

D O I：

10.1016/j.molp.2015.09.017

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na+- and K+-permeable mutants function as ion channels rather than K+ transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na+-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.

引用

页码：428 / 436

页数：9

共 40 条

[1] TsHKT1;2, a HKT1 Homolog from the Extremophile Arabidopsis Relative Thellungiella salsuginea, Shows K+ Specificity in the Presence of NaCl [J].