An Arabidopsis soil-salinity-tolerance mutation confers ethylene-mediated enhancement of sodium/potassium homeostasis.
High soil Na concentrations damage plants by increasing cellular Na accumulation and K loss. Excess soil Na stimulates ethylene-induced soil-salinity tolerance, the mechanism of which we here define via characterization of an Arabidopsis thaliana mutant displaying transpiration-dependent soil-salinity tolerance. This phenotype is conferred by a loss-of-function allele of ethylene overproducer1 (ETO1; mutant alleles of which cause increased production of ethylene). We show that lack of ETO1 function confers soil-salinity tolerance through improved shoot Na/K homeostasis, effected via the ethylene resistant1-constitutive triple response1 ethylene signaling pathway. Under transpiring conditions, lack of ETO1 function reduces root Na influx and both stelar and xylem sap Na concentrations, thereby restricting root-to-shoot delivery of Na. These effects are associated with increased accumulation of respiratory burst oxidase homolog F (RBOHF)-dependent reactive oxygen species in the root stele. Additionally, lack of ETO1 function leads to significant enhancement of tissue K status by an RBOHF-independent mechanism associated with elevated high-affinity K(+) TRANSPORTER5 transcript levels. We conclude that ethylene promotes soil-salinity tolerance via improved Na/K homeostasis mediated by RBOHF-dependent regulation of Na accumulation and RBOHF-independent regulation of K accumulation.
Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.
Caifu
C
Jiang
Eric J
EJ
Belfield
Yi
Y
Cao
J Andrew C
JA
Smith
Nicholas P
NP
Harberd
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D009154:Mutation; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D018520:Plant Shoots / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D011188:Potassium / Q000032:analysis / Q000378:metabolism; D027961:Potassium-Hydrogen Antiporters / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D054712:Salinity; D055049:Salt Tolerance; D015398:Signal Transduction; D012964:Sodium / Q000032:analysis / Q000378:metabolism; D052584:Xylem / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D005030:Ethylenes; D019255:NADPH Oxidases; D010937:Plant Growth Regulators; D011188:Potassium; D027961:Potassium-Hydrogen Antiporters; D017382:Reactive Oxygen Species; D012964:Sodium; C485242:ETO1 protein, Arabidopsis; C501258:potassium transporter, Arabidopsis; C036216:ethylene; C000589475:RBOH F protein, Arabidopsis