title: Natriuretic peptides and cGMP modulate K+, Na+, and H+ fluxes in Zea mays roots.
abstract: Recent evidence suggests that in plants, as in vertebrates, natriuretic peptides (NPs) regulate homeostasis. In this study noninvasive ion-selective vibrating microelectrodes were used to measure net fluxes of K+, Na+, and H+ in Zea mays root conductive tissue. Immunoreactant plant natriuretic peptides (irPNP) cause immediate net H+ influx and delayed net K+ and Na+ uptake. Delayed net K+ influx was also observed in response to 8-Br-cGMP, however, not accompanied by significant changes in net H+ fluxes. Furthermore, 8-Br-cGMP does not stimulate the plasma membrane H+-ATPase implying that cGMP directly affects cation channels. The data are consistent with NP and cGMP-dependent stimulation of nonselective cation channels with P(K) > P(Na) and point to a complex role for NPs in plant homeostasis.
authors.affiliation: School of Biological and Chemical Sciences, Deakin University, Geelong, Victoria, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Pharmawati
authors.forename: S N
authors.initials: SN
authors.lastname: Shabala
authors.forename: I A
authors.initials: IA
authors.lastname: Newman
authors.forename: C A
authors.initials: CA
authors.lastname: Gehring
mesh_terms: D000345:Affinity Labels; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000494:pharmacology; D002414:Cations, Monovalent; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006859:Hydrogen / Q000378:metabolism*; D015151:Immunoblotting; D008954:Models, Biological; D010455:Peptides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D018517:Plant Roots / Q000378:metabolism / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013873:Thionucleotides / Q000378:metabolism* / Q000494:pharmacology; D003313:Zea mays / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*
chemical_list: D000345:Affinity Labels; D002414:Cations, Monovalent; D010455:Peptides; D010940:Plant Proteins; D013873:Thionucleotides; C083763:8-bromoguanosino-3',5'-cyclic monophosphorothioate; D006859:Hydrogen; D009320:Atrial Natriuretic Factor; D012964:Sodium; D006152:Cyclic GMP; D011188:Potassium