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Type: Journal article
Title: Molecular and electrophysiological characterization of anion transport in Arabidopsis thaliana pollen reveals regulatory roles for pH, Ca²⁺ and GABA
Other Titles: Molecular and electrophysiological characterization of anion transport in Arabidopsis thaliana pollen reveals regulatory roles for pH, Ca(2+) and GABA
Author: Domingos, P.
Dias, P.N.
Tavares, B.
Portes, M.T.
Wudick, M.M.
Konrad, K.R.
Gilliham, M.
Bicho, A.
Feijó, J.A.
Citation: New Phytologist, 2019; 223(3):1353-1371
Publisher: Wiley
Issue Date: 2019
ISSN: 0028-646X
Statement of
Patrícia Domingos, Pedro N. Dias, Bárbara Tavares, Maria Teresa Portes, Michael M. Wudick, Kai R. Konrad, Matthew Gilliham, Ana Bicho, and José A. Feijó
Abstract: We investigated the molecular basis and physiological implications of anion transport during pollen tube (PT) growth in Arabidopsis thaliana (Col-0). Patch-clamp whole-cell configuration analysis of pollen grain protoplasts revealed three subpopulations of anionic currents differentially regulated by cytoplasmic calcium ([Ca2+ ]cyt ). We investigated the pollen-expressed proteins AtSLAH3, AtALMT12, AtTMEM16 and AtCCC as the putative anion transporters responsible for these currents. AtCCC-GFP was observed at the shank and AtSLAH3-GFP at the tip and shank of the PT plasma membrane. Both are likely to carry the majority of anion current at negative potentials, as extracellular anionic fluxes measured at the tip of PTs with an anion vibrating probe were significantly lower in slah3-/- and ccc-/- mutants, but unaffected in almt12-/- and tmem16-/- . We further characterised the effect of pH and GABA by patch clamp. Strong regulation by extracellular pH was observed in the wild-type, but not in tmem16-/- . Our results are compatible with AtTMEM16 functioning as an anion/H+ cotransporter and therefore, as a putative pH sensor. GABA presence: (1) inhibited the overall currents, an effect that is abrogated in the almt12-/- and (2) reduced the current in AtALMT12 transfected COS-7 cells, strongly suggesting the direct interaction of GABA with AtALMT12. Our data show that AtSLAH3 and AtCCC activity is sufficient to explain the major component of extracellular anion fluxes, and unveils a possible regulatory system linking PT growth modulation by pH, GABA, and [Ca2+ ]cyt through anionic transporters.
Keywords: Anion transport; Arabidopsis; AtALTMT12; AtCCC; AtSLAH3; AtTMEM16; electrophysiology; pollen
Rights: © 2019 The Authors. New Phytologist © 2019 New Phytologist Trust
DOI: 10.1111/nph.15863
Grant ID:
Appears in Collections:Agriculture, Food and Wine publications
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