title: Transport Across Chloroplast Membranes: Optimizing Photosynthesis for Adverse Environmental Conditions.
abstract: Chloroplasts are central to solar light harvesting and photosynthesis. Optimal chloroplast functioning is vitally dependent on a very intensive traffic of metabolites and ions between the cytosol and stroma, and should be attuned for adverse environmental conditions. This is achieved by an orchestrated regulation of a variety of transport systems located at chloroplast membranes such as porines, solute channels, ion-specific cation and anion channels, and various primary and secondary active transport systems. In this review we describe the molecular nature and functional properties of the inner and outer envelope and thylakoid membrane channels and transporters. We then discuss how their orchestrated regulation affects thylakoid structure, electron transport and excitation energy transfer, proton-motive force partition, ion homeostasis, stromal pH regulation, and volume regulation. We link the activity of key cation and anion transport systems with stress-specific signaling processes in chloroplasts, and discuss how these signals interact with the signals generated in other organelles to optimize the cell performance, with a special emphasis on Ca(2+) and reactive oxygen species signaling.
authors.affiliation: Biomedical Centre, University of Colima, Colima, Colima 28045, Mexico; School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia.
authors.forename: Igor
authors.initials: I
authors.lastname: Pottosin
authors.affiliation: School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia. Electronic address: sergey.shabala@utas.edu.au.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
mesh_terms: D001692:Biological Transport / Q000528:radiation effects; D002736:Chloroplasts / Q000378:metabolism* / Q000528:radiation effects; D004777:Environment; D007425:Intracellular Membranes / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D010788:Photosynthesis / Q000528:radiation effects
keywords: envelope; p.m.f.; programmed cell death; reactive oxygen species; stroma; thylakoid