The energy cost of the tonoplast futile sodium leak

• Published in: The New phytologist Vol. 225; no. 3; pp. 1105 - 1110
• Main Authors: Shabala, Sergey, Chen, Guang, Chen, Zhong-Hua, Pottosin, Igor
• Format: Journal Article
• Language: English
• Published: England Wiley 01.02.2020; Wiley Subscription Services, Inc
• Subjects: bioinformatics; Channels; Cytosol; Energy costs; Energy Metabolism; H+‐ATPase; halophyte; Halophytes; Permeability; Phylogeny; Plant Proteins - metabolism; Proton Pumps - metabolism; Retention; Salinity; Salinity effects; salinity stress; Salinity tolerance; salt tolerance; Salt-Tolerant Plants - metabolism; Sodium; Sodium - metabolism; Tansley insight; tonoplast; tonoplast ion channels; two‐pore channel 1 (TPC1); vacuolar sodium sequestration; Vacuoles; Vacuoles - metabolism; tonoplast ion channels; H+-ATPase; halophyte; two-pore channel 1 (TPC1); vacuolar sodium sequestration; salinity stress
• ISSN: 0028-646X; 1469-8137; 1469-8137
• DOI: 10.1111/nph.15758

Active removal of Na⁺ from the cytosol into the vacuole plays a critical role in salinity tissue tolerance, but another, often neglected component of this trait is Na⁺ retention in vacuoles. This retention is based on an efficient control of Na⁺-permeable slow- and fast-vacuolar channels that mediate the back-leak of Na⁺ into cytosol and, if not regulated tightly, could result in a futile cycle. This Tansley insight summarizes our current knowledge of regulation of tonoplast Na⁺-permeable channels and discusses the energy cost of vacuolar Na⁺ sequestration, under different scenarios. We also report on a phylogenetic and bioinformatic analysis of the plant two-pore channel family and the difference in its structure and regulation between halophytes and glycophytes, in the context of salinity tolerance.