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Tissue tolerance mechanisms conferring salinity tolerance in a halophytic perennial species Nitraria sibirica Pall.

journal contribution
posted on 2023-05-21, 04:15 authored by Tang, X, Zhang, H, Sergey ShabalaSergey Shabala, Li, H, Yang, X
Plant salt tolerance relies on a coordinated functioning of different tissues and organs. Salinity tissue tolerance is one of the key traits that confer plant adaptation to saline environment. This trait implies maintenance low cytosolic Na+/K+ ratio in metabolically active cellular compartments. In this study, we used Nitraria sibirica Pall., a perennial woody halophyte species, to understand the mechanistic basis of its salinity tissue tolerance. The results showed that the growth of seedlings was stimulated by 100-200 mM NaCl treatment. The ions distribution analysis showed that the leaves act as an Na+ sink, while the plant roots possess superior K+ retention. The excessive Na+ absorbed from the soil was mainly transported to the shoot and was eventually sequestrated into mesophyll vacuoles in the leaves. As a result, N. sibirica could keep the optimal balance of K+/Na+ at a tissue- and cell-specific level under saline condition. To enable this, N. sibirica increased both vacuolar H+-ATPase and H+-PPase enzymes activities and up-regulated the expressions of NsVHA, NsVP1 and NsNHX1 genes. Vacuolar Na+ sequestration in the leaf mesophyll, mediated by NsVHA, NsVP1 and NsNHX1, reduced the Na+ concentration in cytosol and inhibited further K+ loss. Meanwhile, N. sibirica enhanced the Two Pore K+ expression at the transcriptional level to promote K+ efflux from vacuole into cytoplasm, assisting in maintaining cytosolic K+ homeostasis. It is concluded that the tissue tolerance traits such as vacuolar Na+ sequestration and intracellular K+ homeostasis are critical to confer adaptation of N. sibirica to soil salinity.

History

Publication title

Tree Physiology

Volume

41

Issue

7

Pagination

1264-1277

ISSN

0829-318X

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Heron Publishing

Place of publication

202, 3994 Shelbourne St, Victoria, Canada, Bc, V8N 3E2

Rights statement

Copyright 2020 The Author(s). Published by Oxford University Press

Repository Status

  • Restricted

Socio-economic Objectives

Hardwood plantations

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