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Improving plant stress tolerance and yield production: is the tonoplast aquaporin SlTIP2;2 a key to isohydric to anisohydric conversion?
Author(s) -
Sade Nir,
Vinocur Basia J.,
Diber Alex,
Shatil Arava,
Ronen Gil,
Nissan Hagit,
Wallach Rony,
Karchi Hagai,
Moshelion Menachem
Publication year - 2009
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2008.02689.x
Subject(s) - aquaporin , transpiration , abiotic component , biology , solanum , vacuole , abiotic stress , solanaceae , horticulture , botany , agronomy , photosynthesis , microbiology and biotechnology , biochemistry , gene , ecology , cytoplasm
Summary• Anisohydric plants are thought to be more drought tolerant than isohydric plants. However, the molecular mechanism determining whether the plant water potential during the day remains constant or not regardless of the evaporative demand (isohydric vs anisohydric plant) is not known. • Here, it was hypothesized that aquaporins take part in this molecular mechanism determining the plant isohydric threshold. Using computational mining a key tonoplast aquaporin, tonoplast intrinsic protein 2;2 (SlTIP2;2), was selected within the large multifunctional gene family of tomato ( Solanum lycopersicum ) aquaporins based on its induction in response to abiotic stresses. SlTIP2;2 ‐transformed plants (TOM‐SlTIP2;2) were compared with controls in physiological assays at cellular and whole‐plant levels. • Constitutive expression of SlTIP2;2 increased the osmotic water permeability of the cell and whole‐plant transpiration. Under drought, these plants transpired more and for longer periods than control plants, reaching a lower relative water content, a behavior characterizing anisohydric plants. In 3‐yr consecutive commercial glasshouse trials, TOM‐SlTIP2;2 showed significant increases in fruit yield, harvest index and plant mass relative to the control under both normal and water‐stress conditions. • In conclusion, it is proposed that the regulation mechanism controlling tonoplast water permeability might have a role in determining the whole‐plant ishohydric threshold, and thus its abiotic stress tolerance.