1. A Solanum lycopersicum polyamine oxidase contributes to the control of plant growth, xylem differentiation, and drought stress tolerance.
- Author
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D'Incà R, Mattioli R, Tomasella M, Tavazza R, Macone A, Incocciati A, Martignago D, Polticelli F, Fraudentali I, Cona A, Angelini R, Tavazza M, Nardini A, and Tavladoraki P
- Subjects
- Stress, Physiological, Oxidoreductases Acting on CH-NH Group Donors genetics, Oxidoreductases Acting on CH-NH Group Donors metabolism, Plants, Genetically Modified, Plant Development genetics, Polyamines metabolism, Spermine analogs & derivatives, Xylem genetics, Xylem growth & development, Xylem metabolism, Xylem physiology, Solanum lycopersicum genetics, Solanum lycopersicum physiology, Solanum lycopersicum growth & development, Solanum lycopersicum enzymology, Droughts, Polyamine Oxidase, Gene Expression Regulation, Plant, Plant Proteins genetics, Plant Proteins metabolism
- Abstract
Polyamines are involved in several plant physiological processes. In Arabidopsis thaliana, five FAD-dependent polyamine oxidases (AtPAO1 to AtPAO5) contribute to polyamine homeostasis. AtPAO5 catalyzes the back-conversion of thermospermine (T-Spm) to spermidine and plays a role in plant development, xylem differentiation, and abiotic stress tolerance. In the present study, to verify whether T-Spm metabolism can be exploited as a new route to improve stress tolerance in crops and to investigate the underlying mechanisms, tomato (Solanum lycopersicum) AtPAO5 homologs were identified (SlPAO2, SlPAO3, and SlPAO4) and CRISPR/Cas9-mediated loss-of-function slpao3 mutants were obtained. Morphological, molecular, and physiological analyses showed that slpao3 mutants display increased T-Spm levels and exhibit changes in growth parameters, number and size of xylem elements, and expression levels of auxin- and gibberellin-related genes compared to wild-type plants. The slpao3 mutants are also characterized by improved tolerance to drought stress, which can be attributed to a diminished xylem hydraulic conductivity that limits water loss, as well as to a reduced vulnerability to embolism. Altogether, this study evidences conservation, though with some significant variations, of the T-Spm-mediated regulatory mechanisms controlling plant growth and differentiation across different plant species and highlights the T-Spm role in improving stress tolerance while not constraining growth., (© 2024 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)
- Published
- 2024
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