Short-term salt stress in Brassica rapa seedlings causes alterations in auxin metabolism

0489040 - ÚEB 2019 RIV FR eng J - Journal Article
Pavlović, I. - Pěnčík, Aleš - Novák, Ondřej - Vujčić, V. - Radić Brkanac, S. - Lepeduš, H. - Strnad, Miroslav - Salopek-Sondi, B.
Short-term salt stress in Brassica rapa seedlings causes alterations in auxin metabolism.
Plant Physiology and Biochemistry. Roč. 125, APR (2018), s. 74-84. ISSN 0981-9428
R&D Projects: GA MŠMT(CZ) LO1204; GA ČR(CZ) GA17-06613S
Institutional support: RVO:61389030
Keywords : Auxin metabolism * Brassica rapa ssp. pekinensis * Growth inhibition * Principal component analysis * Reactive oxygen species * Short-term salinity stress * Stress hormones
OECD category: Plant sciences, botany
Impact factor: 3.404, year: 2018

Salinity is one of major abiotic stresses affecting Brassica crop production. Here we present investigations into the physiological, biochemical, and hormonal components of the short-term salinity stress response in Chinese cabbage seedlings, with particular emphasis on the biosynthesis and metabolism of auxin indole-3-acetic acid (IAA). Upon salinity treatments (50–200 mM NaCl) IAA level was elevated in a dose dependent manner reaching 1.6-fold increase at the most severe salt treatment in comparison to the control. IAA precursor profiling suggested that salinity activated the indole-3-acetamide and indole-3-acetaldoxime biosynthetic pathways while suppressing the indole-3-pyruvic acid pathway. Levels of the IAA catabolites 2-oxoindole-3-acetic acid and indole-3-acetic acid-aspartate increased 1.7- and 2.0-fold, respectively, under the most severe treatment, in parallel with those of IAA. Conversely, levels of the ester conjugate indole-3-acetyl-1-O-ß-d-glucose and its catabolite 2-oxoindole-3-acetyl-1-O-ß-d-glucose decreased 2.5- and 7.0-fold, respectively. The concentrations of stress hormones including jasmonic acid and jasmonoyl-isoleucine (JA and JA-Ile), salicylic acid (SA) and abscisic acid (ABA) confirmed the stress induced by salt treatment: levels of JA and JA-Ile increased strongly under the mildest treatment, ABA only increased under the most severe treatment, and SA levels decreased dose-dependently. These hormonal changes were related to the observed changes in biochemical stress markers upon salt treatments: reductions in seedling fresh weight and root growth, decreased photosynthesis rate, increased levels of reactive oxygen species, and elevated proline content and the Na + /K + ratio. Correlations among auxin profile and biochemical stress markers were discussed based on Pearson's coefficients and principal component analysis (PCA).
Permanent Link: http://hdl.handle.net/11104/0283527