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Physiological, structural and molecular traits activated in strawberry plants after inoculation with the plant growth‐promoting bacterium Azospirillum brasilense REC 3
Author(s) -
GuerreroMolina M. F.,
Lovaisa N. C.,
Salazar S. M.,
MartínezZamora M. G.,
DíazRicci J. C.,
Pedraza R. O.
Publication year - 2015
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/plb.12270
Subject(s) - azospirillum brasilense , biology , callose , inoculation , microbial inoculant , apx , fragaria , microbiology and biotechnology , horticulture , botany , cell wall , oxidative stress , biochemistry , superoxide dismutase
The plant growth‐promoting strain REC 3 of Azospirillum brasilense , isolated from strawberry roots, prompts growth promotion and systemic protection against anthracnose disease in this crop. Hence, we hypothesised that A. brasilense REC 3 can induce different physiological, structural and molecular responses in strawberry plants. Therefore, the aim of this work was to study these traits activated in Azospirillum ‐colonised strawberry plants, which have not been assessed until now. Healthy, in vitro micropropagated plants were root‐inoculated with REC 3 under hydroponic conditions; root and leaf tissues were sampled at different times, and oxidative burst, phenolic compound content, malondialdehyde ( MDA ) concentration, callose deposition, cell wall fortification and gene expression were evaluated. Azospirillum inoculation enhanced levels of soluble phenolic compounds after 12 h post‐inoculation (hpi), while amounts of cell wall bound phenolics were similar in inoculated and control plants. Other early responses activated by REC 3 (at 24 hpi) were a decline of lipid peroxidation and up‐regulation of strawberry genes involved in defence ( Fa PR 1) , bacterial recognition ( Fa FLS 2) and H 2 O 2 depuration ( Fa CAT and Fa APX c ). The last may explain the apparent absence of oxidative burst in leaves after bacterial inoculation. Also, REC 3 inoculation induced delayed structural responses such as callose deposition and cell wall fortification (at 72 hpi). Results showed that A. brasilense REC 3 is capable of exerting beneficial effects on strawberry plants, reinforcing their physiological and cellular characteristics, which in turns contribute to improve plant performance.