Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
Vol. 17, No. 1, 2014, pp. 19-26
Bioline Code: ej14004
Full paper language: English
Document type: Research Article
Document available free of charge
Electronic Journal of Biotechnology, Vol. 17, No. 1, 2014, pp. 19-26
© Copyright 2014 - Electronic Journal of Biotechnology
Effects of 5-aminolevulinic acid (ALA)-containing supernatants from selected Rhodopseudomonas palustris strains on rice growth under NaCl stress, with mediating effects on chlorophyll, photosynthetic electron transport and antioxidative enzymes|
Nunkaew, Tomorn; Kantachote, Duangporn; Kanzaki, Hiroshi; Nitoda, Teruhiko & Ritchie, Raymond J.
Background: Rice is globally one of the most important food crops, and NaCl stress is a key factor reducing rice
yield. Amelioration of NaCl stress was assessed by determining the growth of rice seedlings treated with culture
supernatants containing 5-aminolevulinic acid (ALA) secreted by strains of Rhodopseudomonas palustris (TN114
and PP803) and compared to the effects of synthetic ALA (positive control) and no ALA content (negative control).
Results: The relative root growth of rice seedlings was determined under NaCl stress (50 mM NaCl), after
21 d of pretreatment. Pretreatments with 1 μM commercial ALA and 10X diluted culture supernatant of
strain TN114 (2.57 μM ALA) gave significantly better growth than 10X diluted PP803 supernatant
(2.11 μM ALA). Rice growth measured by dryweight under NaCl stress ordered the pretreatments as: commercial
ALA > TN114 > PP803 > negative control. NaCl stress strongly decreased total chlorophyll of the plants that
correlated with non-photochemical quenching of fluorescence (NPQ). The salt stress also strongly increased
hydrogen peroxide (H2O2) concentration in NaCl-stressed plants. The pretreatments were ordered by reduction
in H2O2 content underNaCl stress as: commercial ALA > TN114 > PP803 > negative control. The ALA pretreatments
incurred remarkable increases of total chlorophyll and antioxidative activities of catalase (CAT), ascorbate peroxide
(APx), glutathione reductase (GR) and superoxide dismutase (SOD); under NaCl stress commercial ALA and TN114
had generally stronger effects than PP803.
Conclusions: The strain TN114 has potential as a plant growth stimulating bacterium that might enhance rice growth
in saline paddy fields at a lower cost than commercial ALA.
5-Aminolevulinic acid (ALA); Antioxidative enzymes; Chlorophyll fluorescence; Rhodopseudomonas palustris; Rice; Salinity
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