Differential Activity of Autochthonous Bacteria in Controlling Drought Stress in Native Lavandula and Salvia Plants Species Under Drought Conditions in Natural Arid Soil

• Published in: Microbial ecology 2014-02, Vol.67 (2), p.410-420
• Main Authors: Armada, Elisabeth, Roldán, Antonio, Azcon, Rosario
• Format: Article
• Language: English
• Subjects: Acid production; Antioxidants; Antioxidants - metabolism; Arid environments; Arid soils; ascorbate peroxidase; Ascorbate Peroxidases - metabolism; Bacillus; Bacillus - growth & development; Bacillus - isolation & purification; Bacillus megaterium; Bacillus thuringiensis; Bacteria; Biological and medical sciences; Biomedical and Life Sciences; Conductance; Dehydration; Drought; Drought resistance; drought tolerance; Droughts; Ecology; Enterobacter; Enterobacter - growth & development; Enterobacter - isolation & purification; Fundamental and applied biological sciences. Psychology; Geoecology/Natural Processes; Glutathione Reductase - metabolism; glutathione-disulfide reductase; Lavandula; Lavandula - microbiology; Lavandula - physiology; Life Sciences; Microbial Ecology; Microbiology; Mycorrhizae - metabolism; Nature Conservation; Physiology; plant characteristics; Plant growth; plant growth-promoting rhizobacteria; Plant Leaves - microbiology; PLANT MICROBE INTERACTIONS; Plant Roots - microbiology; Plant species; Plants; Salvia; Salvia - microbiology; Salvia - physiology; Salvia officinalis; shoots; Soil conditioners; Soil Microbiology; Stomatal conductance; stress tolerance; Stress, Psychological; Water - metabolism; Water Quality/Water Pollution; water stress
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-013-0326-9

The effectiveness of autochthonous plant growth-promoting rhizobacteria was studied in Lavandula dentata and Salvia officinalis growing in a natural arid Mediterranean soil under drought conditions. These bacteria identified as Bacillus megaterium (Bm), Enterobacter sp. (E), Bacillus thuringiensis (Bt), and Bacillus sp. (Bsp). Each bacteria has different potential to meliorate water limitation and alleviating drought stress in these two plant species. B. thuringiensis promoted growth and drought avoidance in Lavandula by increasing K content, by depressing stomatal conductance, and it controlled shoot proline accumulation. This bacterial effect on increasing drought tolerance was related to the decrease of glutathione reductase (GR) and ascorbate peroxidase (APX) that resulted sensitive indexes of lower cellular oxidative damage involved in the adaptative drought response in B. thuringiensis-inoculated Lavandula plants. In contrast, in Salvia, having intrinsic lower shoot/root ratio, higher stomatal conductance and lower APX and GR activities than Lavandula, the bacterial effects on nutritional, physiological and antioxidant enzymatic systems were lower. The benefit of bacteria depended on intrinsic stress tolerance of plant involved. Lavadula demonstrated a greater benefit than Salvia to control drought stress when inoculated with B. thuringiensis. The bacterial drought tolerance assessed as survival, proline, and indolacetic acid production showed the potential of this bacteria to help plants to grow under drought conditions. B. thuringiensis may be used for Lavandula plant establishment in arid environments. Particular characteristic of the plant species as low shoot/root ratio and high stomatal conductance are important factors controlling the bacterial effectiveness improving nutritional, physiological, and metabolic plant activities.