Alleviation of salt stress by plant growth regulators and IAA producing bacteria in wheat. Acta Phys Plant

Acta Physiologiae Plantarum (Impact Factor: 1.58). 07/2009; 31(4):861-864. DOI: 10.1007/s11738-009-0297-0

ABSTRACT The action of phytohormone producing bacteria and plant growth regulators on germination and seedling growth of wheat under saline conditions were studied. Seed dormancy enforced by salinity (100 mM NaCl) was substantially alleviated and the germination was promoted by gibberellin, auxin, zeatin, and ethephon from 54 to 97%. The IAA producing bacterial strains Pseudomonas aureantiaca TSAU22, Pseudomonas extremorientalis TSAU6 and Pseudomonas extremorientalis TSAU20 significantly increased seedling root growth up to 25% in non-salinated conditions and up to 52% at 100 mM NaCl, compared to control plants. It is concluded that growth regulators considerably alleviated salinity-induced dormancy of wheat seeds. The facts mentioned above make it possible to recommend root colonizing bacteria that produce phytohormone to alleviate salt stress of wheat grown under conditions of soil salinity.

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    • "According to Iqbal and Ashraf (2010) and Alqarawi et al. (2014b), salinity perturbs the hormonal balance of plants; therefore, hormonal homeostasis under salt stress might be one possible mechanism of phytohormone induced plant salt tolerance. The exogenous application of phytohormones such as gibberellins (Afzal et al., 2005), auxins (Egamberdieva, 2009), and cytokinins (Gül et al., 2000) mitigate salt stress and stimulate plant root and shoot growth under stress. The content of phytohormones in plants may also be affected by root-associated microorganisms (Turan et al., 2014). "
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    ABSTRACT: Abiotic stresses cause changes in the balance of phytohormones in plants and result in inhibited root growth and an increase in the susceptibility of plants to root rot disease. The aim of this work was to ascertain whether microbial indole-3-acetic acid (IAA) plays a role in the regulation of root growth and microbially mediated control of root rot of cotton caused by Fusarium solani. Seed germination and seedling growth were improved by both NaCl and Mg2SO4 (100 mM) solutions when treated with root-associated bacterial strains Pseudomonas putida R4 and P. chlororaphis R5, which are able to produce IAA. These bacterial strains were also able to reduce the infection rate of cotton root rot (from 70 to 39%) caused by F. solani under gnotobiotic conditions. The application of a low concentration of IAA (0.01 and 0.001 μg/ml) stimulated plant growth and reduced disease incidence caused by F. solani (from 70 to 41-56%, respectively). Shoot and root growth and dry matter increased significantly and disease incidence was reduced by bacterial inoculants in natural saline soil. These results suggest that bacterial IAA plays a major role in salt stress tolerance and may be involved in induced resistance against root rot disease of cotton.
    Saudi Journal of Biological Sciences 05/2015; 1. DOI:10.1016/j.sjbs.2015.04.019 · 1.26 Impact Factor
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    • "Similarly , bacterial IAA has also been shown to alleviate salt stress of plants grown under conditions of soil salinity . For instance , halotolerant bacteria have been reported to enhance the growth by improving the osmotic stress tolerance in plants ( Egamberdieva 2009 ; Tiwari et al . 2011 ; Kim et al . "
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    ABSTRACT: Abstract Salt-tolerant strains of Enterobacter asburiae, Bacillus thuringiensis, Moraxella pluranimalium and Pseudomonas stutzeri were evaluated for their ability to alleviate salt stress of wheat (Triticum aestivum L.) seedlings. 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity of P. stutzeri S-80 and B. thuringiensis S-26 was 190 and 183 nmol h-1, respectively. Maximum levels of auxin were recorded with P. stutzeri S-80 (107 μg ml-1) and E. asburiae S-24 (143 μg ml-1) under normal and salt-stressed conditions (0.25 M NaCl), respectively with 500 μg ml-1 L-tryptophan. Auxin response mediated by rhizobacteria was also demonstrated by microscopically assaying the transgenic auxin-responsive reporter DR5::GUS expression tomato (Solanum lycopersicum L. cv. MicroTom). In pot trials, seedlings fresh and dry biomass witnessed highly significant improvements of 1 and 2.2 folds, Downloaded by [University of the Punjab] at 06:18 14 April 2015 Accepted Manuscript respectively, with M. pluranimalium S-29 (at 100 mM NaCl) and E. asburiae S-24 (150 mM NaCl), over control. At final harvest, maximum increase in number of tillers (up to 94%) and seed weight (up to 40%) were recorded with E. asburiae S-24 and M. pluranimalium S-29 at 200 mM salt stress. In conclusion, newly isolated strains of M. pluranimalium S-29, E. asburiae S-24 and P. stutzeri S-80 enhanced the growth of T. aestivum by mitigating the salt stress of plants.
    Archives of Agronomy and Soil Science 03/2015; DOI:10.1080/03650340.2015.1036044 · 0.55 Impact Factor
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    • "We observed that seed dormancy enforced by salinity was substantially alleviated and germination was promoted by gibberellins and auxins from 80 to 95 % (data not shown). This finding agrees with other studies in which GA and IAA improved the emergence of rice (Wahyuni et al. 2003), wheat seedlings (Egamberdieva 2009), radishes (Egamberdieva 2008), brinjal (Solanum melongena L.) (Gupta 1971), chayote (Sechium edule) (Gregorio et al. 1995), and red sanders (Pterocarpus santalinus Linn. F) (Naidu 2001). "
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    ABSTRACT: This study examined the effects of phytohormone-producing Pseudomonas extremorientalis TSAU6 and plant growth regulators indole-3-acetic acid (IAA) and gibberellic acid (GA) on the growth parameters of jew’s mallow (Corchorus olitorius L.) under salt stress conditions. The inoculated jew’s mallow seeds with IAA- and GA-producing P. extremorientalis TSAU6 strain significantly increased root length by 45 %, shoot length by 84 %, and fresh weight by 28 % at 100 mM NaCl compared to uninoculated control plants. All concentrations of IAA and GA showed stimulatory effect on the root and shoot growth of jew’s mallow seedling under nonsaline and salt stress conditions. Plant growth-promoting properties of the strain in pot experiments with saline soil showed that P. extremorientalis TSAU 6 significantly increased shoot length by 21 % and dry matter of jew’s mallow by 18 %. Based on the results, it may be concluded that the integrative use of phytohormone-producing plant growth-promoting P. extremorientalis strain could be an eco-friendly strategy for increasing plant growth and development of jew’s mallow under saline soil condition. It is also indicated that plant growth regulators such as auxins and gibberellins play an important role in plant salinity tolerance.
    Plant-Growth-Promoting Rhizobacteria (PGPR) and Medicinal Plants, Edited by Dilfuza Egamberdieva, Smriti Shrivastava, Ajit Varma, 02/2015: chapter 9; Springer Verlag., ISBN: 978-3-319-13400-0
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