A novel<i>Azotobacter vinellandii</i>(SRI<i>Az</i>3) functions in salinity stress tolerance in rice

“…According to Glick et al (1998), the use of PGPR (for example, Pseudomonas) as inoculant of wheat seeds in saline soils improved the plant height, root length, the grain yield, chlorophyll content and the ratio K + /Na + . The role of Azotobacter in the production of growth-promoting substances and plant improving resistance to abiotic and biotic stresses must also be considered (Chaudhary et al, 2013;Sahoo et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Growing varieties durum wheat (Triticum durum) in response to the effect of osmolytes and inoculation by Azotobacter chroococcum under salt stress

Silini¹,

Cherif‐Silini²,

Yahiaoui³

2016

Afr. J. Microbiol. Res.

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This study was conducted to determine the effect of plant growth promoting rhizobacteria Azotobacter chroococcum AZ6 isolated from arid soil and osmolytes such as glycine betaine (GB) or proline (P) on the growth of durum wheat varieties under salinity stress. Inoculation by A. chroococcum AZ6 in the presence or absence of P (5 mM) or GB (5 mM) reduced substantially the effect of salt stress on plant growth parameters such as root length, plant height, fresh shoot and root weight and dry shoot and root weight. The differences between the two varieties were low but with a fresh and dry weight higher in Waha. The rate of Na + accumulation in the roots and the shoots was important up to 100 mM and increased at 200 mM. The K + concentration and chlorophyll content decreased but proline and amino acid contents were enhanced with increasing salinity. Treatment by inoculation in the presence or absence of osmolytes improved the chlorophyll (a and total) and the K + concentrations and reduced intracellular proline accumulation and amino acids contents. Also, as result, the use of A. chroococcum AZ6 and osmolytes treatment may provide a means of improving tolerance of durum wheat to salt stress.Key words: Durum wheat, salinity, osmolytes, Azotobacter chroococcum, INTRODUCTIONSalinity and aridity are major environmental constraints limiting the growth and productivity of crops. In arid and semi-arid areas of the world, rainfall is inadequate for the leaching of salts from the root zone. Accordingly, the soluble salts are accumulated in the soil surface with the Na + as a dominant cation. Soil salinity presents a growing threat to agriculture and causes salinization of arable land on the planet. One third of arable land resources in the world are affected by salinity (Munns, 2002). Losses in crop yields in saline areas are important. High concentrations of salts cause ion imbalance and hyperosmotic stress in plants leading to cellular dehydration. The osmotic potential resulting from high concentrations of the Na + in the soil prevents the absorption of water which causes a variety of structural, biochemical and physiological seed changes and reduces the rate of germination causing a delay in the development of the plant (Poljakoff-Mayeber et al., 1994). Several experiments have been attempted to reduce the drastic effect of salt stress in the growth and productivity of plants. Most work focuses on the development of saltresistant varieties. Thus, efforts to reproduce genotypes which are highly salt tolerant are hampered by a lack of understanding the complex nature of tolerance. Plant tolerance seems to be based on a number of mechanisms, many of which are based on physiological processes such as transport mechanisms that reduce or eliminate the Na + and the Cl -of xylem (Tester and Davenport, 2003). Indeed, these varieties have developed various biochemical and physiological mechanisms against this type of stress. Such mechanism, ubiquitous in plants, is the accumulation of some organic metabolites of low molecular weigh...

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“…Over the last few years, several studies have reported the ability of isolated microorganisms to induce plant tolerance to salinity once they have been inoculated to seeds or young plantlets (reviewed in Yang et al, 2009; Dodd and Pérez-Alfocea, 2012; Shrivastava and Kumar, 2015), including a variety of hosts, like wheat (Nadeem et al, 2013; Singh et al, 2015), maize (Hamdia et al, 2004; Nadeem et al, 2009), cotton (Liu et al, 2013; Egamberdieva et al, 2015), tomato (Mayak et al, 2004; Ali et al, 2014), lettuce (Barassi et al, 2006; Kohler et al, 2009), sunflower (Shilev et al, 2010; Tewari and Arora, 2014) and Arabidopsis (Zhang et al, 2008; Kim et al, 2014; Sukweenadhi et al, 2015). Among the PGPR that have been demonstrated to play a role in salt stress tolerance induction, a wide diversity of bacteria is included, encompassing several members of the γ-proteobacteria class, specially within the genus Pseudomonas (Ahmad et al, 2013; Nadeem et al, 2013; Chang et al, 2014; Han et al, 2015), α-proteobacteria belonging to the Azospirillum genus (del Amor and Cuadra-Crespo, 2011; Nia et al, 2012; Sahoo et al, 2014), and β-proteobacteria like Achromobacter (Mayak et al, 2004) or Paraburkholderia (Talbi et al, 2013; Pinedo et al, 2015). Several examples have also been described for the phylum Firmicutes, with special emphasis on the genus Bacillus (Zhang et al, 2008; Kohler et al, 2009; Karlidag et al, 2013; Ramadoss et al, 2013; Han et al, 2015), and also some examples have been described within the Actinobacteria phylum (Sadeghi et al, 2012; Palaniyandi et al, 2014; Gond et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Volatile-Mediated Effects Predominate in Paraburkholderia phytofirmans Growth Promotion and Salt Stress Tolerance of Arabidopsis thaliana

et al. 2016

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Abiotic stress has a growing impact on plant growth and agricultural activity worldwide. Specific plant growth promoting rhizobacteria have been reported to stimulate growth and tolerance to abiotic stress in plants, and molecular mechanisms like phytohormone synthesis and 1-aminocyclopropane-1-carboxylate deamination are usual candidates proposed to mediate these bacterial effects. Paraburkholderia phytofirmans PsJN is able to promote growth of several plant hosts, and improve their tolerance to chilling, drought and salinity. This work investigated bacterial determinants involved in PsJN stimulation of growth and salinity tolerance in Arabidopsis thaliana, showing bacteria enable plants to survive long-term salinity treatment, accumulating less sodium within leaf tissues relative to non-inoculated controls. Inactivation of specific bacterial genes encoding ACC deaminase, auxin catabolism, N-acyl-homoserine-lactone production, and flagellin synthesis showed these functions have little influence on bacterial induction of salinity tolerance. Volatile organic compound emission from strain PsJN was shown to reproduce the effects of direct bacterial inoculation of roots, increasing plant growth rate and tolerance to salinity evaluated both in vitro and in soil. Furthermore, early exposure to VOCs from P. phytofirmans was sufficient to stimulate long-term effects observed in Arabidopsis growth in the presence and absence of salinity. Organic compounds were analyzed in the headspace of PsJN cultures, showing production of 2-undecanone, 7-hexanol, 3-methylbutanol and dimethyl disulfide. Exposure of A. thaliana to different quantities of these molecules showed that they are able to influence growth in a wide range of added amounts. Exposure to a blend of the first three compounds was found to mimic the effects of PsJN on both general growth promotion and salinity tolerance. To our knowledge, this is the first report on volatile compound-mediated induction of plant abiotic stress tolerance by a Paraburkholderia species.

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A novelAzotobacter vinellandii(SRIAz3) functions in salinity stress tolerance in rice

Cited by 45 publications

References 17 publications

A phytobeneficial strainPlanomicrobiumsp. MSSA-10 triggered oxidative stress responsive mechanisms and regulated the growth of pea plants under induced saline environment

A phytobeneficial strainPlanomicrobiumsp. MSSA-10 triggered oxidative stress responsive mechanisms and regulated the growth of pea plants under induced saline environment

Growing varieties durum wheat (Triticum durum) in response to the effect of osmolytes and inoculation by Azotobacter chroococcum under salt stress

Volatile-Mediated Effects Predominate in Paraburkholderia phytofirmans Growth Promotion and Salt Stress Tolerance of Arabidopsis thaliana

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