Halophilic bacteria mediated phytoremediation of salt-affected soils cultivated with rice Gulmeena Shah, Mehmood Jan, Mehvish Afreen, Muhammad Anees, Shafiq Rehman, Muhammad Jamil PII: DOI: Reference:
S0375-6742(16)30070-X doi: 10.1016/j.gexplo.2016.03.011 GEXPLO 5723
To appear in:
Journal of Geochemical Exploration
Received date: Revised date: Accepted date:
3 December 2015 29 February 2016 15 March 2016
Please cite this article as: Shah, Gulmeena, Jan, Mehmood, Afreen, Mehvish, Anees, Muhammad, Rehman, Shafiq, Jamil, Muhammad, Halophilic bacteria mediated phytoremediation of salt-affected soils cultivated with rice, Journal of Geochemical Exploration (2016), doi: 10.1016/j.gexplo.2016.03.011
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ACCEPTED MANUSCRIPT Halophilic bacteria mediated phytoremediation of salt-affected soils cultivated with Rice
and Muhammad Jamil1* 1
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Gulmeena Shah1, Mehmood Jan1, Mehvish Afreen2, Muhammad Anees2, Shafiq Rehman3
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Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology, Kohat 26000, Pakistan 2 Department of Microbiology, Kohat University of Science and Technology, Kohat 26000, Pakistan 3
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Department of Botany, Kohat University of Science and Technology, Kohat 26000, Pakistan *Corresponding Author: Muhammad Jamil, Department of Biotechnology and Genetic Engineering, Kohat University of Science & Technology, Kohat 26000, Pakistan E-mail:
[email protected]
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Abstract: Salinity is a most important ecological constraint for cereal crop including rice nowadays. Phytoremediation have been used to remediate salt affected soil but the use of
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halophilic bacteria is limited. In this study, the salt resistant Thalassobacillus denorans (NCCP-58) and Oceanobacillus kapialis (NCCP-76), halophilic bacteria isolated from salt mines near Karak, Pakistan were used to evaluate its effect on rice variety (Basmati385)in soil contaminated with different concentrations (control, 50, 100 and 150mM) of NaCl. It has been observed that significant increase in germination percentage and germination rate occurred in seeds primed with bacterial strains as compared to non primed seeds. Root and shoot length was more in plants raised from primed seeds than non treated seeds. Plants raised from inoculated seeds showed a significant increase in fresh and dry weight of seedling after 15 days. Significant increase in photosynthetic pigment; chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoid contents occurred in 28 days old plants inoculated with bacterial strains under different saline condition. Similarly significant increase occurred in total nitrogen and protein contents in inoculated plants. Ca+2 and K+ ion concentration significantly increased while Na+ ion concentration decreased in plants inoculated with bacterial strains as compared to non inoculated plants under different saline condition. Bacterial strains Oceanobacillus Kapialis (NCCP-76) 1
ACCEPTED MANUSCRIPT was more responsive in term of physiological and biochemical parameters than Thalassobacillus denorans Sp. (NCCP-58). The corresponding strains have a positive effect in alleviating the salt stress in plants growing in saline condition.
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Keywords: Phytoremediation, halophilic bacteria, Oryza sativa L., plant growth, salinity
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Introduction
Rice production is badly affected by abiotic stresses which result in physio-chemical
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changes in the qualitative and quantitative environment of rice (Ferrero et al. 2001; Caliskan, 2009). In Pakistan, more than 64% area is salt affected (Afzal et al., 2005). Day
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by day, salinity is going a wide spread problem all over the world in the agriculture field cause reduction in growth and yield (Ashraf, 2009). Salinity affects all stages of growth and development of rice plant and the crop responses to salt stress varies with growth
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stages, concentration and duration of exposure to salt (Michael et al., 2004).
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In the last few years, a number of plant growth promoting rhizobacteria (PGPRs) has been identified and seen an increased in demand because of its role in plant growth.
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PGPRs were reported to facilitate the growth of various plantspecies, particularly under biotic and abiotic stress conditions such as phytopathogens, flooding, heavy metals, drought and salinity (Kloepper, 1989; Joseph et al., 2007; Mayak et al., 2004). They are mainlycontributed in increased uptake of nitrogen, phytohormones synthesis, minerals solubilization such as phosphorus, and production of siderophores that chelate iron and make it accessible to the plant root (Glick, 1995). They are also able to solubilize inorganic and organic phosphates in soil (Liu et al., 1992). These PGPR can produce bacterial exopolysaccharides (EPS) which bind in the root zone, decreased the Na uptake and thus help in alleviating salt stress (Han and Lee, 2005). Inoculation of crop plants with certain strains of PGPR improves the percentage of seed germination (Kaymak et al., 2008; Mishra et al., 2010), plant vigor, chlorophyll content, yield, and nutrient uptake by variety of mechanisms under salt stress condition (Saharan and Nehra, 2011). The increased level of salt in soil has serious effects on plants such as rice, which serve as staple food for the majority of the world’s population. Conventional methods to 2
ACCEPTED MANUSCRIPT remove salt from soil are expensive and also destroying the soil structure. Phytoremediation is a technique that is used to mitigate organic or inorganic contaminants in soils. The use of rhizobacteria in phytoremediation of soil contaminated
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with organic or inorganic metals has recently received more attention but the use of halophilic bacteria in phytoremedation is limited. Therefore the present experiment was
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designed to assess the effects of halophilic bacteria namely Thalassobacillus devorans
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(NCCP-58) and Oceanobacillus kapialis (NCCP-76) in remediation of salt-affected soils
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cultivated with Rice using different physiological and biochemical characteristics.
Materials and Methods
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Seeds of Basmati-385 were obtained from the National Agriculture Research Center (NARC) Islamabad, Pakistan. Seeds were surface sterilized in 3.5% NaOCl solution for 3mins.
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Colony formulating unit (CFU)
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Thalasso bacillus Sp. (NCCP-58) and Oceano bacillus Sp. (NCCP-76) were isolated from salt mines near Karak, Pakistan (Roohi et al., 2012) and grown in L.B media,
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incubated at 37˚C for 24h. Bio-priming Two
strains
of
Bacillus
(Thalassobacillus
devorans
Sp.
NCCP-58)
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(Oceanobacillus Kapialis Sp. NCCP-76) were cultured in L.B broth for 24 h at 37˚C. Seeds were bio-primed in broth at 37˚C for 30 min in the presence of 2% sucrose for adhesion of bacteria with seeds. Seed germination Bio-primed seeds were grown on nutrient agar media in Petri plates, having a different NaCl solution (Control, 50, 100, and 150mM), sealed with parafilm to prevent contamination. Seed germination was evaluated after every 12 h up to 5 days. After 15 days of germination, root and shoot length was measured. Root and shoot were dried at 80˚C in an incubator for 2 days to take dry weights. Pot experiment After one week of germination in distilled water, seedlings were shifted to sand culture in plastic pots. After 3 weeks, NaCl of different concentrations i.e. control, 50, 3
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Cell membrane stability
The cell membrane stability was calculated by using formula recommended by Jamil
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et al. (2009).
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Determination of chlorophyll and carotenoids
The chlorophyll and carotenoid contents were calculated by using the formula’s
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suggested by Lichtenthaler and Wellburn (1985).
Determination of total organic nitrogen and protein content
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The protein and nitrogen contents were calculated by using the equations suggested by Pellett and Young (1980). Ion analysis
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Plant materials (25mg dried) were digested with the help of H2SO4 and H2O2 (2:1).
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Then the digested material was diluted with 20 ml of distilled water. The Na, K and Ca ion concentrations were estimated with the help of flame photometer (jenway pf7f).
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Data analysis
Analysis of variance was performed using the Statistix 9 software. Mean values for different rice characteristics were compared via LSD test (Li, 1964).
Results
Physiological parameters
Decrease occurred in seed germination and germination rate with increasing NaCl concentration from 50 to 150mM, while bio-primed seeds with both bacterial strains (NCCP-76 and NCCP-58) had higher seed germination and germination rates as compared to untreated seeds. However, seeds treated with NCC-76 had more seed germination than NCCP-58 (Fig. 1). A gradual decrease occurred in rice seedling as the NaCl concentration increase from 50 to 150mM while seedling raised from seeds treated with bacterial strains had more seedling length (Fig. 2). A considerable decrease was observed in root and shoot lengths as the salinity level increased but seedling raised from seeds inoculated with bacterial strain had more root 4
ACCEPTED MANUSCRIPT and shoot lengths. In roots, at 100mM the plants raised from bio primed seeds with bacterial strain (NCCP-76) had more length as compared to control and other NaCl treatments (Fig. 3). There was a remarkable decreased in non bio-primed seedling of
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fresh and dry weights of root and shoot when compared with bio-primed seedlings of both the strains (Fig. 4 and 5). The plant raised from seed inoculated with NCCP-76 had
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more fresh and dry weights than control.
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Biochemical analysis
All the plant inoculated with bacteria strains had more vigorous growth as compared
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to non-treated plants (Fig. 6). By increasing NaCl concentration, cellular injury was increased, however higher cellular injury was observed at 150mM as compared to 50 and
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100mM NaCl. Plants inoculated with bacterial strains alleviated the stress and had less cellular injury as compared to non-inoculated plants particularly in case of NCCP-76 (Fig. 7). NaCl concentration decreased chlorophyll and carotenoid content with
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increasing salinity levels (Fig. 8). By comparing with non-inoculated plants both bacterial
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strains had promoting effect on the Chl a, Chl b and total carotenoid content in inoculated plants. However, Chl a content was affected more as compared to Chl b. In case of Chl a
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and carotene both strain had a similar effect on the plants but NCCP-58 was more effective than NCCP-76 in case of Chl b (Fig. 8). NaCl concentration had great effect on total nitrogen and protein contents. By increasing NaCl concentration decreased occur in total nitrogen and protein contents (Fig. 9). In contrast, the rice plants inoculated with bacterial strains had more nitrogen and protein content than non-inoculated plants (Fig. 9). Both bacterial strains had a similar effect on total nitrogen and protein contents under saline condition. Increase in NaCl concentration caused significant decrease in Ca+2 and K+ ion, in control as well as in 50, 100and 150mM.While plants inoculated with bacterial strains promoted the ion concentration in control as well as in NaCl concentrations (Fig. 10). But in case of Na+ by increasing the salt concentration, an increase occurred from control to 150mM, however priming with bacterial strains had low Na+ ion concentration thus it helps in alleviating salt stress (Fig. 10A). Rice plants treated with NCCP-76 had more K+ ion than plants treated with NCCP-58 (Fig. 10C).
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ACCEPTED MANUSCRIPT Discussion Phytoremediation technique has been widely used to remediate metals, petroleum waste, pesticides, and saline soils (Bose et al., 2008; Huang et al., 2005; Huang et al., 2004;
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Qadir et al., 2007). Phytoremediation can be economical and environment friendly technique for remediation of salt-affected soils, if it can be appropriately utilized.
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Sometime phytoremediation process can prolong since it needs numerous growing
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seasons to decrease the amount of salt in soil. The efficiency of this process can be improved by the use of halophilic bacteria. Therefore, in the present study, halophlic
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Bacillus strains (Thalassobacillus devorans (NCCP-58) and Oceanobacillus kapialis (NCCP-76) were used for remediation of salt affected soil.
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We had observed that by increasing NaCl concentration, germination percentage and rate decreases but inoculation with bacterial strain considerably improved the germination percentage and germination rate (Fig. 1). It may be due to the fact that the
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bacterial strains use Na+as a factor for its metabolism and due to this, the Na+ amount
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reduced as a result seeds were able to grow normally. Inoculation of PGPR strains significantly improves the seed germination under salt stress conditions (Mishra et al.,
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2010). Similar kind of results has been reported by Kaymak et al. (2008). They had observed that treatment with PGPR under stress conditions might be helpful to obtain a higher seed germination percentage. PGPRs are naturally present in the soil that insistently colonize plant root zone and promote plant growth. The NaCl concentration caused a considerable decrease in lengths and fresh and dry weights of shoot and root while bio-priming alleviated the adverse effect (Figs 3 and 4). Bacterial strains can make bacterial exopolysaccharides (EPSs) to bind cations as well as increasing the population density of EPS-producing bacteria in the root zone would reduce the content of Na+ accessible for plant uptake (Han and Lee, 2005). The improved growth of rice seedlings by application of halophilic bacteria may also be due to production of IAA. According to Misra et al. (2010), inoculation of bacterial strains caused a considerable increase in root and shoot length and dry matter production of shoot and root of Cicer arietinum seedlings. Similar results were reported by Ashrafuzzaman et al. (2009) that plant length, root length and dry matter production of
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ACCEPTED MANUSCRIPT shoot and root of rice seedlings increased in PGPR treated plants over non-inoculated control. It has been confirmed through many reports that the measurement of the membrane
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stability important technique to identify salinity tolerance in plants.Salt had a negative effect on the cell membrane stability and as the salt concentration was increased so does
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the membrane injury (Fig. 6).It may due to the reason that plants absorbed insufficient
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amount of water under stress condition, due to which Na+ accumulates in plant cells causing excessive cellular damage. Halophilic bacteria alleviated the salt stress due to
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less uptake of Na+ (Fig. 6). Jamil et al. (2010) also showed that by increasing NaCl concentration cell injury rate increases which is also in accord with our result. The
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plasma membrane and activities of antioxidant enzymes are synchronized by Nadeposition to avoid the damage of chloroplasts under salinity stress, which contain photosynthetic pigment (Demiral and Türkan, 2005).
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Leaf chlorophyll content is most important physiological traits directly related to
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photosynthesis ability in rice (Teng et al., 2004).Chlorophyll and carotene contents of plant leaves were significantly reduced with the increase in salt stress but plant inoculated
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with bacteria had more leaf chlorophyll contents (Fig. 7). PGPR can directly affect plant growth through the production of phytohormones i.e. indole-3-acetic acid and cytokines (Yildirim et al., 2011). Yildirim et al. (2011) also reported that PGPR strains increase the chlorophyll and carotenoid content in NaCl conditions. PGPR are also contributing to increasing crop nutrient uptake of nitrogen from nitrogen fixing bacteria linked with roots. Decreased occur in nitrogen and protein content with increasing NaCl concentrations, in contrast to inoculated plants (Fig. 8). Saharan and Nehra (2011) also reported that nitrogen fixing bacteria provide only a modest increase in crop nitrogen uptake. PGPR are mainly involved in increased uptake of nitrogen, synthesis of phytohormones and solubilization of minerals (Glick, 1998). The possible role of PGPRs in solubilization of mineral nutrients and thus alleviating soil salinity stress during plant growth has not yet been established. NaCl treatment induced decrease in Ca+2 and K+ and increase in Na+ contents in the rice plant, however the inoculation with both the bacterial strains improved the rate of Ca+2 and K+ ion uptake but reduced uptake of Na+ ion content (Fig. 9). Salinity not only reduces macro mineral 7
ACCEPTED MANUSCRIPT contents of plant leaves, especially Ca+2 and K+ availability, but reduces Ca+2 and K+ transport and mobility to growing regions of the plants (Yildirim et al., 2011). PGPR are reported to affect the plant growth, yield, and nutrient uptake by a variety of mechanisms
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(Saharan and Nehra, 2011). Direct mechanisms may act on the plant itself and affect growth by means of plant growth regulators, solubilization of mineral materials and
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fixation of atmospheric nitrogen (Glick, 1998; Yildirim et al., 2011). PGPR can produce
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bacterial exopolysaccharides to bind cations as well as increasing the population density of EPS-producing bacteria in the root zone would reduce the content of Na+ available for
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plant uptake, thus help alleviating salt stress in plants growing in saline environments (Han and Lee, 2005).
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In conclusion, both bacterial strains Thalassobacillus denoran (NCCP-58) Oceanobacillus Kapialis (NCCP-76) were effective to improved plant growth but NCCP76 was more responsive in term of physiological and biochemical parameters in
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alleviating the salt stress. The NCCP-76 strain has a potential to be used for
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References
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phytoremediation under saline condition.
Afzal, I., Basra, S.M.A., Ahmad, N., Farooq, M. 2005. Optimization of hormonal priming techniques foralleviation of salinity stress in wheat (Triticum aestivum L.). Cadernode Pesquisa Serie.. Biol. 17, 95-109. Ashraf, M. 2009. Biotechnological approach of improving plant salt tolerance using antioxidants as markers. Biotechnol. Adv. 27; 84-93. Ashrafuzzaman, M., Akhtar, H.F., Razi, I.M., Anamul, H.M., Islam, M.Z., Shahidullah, S.M., Meon, S. 2009. Efficiency of plant growth-promoting rhizobacteria (PGPR) for the enhancement of rice growth. African J. Biotechol. 8, 1247-1252. Caliskon, M. 2009. Salt stress causes a shift in the localization pattern of germination and gene expression. Genet. Mol. Res. 8, 1250-1256. Bose, S., Vedamati, J., Rai, V., Ramanathan, A.L. 2008. Metal uptake and transport by Typhaangustata L. grown on metal contaminated waste amended soil: an implication of phytoremediation. Geoderma 145, 136-142.
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ACCEPTED MANUSCRIPT Chanwav, C.P, Nelson, L.M. 1990. Field and laboratory studies of Triticum aestivum L. Inoculated with co-existent growth-promoting Bacillus strains. Soil Biol. Biochem. 22, 789-795.
PT
Demiral, T., Türkan, I.. 2005. Comparative lipid peroxidation, antioxidant defense systems and proline content in roots of two rice cultivars differing in salt tolerance.
RI
Environ. Exp. Bot. 53, 247–257.
SC
Ferrero, A., Vidotto, F., Gennari, M., Negre, N. 2001. Behaviour of cinosulfuron in paddy surface water and ground. J. Environ. Qual. 30, 131- 140.
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Glick, R.B., Karaturovic, D.M., Newell, P.C.1995. A novel procedure for rapid isolation of plant growth promoting Pseudomonas. Can. J. Mirobiol. 41, 533-536.
MA
Glick, R.B., Penrose, D.M., Li, J. 1998.A model for the lowering of plant ethylene concentrations by plant growth-promoting bacteria. J. Theor. Biol. 190, 63-68. Han, H.S., Lee, K.D. 2005. Physiological responses of soybean-inoculation of
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Bradyrhizobium japonicum with PGPR in saline soil conditions. Res. J. Agric. Biol. Sci.
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1, 216-221.
Huang, X.D., El-Alawi, Y., Gurska, J., Glick, B.R., Greenberg, B.M. 2005. A multi-
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process phytoremediation system for decontamination of persistent total petroleum hydrocarbons (TPHs) from soils. J. Microchem. 81, 139-147. Huang, X.D., El-Alawi, Y., Gurska, J., Glick, B.R., Greenberg, B.M. 2004. A multiprocess phytoremediation system for removal of polycyclic aromatic hydrocarbons from contaminated soils. Environ. Pollut. 130 (3), 465-476. Jamil, M., Iqbal, W., Bangash, A., Rehman, U.S., Imran, Q.M., Rha, E.S. 2010. Constitutive Expression of OSC3H33, OSC3H50 AND OSC3H37 Genes in Rice under Salt Stress.Pak. J. Bot. 42, 4003-4009. Jamil, M., Bashir, S., Anwar, S., Bibi, S., Bangash, A., Ullah, F, Rha, E.S. 2010. Effect of salinity on physiological and biochemical characteristics of different varieties of rice. Pak. J. Bot. 44, 7-13. Jamil, M., Ashraf, M., Rehman, S., Rha, E.S. 2009. Cell membrane stability (CMS): A simple technique to check salt Stress alleviation through seed priming with GA3 in canola In: Ashraf, M., Ozturk, M., Ather, H.R. (Eds.) Salinity and water Stress. Springer Science + Business Media B. pp.117-127. 9
ACCEPTED MANUSCRIPT Joseph, B., Patra, R.R., Lawrence, R. 2007. Characterization of plant growth promoting Rhizobacteria associated with chickpea (Cicer arietinum L) . Int. J. Plant Prod. 1, 141152.
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Kaymak, C.H., İsmail, G., Faika, Y., Mesude, F.D. 2008. The effects of bio-priming with PGPR on germination of radish (Raphanus sativus L.) seeds under saline conditions.
RI
Turk. J. Agric. Forest. 33, 173-179.
SC
Kloepper, J.W., Lifshitz, R., Zablotowicz, R.M. 1989. Free-living bacterial inoculation for enhancing crop productivity. Trends Biotechnol, 7, 39–43.
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Li, C.C. 1964. Introduction to Experimental Statistics. McGraw Hill, New York. Lichtenthaler, H.K., Wellburn, A.R. 1985. Determination of total carotenoids and
MA
chlorophylls a and b of leaf in different solvents. Biochem. Soc. Trans. 11, 591-592. Liu, S.T., Lee, L.Y., Tai, C.Y., Hung, C.H., Chang, Y.S., Wolfram, J.H., Rogers, R., Goldstein, A.H. 1992. Cloning of an Erwiniaherbicola gene necessary for gluconic acid
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Bacteriol. 174, 5814-5819.
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production and enhanced mineral phosphate solubilization in Escherichia coli HB101. J.
Mayak, S., Tirosh, T.B.R., Glick, B.R. 2004. Plant growth-promoting bacteria confer
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resistance in tomato plants to salt stress. Plant Physiol. Biochem. 42, 565-572. Michael, D., Peel, B., Waldron, L., Kevin, B. 2004. Screening for salinity tolerance in Alfalfa. Crop Sci. 44, 2049-2053. Mishra, M., Kumar, U., Kishor, M.P., Prakash, V. 2010. Efficiency of Plant Growth Promoting Rhizobacteria for the Enhancement of Cicer arietinum L. Growth and Germination under Salinity. Advance Biol. Res. 4, 92-96. Pellett, L.P., Young, V.R. 1980. Nutritional Evaluation of Protein Foods. UN Uni Publ. pp. 45-47. Qadir, M., Oster, J.D., Schubert, S., Noble, A,D,, Sahrawat, K.L. 2007. Phytoremediation of sodic and saline-sodic soils. In: Sparks, D.L. (Ed.) Adv. Agron. 96, 197-247. Roohi, A., Ahmed, I., Masood, M.S., Jamil, M. 2012. Biodiversity of halophilic bacteria isolated from the salt mines of Karak, Pakistan. Pak. J. Bot. 44, 365-370. Saharan, B.S., Nehra, V. 2011. Plant growth promoting rhizobacteria: A critical review. Life Sci. Med. Res. 21, 1-30.
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ACCEPTED MANUSCRIPT Teng, S.Q., Qian, D,, Zenq, Y., Kunihiro, K., Fujimoto, D., Huang, L., Zhu. 2007. QTL analysis of leaf photosynthesis rate and related physiological traits in rice (Oryza sativa L.). Euphytica 135, 1-7.
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Yildirim, E., Turan, M., Ekinci, M., Dursun, A., Cakmakci, R. 2011. Plant growth promoting rhizobacteria ameliorate deleterious effect of salt stress on lettuce. Sci. Res.
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Fig. 1. Germination (A) and germination rate (B) of seeds inoculated with halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition.
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Fig. 2. Seedlings growth of rice plant treated with distill water (A), NCCP-76 (B) and NCCP-58 (C) under different NaCl concentration.
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ACCEPTED MANUSCRIPT Fig. 3. Shoot (A) and root length (B) of plants raised from seeds inoculated with
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halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition.
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ACCEPTED MANUSCRIPT Fig. 4. Fresh shoot (A) and root (B) weight of plants raised from seeds inoculated with
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halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition.
Fig. 5. Dry shoot (A) and root (B) weight of plants raised from seeds inoculated with halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition. 16
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Fig. 6. Growth of the rice plant inoculated with halophilic bacterial strains NCCP-76 and NCCP-58. (A) Control, NCCP-76 and NCCP-58 (B) 50 mM NaCl, NCCP-76 + 50 mM NaCl and NCCP-58 + 50 mM NaCl (C) 100 mM NaCl, NCCP-76 + 100 mM NaCl and
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+ 50 mM NaCl.
Fig. 7. Cellular injury of plants inoculated with halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition
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ACCEPTED MANUSCRIPT Fig. 8. Chl a (A) Chl b (B) and carotenoid (C) contents of plants inoculated with
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halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition.
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ACCEPTED MANUSCRIPT Fig. 9. Total organic nitrogen (A) and total protein (B) contents of plants inoculated with
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halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition.
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ACCEPTED MANUSCRIPT Fig.10. Sodium (A) calcium (B) and potassium (C) contents of plants inoculated with
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halophilic bacterial strains NCCP-76 and NCCP-58 under various saline condition.
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Highlights
Halophilic bacteria was used to mediated phytoremediation of salt-affected soils
Both bacterial strains Thalassobacillus denoran (NCCP-58) Oceanobacillus Kapialis (NCCP-76) were effective to improved plant growth
Bacterial strains NCCP-76 was more responsive in term of physiological and
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NCCP-76 strain has a potential to be used for phytoremediation under saline
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condition
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biochemical parameters than NCCP-58
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