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This research was designed to elucidate the role of exopolysaccharides (EPS) producing bacterial strains for the amelioration of drought stress in wheat. Bacterial strains were isolated from a farmer’s field in the arid region of Pakistan. Out of 24 isolated stains, two bacterial strains, Bacillus subtilis (Accession No. MT742976) and Azospirillum brasilense (Accession No. MT742977) were selected, based on their ability to produce EPS and withstand drought stress. Both bacterial strains produced a good amount of EPS and osmolytes and exhibited drought tolerance individually, however, a combination of these strains produced higher amounts of EPS (sugar 6976 µg/g, 731.5 µg/g protein, and 1.1 mg/g uronic acid) and osmolytes (proline 4.4 µg/mg and sugar 79 µg/mg) and significantly changed the level of stress-induced phytohormones (61%, 49% and 30% decrease in Indole Acetic Acid (IAA), Gibberellic Acid (GA), and Cytokinin (CK)) respectively under stress, but an increase of 27.3% in Abscisic acid (ABA) concentration was observed. When inoculated, the combination of these strains improved seed germination, seedling vigor index, and promptness index by 18.2%, 23.7%, and 61.5% respectively under osmotic stress (20% polyethylene glycol, PEG6000). They also promoted plant growth in a pot experiment with an increase of 42.9%, 29.8%, and 33.7% in shoot length, root length, and leaf area, respectively. Physiological attributes of plants were also improved by bacterial inoculation showing an increase of 39.8%, 61.5%, and 45% in chlorophyll a, chlorophyll b, and carotenoid content respectively, as compared to control. Inoculations of bacterial strains also increased the production of osmolytes such asproline, amino acid, sugar, and protein by 30%, 23%, 68%, and 21.7% respectively. Co-inoculation of these strains enhanced the production of antioxidant enzymes such as superoxide dismutase (SOD) by 35.1%, catalase (CAT) by 77.4%, and peroxidase (POD) by 40.7%. Findings of the present research demonstrated that EPS, osmolyte, stress hormones, and antioxidant enzyme-producing bacterial strains impart drought tolerance in wheat and improve its growth, morphological attributes, physiological parameters, osmolytes production, and increase antioxidant enzymes.
Noshin Ilyas; Komal Mumtaz; Nosheen Akhtar; Humaira Yasmin; R. Sayyed; Wajiha Khan; Hesham Enshasy; Daniel Dailin; Elsayed Elsayed; Zeshan Ali. Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat. Sustainability 2020, 12, 8876 .
AMA StyleNoshin Ilyas, Komal Mumtaz, Nosheen Akhtar, Humaira Yasmin, R. Sayyed, Wajiha Khan, Hesham Enshasy, Daniel Dailin, Elsayed Elsayed, Zeshan Ali. Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat. Sustainability. 2020; 12 (21):8876.
Chicago/Turabian StyleNoshin Ilyas; Komal Mumtaz; Nosheen Akhtar; Humaira Yasmin; R. Sayyed; Wajiha Khan; Hesham Enshasy; Daniel Dailin; Elsayed Elsayed; Zeshan Ali. 2020. "Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat." Sustainability 12, no. 21: 8876.
Halo-tolerant plant growth-promoting rhizobacteria (PGPR) have the inherent potential to cope up with salinity. Thus, they can be used as an effective strategy in enhancing the productivity of saline agro-systems. In this study, a total of 50 isolates were screened from the rhizospheric soil of plants growing in the salt range of Pakistan. Out of these, four isolates were selected based on their salinity tolerance and plant growth promotion characters. These isolates (SR1. SR2, SR3, and SR4) were identified as Bacillus sp. (KF719179), Azospirillum brasilense (KJ194586), Azospirillum lipoferum (KJ434039), and Pseudomonas stutzeri (KJ685889) by 16S rDNA gene sequence analysis. In vitro, these strains, in alone and in a consortium, showed better production of compatible solute and phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), cytokinin (CK), and abscisic acid (ABA), in culture conditions under salt stress. When tested for inoculation, the consortium of all four strains showed the best results in terms of improved plant biomass and relative water content. Consortium-inoculated wheat plants showed tolerance by reduced electrolyte leakage and increased production of chlorophyll a, b, and total chlorophyll, and osmolytes, including soluble sugar, proline, amino acids, and antioxidant enzymes (superoxide dismutase, catalase, peroxidase), upon exposure to salinity stress (150 mM NaCl). In conclusion, plant growth-promoting bacteria, isolated from salt-affected regions, have strong potential to mitigate the deleterious effects of salt stress in wheat crop, when inoculated. Therefore, this consortium can be used as potent inoculants for wheat crop under prevailing stress conditions.
Noshin Ilyas; Roomina Mazhar; Humaira Yasmin; Wajiha Khan; Sumera Iqbal; Hesham El Enshasy; Daniel Joe Dailin. Rhizobacteria Isolated from Saline Soil Induce Systemic Tolerance in Wheat (Triticum Aestivum L.) against Salinity Stress. Agronomy 2020, 10, 989 .
AMA StyleNoshin Ilyas, Roomina Mazhar, Humaira Yasmin, Wajiha Khan, Sumera Iqbal, Hesham El Enshasy, Daniel Joe Dailin. Rhizobacteria Isolated from Saline Soil Induce Systemic Tolerance in Wheat (Triticum Aestivum L.) against Salinity Stress. Agronomy. 2020; 10 (7):989.
Chicago/Turabian StyleNoshin Ilyas; Roomina Mazhar; Humaira Yasmin; Wajiha Khan; Sumera Iqbal; Hesham El Enshasy; Daniel Joe Dailin. 2020. "Rhizobacteria Isolated from Saline Soil Induce Systemic Tolerance in Wheat (Triticum Aestivum L.) against Salinity Stress." Agronomy 10, no. 7: 989.