Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat

Noshin Ilyas, Komal Mumtaz, Nosheen Akhtar, Humaira Yasmin, R. Z. Sayyed, Wajiha Khan, Hesham A. El Enshasy, Daniel J. Dailin, Elsayed A. Elsayed and Zeshan Ali
Additional contact information
Noshin Ilyas: Department of Botany, PMAS Arid Agriculture University, Rawalpindi 46300, Pakistan
Komal Mumtaz: Department of Botany, PMAS Arid Agriculture University, Rawalpindi 46300, Pakistan
Nosheen Akhtar: Department of Botany, PMAS Arid Agriculture University, Rawalpindi 46300, Pakistan
Humaira Yasmin: Department of Biosciences, COMSATS University, Islamabad 45550, Pakistan
R. Z. Sayyed: Department of Microbiology, PSGVP Mandal’s Arts, Science and Commerce College, Shahada 425409, Maharashtra, India
Wajiha Khan: Department of Biotechnology, COMSATS University Islamabad, Abbottabad Campus, Abbottabad 22010, Pakistan
Hesham A. El Enshasy: Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia (UTM), Skudai 81310, Johor, Malaysia
Daniel J. Dailin: Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia (UTM), Skudai 81310, Johor, Malaysia
Elsayed A. Elsayed: Zoology Department, College of Science, King Saud University, P.O. 2455, Riyadh 11451, Saudi Arabia
Zeshan Ali: Plant Physiology Program, Crop Sciences Institute, National Agricultural Research Centre, Park Road, Islamabad 45500, Pakistan

Sustainability, 2020, vol. 12, issue 21, 1-19

Abstract: 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.

Keywords: antioxidant enzymes; Azospirillum brasilense; Bacillus subtilis; stress hormones; osmolytes; plant growth promotion; wheat (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (6)

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