title: Influence of Pseudomonas aeruginosa as PGPR on oxidative stress tolerance in wheat under Zn stress.
abstract: Plant Growth Promoting Rhizobacteria (PGPR), whose role is still underestimated, plays an important (or perhaps essential) role in improving plant growth. The comprehensive understanding of bacterial plant growth promoting mechanism helps to get sustainable agriculture production under biotic and abiotic stresses. In the present study, plant growth promoting (PGP) bacterial strain Pseudomonas aeruginosa having maximum inhibitory concentration of 1500mg kg(-1) against Zn was isolated from arable land, irrigated with industrial effluent and evaluated to determine it bioremediation potential. The study was mainly focused on plant biomass production, nutrient uptake and oxidative stress tolerance in relation to the activities of antioxidative enzymes and the content of non-enzymatic antioxidants. The oxidative stress tolerance was measured by estimating the MDA accumulation as well as H2O2 production in wheat plants under Zn (1000mg kg(-1)) stress and inoculation of soil with Zn resistant Pseudomonas aeruginosa. Zn in rooting medium reduced the plant growth, leaf photosynthetic pigments as well as uptake of N and P. However, content of MDA and H2O2 increased at higher concentration of Zn. Inoculation of P. aeruginosa improved the uptake of P and N in wheat plants with an increase in leaf chlorophyll, total soluble protein and plant biomass production. Analysis of plant root and shoot disclosed that Zn concentration was significantly lowered in P. aeruginosa inoculated zinc stressed plants as compare to the plants grown under Zn stress only. The amelioration of adverse effects of Zn stress on biomass production due to P. aeruginosa inoculation was related with enhanced antioxidative enzyme activities (SOD, POD and CAT), and the contents of non-enzymatic components such as ascorbic acid and total phenolics (TPC) as compare to Zn-treated plants. The up-gradation in antioxidative defense mechanism, resulted a reduction in H2O2 and MDA content due to the scavenging of ROS by antioxidants. It was concluded that P. aeruginosa is an ideal candidate for bioremediation and wheat growth promotion against Zn-induced oxidative stress by improving the availability of necessary nutrient, eliciting antioxidant defense system as well as by lowering the Zn metal uptake.
authors.affiliation: Department of Environmental Sciences, Government College University, Faisalabad 38000, Pakistan.
authors.forename: Faisal
authors.initials: F
authors.lastname: Islam
authors.affiliation: Department of Environmental Sciences, Government College University, Faisalabad 38000, Pakistan. Electronic address: rida_akash@hotmail.com.
authors.forename: Tahira
authors.initials: T
authors.lastname: Yasmeen
authors.affiliation: Department of Botany, Government College University, Faisalabad 38000, Pakistan.
authors.forename: Qasim
authors.initials: Q
authors.lastname: Ali
authors.affiliation: Department of Environmental Sciences, Government College University, Faisalabad 38000, Pakistan.
authors.forename: Shafaqat
authors.initials: S
authors.lastname: Ali
authors.affiliation: Department of Environmental Sciences, Government College University, Faisalabad 38000, Pakistan.
authors.forename: Muhammad Saleem
authors.initials: MS
authors.lastname: Arif
authors.affiliation: Department of Environmental Sciences, Government College University, Faisalabad 38000, Pakistan.
authors.forename: Sabir
authors.initials: S
authors.lastname: Hussain
authors.affiliation: Department of Environmental Sciences, Government College University, Faisalabad 38000, Pakistan.
authors.forename: Hina
authors.initials: H
authors.lastname: Rizvi
mesh_terms: D001673:Biodegradation, Environmental; D002734:Chlorophyll / Q000032:analysis; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000502:physiology*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism / Q000633:toxicity; D014908:Triticum / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology / Q000382:microbiology*; D015032:Zinc / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002734:Chlorophyll; D006861:Hydrogen Peroxide; D015032:Zinc
keywords: Anti-oxidant enzymes; Oxidative stress; PGPR; Pseudomonas aeruginosa; Wheat; Zinc