Muhammad Amir Zia

Antimicrobial and antioxidant activities of Mimosaceae plants; Acacia modesta Wall (Phulai), Prosopis cineraria (Linn.) and Prosopis juliflora (Swartz)

In the present study the methanolic leaf extracts of three plant species of familyMimosaceaexa0viz.,xa0Acacia modestaxa0Wall (Phulai),xa0Prosopis cinerariaxa0(Linn.) Drucexa0andProsopis julifloraxa0(Swartz) DC. were used to evaluate their antibacterial antifungal and antioxidant activity. Simple maceration method was used for the preparation of plant extracts. The extracts were tested against four strains of bacteria (Bacillus subtilis,Escherichia coli,xa0Vibrio choleraxa0andxa0Enterobacter aerogenes) and two strains of fungi (Aspergillus nigerxa0andxa0Aspergillus fumigatus). At 15 mg/ml extract concentration the maximum inhibitory zones observed inxa0Acacia modesta, P. cinerariaxa0andxa0P. julifloraxa0were 20, 18 and 25 mm, respectively.xa0P. cinerariaxa0gave best response againstxa0A. nigerxa0andxa0A. fumigatusxa0by producing 15.38 and 8% inhibition, respectively.xa0P. julifloraxa0showed 7.69% inhibition againstxa0A. niger.xa0Whilexa0A. modestaxa0showed 11.53% activity againstxa0A. nigerxa0and 0.8% againstxa0A. fumigatus.xa0The Antioxidant activities of these medicinal plants also showed significant results. Maximum radical scavenging activity (%RSA) was observed inxa0P. cineraria and P. juliflora, that is, 60.48 and 47.82%, respectively, as compared toxa0A. modestaxa0which gave minimum %RSA value of 41.42%. n n xa0 n n Key words:xa0Medicinal plants,xa0Mimosaceaexa0plants, methanol extracts, antibacterial, antifungal, antioxidant.

Influence of Metal-Resistant Rhizobacteria on the Growth of Helianthus annuus L. in Cr(VI)-Contaminated Soil

Use of heavy metal-tolerant bacteria for bioremediation is an environmentally safe and economical approach. Selected chromium-tolerant bacteria were tested in a greenhouse experiment. Different sets of pots were contaminated with three rates of Cr, i.e., 20, 30, and 40xa0ppm, using K2Cr2O7 and incubated for 1xa0month. Helianthus annuus (sunflower) seeds of Hysun-33 variety were inoculated with already screened Cr-tolerant bacteria (SS1, SS3, and SS6) along with un-inoculated seeds as control. Completely randomized design was used and two plants per pot were maintained after thinning. At harvesting, fresh as well as dry shoot and root weights were measured. Shoot and root samples were analyzed for Cr contents. The maximum increase in dry shoot and root weight (58 and 63%) was obtained by SS6 followed by SS1 (48 and 42%) and SS3 (37 and 47%) over control at various Cr concentrations. Cr accumulation in shoot and root was also enhanced by all the bacteria compared to control. Regarding the extent of total Cr uptake, SS6 enhanced Cr accumulation up to 107–171%, SS1 99.3–135%, and SS3 91–138% at 20, 30, and 40xa0ppm Cr, respectively. It is concluded from the study that there was a decreasing trend in growth with the increase of Cr concentration. All the bacteria improved growth and Cr accumulation significantly over control; however, SS6 found best among all Cr-tolerant bacteria. These bacteria can effectively be used for crop improvement and bioremediation.

Chilling tolerance in three tomato transgenic lines overexpressing CBF3 gene controlled by a stress inducible promoter

Plants integrate and monitor low temperature signals to cope with the continual variations in their environment. Arabidopsis thaliana cold responsive-element binding factor 3 (AtCBF3) plays its role in various cellular activities by modulating multiple genes induced under chilling stress. In this work, AtCBF3 transcription was remarkably induced following chilling stress. AtCBF3-overexpressors namely AtCBF3-Rio Grande, AtCBF3-Moneymaker, and AtCBF3-Roma showed defensible response to various levels of chilling stress, while their isogenic wild type plants indicated hypersensitive response to chilling stress. Detailed photosynthetic studies revealed that AtCBF3 gene has harmonious influences on the expression of a large set of genes by virtue of improved stomatal conductance, transpiration rate, intercellular CO2 concentration, and photosynthetic rate compared to wild type plants. The AtCBF3 lines limited the water status-mediated hypersensitive response by lowering leaf osmotic potential due to overexpression of AtCBF3 under chilling stress. Biochemical analyses followed by phenotypic studies demonstrated that AtCBF3 plants exhibited membrane stability and lush green appearance by limiting membrane ions leakage and malondialdehyde contents and by accumulating more proline, soluble sugars, chlorophyll contents, carotenoid contents, and antioxidant enzymes relative to wild type plants. Hence, with a several lines of evidence, these findings support that tomato transgenic plants overexpressing Arabidopsis CBF3 show enhanced chilling tolerance.

WITHDRAWN: Physiological and biochemical characterization of tomato transgenic lines overexpressing Arabidopsis thaliana cold responsive-element binding factor 3 (AtCBF3) gene under chilling stress.

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