<Emphasis Type="Italic">Pseudomonas</Emphasis> spp. increases root biomass and tropane alkaloid yields in transgenic hairy roots of <Emphasis Type="Italic">Datura</Emphasis> spp.

Transgenic hairy roots of Datura spp., established using strain A4 of Agrobacterium rhizogenes, are genetically stable and produce high levels of tropane alkaloids. To increase biomass and tropane alkaloid content of this plant tissue, four Pseudomonas strains, Pseudomonas fluorescens P64, P66, C7R12, and Pseudomonas putida PP01 were assayed as biotic elicitors on transgenic hairy roots of Datura stramonium, Datura tatula, and Datura innoxia. Alkaloids were extracted from dried biomass, and hyoscyamine and scopolamine were quantified using liquid chromatography-tandem mass spectrometry analysis. D. stramonium and D. innoxia biomass production was stimulated by all Pseudomonas spp. strains after a 5-d treatment. All strains of P. fluorescens increased hyoscyamine yields compared to untreated cultures after both 5 and 10 d of treatment. Hyoscyamine yields were highest in D. tatula cultures exposed to a 5-d treatment with C7R12 (16.633 + 0.456 mg g^?1 dry weight, a 431% increase) although the highest yield increases compared to the control were observed in D. stramonium cultures exposed to strains P64 (511% increase) and C7R12 (583% increase) for 10 d. D. innoxia showed the highest scopolamine yields after elicitation with P. fluorescens strains P64 for 5 d (0.653 + 0.021 mg g^?1 dry weight, a 265% increase) and P66 for 5 and 10 d (5 d, 0.754 + 0.0.031 mg g^?1 dry weight, a 321% increase; 10 d 0.634 + 0.046 mg g^?1 dry weight, a 277% increase). These results show that the Pseudomonas strains studied here can positively and significantly affect biomass and the yields of hyoscyamine and scopolamine from transgenic roots of the three Datura species.     

Isolation and characterization of three new PGPR and their effects on the growth of Arabidopsis and Datura plants

This study characterizes three bacterial strains isolated from plant rhizospheres and evaluates their performance as plant-growth-promoting rhizobacteria. Pseudomonas plecoglossicida strain Pp20 was isolated from the rhizosphere of a date palm in Bechar (Algerian Sahara), Bacillus spec. strain Bt04 isolated from the rhizosphere of pear in Ghardaia (Algerian Sahara) and Lysinibacillus fusiformis strain Lf89 was isolated from the rhizosphere of tomato in Ain Defla (northern Algeria). Their effects on plant growth and development were analyzed in different in vitro cultures: an Arabidopsis thaliana plate assay and two hydroponic systems for Datura stramonium and Datura tatula. Our results show that all strains significantly improve plant growth of the plant species tested and some strains produce a shift in the C/N ratio in A. thaliana. Inoculation had no effect on alkaloid production per gram leaf dry weight in D. stramonium, but specific plant-growth-promoting rhizobacteria interactions may alter the alkaloid composition in the shoot.     

Optimization of caulogenesis in Populus nigra under lead (Pb) stress via response surface methodology (RSM) and desirability function analysis

Plant Cell, Tissue and Organ Culture (PCTOC) - Polyethylene glycol (PEG)-mediated transient expression system in plant protoplasts has been widely used in a variety of plants for gene function...