title: RT-PCR analysis and stress response capacity of transgenic gshI-poplar clones (Populus x canescens) in response to paraquat exposure.
abstract: Stress response capacity (Fv/Fm at 690 nm and F690/F735 at Fmax) of untransformed hybrid poplar, Populus x canescens (P tremula x P alba), and two transgenic lines overexpressing gamma-ECS (gamma-glutamylcysteine synthetase) either in the cytosol (cyt-ECS) or in the chloroplast (chl-ECS) was studied in response to the herbicide paraquat (4.0 x 10(-9) to 4.0 x 10(-6) M) for 21 days. Significant differences at sublethal (4.0 x 10(-7) M) and bleaching (4.0 x 10(-6) M) concentrations of paraquat were observed with about a two-fold and eight-fold decrease in the photosynthetic activity (Fv/Fm at 690 nm and F690/F735 at Fmax), respectively. None of the gshI transgenic lines (cyt-ECS, chl-ECS) with elevated GSH content exhibited significant tolerance to paraquat. Semiquantitative RT-PCR of the cyt-ECS clone was used for gene expression analysis of the nuclear encoded rbcS gene and the stress responsive gst gene. Expression of the constitutively expressed 26SrRNA ribosomal gene was probed as a control for all RT-PCR reactions. The relative intensities of gene expressions normalized to the level of 26SrRNA intensity showed a 50% decrease in the nuclear encoded rbcS expression and a 120% increase in the stress responsive gst gene expression of the paraquat treated (4.0 x 10(-7) M) samples of the transgenic poplar line (cyt-ECS).
authors.affiliation: St. Stephanus University, HAS-SIU RG, Department of Genetics and PB, Gödöllo 2103, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Bittsánszky
authors.forename: Gábor
authors.initials: G
authors.lastname: Gyulai
authors.forename: Mervyn
authors.initials: M
authors.lastname: Humphreys
authors.forename: Gábor
authors.initials: G
authors.lastname: Gullner
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Csintalan
authors.forename: József
authors.initials: J
authors.lastname: Kiss
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Szabó
authors.forename: Richárd
authors.initials: R
authors.lastname: Lágler
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Tóth
authors.forename: Heinz
authors.initials: H
authors.lastname: Rennenberg
authors.forename: László
authors.initials: L
authors.lastname: Heszky
authors.forename: Tamás
authors.initials: T
authors.lastname: Komíves
mesh_terms: D000818:Animals; D001042:Aphids / Q000472:pathogenicity; D048588:Benzoxazines; D002851:Chromatography, High Pressure Liquid; D005838:Genotype; D010078:Oxazines / Q000378:metabolism*; D012434:Secale / Q000378:metabolism; D012639:Seeds / Q000378:metabolism; D014908:Triticum / Q000254:growth & development* / Q000378:metabolism* / Q000469:parasitology; D003313:Zea mays / Q000378:metabolism
chemical_list: D048588:Benzoxazines; D010078:Oxazines; C104846:2,4-dihydroxy-1,4-benzoxazin-3-one; C050733:2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one