Expression of the PsMTA1 gene in white poplar engineered with the MAT system is associated with heavy metal tolerance and protection against 8-hydroxy-2'-deoxyguanosine mediated-DNA damage.
Marker-free transgenic white poplar (Populus alba L., cv 'Villafranca') plants, expressing the PsMT (A1) gene from Pisum sativum for a metallothionein-like protein, were produced by Agrobacterium tumefaciens-mediated transformation. The 35SCaMV-PsMT (A1)-NosT cassette was inserted into the ipt-type vector pMAT22. The occurrence of the abnormal ipt-shooty phenotype allowed the visual selection of transformants, while the yeast site-specific recombination R/RS system was responsible for the excision of the undesired vector sequences with the consequent recovery of normal marker-free transgenic plants. Molecular analyses confirmed the presence of the 35SCaMV-PsMT (A1)-NosT cassette and transgene expression. Five selected lines were further characterized, revealing the ability to withstand heavy metal toxicity. They survived 0.1 mM CuCl(2), a concentration which strongly affected the nontransgenic plants. Moreover, root development was only slightly affected by the ectopic expression of the transgene. Reactive oxygen species were accumulated to a lower extent in leaf tissues of multi-auto-transformation (MAT)-PsMT(A1) plants exposed to copper and zinc, compared to control plants. Tolerance to photo-oxidative stress induced by paraquat was another distinctive feature of the MAT-PsMT(A1) lines. Finally, low levels of DNA damage were detected by quantifying the amounts of 8-hydroxy-2'-deoxyguanosine in leaf tissues of the transgenic plants exposed to copper.
Balestrazzi
Alma
A
Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy.
Botti
Silvia
S
Zelasco
Samantha
S
Biondi
Stefania
S
Franchin
Cinzia
C
Calligari
Paolo
P
Racchi
Milvia
M
Turchi
Adelaide
A
Lingua
Guido
G
Berta
Graziella
G
Carbonera
Daniela
D
D000080242:8-Hydroxy-2'-Deoxyguanosine; D016960:Agrobacterium tumefaciens / Q000235:genetics; D003300:Copper / Q000633:toxicity*; D004249:DNA Damage; D018744:DNA, Plant / Q000235:genetics; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D015227:Lipid Peroxidation; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D010269:Paraquat / Q000494:pharmacology; D018532:Pisum sativum / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D014170:Transformation, Genetic; D015032:Zinc / Q000633:toxicity*
D018744:DNA, Plant; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D003300:Copper; D000080242:8-Hydroxy-2'-Deoxyguanosine; D008668:Metallothionein; D003849:Deoxyguanosine; D015032:Zinc; D010269:Paraquat