PPT and chloroplasts

Jane E. Knapp knapp at ocelot.Rutgers.EDU
Mon Oct 6 12:00:58 EST 1997


I am using the bar gene as a selectable marker for transformation of
monocots with PPT as the selectable agent. I know that PPT is a
competeitive inhibitor of cytosolic glutamine synthetase and this is its
mode of herbicidal activity. In cultures or tissues lacking mature
chloroplasts, this is a very efficient herbicide. My question is: Can
PPT  inhibit plastid glutamine synthetase? Maybe it doesn't, and this is
why green tissues need much higher levels of PPT for efficient
selection? Does PPT even enter the chloroplast? Would bialaphos have
significantly different cp import capabilities? Has anyone checked
either of these forms for cp uptake? Any help, predictions or
suggestions would be appreciated.






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