Potato productivity losses, comparative

Smeda et al. (1993) reported that in a mutation of the psb A gene in a photoautotropic potato, atrazine resistance was attributable to a mutation from AGT (ser) to ACT (threonine) in codon 264 of the psb A gene that encodes the Qb protein. Although the mutant cells exhibited extreme levels of resistance to atrazine, no concomitant reductions in photosynthetic electron transport or cell growth rates were detected compared to the unselected cells. This is in contrast with the losses in productivity observed in atrazine-resistant mutants that contain a Ser to Gly 264 alteration. Research has shown that triazine resistance by various algae and photosynthetic bacteria has been due to changes in many different binding sites (Oettmeier, 1999). 

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