title: Partial characterization of two stable auxotrophic cell strains of Datura innoxia Mill.
abstract: A growth analysis of several presumptive "leaky" auxotrophs from Datura innoxia suspension cultures led to the discovery of an adenine-requiring cultures led to the discovery of an adenine-requiring cell strain (Ad1). Both Ad1 and Pn1, a pantothenate-requiring strain isolated earlier from these cultures, still require either adenine or pantothenate for growth after more than one year in culture. Attempts to select prototrophic revertants have failed. Ad 1 also grew well in a medium containing either 5-aminoimidazole-4-carboxamide ribotide or inosine instead of adenine; Pn 1 with pantoic acid alone but not at all in the presence of β-alanine or α-ketoisovalerate alone instead of pantothenate. Pn 1 cells starved of pantothenate for up to 4d and Ad1 of adenine for 10d or more resumed growth when transferred to appropriately supplemented media. Wild-type Datura cells grown on unsupplemented medium would not crossfeed the required nutrients to the auxotrophs. The starvation and cross-feeding experiment showed that both auxotrophs could be used in reconstruction experiments to develop enrichment-selection techniques for the isolation of more auxotrophs.
authors.affiliation: Department of Biology, University of Saskatchewan, S7N 0W0, Saskatoon, Sask, Canada.
authors.forename: J
authors.initials: J
authors.lastname: King
authors.forename: R B
authors.initials: RB
authors.lastname: Horsch
authors.forename: A D
authors.initials: AD
authors.lastname: Savage