Nicotiana glutinosa compensated for a mutated
tumor-morphology-shooty (tms) (
auxin biosynthesis) locus of Agrobacterlum tumefaciens strain A66 and showed the same virulent
tumor response to
infection by strain A66 or the wild-type strain A6. Cloned cell lines transformed by strains A6 or A66 were fully
hormone independent in culture and grew rapidly as friable, unorganized tissues on
hormone-free growth medium. Growth of N. glutinosa
tumor cells was inhibited by addition of
alpha-naphthaleneacetic acid to the growth medium, and A6- and A66-transformed cells showed similar dose responses to this
auxin. On the other hand, A6-transformed cells contained much higher levels of
indole-3-acetic acid (IAA) and
1-aminocyclopropane-1-carboxylic acid (ACC) than A66-transformed cells. Differences in IAA and ACC levels in N. glutinosa
tumor lines were consistent with the expected activity of the tms locus and were quantitatively similar to results obtained previously with A6- and A66-transformed cells of Nicotiana tabacum, which does not compensate for mutated tms genes. Thus, compensation for mutated tms genes in N. glutinosa did not result from increased
auxin accumulation and did not appear to be related to the capacity of this host for
auxin biosynthesis.