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The effect of light on the dwarfing allele, le, in Pisum sativum L. was tested as the growth response to gibberellins prior to or beyond the presumed block in the gibberellin biosynthetic pathway. The response to the substrate (GA20), the product (GA1), and a nonendogenous early precursor (steviol) was compared in plants bearing the normal Le and the deficient lele genotypes in plants made low in gibberellin content genetically (nana lines) or by paclobutrazol treatment to tall (cv Alaska) and dwarf (cv Progress) peas. Both genotypes responded to GA1 under red irradiation and in darkness. The lele plants grew in response to GA20 and steviol in darkness but showed a much smaller response when red irradiated. The Le plants responded to GA20 and steviol in both light and darkness. The red effects on lele plants were largely reversible by far-red irradiation. It is concluded that the deficiency in 3j@-hydroxylation of GA20 to GA1 in genotype lele is due to a Pfr-induced blockage in the expression of that activity.Light grown dwarf peas lack the ability to convert GA202 to GA1 (6, 7), yet GA1 and GA8 were recently identified in extracts ofetiolated dwarf pea shoots (3). We will present evidence which suggests that etiolated dwarf pea plants lose the ability to convert GA20 to GA, upon formation of Pfr as a consequence ofexposure to R. Attempts by earlier workers to measure light-induced changes in GA metabolism or GA levels in tall and dwarf peas led to inconsistent results (reviewed in Smith [20]). Some experiments indicated phytochrome-mediated changes in GA metabolism, while other reports suggested an effect of light on "sensitivity" to endogenous GAs.Some genes which help determine plant stature in Pisum have recently been characterized (6,7,13,14,17). At least five loci have been shown to influence stem elongation, including the Na and Le loci, which affect GA metabolism. The recessive na allele apparently blocks an early step in GA biosynthesis, since nana plants do not contain detectable levels of GAs (13). The early C-13 hydroxylation pathway of GA biosynthesis predominates in peas (3,8

SummaryExpression of bean seed storage protein phaeeolin is under strict developmental control. Four distinct nuclear proteins recognize in vitro the proximal ,8-phaseolin promoter (-295/+45) which confers spatial and temporal regulation of the native gene. Functional significance of these protein-binding sitas was evaluated by substitution mutation of the motifs in the promoter, which was fused to GUS reporter gene, and subsequent transient gene expression assay using protopleets from developing bean cotyledons. DNA-binding protein CAN binds three CANNTG motifs, CACGTG (-248/-243), CACCTG (-163/-158), and CATATG (-100/-95). Subetifution mutation of the CACGTG motif, which is commonly known as G-box, reduced the -295 promoter activity by 75%, indicaring that the G-box is a major positive c/s-element. Mutation analyses also demonstrated that the CACCTG and CATATG motifs act as positive and negative ciselements, respectively. Substitution mutation of all three CANNTG motifs essentially eliminated the -295 promoter activity. A construct containing the G-box and CACCTG motif resulted in a transcriptional level that is much greeter than the sum of the transcriptional levels from the individual ciHlements, demonstrating that the G-box and CACCTG act synergistically. Substitution mutations of two AT-rich sequences, to which a nuclear protein AG-1 binds, showed that these sitas function as major negative (-376/-367, -356/-347) or positive (-191/-182) ciselements, and that the effect of the two AG-1 binding sites was counteractive in the -391 promoter. These

weight)-' of both zeatin riboside and isopentenyladenosine. The crown gall lines had 100-to 1000-fold higher levels of each cytokinin. In contrast, the three radiation-induced tumor lines analyzed contained cytokinin levels similar to the control tissue. The radiation-induced tumor tissues produced very little ethylene, although each contained relatively high levels of ACC. Normal callus contained similar amounts of ACC but produced several times more ethylene than the radiation-induced tumor lines. Each of the radiation-induced tumor tissues displayed a unique set of responses to exogenously supplied growth regulators. Only one tumor line showed the same response as normal callus to both auxin and cytokinin feeding. In some cases, one or more tumor lines showed increased sensitivity to certain growth substances. In other cases, growth regulator feeding had no significant effect on tumor tissue growth. Morphology of the radiation-induced tumor tissues generally did not correlate with auxin to cytokinin ratio in the expected manner. The results suggest that a different primary genetic event led to the formation of each tumor and that growth and differentiation in the tumor tissue lines are uncoupled from the normal hormonal controls.

Nlcotana gluUnosa compensated for a mutated tumor-morphology-shooty (tms) (auxin biosynthesis) locus of Agrobacterium tumefaclens 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 AS 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 additon of a-naphthaleneacetic acid to the growth medium, and AS-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.

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