Developmental and Structural Section
DeMason, Darleen .
DR5::GUS expression and auxin response in pea leaf morphogenesis.
DR5::GUS, a highly active synthetic auxin response reporter, was transformed into a wild-type (wt) inbred line of pea, Pisum sativum. It was also crossed into two leaf form mutants: tendrilless (tl) and tendrilled acacia (uni-tac). When wt pea shoots are cultured on auxin transport inhibitors, like NPA or gibberellic acid biosynthetic inhibitors, like PAC, leaf form is reduced in complexity and converted into the range of leaf phenotypes present on uni-tac mutants. Conversely, uni-tac plantlets grown on auxin or gibberellic acid (GA) produce leaves similar to those typical of wt plants. GUS expression using the standard staining protocol was used to evaluate auxin response in shoot tips of greenhouse grown plants and plantlets grown in tissue culture. In wt shoot tips, dark blue staining occurred in the distal tip of the leaf primordium from P0 through mid-P5. Lateral tendril primordia and tendril tips stained more intensely blue and for more plastochrons than leaflet primordia and tips. In shoot tips of tl plants, leaf tips and leaflet primordia staining was similar to that of wt plants. However, GUS staining was severely reduced in the shoot tips and root tips of uni-tac plants. Shoot tips and leaf primordia on wt plantlets cultured on NPA also had severely reduced GUS staining whereas, GUS staining of shoot tips and leaf primordia of plantlets grown on PAC was similar to that of controls. GUS staining in shoot tips and leaf primordia of cultured uni-tac plantlets was restored when cultured on cytokinin, auxin, cytokinin + auxin, and cytokinin + GA. DR5::GUS expression confirms that auxin plays an important role in pea leaf morphogenesis. Auxin response, levels or transport is compromised in the uni-tac mutant. NPA treatment replicates the mutant phenotype.
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1 - University of California Riverside, Department of Botany & Plant Sciences, Riverside, California, 92521-0124, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 9:15 AM