Developmental and Structural Section
DeMason, Darleen , Jaganatha, Venkateswari , Barkawi, Lana , Cohen, Jerry D. .
Unifoliata-Afila interactions in pea leaf morphogenesis.
Unifoliata (Uni) is a major gene controlling the number of pinna pairs produced during leaf morphogenesis in pea. Afila (Af) promotes leaflet formation in the proximal blade region. Uni expression is distinctly higher in af genotypes because it is expressed in the developing branched tendrils, whereas it is not expressed in tendril or leaflet primordia in wildtype plants. We observed af uni double mutants, af tendrilless (tl) uni triple mutants, used DR5::GUS transgenics to compare auxin response, measured auxin levels in shoot tips and compared qRT-PCR levels of auxin regulated genes to understand the interactions between Uni and Af. Mature leaves on af uni plants typically had two lateral pinna pairs (consisting of both tendrils and leaflets) and a terminal leaflet, and af tl uni had two leafet pairs and a terminal leaflet, whereas leaves on uni mutants ranged from simple to trifoliate. GUS expression was present during initiation of leaf, pinna, stipule and all lateral primordia on compound pinnae as well as in procambial strands in shoot tips of all genotypes. GUS expression was more abundant and of longer duration in the af genotypes. Auxin levels were higher in af and af tl than in wildtype shoot tips and lower in uni. Four genes (Uni, Tl, CUC and NAM) thought to be auxin regulated, showed similar expression patterns in that they were much more abundant in the af genotypes compared to others. These results suggest that Uni and Af have an antagonistic interaction. Af prevents Uni, Tl and other auxin regulated genes from being expressed in lateral primordia during leaf development. Although the Af gene has not been identified, it may regulate auxin sensitivity allowing Uni to be expressed in a greater range of domains.
Leaves are the primary site of photosynthesis on terrestrial plants. Leaf development and morphology has inpacts on photosynthesis, transpiration and pathogen invasion. Legumes are amoung the most important crop plants and many are also nitrogen fixers. Understanding the genetic control of leaf development could have biotechnological consequences in the future.
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1 - University of California Riverside, Department of Botany & Plant Sciences, Riverside, California, 92521-0124, USA
2 - University of California, Riverside, Department of Botany and Plant Sciences and Center for Plant Cell Biology, 2211 Batchelor Hall, University of California, Riverside, Riverside, California, 92521, USA
3 - University of Minnesota, Horticultural Science
4 - University of Minnesota, Horticultural Science, 305 Alderman Hall, 1970 Folwell Avenue, Saint Paul, MN, 55108, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 551A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 8:30 AM