Evolutionary Developmental Biology (Evo-Devo)
Bai, Fang , DeMason, Darleen .
Hormone interactions and regulation of Unifoliata, PsPK2, PsPIN1, and LE gene expression in pea (Pisum sativum) shoot tips.
THE Unifoliata (Uni), PsPK2, and PsPIN1 are pea orthologs of LEAFY, PINOID, PINFORMED1 in Arabidopsis. Uni, PsPK2, PsPIN1, and LE all play important roles in pea leaf development, but mechanisms for their regulation are not known. This study was done to determine whether hormones and their interactions could play a role in Uni, PsPK2, PsPIN1, and LE regulation in pea leaf development. The Uni promoter was sequenced and possessed auxin and gibberellin response elements. All genes were differentially expressed in the pea leaf mutants afila (af), tendrilless (tl), af tl, uni-tac, and uni. mRNA levels of PsPIN1, Uni, and PsPK2 were higher in af and low in tl, but LE mRNA levels were higher in uni and tl and low in af. In the GA mutants lh, ls, le, and na, Uni, PsPK2, and PsPIN1 had consistently lower levels of expression in the mutants compared to wildtype, but LE had higher levels in the mutants compared to wildtype. Uni, PsPK2, and PsPIN1 were all induced by gibberellic acid (GA3) treatment. Both PsPIN1 and LE showed differential sensitivity to different auxins. PsPIN1 was most sensitive to 4-chloro-indole acetic acid and LE was most sensitive to indole-3-acetic acid. Uni was also auxin regulated, but this regulation required much higher levels of auxin than those necessary to regulate PsPK2 or PsPIN1. Uni, PsPK2, and PsPIN1 are directly regulated by auxin and are early auxin response genes. The cytokinin, N6-benzyladenine enhanced LE expression but less so for the other genes. The combination of auxin and GA induced higher mRNA levels in Uni, PsPK2, and PsPIN1 than any single hormone treatment. These gene expression experiments support roles for hormone regulation of Uni expression in pea leaf development. -DU
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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 Topics
Location: 303/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 2:30 PM