DePaoli, Henrique C. , Brito, Michael S. , Quiapim, Andrea C. , Rodrigues, Ricardo A.O. , Dornelas, Marcelo C. , Teixeira, Simone P. , Goldman, Gustavo H. , Goldman, Maria-Helena S. .
A Tobacco Pistil-Specific Lysine-Rich Protein Controls Stigma Size And Inhibits Style Elongation.
Pistil-specific genes are generally involved in important plant reproduction processes. To better understand pistil development and plant reproduction, we have undertaken the characterization of a pistil gene (clone 2E06), identified in a Suppressed Subtractive Hybridization cDNA library. This gene is homologous to an Arabidopsis gene with unknown function and encodes a lysine-rich protein which contains a putative nuclear localization signal. Real time RT-PCR experiments confirmed its pistil-specific expression pattern. The expression is developmentally regulated with the highest transcript levels occurring at the early stages of flower buds and the lowest levels in mature flowers. The in situ hybridization revealed expression at the specialized tissues of the stigma/style (stigmatic secretory zone and transmitting tract) and some cells of the ovary (funiculus and integuments). The RNAi-mediated silencing of this gene resulted in transgenic plants exhibiting remarkably longer styles and an enlarged stigma area. Additionally, the overexpression transgenic plants had stigmas with decreased area. Preliminary data with transversal sections of the transgenic styles suggests that the number of cells in the specialized tissues is increased in RNAi plants and decreased in overexpression plants; however the cell size is maintained. These results suggest that this new gene is a component of the molecular network controlling stigma size and style elongation, probably acting as a negative regulator of cellular proliferation. The identification of a single gene with a major influence on stigma exsertion is very interesting, since this characteristic is considered to have an important contribution to the rate of outcrossing.
Financial support: FAPESP, CNPq, CAPES (BRAZIL)
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1 - FMRP/USP, PPG Genetica
2 - FFCLRP/USP, PPG Biologia Comparada
3 - UNICAMP, Fisiologia Vegetal
4 - FCFRP/USP, CiÍncias FarmacÍuticas
5 - FFCLRP/USP, Biologia, Av. Bandeirantes, 3900, Ribeirao Preto, SP, 14040-901, BRAZIL
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM