Expression Analysis of the Retrotransposon Retrolyc1 in tomato mutants and in tobacco cells

Author(s)

Juliane Karine Ishida

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2008-03-31

Examining board members

Marie Anne van Sluys; Ana Paula Pimentel Costa; Helenice Mercier

• Advisor: Marie Anne van Sluys

Abstract

Retrolyc1 is a retroelemento originally isolated from genomic library of L. peruvianum (Solanaceae). Analysis based on promoter region of this element indicated that Retrolyc1 are composed of two subfamilies Retrolyc1A and Retrolyc1B (Araujo et al., 2001). This study aimed to demonstrate the transcriptional activity of Retrolyc1 A and Retrolyc1B. The results showed the promoter region of Retrolyc1B is functional. In addition, the expression pattern of Retrolyc1A and Retrolyc1B are different when they were induced by signaling molecules of plant defense response. The activity of promoter region of these elements is also activated during the treatment with natural and synthetic auxin. The expression analysis of Retrolyc1 and Tnt1 showed modulation along the cell cycle. Both elements have transcription level increased in phases G1 / S. In order to analyze the modulation of Retrolyc1A by hormone, its transcription level was analyzed in tomato mutants. The lower expression of Retrolyc1A in roots of mutants with defective perception in auxin pathway (dgt) and higher in defective cytokinin pathway (brt), reinforce the positive modulation by auxin and suggest a negative modulation by cytokinin. Our results suggest the route of activation of Retrolyc1A differs from Retrolyc1B. The expression of Retrolyc1A has been modulated during plant development, especially in cells in the process of cell division and active in the tissues where the endogenous auxin is essential for the correct organogenesis (roots and fruits). (AU)