| Abstract Detail
Mechanisms of Gene Regulation Brandão, Aline [1], Vincentz, Michel [2], Buckeridge, Marcos [3]. Expression of genes enconding for xyloglucan and sucrose metabolism in seedlings of the tropical legume tree Hymenaea courbaril is controlled by light, auxin and sugars. The cotyledons of Hymenaea courabaril L. contain large proportions of xyloglucan as a carbon reserve that is used for seedling development. This work presents data on gene expression of XET (xyloglucan endontranglycosylase), beta-galactosidase (BG), neutral invertase (IN) and sucrose synthase (SS) during xyloglucan mobilization in the cotyledons. Treatments were used in which seedling were left intact, shoot excised and treated with NPA (auxin transport inibitor). Gene expression in cotyledons, hypocotyls, leaves and roots was evaluated every six hours with 12h light and 12h dark using semi-quantitative RT-PCR for steady state RNA quantification and seedling grown for 45 days after sowing for sampling. In source tissues (cotyledons and leaves), expression of all genes peaked during the light period, except for SS in NPA treatment. In stems, BG peaked during the light period and IN and SS during the night period. Two peaks, one at midnight and other at midday were observed for XET. In roots, all genes peaked at night period except for IN in leaves. We also showed that NPA inhibited expression of all genes in both source and sink tissues except for SS in cotyledons and BG in the roots. In order to evaluate the importance of emerging leaves in the control of BG, XET, IN and SS expression in cotyledons, stems and roots, auxin transport was inhibited by NPA treatment or excised shoot. Our results suggest that signaling between source and sink in seedlings of H. courbaril is associated with auxin transport as well as with sugar sensing.
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1 - Unicamp, CBMEG, Rua Zeferino Vaz S/N, Campinas, São Paulo, 13084520, Brazil
2 - Unicamp, CBMEG
3 - USP, Botany
Keywords:
gene expression
sucrose metabolism
xyloglucan
Hymaneae courbaril.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P36050
Abstract ID:2222 |
