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| Author(s): |
Maria Rosecler Miranda Rossetto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2005-06-10 |
| Examining board members: |
Beatriz Rosana Cordenunsi;
Ricardo Alfredo Kluge;
Giuseppina Pace Pereira Lima;
João Roberto Oliveira do Nascimento;
Marco Aurélio Silva Tiné
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| Advisor: | Beatriz Rosana Cordenunsi; João Roberto Oliveira do Nascimento |
| Abstract | |
The glucosinolate-myrosinase system is part of the defense mechanism in plants, when tissue is damaged, the glucosinolates are degraded by myresinases and toxic compounds are released. In papaya fruit, the major compounds released are the benzylisothiocyanates, frem the degradation of benzylglucosinolate (BG). High levels of BG and BITC are present in the beginning of the fruit formation and they decreased during the development. The seed is the tissue that accumulates higher contents of these compounds, followed by skin and pulp and these levels seems to be disturb by 1-MCP, but not by ethylene. Moreover, it was observed in this work, that exactly the lowest activity of myresinase seems to have been enought to liberate the BITC, that in these amounts, could to act against fruit f1ies and other microorganisms. The partial sequence of myresinase of the papaya fruit showed high degree of similarity with with Arabidopisis (67%), white mustard (62%) and rape (51 %), plants model in the study of glicosinolatos, being found a lot of regions and residues highly conserved. The transcript prefile of myresinase showed that it is present only in the seed, and frem the 90 dpa, having a significant increase in the point of harvest, concomitant to the activity increase. (AU) | |