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| Author(s): |
Ane Hackbart de Medeiros
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2008-09-04 |
| Examining board members: |
Marcio de Castro Silva Filho;
Celia Regina Ribeiro da Silva Carlini;
Antonio Vargas de Oliveira Figueira;
Flávio Henrique da Silva;
José Djair Vendramim
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| Advisor: | Marcio de Castro Silva Filho |
| Abstract | |
Plants respond to insect damage by induction and accumulation of a large set of defense proteins. An investigation was undertaken to study the sugarcane transcriptional changes following Diatraea saccharalis damage. The first approach was a detailed study about the induction of two isoforms of a sugarcane homologue of a barley wound inducible gene, barwin, named sugarwin (sugarcane wound-inducible). Induction of sugarwin transcripts occurs in response to mechanical wounding, D. saccharalis feeding and methyl jasmonate treatment. Their expression is restricted to the site of damage. Sugarwins are members of the late wound-inducible genes. The subcellular localization of the signal peptide fused to the gfp (green fluorescent protein) shows that these proteins are secreted. Although the exact function of the barwin domain has not been completely elucidated, antipathogenic activities has been described for a number of homologues. Multiple sequence alignment of barwin domain-containing sugarcane proteins and of mono and dicotiledoneous proteins reveals high similarity, suggesting that their function is conserved among species. This is the first report of a barwin-like protein induced by herbivory. The activity of this type of proteins against insects has never been studied. Based on the results presented here, it can be concluded that SUGARWINS are part of the sugarcane defense response strategy. The second approach to study the sugarcane response to D. saccharalis damage was the large-scale analysis, using DNA macroarrays, of serine proteases and serine protease inhibitors differently expressed in response to herbivory. While the protease inhibitors function in defense is well-established, the involvement of proteases in defense has been recently proposed. The transcript monitoring of sugarcane serine proteases in response to herbivory revealed several candidate genes for further functional studies. One of the greatest applications of these results is the identification of genes for use in biotechnological strategies to improve sugarcane insect resistance. (AU) | |