Abstract

ARAUJO-BURGOS, T  and  RAO, R.. Análisis de expresión génica en tabaco transgénico expresando molécula señal de defensa. Rev.Cient.Agro.Amaz. [online]. 2014, n.3, pp. 17-27. ISSN 2307-9606.

Signal molecules play an important role in different plant aspects from plant growth until stress responses. One of the best known is the systemin, a molecule isolated from tomato which is released from its precursor prosystemin in response to herbivore attacks. It is the primary signal for systemic defense and also a potent activator of the octadecanoid pathway that generates jasmonic acid and provokes the activation of many plant defensive genes. In order to study the role of the prosystemin in the activation of defense genes in tobacco, transgenic plants were analyzed: MZ119 line expressing the full-length prosystemin cDNAand also PRx56 line expressing the deleted prosystemin missing the systemin encoding exon, to evaluate a possible function of the precursor N-terminal. Real time RT-PCR was used for the gene expression analysis in the transgenic tobacco plants. The analysis showed that prosystemin affects the expression of some stress and defense-related genes (HSP, GST, Pin II and TobHypSys) similar in both transgenic plants but GST, suggesting that the N-terminal is also active. Furthermore, the over-expression level induced by prosystemin of HSP and Pin II was similar to the effect of wounding. Then, a bioassay with the pathogenic fungus Botrytis cinerea showed a moderate resistance in the PRx56 tobacco plants. All these data imply that the constitutive accumulation of a signaling molecule precursor, such as the prosystemin, is associated with unexpected gene expression changes in tobacco.

Keywords : prosystemin; systemin; defense genes.