Biotechnologie et biomatériaux

Abstrait

Physiological and Molecular Studies of Transgenic Tomato (Solanumly copersicumL.) Fruits Over-expressing the Gene Solyc11g011300 Encoding a Rhamno-galacturonanLyase Enzyme

Trillo-Hernández, Eduardo-Antonio1; Orozco-Avitia, Jesús-Antonio1 ;Ojeda-Contreras, Angel-Javier1; Berumen-Varela, Guillermo2; Ochoa-Jiménez, Verónica-Alhelí2; Troncoso-Rojas, Rosalba1; Rivera-Dominguez, Marisela1; Baez-Flores, Maria-Elena3;;Hernández-Oñate, Miguel-Angel1 and Tiznado-Hernández, Martín-Erne

The plant cell wall is made up of three domains: cellulose, hemicellulose and pectin. The pectin is a very complex dynamic domain and plays the most important role in the plant cell wall physiology. Furthermore, pectin is constitutedof the polysaccharides homogalacturonan, rhamnogalacturonan I (RG-I) and rhamnogalacturonan II. The RG-I is a polysaccharide whose backbone is composed by repeated moieties of rhamnose and galacturonic acid joined by a glyosidic bond with the conformation of -L-Rhap-(1,4)--D-GalpA. The RG-I is degraded by the rhamnogalacturonanlyase (RGL) enzyme through a -elimination mechanism. Despite the biochemical mechanism of this enzyme is well known, the role of RGL during fruit ontogeny is still largely unknown.According with previous investigations, RGL enzyme isinvolved in cell wall enlargement by changing the cohesion network as a consequence of the RG-I cleavage, activation of the tomato fruit defense system by releasing RG-I fragments which acts as elicitors, mesocarp softening during fruit ripening by degradation of the middle lamellae, regulation of potato (Solanumtuberosum) cell division and periderm development in flax (Linumusitatissimum).