A reversibly glycosylated polypeptide of rice plants is hormonal and developmentally regulated.

VERÓNICA DE PINO; SILVIA MORENO

Ciudad Autonoma de Buenos Aires. Buenos Aires

Congreso; V Jornadas multidiciplinarias de la Sociedad Argentina de Biologia; 2003

Sociedad Argentina de Biologia

A Reversibly Glycosylated Polypeptide of rice plants is hormonal and developmentally regulated Verónica De Pino and Silvia Moreno Fundación Instituto Leloir (formerly “Fundación Campomar”), Instituto de Investigaciones Bioquímicas, Buenos Aires- CONICET. Patricias Argentinas 435, (1405) Buenos Aires, Argentina. E-mail : smoreno@leloir.org.ar Rice has become the model plant for all cereal genes mapping because of its small genome size (430 Mb), detailed RFLP map and well-known classical genetics. It was reported extensively that the internodal growth of rice is hormonally regulated (Lorbiecke and Sauter, 1998).Rice plants grow very fast during the first stage of the culture. In the youngest internode the synthesis of ethylene are stimulated. The increased in the ethylene, synthesis causes  el cual aumenta a su vez la concentración de giberellina en el tejido, lo que desencadena un rápido crecimiento. It is well known that in elongating plant tissues there is an active synthesis of cell wall components. Among other components, a rapid synthesis of cellulose and hemicellulose polysaccharides occurs. Sin embargo, muy poco se sabe sobre como se interrelaciona el control hormonal y la síntesis de polisacáridos durante el crecimiento. Más aún, todavía no se sabe como se inicia la síntesis de los polisacáridos en las plantas. Many questions should be addressed about the physiological role of the self-glycosylating proteins and their regulation. Here, we study the expression of the RGP protein in rice seeds and in in vitro plants with the aim to analyze the probable relation between a protein involved in polysaccharide synthesis with the hormonal control of the growth of rice plants. Recently Langeveld et al., 2002, reported the isolation of RGP-like cDNAs from wheat and rice. Although, they described that the recombinant proteins have self-glycosylating activity, they not mentioned anything about data of RGP activity in rice plants. We found RGP self glycosilation activity in rice seeds and in  vitro plants. We observed an increase in the activity  asociated with hormonal induction  in plants of 8 days of culture. The hormonal induction were not only modulating the activity of the RGP , but also the amount of  RGP protein.