SYSTEMIC CHANGES IN THE SOYBEAN (Glycine max L.) - Bradyrhizobium japonicum INTERACTION

DEANNA ROCÍO; MUÑOZ NACIRA; LASCANO RAMIRO

San Juan

Congreso; Segunda Reunión Conjunta de Sociedades de Biología de la República Argentina; 2011

Sociedad Argentina de Biología, Sociedad de Biología de Cuyo, Sociedad de Biología de Córdoba

In the last decades many complex local mechanisms involved in Rhizobium-legume association have been elucidated. Besides this exist a systemic signaling that it hasn´t been descript in early stages of the symbiotic infection. The objective was analyze redox systemic changes during the early stages of soybean-B. japonicum interaction. Soybean (Glycine max L. DM4800) plants 12 days old were inoculated with B. japonicum USDA138 and the first trifoliate leaf was used for several measurements. We also determined the involvement of NADPH oxidase through DPI inhibition. We found an increase of superoxide radical and hydrogen peroxide in inoculated plants after 30 and 30, 60 and 120 min respectively. Inoculated and DPI-treated plants at both leaf and root showed hydrogen peroxide measurements without differences with control plants. Moreover we found an activation of enzymatic/ non enzymatic antioxidant system after 30 min post-inoculation, an increment of PAL activity after 30 and 60 min, and an increment of ethylene after 120 min post- inoculation. Our results show that inoculation of soybean with B. japonicum induces redox changes in conjunction with early systemic activation of secondary metabolism, and subsequent increases in ethylene content. This oxidative early signaling would be mediated by the NADPH oxidase complex and would have a fundamental importance in modulating of systemic responses induced by symbiotic microorganisms.