Response of the heme oxygenase of soybean nodules to drought stress

BARCIA, RA; SANTA CRUZ, DM; BALESTRASSE, KB; TOMARO ML.

Miami, Florida. USA

Congreso; Heme Oxygenases in Biology and Medicine, 6th International Congress on Heme Oxygenases.; 2009

<!-- @page { size: 21cm 29.7cm; margin: 2cm } P { margin-bottom: 0.21cm } --> Drought stress is among the most serious challenges to crop production worldwide. Upon exposure of plants to drought conditions, many stress-related genes are induced and their products are thought to function as cellular protectants of stress-induced damage. The aim of this study was to evaluate whether there is a link between drought stress and soybean plants nodules heme oxygenase (HO-1) behaviour. To this purpose, soybean plants inoculated with Bradyrhizobium japonicum. After 30 days growth theywere subjected to drought for 5 days. Under this condition no difference was found in TBARS content respect to controls. Nevertheless, an increase of catalase (CAT) activity (60%) was observed. No induction of heme oxygenase-1 gene expression was detected, as demonstrated by RT-PCR analysis. To further investigate the effect of drought was performed with plants exposed to 10 days without Hoagland. Under this condition, there is an augmentation in TBARS levels (45%), beside CAT activity increase by 20% respect to controls and HO-1 gene expression was enhanced by 40%. After these plants were recovered for 6 days using Hoagland solution. Results obtained showed that no production of TBARS occurred, whereas an increase in CAT activity (30% respects to controls) and HO-1 gene expression (35% respect to controls) were evidenced. These results let us assume that HO-1 gene response to drought after 10 days of drought when lipid peroxidation is increase. On the other hand, CAT and HO- reduced the damage oxidative in soybean nodules after 6 days recovery.