Indole acetic acid is responsible for the protection against oxidative stress caused by drought in soybean plants: The role of heme oxygenase induction.

NORIEGA G.O.; ZILLI, CG; SANTA CRUZ, DM; LOPEZ LECUBE, M; TOMARO, M.L; BATLLE, A; BALESTRASSE, KB

Mar del Plata

Congreso; XV Congreso Latinoamericano de Fisiología Vegetal | XXX Reunión Argentina de Fisiología Vegetal; 2014

This study was focused on the role of indole acetic acid (IAA) in the defense against oxidative stress damage caused by drought in soybean plants and to elucidate whether heme oxygenase 1 (HO-1) and nitric oxide (NO) are involved in this mechanism. Soybean plants were treated with 8% polyethylene glycol (PEG) or 100µM IAA. Drought treatment (8% PEG) caused a significant increase in TBARS levels as well as a marked decrease in non- enzymatic and enzymatic defense system. Pretreatment with IAA prevented the alterations of stress parameters caused by drought, while treatment with IAA alone did not produce changes defense system. Furthermore, this hormone could enhance HO-1 activity (75% respect to controls), and this increase is positively correlated with protein content as well as gene expression. The direct participation of HO-1 as an antioxidant enzyme was established by performing experiments in the presence of Zn-protoporphyrin IX a well known irreversible inhibitor of this enzyme. It was also demonstrated that HO-1 is modulated by NO. It is concluded that IAA is responsible, at least in part, for the protection against oxidative stress caused by drought in soybean through the modulation of NO levels which, in turn, enhances HO-1 synthesis and activity.