The role of salicylic acid in the prevention of oxidative stress elicited by cadmium in soybean plants

Abstract

The protective action of salicylic acid (SA) pre-treatment on soybean plants before cadmium (Cd) addition was tested. Oxidative stress parameters, such as TBARS formation, glutathione and chlorophyll content, were altered by Cd, instead no differences were observed in plants only pre-treated with SA. Antioxidant enzymes were affected by Cd treatment, while SA protected against these effects. These findings indicated that SA could act as a protector against oxidative stress induced by Cd. Taking into account the fact that heme-oxygenase-1 (HO-1) has been previously described as a novel antioxidant enzyme, experiments were carried out to determine whether it was involved in the protection exerted by SA. As expected, Cd brought about an enhancement of 57 % in HO-1 activity and 150 % in protein content (150 %), SA also increased both the enzyme activity and its protein content (28 and 75 %, respectively). Surprisingly, the observed rise of HO activity and protein content under SA treatment was lower than that produced by Cd alone. These lower values indicated, that HO-1 could not be directly involved in the protection of SA against Cd effects. In order to shed light in the mechanisms involved in SA effects, Cd content was determined in the tissues of Cd treated plants with and without SA pre-treatment. Results indicated that, in the presence of SA, Cd uptake was inhibited, thus avoiding its deleterious effects. Moreover, the observed HO-1 activity enhancement by SA indicates that this phytohormone could be engaged in the signalling pathway of heme degradation.

Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress

“…In response to HMs, not only ethylene but other hormones, including brassinosteroids, auxin, SA, GA 3 , and cytokinin, were shown to stimulate the antioxidant responses in order to scavenge different ROS when plants were grown under Cd, Cu, or Pb stress (Hayat et al, 2007;Noriega et al, 2012;PiotrowskaNiczyporuk et al, 2012). SA treatment increased the GSH content and resulted in an induction of antioxidant and metal detoxification systems, which led to Cd stress tolerance in wheat (Triticum aestivum) and pea (Pisum sativum) as well as amelioration of the negative effects of Cu stress in Brassica napus (Srivastava and Dwivedi, 1998;Khademi et al, 2014;Kovács et al, 2014).…”

H2O2 pretreated rice seedlings specifically reduces arsenate not arsenite: difference in nutrient uptake and antioxidant defense response in a contrasting pair of rice cultivars

“…This is reported to increase chilling tolerance (Murphy et al 2002), salt tolerance (Wahid et al 2007), tolerance to osmotic stress (Liu et al 2010), and low light (Zhang et al 2011). Alleviation of heavy metals induced oxidative stress have also been demonstrated during Cd treatment in rice, barley, maize, pea seedlings, Arabidopsis thaliana and Glycine max (Pal et al 2002;Metwally et al 2003;Choudhury and Panda 2004;Drazic and Mihailovic 2005;Noriega et al 2012;Guo et al 2007;Zawoznik et al 2007;Popova et al 2009;Xiao-Juan et al 2010). Reduction of Pb and Hg induced membrane damage in Oryza sativa have been studied by pretreatment with SA (Mishra and Choudhuri 1999), pre-treatement of a rice cultivar with H 2 O 2 has been reported to increase its tolerance towards Cd toxicity by increasing GSH, phytochelatins and nonprotein thiols (Chou et al 2012).…”

Salicylic acid increases tolerance to oxidative stress induced by hydrogen peroxide accumulation in leaves of cadmium-exposed flax (Linum usitatissimum L.)

“…Recent studies demonstrated that it also participates in the signaling of abiotic stresses such as Cd stress (Hayat et al 2012;Noriega et al 2012). Exogenous SA was also found to enhance the efficiency of antioxidant defense system in plants and their tolerance to oxidative stress (Shi et al 2009).…”