Maize ABP9 enhances tolerance to multiple stresses in transgenic Arabidopsis by modulating ABA signaling and cellular levels of reactive oxygen species

Abstract

The phytohormone abscisic acid (ABA) and reactive oxygen species (ROS) play critical roles in mediating abiotic stress responses in plants. It is well known that ABA is involved in the modulation of ROS levels by regulating ROS-producing and ROS-scavenging genes, but the molecular mechanisms underlying this regulation are poorly understood. Here we show that the expression of maize ABP9 gene, which encodes a bZIP transcription factor capable of binding to the ABRE2 motif in the maize Cat1 promoter, is induced by ABA, H2O2, drought and salt. Constitutive expression of ABP9 in transgenic Arabidopsis leads to remarkably enhanced tolerance to multiple stresses including drought, high salt, freezing temperature and oxidative stresses. ABP9 expressing Arabidopsis plants also exhibit increased sensitivity to exogenously applied ABA during seed germination, root growth and stomatal closure and improved water-conserving capacity. Moreover, constitutive expression of ABP9 causes reduced cellular levels of ROS, alleviated oxidative damage and reduced cell death, accompanied by elevated expression of many stress/ABA responsive genes including those for scavenging and regulating ROS. Taken together, these results suggest that ABP9 may play a pivotal role in plant tolerance to abiotic stresses by fine tuning ABA signaling and control of ROS accumulation.Electronic supplementary materialThe online version of this article (doi:10.1007/s11103-011-9732-x) contains supplementary material, which is available to authorized users.

Cloning and characterization of a maize bZIP transcription factor, ZmbZIP72, confers drought and salt tolerance in transgenic Arabidopsis

“…Thus, these results indicated that ZmbZIP72 functioned as ABAmediating transcription factor. Previously, it was reported that the bZIP-type transcription factors could form heteroor homodimers to function cooperatively and required ABA-dependent modification for full activation in Arabidopsis and rice (Hobo et al 1999;Uno et al 2000;Kobayashi et al 2004Kobayashi et al , 2005Ehlert et al 2006;Furihata et al 2006;Liao et al 2008a, b;Yoshida et al 2010;Zhang et al 2011). We speculated that ZmbZIP72 might undertake its transcriptional activity through the homodimerization in vivo, and further studies are needed to investigate the mechanism of these interactions.…”

“…A number of stress-related genes in maize have been identified and characterized well. However, only a few of maize bZIP transcription factor genes related to abiotic stress were reported (Nieva et al 2005;Zhang et al 2008Zhang et al , 2011Jia et al 2009). In present study, we isolated a putative bZIP gene, ZmbZIP72, analyzed its expression profile under different treatments, and characterized its role in stress tolerance.…”

Organ-specific effects of the auxin herbicide 2,4-D on the oxidative stress and senescence-related parameters of the stems of pea plants

“…Moreover, in tomato plants it was reported that stems possess higher antioxidant activities as compared to leaves and roots (Gratão et al 2008), which could make these organs more resistant to stress as compared to the other plant parts. In that sense, auxin herbicide-induced ET, ABA and JA might have contributed to the up-regulation of the antioxidant activities in the stems of 2,4-D-treated pea plants, as induction of CAT, SOD, APX, and GST by these phytohormones has been demonstrated in other systems (Jiang and Zhang 2003;Lafuente et al 2004;Zhou et al 2005;Wang et al 2008;Zhang et al 2011). Also, the H 2 O 2 generated by the oxidative stress of leaves (McCarthy-Suárez 2004;RomeroPuertas et al 2004) or by the increased H 2 O 2 -producing acyl-CoA oxidase activity of stems (Table 1) could have stimulated the antioxidant activities in the stems of 2,4-Dtreated pea plants, as H 2 O 2 up-regulates the genes of antioxidant enzymes (Wan et al 2009).…”

Halotolerant Plant Growth Promoting Bacteria Mediated Salinity Stress Amelioration in Plants

“…Macro nutrient Ca 2+ and K + are mobile and move from roots to shoots/leaves in plants grown under salt stress, partly protecting the plant from Na + toxicity and reducing the effect of stress (Cramer, 2002). Zhang et al (2011) reported that high salinity lead to depletion in cellular water content and osmotic stress resulting in loss of yield. Jiang et al (2013) reported that Na + ions in excess stimulates ethylene induced tolerance mechanism based on his studies with Arabidopsis thaliana mutant.…”