Ascorbate peroxidase from Jatropha curcas enhances salt tolerance in transgenic Arabidopsis

Abstract

ABSTRACT. Ascorbate peroxidase (APX) plays a central role in the ascorbate-glutathione cycle and is a key enzyme in cellular H 2 O 2 metabolism. It includes a family of isoenzymes with different characteristics, which are identified in many higher plants. In the present study, we isolated the APX gene from Jatropha curcas L, which is similar with other previously characterized APXs as revealed by alignment and phylogenetic analysis of its deduced amino acid sequence. Real-time qPCR analysis showed that the expression level of JcAPX transcript significantly increased under NaCl stress. Subsequently, to elucidate the contribution of JcAPX to the protection against salt-induced oxidative stress, the expression construct p35S: JcAPX was created and transformed into Arabidopsis and transcribed. Under 150-mM NaCl stress, compared with wild type (WT), the overexpression of JcAPX in Arabidopsis increased the germination rate, the number of leaves, Y. Chen et al. 4880©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (2): 4879-4889 (2015) and the rosette area. In addition, the transgenic plants had longer roots, higher total chlorophyll content, higher total APX activity, and lower H 2 O 2 content than the WT under NaCl stress conditions. These results suggested that higher APX activity in transgenic lines increases the salt tolerance by enhancing scavenging capacity for reactive oxygen species under NaCl stress conditions.

Expression Patterns of Genes Involved in Ascorbate-Glutathione Cycle in Aphid-Infested Maize (Zea mays L.) Seedlings

“…Interestingly, Gomez et al [ 42 ] demonstrated that a long-term (6- or 9-day) infestation of cotton ( Gossypium hirsutum L.) leaves with the cotton aphids ( Aphis gossypii G.) did not influence significant alternations in total activity of APX relative to the non-stressed control. Moreover, it has been well documented that overexpressed or silenced APX mutants of the several plant species displayed circumstantial alternations in their growth and development, ROS homeostasis, signaling networks, efficiency of the antioxidative machinery and/or defensive responses to diverse stressing factors [ 38 , 43 ]. Exemplarily, it has been uncovered that the transgenic lines of A. thaliana overexpressing APX gene from Jatropha curcas L., exhibited an elevated salt tolerance in relation to the WT plants [ 43 ].…”

“…Moreover, it has been well documented that overexpressed or silenced APX mutants of the several plant species displayed circumstantial alternations in their growth and development, ROS homeostasis, signaling networks, efficiency of the antioxidative machinery and/or defensive responses to diverse stressing factors [ 38 , 43 ]. Exemplarily, it has been uncovered that the transgenic lines of A. thaliana overexpressing APX gene from Jatropha curcas L., exhibited an elevated salt tolerance in relation to the WT plants [ 43 ]. Similarly, A. thaliana transformants overexpressing the two transgenes: APX and superoxide dismutase ( SOD ), derived from Rheum australe Don and Potentilla atrosanguinea Lodd., accordingly, characterized with an enhanced salt stress tolerance, increased expression of the genes involved in biosynthesis of the secondary cell wall and encoding the numerous transcription factors (e.g., C3Hs, MYBs, NACs and WRKY) in comparison with the control plants [ 44 ].…”

Identification and Characterization of the APX Gene Family and Its Expression Pattern under Phytohormone Treatment and Abiotic Stress in Populus trichocarpa

“…Accumulation of excessive ROS and H 2 O 2 may cause cellular injury [59]. Ascorbate peroxidase catalyzes the conversion of H 2 O 2 to H 2 O and O 2 , and scavenges ROS to protect against the toxic effects of ROS accumulation in higher plants [60]. Previous research has shown that AtAPX1 performs an important function in the drought stress response by protecting chloroplasts from oxidative damage in Arabidopsis.…”

Expression of an alfalfa (Medicago sativa L.) peroxidase gene in transgenic Arabidopsis thaliana enhances resistance to NaCl and H2O2

“…In the enzymatic system, SOD constitutes the first line of defense against ROS by dismutating O 2 -to H 2 O 2 . Subsequently, H 2 O 2 is broken down by CAT, POD, and APX (Chen et al, 2015). We found that POD levels had significantly increased in MsPOD transgenic Arabidopsis plants compared to those in WT plants, but CAT levels had not changed.…”