Overexpression of Populus tomentosa cytosolic ascorbate peroxidase enhances abiotic stress tolerance in tobacco plants

• Published in: Russian journal of plant physiology Vol. 64; no. 2; pp. 224 - 234
• Main Authors: Cao, S., Du, X.-H., Li, L.-H., Liu, Y.-D., Zhang, L., Pan, X., Li, Y., Li, H., Lu, H.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-03-2017; Springer Nature B.V
• Subjects: Abiotic stress; Ascorbic acid; Biomedical and Life Sciences; Chlorophyll; Drought; Enzymes; Gene expression; Hydrogen peroxide; L-Ascorbate peroxidase; Leaves; Life Sciences; Malondialdehyde; NADP; Oxidation resistance; Oxidative stress; Peroxidase; Plant Physiology; Plant Sciences; Plants; Polymerase chain reaction; Reactive oxygen species; Real time; Research Papers; Salts; Scavenging; Stems; Tobacco; Transgenic plants; transgenic tobacco; cytosolic ascorbate peroxidase; abiotic stress
• ISSN: 1021-4437; 1608-3407
• DOI: 10.1134/S1021443717020029

Reactive oxygen species (ROS) play key roles in plants and are regulated by several ROS-scavenging enzymes. Ascorbate peroxidase (APX), which catalyzes the reduction of hydrogen peroxide to water, a vital part of ROS formation, plays a significant role in higher plants. In this study, a cytosolic
APX
gene from
Populus tomentosa
, named
PcAPX
, was identified and characterized. Recombinant
PcAPX
had a calculated mass of 33.24 kD and showed high activity towards ascorbic acid (ASA) and hydrogen peroxide (H
2
O
2
). Real-time PCR analysis showed that
APX
mRNA expression levels were higher in leaves than roots or stems of
P. tomentosa
. Compared with wild-type, transgenic tobacco plants overexpressing
PcAPX
showed no significant difference in morphology under normal conditions. However, the transgenic plants were more resistant to drought, salt and oxidative stress conditions, as shown by decreased levels of malondialdehyde and increased levels of chlorophyll. Moreover, decreased H
2
O
2
levels, increased ASA consumption, an increase in the NADP to NADPH ratio, and higher APX activity in the transgenic plants suggested an increased ability to eliminate ROS. These data suggest that
PcAPX
overexpression in transgenic tobacco plants can enhance tolerance to drought, salt and oxidative stress. Therefore, APX has a crucial role in abiotic stress tolerance in plants.