Response of vacuolar processing enzyme in Malus hupehensis and MhVPE gamma-overexpressing Arabidopsis to high temperature stress

Author:

Su, Qian  Ran, Kun  Men, Xiu-Jin  Zhang, Wei-Wei  Fan, Shu-Lei  Yan, Li-Juan  Yang, Hong-Qiang  

Journal:

ACTA PHYSIOLOGIAE PLANTARUM

Issue Date:

2015

Abstract(summary):

Malus hupehensis Rehd. is often used as rootstock of apple trees. Vacuolar processing enzyme (VPE) is one type of cysteine protease with substrate specificity to residues of asparagine and aspartic acid. The VPE activity, MhVPE gamma gene (GenBank number: FJ891065) expression and the amount of cell death in seedlings of M. hupehensis Rehd. all gradually increased with the increase of temperature from 26 to 42 degrees C. To explore the function of VPE response to temperature stress, the overexpressing vector of MhVPE gamma was constructed and transformed into wild-type Arabidopsis thaliana Columbia. The responses of VPE, MhVPE gamma and apoptosis to high temperature stress were determined in the Arabidopsis seedlings of wild-type, MhVPE gamma-overexpressing lines and the VPE-null mutant. The leaves of MhVPE gamma-overexpressing lines were smaller and VPE activity and MhVPE gamma expression level were both obviously higher than the levels found in the wild-type and VPE-null mutant seedlings. Under high temperature treatment, VPE activity and MhVPE gamma expression level significantly increased accompanied by leaf withering, shorter roots, lipid peroxidation and increased cell death and apoptosis rate in all types of plants. The changes of these indicators were highest in MhVPE gamma-overexpressing transgenic plants, followed by the wild-type and were lowest in VPE-null mutant plants. These results suggest that MhVPE gamma overexpression in Arabidopsis accelerated cell membrane lipid peroxidation, promoted cell death and reduced the tolerance to high temperature stress compared with wild-type plants.