Cloning and Expression Analysis of a Gene Encoding for Ascorbate Peroxidase and Responsive to Salt Stress in Beet (Beta vulgaris).
BvpAPX is a full-length cDNA-encoding peroxisomal ascorbate peroxidase isolated from leaves of salt-stressed beet (Beta vulgaris) plants. A high level of identity has been reported between the deduced amino acid sequence ofBvpAPX and other known ascorbate peroxidases. The genomic sequence ofBvpAPX revealed a gene composed of 5 exons and 4 introns. Several sequence motifs revealed in the 5'UTR region of the gene confer toBvpAPX a putative responsiveness to various abiotic stresses. We determined the effect of salt stress onBvpAPX expression in leaves of the cultivated beet varieties,HuzarandJanosik, and their wild salt-tolerant relativeB. vulgarisssp.maritima. Plants were subjected to salt stress during a 32-day culture period (long-term salt treatment). An alternative salinization protocol consisted of an 18-h incubation of detached beet leaves in media supplemented with toxic salt concentrations (short-term salt treatment). RT-Q-PCR analysis revealed thatBvpAPX expression markedly increased in leaves of plants subjected to conditions of long-term treatment with salinity, whereasBvpAPX transcript levels remained unaffected in detached leaves during short-term salt treatment. In addition, several leaf redox system parameters, such as ascorbate peroxidase activity or ascorbic acid, hydrogen peroxide, and lipid hydroperoxide concentration, were determined in the leaves of beet plants subjected to salt stress conditions.
Kamila
K
Dunajska-Ordak
Monika
M
Skorupa-Kłaput
Katarzyna
K
Kurnik
Andrzej
A
Tretyn
Jarosław
J
Tyburski
Ascorbate; Ascorbate peroxidase; Beta vulgaris; Hydrogen peroxide; Salt stress