A Phytocystatin Gene from Malus prunifolia (Willd.) Borkh., MpCYS5, Confers Salt Stress Tolerance and Functions in Endoplasmic Reticulum Stress Response in Arabidopsis

Autor: Ping Wang, Yanxiao Tan, Xun Sun, Mingjun Li, Fengwang Ma, Xiaoyu Wei
Rok vydání: 2015
Předmět:
Zdroj: Plant Molecular Biology Reporter. 34:62-75
ISSN: 1572-9818
0735-9640
DOI: 10.1007/s11105-015-0900-z
Popis: Cystatins, or phytocystatins (PhyCys), comprise a family of plant-specific inhibitors of cysteine proteinases. They are thought to help regulate endogenous processes and protect plants against biotic or abiotic stresses, such as heat, salinity, cold, water deficit, chilling, and abscisic acid (ABA) treatment. We isolated and identified a novel cystatin gene from Malus prunifolia, MpCYS5. Its expression was typically induced by salt stress treatment; ectopic expression in Arabidopsis enhanced salt tolerance. Physiological parameters confirmed this phenotype, with the transgenics having remarkably lower electrolyte leakage (EL) values, higher chlorophyll concentrations, and lower levels of malondialdehyde (MDA) upon salt treatment. In addition, the accumulation of reactive oxygen species was markedly regulated by MpCYS5 under stress conditions, as shown by fluctuations in the concentrations of hydrogen peroxide and superoxide radicals and the activities of antioxidant enzymes. We also noted that this gene modulated tunicamycin (TM)-induced endoplasmic reticulum (ER) stress tolerance and functioned in the unfolded protein response (UPR)-signaling pathway in Arabidopsis. This was confirmed by the expression of eight ER stress-responsive genes. All marker genes examined were strongly induced in the wild type, while most of them maintained relatively stable over time in the transgenics. These results demonstrated that ectopic expression of a cystatin gene is associated with salt-tolerant and TM-tolerant phenotypes. Therefore, the discovery of MpCYS5 from M. prunifolia might establish a molecular link between the ER stress response and salt tolerance in plants.
Databáze: OpenAIRE
Externí odkaz: