PJB-2018-654
H+-ATPASE INVOLVEMENT IN THE PROGRAMMED CELL DEATH OF PSAMMOSILENE TUNICOIDES INDUCED BY EXOGENOUS OXALIC ACID TREATMENT
Zhang Zongshen
Abstract
Previous studies have reported the enhanced resistance of plant cells against environmental insults by oxalic acid (OA) as an effective abiotic elicitor; however, the role of OA in this process remains to be mechanistically explored. OA-induced cell death was analyzed using an inverted fluorescence microscope after staining with Evans blue, FDA, PI, and Rd123. OA-stimulated changes in flows of K+ and Ca2+ trans-membrane currents were also examined using patch clamp method, together with OA modulation of H+-ATPase activity. Treatment of OA increased the rate of cell death in a dosage-dependent and duration-dependent manner. OA significantly decreased the mitochondria activity and damaged its electron transport chain. The OA treatment also decreased intracellular pH, while fusicoccine (FC) increased the pH value. Simultaneously, NH4Cl caused intracellular acidification which then returned to normal. OA treatment independently resulted in a cell death rate of 90%, and FC led to a rate of 25%. Consistently, the combined treatment caused a cell death rate of 25%. Furthermore, the EGTA treatment caused a similar change in intracellular pH value to that of the La3+ and OA treatment. Combined results suggest that cell death induced by OA- could be attributed to intracellular acidification, and influx of extracellular Ca2+, thereby leading to membrane depolarization
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