胡杨PeAPY1和PeAPY2调控拟南芥耐盐机制研究

本文研究了胡杨apyrase基因(PeAPY1和PeAPY2)对植物耐盐性的影响。以PeAPY1和PeAPY2过表达拟南芥、拟南芥Atapy1和Atapy2突变体、野生型(WT)拟南芥及空载体(VC)为实验材料，研究盐胁迫条件下的植物根长、相对电导率、细胞活力、H₂O₂水平、eATP浓度、抗氧化酶活性的变化。研究结果显示:低盐浓度(50 mmol/L NaCl)对拟南芥各基因型的生长和生理生化指标没有显著影响；而高盐浓度(100 mmol/L NaCl)抑制了各株系的根长生长、细胞活力和抗氧化酶(超氧化物歧化酶/SOD、抗坏血酸过氧化酶/APX、过氧化氢酶/CAT)活性，却提高了相对电导率、H₂O₂水平和eATP浓度。但与Atapy突变体株系相比较，PeAPY过表达株系受高盐胁迫的影响较小。主要是由于PeAPY1/2的过表达提高了apyrase酶活，下调了eATP浓度及其诱发的活性氧水平，同时，过表达株系还通过保持抗氧化酶活性来抑制H₂O₂的水平，从而降低活性氧及其对膜脂的过氧化，保持了膜的稳定性、细胞活力和生长，最终提高了植物耐盐性。 

PeAPY1 and PeAPY2 of Populus euphratica regulating salt tolerance in Arabidopsis thaliana

We investigated the effects of Populus euphratica apyrase genes ( PeAPY1 and PeAPY2 ) on salt tolerance of higher plants. Using PeAPY1 and PeAPY2 transgenic plants, Atapy1 and Atapy2 mutants, Arabidopsis wild type ( WT) and vector controls ( VC) , we examined the effects of NaCl on root length, relative electrolyte leakage, cell viability, H2O2 , extracellular ATP ( eATP ) and antioxidant enzyme activities. Results showed that the low salinity ( 50 mmol/L NaCl ) had no significant effects on root growth, physiological and biochemical parameters. However, a high salinity ( 100 mmol/L NaCl ) markedly reduced root length, cell viability and activities of antioxidant enzymes ( superoxide dismutase /SOD, ascorbate peroxidase /APX, catalase /CAT ) . In contrast, the high NaCl increased relative electrolyte leakage, H2O2 , and eATP levels in all the tested lines. PeAPY1/2-transgenic lines exhibited a less pronounced effects as compared with the Arabidopsis Atapy mutants under high salinity. We inferred that the overexpression of PeAPY1/2 led to an up-regulated apyrase, which hydrolyzed eATP and down-regulated the ATP induction of H2O2 . Moreover, PeAPY1/2 -transgenic lines maintained activity of antioxidant enzymes under salt stress. This would reduce the membrane peroxidation induced by the reactive oxygen species. As a result, the membrane integrity and cell viability were less affected by salt stress, leading to an increased salt tolerance in PeAPY1/2-transgenic plants.