逆境蛋白在植物抵抗逆境胁迫中具有重要作用。广泛存在于植物中的磷脂酶(Phospholipase C/D, PLC/PLD)是一种逆境信号传递物质，在逆境蛋白的诱导表达中具有重要意义。该文探讨了不同胁迫及PLC/PLD抑制剂处理后一种新发现的69.5 kD热稳定蛋白的表达情况，为进一步研究PLC/PLD在逆境蛋白表达中的作用机理提供依据。以玉米(Zea mays)‘鲁单9002’幼苗为材料，用270 mmol·L－1 NaCl 胁迫处理，然后进行SDS-PAGE (Sodium dodecyl sulfate-Polyacrylamide gel electrophoresis)电泳，从受胁迫的玉米幼苗根系中分离出一种新的69.5 kD热稳定蛋白，其表达量随胁迫时间的延长逐渐增加。该蛋白在恢复正常条件后仍然表达，表明其可能是一种胁迫适应性蛋白；20 μmol·L－1 ABA处理也能引起该蛋白的表达，但表达量远低于同期的270 mmol·L－1 NaCl胁迫处理。NaCl+ABA处理后该蛋白表达量低于NaCl处理,但高于ABA处理。 PLC/PLD抑制剂硫酸新霉素(Neomycin sulfate, NS)和正丁醇(n-Butyl alcohol, BA)对NaCl、ABA和NaCl+ABA诱导的69.5 kD热稳定蛋白表达均有明显的抑制作用，且对ABA和NaCl+ABA两个处理蛋白表达的抑制作用均随抑制剂浓度升高或处理时间延长而逐渐增强，但对NaCl处理蛋白表达的抑制作用则表现出复杂性。结果表明，不同处理诱导69.5 kD热稳定蛋白表达的敏感程度不同，而磷脂酶在不同处理诱导的信号传递途径中的作用机理有一定的差别。
Stress proteins play important roles in plant stress resistance. Phospholipase C/D (PLC/PLD) commonly exists in plants as a kind of signal transfer substance that can induce the expression of some stress proteins. The purpose of our study was to investigate the difference of protein expression between stress treatments and non-stress treatments. Furthermore, the function of PLC/PLD was studied in order to have a deeper insight into the mechanism of PLC/PLD in expression and regulation of stress proteins. Our results showed that a novel heat-stable protein with 69.5 kD-MW in stressed maize (Zea mays) (`LuDan-9002‘) seedling roots was induced in the 270 mmol·L-1 NaCl treatment and was separated by SDS-PAGE (Sodium dodecyl sulfate-Polyacrylamide gel electrophoresis). The expression content of this protein increased gradually with prolonged treatment of NaCl and still was maintained after the stress treatment was removed. The above results indicate that the 69.5 kD protein may be a kind of stress-adaptable protein. At the same time, a 20 μmol·L-1 ABA treatment could also induce the expression of the 69.5 kD protein, but its expression content was distinctly less than that treated with 270 mmol·L-1 NaCl. In plants treated with NaCl+ABA, the expression content of the 69.5kD protein was less than that treated with NaCl but more than that treated with ABA alone. Neomycin Sulfate (NS)+n-Butyl Alcohol (BA) treatment markedly diminished the expression of the 69.5 kD protein induced by NaCl, ABA or NaCl+ABA, and the inhibition of the two latter treatments strengthened with increasing concentrations of PLC/PLD inhibitors or increased time of treatment, whereas the inhibition of NaCl treatment was more complicated. The results suggest that different treatments have different sensitivities on inducing the expression of the 69.5 kD protein, and the function of PLC/PLD in signal transduction induced by different treatments is somewhat different.
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