小麦悬浮细胞应答激发子刺激的过敏性反应中Ca^(2+)和NO的动态变化及其相互作用

Dynamics and Interaction of Ca^(2+) and Nitric Oxide in Wheat Suspension Cells in the Hypersensitive Response

以感染叶锈菌的小麦(Triticum aestivum)叶片细胞间隙液IWF-260作为激发子,刺激小麦品种洛夫林10和郑州5389的悬浮细胞,探讨由激发子引发悬浮细胞过敏性反应中Ca2+和NO的变化及相互作用。以荧光分子探针Fluo-3AM和DAF-FM DA分别对细胞内Ca2+和NO进行标记,利用激光共聚焦扫描显微镜对其动态变化进行实时监测,通过药物学实验对Ca2+和NO的产生机制及其可能存在的相互关系进行探讨。结果表明,2个小麦品种悬浮细胞的[Ca2+]cyt水平对激发子刺激的反应表现出明显的差异,对叶锈菌小种表现不亲和的洛夫林10悬浮细胞分别在激发子刺激后330秒和700秒出现2个钙峰;而对该小种表现亲和的郑州5389悬浮细胞在激发子刺激后[Ca2+]cyt水平稍有波动但变化不明显。药物学实验证明,[Ca2+]cyt的升高依赖于胞外钙离子内流,钙离子与激发子刺激诱发的过敏性防卫反应紧密相关。同样,在激发子刺激后,洛夫林10悬浮细胞出现1个NO峰,而郑州5389悬浮细胞胞质NO变化不明显。药物学实验初步证明,NO的产生与胞外钙离子内流密切相关。由此推测,在小麦悬浮细胞应答激发子刺激诱发的过敏性反应中,NO可能在钙的下游发挥作用。

Suspension cells of wheat varieties Lovrin 10 and Zhengzhou 5389 were stimulated with IWF-260, a leaf in- tercellular washing fluid induced by leaf rust. The dynamics and interaction of Ca2＋ and nitric oxide （NO） in the hypersen- sitive response induced by IWF-260 were analysed. The fluorescence molecular probe Fluo-3AM and DAF-FM DA were used to mark Ca2＋ and NO, respectively. The two kinds of suspension cells showed differences in the concentration of Ca2＋. Lovrin 10, a disease-resistant variety, showed two peaks of [Ca2＋]cyt, at 330 and 700 s, on stimulation, whereas Zhengzhou 5389, a susceptible variety, showed no obvious change in [Ca2＋]cyt with stimulation. The increased [Ca2＋]cyt depended on Ca2＋ flowing into cells, which suggests that Ca2＋ may be involved in the hypersensitive response. Like Ca2＋, NO showed a similar pattern after elicitor stimulation. For Lovdn 10, NO showed a peak, with no change for Zhengzhou 5389. Thus, NO production and extracellular calcium influx are closely related to wheat suspension cells＇ response to stimulation; NO may play a role downstream of calcium.