小麦悬浮细胞应答激发子刺激的过敏性反应中Ca2+和 NO的动态变化及其相互作用

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。

Dynamics and Interaction of Ca2+ and Nitric Oxide in Wheat Suspension Cells in the Hypersensitive Response

Suspension cells of wheat varieties Lovrin 10 and Zhengzhou 5389 were stimulated with IWF-260, a leaf intercellular washing fluid induced by leaf rust. The dynamics and interaction of Ca²⁺ and nitric oxide (NO) in the hypersensitive 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 Lovrin 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.