温度对果梅离体花柱S-RNase识别特异性的影响

Effects of Temperature on Recognition Specificity of Stylar S-RNase in vitro in Prunus mume

【目的】研究不同温度对果梅花柱S-RNase降解花粉管RNA的影响,为揭示果梅自交不亲和性机制提供依据。【方法】在液体培养基中添加从果梅‘月世界’花柱中纯化的S-RNase,并分别于10℃、25℃和35℃条件下培养自花(‘月世界’)、异花(‘莺宿’)花粉,测定不同培养时间后的花粉萌发率和花粉管生长长度;离体条件下进行果梅花柱S-RNase降解花粉管RNA反应后,用琼脂糖凝胶电泳检测不同温度条件下自花、异花花粉管RNA被降解的程度。【结果】10℃、25℃时,花柱S-RNase抑制自花花粉萌发和花粉管生长的程度极显著大于抑制异花花粉的程度;花柱S-RNase降解自花花粉管RNA的程度也明显大于降解异花花粉管RNA的程度;温度升高到35℃时,自花和异花间花粉萌发和花粉管生长被花柱S-RNase抑制的程度不存在显著性差异;花柱S-RNase降解自花和异花花粉管RNA的程度也相似。随着反应温度的升高,花柱S-RNase较大程度抑制自花花粉萌发和花粉管生长的特异性及较大程度降解花粉管RNA的特异性逐渐减弱,当温度达到35℃时,该抑制特异性和降解特异性消失。【结论】果梅花柱S-RNase特异性识别并降解自花花粉管RNA,导致自花花粉管停止生长;随着温度的升高花柱S-RNase对花粉管RNA的识别特异性减弱,从而调节果梅的自交不亲和性反应。

[Objective] Effects of temperature on degradation of pollen tube RNA by the stylar S-RNase from Prunus mume were investigated, which provided an experimental basis for elucidating the mechanisms of self-incompatibility in Prunus mume. [Method] Adding purified stylar S-RNase from Prunus mume cultivar ‘Gessekai＇ to liquid medium, for cultivating self- （‘Gessekai＇） and cross-pollen （‘Oushuku＇） at temperatures 10℃, 25℃ and 35℃, respectively, then determining the rate of pollen germination and the length of pollen tube after different periods of cultivating time. The degradation of pollen tube RNA in vitro by stylar S-RNase at different temperatures was performed to detect the extent of degradation using the agarose gel electrophoresis. [Result] The germination and tube growth of self-pollen and the RNA of self-pollen tube were inhibited and degraded significantly greater than cross-pollen respectively at 10℃ and 25℃, but no significant difference when the temperature rose to 35℃. The specific inhibition of a large degree for self-pollen germination and tube growth and the specific degradation for self-pollen tube RNA gradually weakened as the temperature increased and disappeared when the temperature came to 35℃. [Conclusion] Specific recognition and degradation of stylar S-RNase for self-pollen tube RNA, resulted in the stop of self-tube growth in Prunus mume. The recognition specificity of stylar S-RNase for the RNA weakened with the rise of temperature, consequently regulating the self-incompatibility reaction in Prunus mume.