条锈病侵染对小麦抗氰呼吸和活性氧代谢的影响

 以不同抗病性的小麦为材料,观察了条锈病菌侵染小麦幼苗叶片时活性氧代谢和抗氰呼吸发生、运行的变化。讨论了二者在长期病程下的平衡关系。实验显示:接种8d后,感病小麦中H₂O₂含量开始高于抗病小麦,O₂^-·含量变化差异不明显。SOD、CAT和POD活性整体上表现为接种后的前4d有所上升,接种4d之后呈下降的趋势;感病小麦中3种抗氧化酶的活性均高于抗病小麦。条锈菌侵染下小麦幼苗抗氰呼吸容量和运行活性的变化在两类小麦中与H₂O₂的变化一致,在侵染初期上升缓慢,以后迅速上升;aoxl的mRNA水平仅在侵染后4d的幼苗叶片中略有上升,在以后的侵染过程中没有发生显著的变化。我们推测,活性氧可以在多种水平上参与条锈病菌侵染下抗氰呼吸的诱导,而抗氰呼吸也在某种程度上参与小麦在条锈病菌侵染下活性氧的清除与机体的生理保护机制。

Effect of Puccinia striiformis West infection on cyanide-resistant respiration and metabolism of reactive oxygen in wheat

Induction and operation of the alternative pathway, the changes of active oxygen species levels and antioxidant enzymes activity during stripe rust infection were studied and discussed in this paper. Experiments showed that the content of H₂O₂ in the disease-susceptible cultivars was higher than that in the disease-resistant ones after 8 d of inoculation. But the change of O₂^-·content was regular. The activities of SOD, CAT and POD increased at the early stage of infection. But after 4 d of inoculation,they presented a trend of decreasing in susceptible wheats and were higher in the disease-susceptible ones than those in the disease-resistant ones. During stripe rust infection, the changes in the capacities and operation of alternative pathway in wheat seedling leaves was similar as the changes of content of H₂O₂. And no significant variance was observed in the aoxl mRNA level in wheat seedling leaves by Northem blotting, except an increase in the fourth day after inoculation. All those results indicate that active oxygen species induce the alternative pathway in some extend,and alternative pathway may participate in the lower active oxygen species and the protection mechanism against pathogen attacking.