不同抗性杨树接种溃疡病菌后过氧化氢及其氧化酶的表达差异

Difference in Expression of Hydrogen Peroxide and Oxidative Enzymes in Different Resistant Poplars Inoculated with Botryosphaeria dothidea

为探讨不同抗性杨树接种溃疡病菌(Botryosphaeria dothidea)后过氧化氢(H2O2)及相关酶与其抗性间的关系,对抗病毛白杨(Populus tomentosa)和感病北京杨(P.×beijingensis)接种溃疡病菌后H2O2摩尔质量浓度、APX和POD酶活性及基因表达进行了研究。结果发现,毛白杨在接种溃疡病菌后,H2O2摩尔质量浓度显著高于北京杨,在接种72 h时,H2O2摩尔质量浓度达到最大值(737.52 mol/g),此时对杨树韧皮部进行H2O2亚细胞化学定位,发现抗病毛白杨有大量H2O2-CeCl3沉淀颗粒,且增加的沉淀主要起源于细胞壁;两种杨树接种溃疡病菌后的APX和POD酶活性,毛白杨的变幅显著高于北京杨,且APX和POD的活性变化与寄主抗病性呈正相关;RT-PCR研究表明,溃疡病菌诱导了两种互作体系中杨树APX和POD基因的表达。实验结果表明不同抗性杨树接种溃疡病菌后,其体内H2O2、APX和POD表达差异与其抗性密切相关,H2O2摩尔质量浓度的积累程度对杨树抗病性具有重要的作用。

The contents of hydrogen peroxide （ H2O2 ） and the dynamic changes of POD and APX activities in resistant Populus tomentosa and susceptible P. xbeijingensis inoculated with Botryosphaeria dothidea were analyzed to study the relationship between activity differences of H2O2 and related enzymes. Results showed that the content of H2O2 in P. tomentosa was obviously higher than that in P. beifingensis at the early stage of inoculation. After 72 hours of inoculation, H2O2 content reached its maximum （757.52 mol/g）. H2O2 in poplar plant phloem was detected by cytochemical method with CeC13 stai- ning, which suggested that there were a large number of H2O2-CeC13 precipitate particles on both sides of cell wall of P. tomentosa phloem at 72 h after inoculation. After inoculation with B. dothidea, the activity amplitudes of APX and POD of P. tomentosa were significantly higher than those of P. xbeifingensis. The activities of APX and POD were positively correlated with poplar resistance. The results indicated that APX and POD were induced by B. dothidea in all interactions. The dynamic changes of H2O5 , APX and POD in different resistant poplar trees inoculated with B. dothidea were closely related to their resistances, and the accumulation level of H2O2 in the poplars had an important influence on the resistance of poplars to B. dothidea.