松材线虫侵染对马尾松苯丙烷类代谢的影响

Effect of Pine Wood Nematode(PWN) Infection on PhenylpropanesMetabolism in Masson Pine Seedlings

1.5年生马尾松植株接种松材线虫后,苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)的活性水平均高于对照,活性高峰通常出现在症状表现前夕,并在植株发病后下降。叶内PAL和POD活性高峰的出现晚于茎,与叶部病害发展一致。茎中酚类物质的含量随着线虫侵染时间的延长逐渐增加,至发病时达到高峰。酚类物质含量的变化与PAL、POD、PPO3种酶活性的变化趋势基本一致。松材线虫的侵染明显影响寄主植物的苯丙烷类代谢,由此可知,松材线虫病的发生发展与松材线虫诱导感病寄主苯丙烷类代谢的异常变化有关。

After the 1.5-year-old Masson Pine （ Pinus massoniana ） seedlings was inoculated with Pine Wood Nematode （ Bursaphelenchus xylophilus, PWN）, the changes of phenylpropanes metabolism in the pine seedlings and the internal relations between the changes and disease development were studied. The results showed that PWN infection had obvious influence on the way of phenylpropanes metabolism of the host plants. The activities of phenylalanine ammonia-lyase（PAL） , peroxidase （POD） and polyphenoloxidase（PPO） in the stems of the infected seedlings increased with the elapse of time but decreased after the attack of the disease, the peak of activities of phenylalanine ammonia-lyase（PAL） , peroxidase （POD） in the needles appeared behind that in the stems and were coincident with the development of the disease in the needles. The total phenols content in the stems increased gradually with the extending of the attack time and came up to the top. The increase of the total phenols content was related to the acceleration of phenylpropanes metabolism. The accumulation of phenol substances and the rising of PPO activity might be the main factors to cause the brown stain and necrosis of the cells in the hosts. All these showed that activity changes of the three enzymes were closely related to PWN disease and some changes of the ways of metabolism controlled by them had participated in the occurrence and development of the disease.