禾谷孢囊线虫侵染对小麦根部防御酶的影响

Effect of Cereal Cyst Nematode Infection on Defense Enzyme Activity of Wheat Root

以抗禾谷孢囊线虫(Heterodera avenae Wollenweber,cereal cyst nematode,CCN)小麦品系‘E-10’和易感材料‘中国春’为材料,通过人工接种禾谷孢囊线虫二龄幼虫,并在接种线虫后测定根部防御酶苯丙氨酸转氨酶(PAL)和脂氧合酶(LOX)活力变化,研究抗感性材料对线虫侵染后防御酶的响应,以了解作物的抗虫机制.结果发现,‘E-10’和‘中国春’防御酶活力变化存在显著差异,‘E-10’在线虫侵染后6 h,LOX酶活增强,在24 h达到最大值,酶活变化比‘中国春’迅速,暗示‘E-10’启动线虫防御反应更为有效直接.此外,发现小麦在接种线虫后会引起邻近未接种植株根部防御酶活力变化.‘E-10’在接种线虫后12 h,其接触组未接种材料根部PAL酶活增加0.9倍,LOX酶活增加1.1倍,并且‘E-10’未接种植株的酶活变化比‘中国春’更迅速,幅度更剧烈.表明可能有某些气态或挥发性物质参与了小麦防御线虫侵染过程,并且这种现象在抗感材料间差异显著.使用茉莉酸甲酯处理‘E-10’和‘中国春’,小麦根部PAL和LOX酶活并未产生与接触接种线虫材料相一致的变化,表明该气态或挥发性物质并非茉莉酸甲酯.

Cereal cyst nematode,a soil-borne pest,is harmful to wheat and other cereal crops,but the mechanism of insectresistance is still unknown.In this study,the changes of defensive enzymes（PAL and LOX） in the roots of cereal cyst nematode（CCN） resistant and susceptible materials ‘E-10’ and ‘Chinese Spring’ were tested,respectively.It was found that the changes of the defensive enzymes were significantly different between resistant and susceptible materials.It implied that the defense of ‘E-10’ was triggered more quickly and effectively than that of ‘Chinese Spring’.The LOX activity of ‘E-10’ reached the highest level at 24 h after CCN infection with a increase of 0.8 times;while the LOX activity of ‘Chinese Spring’ rose to the highest level at 48 h with a increase of 1.0 times.The activity of defensive enzymes also changed in uninfected plants adjacent to the CCN infected plants,and significantly different between resistant and susceptible materials.After being infected by CCN,the PAL activity of ‘E-10’ in roots neighboring intact plant increased by 0.9 times at 12 h,and the LOX activity increased by 1.1 times at 12 h.The PAL activity of ‘Chinese Spring’ in neighboring intact plant roots increased by 0.6 times at 12 h,and the LOX activity increased 0.4 times at 48 h.These results suggested that some kind of gaseous or volatile organic compounds（VOCs） might be released from CCN infected plants and induced wheat systemic resistance.The PAL and LOX activities in roots of ‘E-10’ and ‘Chinese Spring’ dealt with methyl jasmonate were not consistent with those induced by CCN inoculated plants,which suggested that the gaseous or volatile organic compound was not methyl jasmonate.