感染大斑病菌后玉米抗感近等基因系丁布含量变化的比较研究

Changes of DIMBOA Contents in Resistant and Susceptible Near-Isolines of Maize during Infection by Exserohilum turcicum

本文比较了玉米抗,感大斑病菌近等基因系丁布含量及其在感病过程中的动态变化。结果发现,在未受病菌侵染的情况下,Ht1Ht1、Ht2Ht2和HtNHtN3种抗病系以及htht感病系间丁布含量没有明显差异。接种大斑病菌后,各种抗病系在病菌侵染初期丁布含量迅速大幅度上升,在整个病程中始终明显高于感病系。感染大斑病菌最终导致罹病植株丁布含量比未接种的健康植株明显减少,各种抗病系减少的百分率明显低于感病系。可见丁布与玉米大斑病单基因抗性有密切关系。本文认为研究病虫危害后寄主丁布含量变化的规律,对了解植物对不同病虫抗性的关系,筛选培育多抗品种有一定的指导意义。

Contents of DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) and their dy-namic changes during infection with Exserohilum turcicum were comparatively analysed in two sets of maize near-isolines, each composed of a susceptible recurrent parent and three resistant backcross-derived lines with one of Ht1, Ht2 and HtN genes for resistance to the pathogen. It was revealed that no significant difference in DIMBOA contents in non-inoculated plants exsisted among various resistant and susceptible inbred lines with a identical genetic background. But in in-itial stage of penetration by the fungus the contents in all resistant isolines had a quicker and greater increase, which resulted in a significantly higher amount of DIMBOA in resistant isolines than that in susceptible one throughout the period of disease development. However, the infection ultimately led to a decline in DIMBOA amount in diseased plant with a less decrease in all resistant lines than that in susceptible one. The results above show that DIMBOA is associated with monogenic resistance in maize to E. turcicum. It is suggested that studies on DIMBOA con-tent changes in plants suffering diseases and pests would be useful for us to understand the rela-tionship of resistance to them and to screen and breed varieties for multiple resistance.