麦田不同杂草对苯磺隆敏感性差异的分子机制

Molecular basis of sensitivity difference in wheat weeds to tribenuron-methyl

为了探讨麦田常见杂草对苯磺隆敏感性差异的分子机制,测定了苯磺隆对4种杂草活性及对杂草体内靶标酶(ALS)和代谢酶(GSTs)的影响差异。结果表明,泽漆对苯磺隆的敏感性最低,IC50为123.16gai/hm2;猪殃殃和荠菜次之,分别为8.47、1.07gai/hm2;播娘蒿最敏感,为0.29gai/hm2。离体条件下,苯磺隆对播娘蒿、泽漆ALS的IC50值分别为6.40、54.90mgai/L。活体条件下,苯磺隆处理后,播娘蒿体内ALS活力低于对照,第9天降为对照的31.20%,而敏感性低的泽漆处理后1～2天ALS活力虽略有下降,但第3天明显提高,第4天达到峰值,为对照的2.90倍,此后逐渐恢复至对照水平。4种杂草本身所含GSTs活性存在较大差异,泽漆GSTs活性最高。经苯磺隆处理后,泽漆与猪殃殃GSTs活性明显提高,第4天时达到峰值,相对活性分别为1.23和1.25,并持续在较高水平;而荠菜、播娘蒿GSTs活性虽分别在第3、5天达到峰值,但多数时间相对活性低于1。结果表明,麦田不同杂草体内ALS的敏感性差异和GSTs的代谢差异是对苯磺隆敏感性不同的两个重要原因。

In order to study the molecular mechanism of sensitivity difference in common wheat weeds to tribenuron-methyl, the control effects and molecular difference on ALS and GSTs of 4 wheat weeds to tribenuron-methyl were preliminarily determined. It showed that the sensitivity of Euphorbia helioscopia L, to tribenuron-methyl was the smallest, and Descurainia sophia L. was the strongest, IC50 of tribenuron-methyl to Descurainia sophia L. , Capsella bursa-pastoris L. , Galium aparine L. and Euphorbia he- lioscopia L. were 0.29, 1.07, 8.47 and 123.16gai/hm2 , respectively. In vitro, IC50 of Descurainia sophia L. and Euphorbia helioscopia L.＇s ALS were respectively 6.40 and 54.90 mg ai/L. In vivo, AIS specific activities of Descurainia sophia L. were all lower than that of contemporaneous comparisons and decreased to 31.20% of it＇s comparison when it was the 9th day after treated with tribenuron-methyl. Al- though AIS specific activities of Euphorbia helioscopia L. in the first 2 days were slightly falling, it had a rapid increasing tendency on the 3rd day and reached the peak value which was 2.90 times higher than that of comparison on the 4th day, then it renewed the normal level. GSTs activity differed in 4 wheat weeds ; after treated with tribenuron-methyl, GSTs relative activities of Euphorbia helioscopia L. and Galium aparine L had obvious enhancement on the 1 st day and reached the peak value 1.23, day, it remained a higher level; although GSTs relative activity of Capsella bursa-pastoris L. 1.25 on the 4th and Descurainia sophia L. reached respectively their peak values on the 3rd day and 5th day, the values were all lower than 1 in most days. It was induced that the two important reasons of wheat weeds had different sensitivity to tribenuron-methyl were the difference of sensitivity of ALS and the metabolizing mechanism of GSTs.