Department of Entomology, University of Wisconsin, Madison, Wisconsin 53706.
Plant Physiol. 1992 Nov;100(3):1479-85. doi: 10.1104/pp.100.3.1479.
The hypocotyl of different soybean genotypes was tested for its inducible phytoalexin (i.e. glyceollin or coumestrol) accumulation and its inducible soybean looper resistance in response to chemical elicitation. A very highly insect-resistant soybean genotype (PI 227687) produced significantly more phytoalexins than a relatively insect-susceptible one (Davis) in response to the same chemical elicitation. The resultant standardized hypocotyl assay allowed quick categorization of unknown soybean genotypes regarding the level of insect resistance in the fully developed plants. Glyceollin was a better indicator of inducible resistance than coumestrol. Elicitor concentration influenced the amount of glyceollin and coumestrol accumulated. Younger seedlings (4-5 d old) responded stronger to chemical elicitation than did older ones (7-10 d old). The elicited accumulation of glyceollin showed a temporal pattern that peaked at 72 h. Accumulation of coumestrol showed a gradual increase. Elicitation of phytoalexins in juvenile soybean plants by sulfhydryl-binding reagents was found to be useful for the prediction of genotypic differences in the level of insect resistance in the fully developed plants.
不同大豆基因型的下胚轴被测试其诱导的植物抗毒素（即大豆苷元或香豆雌酚）积累及其对化学诱导的诱导性大豆卷叶蛾抗性。一种非常高抗虫的大豆基因型（PI 227687）比相对易感虫的基因型（戴维斯）在相同的化学诱导下产生了更多的植物抗毒素。由此产生的标准化下胚轴测定法允许根据完全发育植物中的昆虫抗性水平对未知大豆基因型进行快速分类。大豆苷元比香豆雌酚更能指示诱导抗性。诱导剂浓度影响积累的大豆苷元和香豆雌酚的量。与较老的幼苗（7-10 天大）相比，较年轻的幼苗（4-5 天大）对化学诱导的反应更强。大豆苷元的诱导积累呈现出一个时间模式，在 72 小时达到峰值。香豆雌酚的积累呈逐渐增加的趋势。发现通过含巯基结合试剂诱导幼年大豆植株中的植物抗毒素对于预测完全发育植物中昆虫抗性水平的基因型差异是有用的。
