期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：20
页码：13319-13323
DOI：10.1073/pnas.202224899
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Plants frequently respond to herbivorous insect attack by synthesizing defense proteins that deter insect feeding and prevent additional herbivory. Maize (Zea mays L.) lines, resistant to feeding by a number of lepidopteran species, rapidly mobilize a unique 33-kDa cysteine protease in response to caterpillar feeding. The accumulation of the 33-kDa cysteine protease in the maize mid-whorl was correlated with a significant reduction in caterpillar growth that resulted from impaired nutrient utilization. Black Mexican Sweetcorn callus transformed with mir1, the gene encoding the 33-kDa cysteine protease, expressed the protease and growth of caterpillars reared on the transgenic callus was reduced 60-80%. Scanning electron microscopy was used to examine the effect of plant material expressing the 33-kDa cysteine protease on the structure of the caterpillar peritrophic matrix. Because the peritrophic matrix surrounds the food bolus, assists in digestive processes, and protects the caterpillar midgut from physical and chemical damage, disruption of peritrophic matrix may reduce caterpillar growth. The results indicated that the peritrophic matrix was severely damaged when caterpillars fed on resistant maize plants or transgenic Black Mexican Sweetcorn. The accumulation of the 33-kDa cysteine protease in response to caterpillar feeding, and its ability to damage the insect peritrophic matrix, represents an unusual host-plant resistance mechanism that may have applications in agricultural biotechnology.
