Association of a 33-Kilodalton Cysteine Proteinase Found in Corn Callus with the Inhibition of Fall Armyworm Larval Growth

Abstract

protein suggested that it was cysteine proteinase. Purification of the 33-(Mp708) and 36-kD (Ab24E) proteins indicated that they were both cysteine proteinases. The 33-kD cysteine proteinase had 7-fold higher specific activity than the 36-kD enzyme. ~ ~~~~Fall armyworm (Spodoptera frugiperda [J.E. Smith]) and southwestern corn borer (Diatuaeu grandiosella Dyar) are serious insect pests of corn (Zea mays L.) in the southern United States. Larvae of both species damage plants by feeding on leaves within the whorls. Several germplasm lines with resistance to these two insects have been developed and released Davis, 1982, 1984;Williams et al., 1990b). These lines also show resistance to '

A Unique 33-kD Cysteine Proteinase Accumulates in Response to Larval Feeding in Maize Genotypes Resistant to Fall Armyworm and Other Lepidoptera

“…Second, when the morphology of the callus from the resistant inbred Mp704 changed from nonfriable to friable, the 33-kD cysteine proteinase was not detected. Larvae reared on the friable callus were substantially larger than those reared on nonfriable callus (Jiang et al, 1995). Third, the 33-kD cysteine proteinase purified from Mp704 had sevenfold greater specific activity and 15-fold more enzymatic efficiency than an immunologically related 36-kD cysteine proteinase purified from callus of the susceptible inbred Ab24E (Jiang et al, 1995).…”

“…Therefore, attempts have been made to determine if there are differences in the proteins present in callus initiated from several resistant and susceptible inbreds. A 33-kD cysteine proteinase was identified in nonfriable callus initiated from resistant (Mp704 and Mp708) but not susceptible (Tx601 and Ab24E) inbreds (Jiang et al, 1995). Several lines of evidence suggested that this proteinase was involved in the ability of callus from Mp704 and Mp708 to retard larval growth.…”

“…Several lines of evidence suggested that this proteinase was involved in the ability of callus from Mp704 and Mp708 to retard larval growth. First, there was a negative correlation between larval weight and the relative concentration of the 33-kD cysteine proteinase when larvae were reared on callus initiated from F 2 progeny of Mp704 ϫ Tx601 (Jiang et al, 1995). Second, when the morphology of the callus from the resistant inbred Mp704 changed from nonfriable to friable, the 33-kD cysteine proteinase was not detected.…”

“…The Plant Cell callus initiated from resistant (Mp704 and Mp708) but not susceptible (Tx601 and Ab24E) inbreds (Jiang et al, 1995). Several lines of evidence suggested that this proteinase was involved in the ability of callus from Mp704 and Mp708 to retard larval growth.…”

“…Larvae reared on the friable callus were substantially larger than those reared on nonfriable callus (Jiang et al, 1995). Third, the 33-kD cysteine proteinase purified from Mp704 had sevenfold greater specific activity and 15-fold more enzymatic efficiency than an immunologically related 36-kD cysteine proteinase purified from callus of the susceptible inbred Ab24E (Jiang et al, 1995).The 33-kD cysteine proteinase is encoded by mir1 , which was isolated from a cDNA library prepared from Mp708 callus (Pechan et al, 1999). The derived amino acid sequence indicates that the cysteine proteinase is synthesized as a preproprotein that must be post-translationally processed to form the 33-kD enzyme.…”