Several non-homologous families of proteinase inhibitors are recognized among .. of the plant protease inhibitors to the insect proteases appear to be similar with study of Bacillus thuringiensis (Bt) and its transfer to developing countries. digestive enzymes and protease inhibitors is a prerequisite to plan strategies for successful and agents Bt toxin is effective in deterring plant predators, but in spite of its .. in some non solanaceous plants like alfalfa, broad bean, clover. The potential risks of Bt rice to arthropod communities, non-target . Three weeks later, rice seedlings of similar sizes were transplanted into glass .. class family protein (LOC_Os04g); LTPL65, protease inhibitor/seed.


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These results indicate that the toxic effect of ScathL on insects can be explained primarily as a result of the proteolytic damage done to basement membranes and the underlying tissues [ 93 ].

The formation of melanin by-products may contribute to its toxicity in lepidopteran larvae.

Proteases as Insecticidal Agents

Figure 2 Cuticular melanization non bt like protease inhibitors from baculovirus expression of ScathL in larvae of Heliothis virescens. Control uninfected and wild type virus-infected larvae are shown for comparison.

A, B, Scanning electron micrographs of the basement membrane overlying the fat body of larvae infected with recombinant baculoviruses expressing the catalytic site mutant ScathL-CA A or wild-type ScathL B showing ScathL-mediated perforations.


Reprinted with permission from Elsevier, [ 95 ]. A homolog of ScathL has been identified from the guts of larvae of the wheat bulb fly, Delia coarctata [ 96 ].

This protease, DcCathL, is also toxic when injected into the hemocoel of larvae of L.


DcCathL selectively degraded serine protease inhibitors serpins from the cabbage moth, Mamestra brassicae, and M. The melanization normally observed with larvae injected with DcCathL was also blocked when the serpins were co-injected, indicating that the serpins could block the proteolytic cascade, presumably initiated by DcCathL-mediated activation of a serine protease in the non bt like protease inhibitors, that led to prophenoloxidase activation and melanin formation.

Proteinase inhibitors in plants - Wikipedia

This result suggests that melanization in larvae injected with DcCathL may be facilitated by the degradation of endogenous serpins by DcCathL. A cathepsin B-like protease identified from Helicoverpa armigera reduced the survival time of baculovirus-infected H.

The venoms of arthropod predators sometimes contain metalloproteases and gelatinolytic serine proteases that are capable of non bt like protease inhibitors basement membrane proteins [,].

These proteases may also have an insecticidal effect when delivered to the hemocoel of an insect.

Proteases as Insecticidal Agents

The reprolysin metalloprotease homolog EpMP3 from the venom of the parasitic wasp Eulophus pennicornis [ ] caused mortality in L.

The mortality occurred just prior to or during molting to the next instar, and surviving larvae exhibited a slower rate of growth and development after injection.

Soldier-caste nymphs of the social aphid species, Tuberaphis styraci, produce a toxic cathepsin B protease in their intestine [ ]. When aphid predators threaten the galls produced by reproductive aphids, the soldier nymphs thrust their piercing mouthparts stylets into the intruders and orally excrete this cathepsin B, causing paralysis or non bt like protease inhibitors of the intruders.

Pathogenic bacteria often express proteases that are toxic to their hosts [ ]. Genetic studies with inhA mutants indicated that it was not required for B.

Insect Resistance in Plants | Genetics

However, the toxic effect of proteases that hydrolyze non bt like protease inhibitors on the cuticle or in the hemocoel generally depends upon an appropriate means to deliver the proteases to their targets. As described above, one popular means to deliver proteases into the insect hemocoel is by means of an insect pathogen, such as entomopathogenic fungi or viruses.

However, these proteases can be applied as an insecticide by themselves, without the requirement non bt like protease inhibitors an insect pathogen to deliver them to their target sites. The toxicity of PR1A and other fungal cuticle-degrading enzymes described above occurred when those enzymes were expressed in the hemocoel via a fungal vector.

However, significant mortality of an arthropod, the hard tick, Haemaphysalis longicornis, could be achieved by topical application of medium from insect cells infected with a recombinant baculovirus that expressed an H. Most of the observed mortality could be achieved with medium from which budded virus had been clarified by ultracentrifugation.


As it is not expected that the baculovirus used in this study AcMNPV would infect and kill ticks, this result suggests that the chitinase alone was toxic to the ticks. Cuticle-degrading proteases such as PR1A also may have toxicity towards insects when applied topically.

non bt like protease inhibitors

Insect Resistance in Plants | Genetics

There is further evidence for this idea as the chitinolytic and proteolytic activities in a B. In addition, there is substantial evidence that proteins can non bt like protease inhibitors transported intact from the guts of insects and related arthropods to the hemocoel [ ].

Translocation of protein from the gut to the hemocoel is inefficient, with less than 0.

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