ALKALOIDS AND GLUCOSINOLATES ROLE IN PLANT’S RESISTANCE AGAINST INSECTS

ALKALOIDS AND GLUCOSINOLATES ROLE IN PLANT’S RESISTANCE AGAINST INSECTS

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  BY: MUHAMMAD KAMRAN SIAL SERIAL#16 SUBMITTED TO: DR. MUHAMMAD ANJUM AQUEEL
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  o Heterogeneous classof natural products o Their basic substances contain one or more nitrogen atoms o They interfere with key components in acetylcholine transmission in nervous system o Most common in plants o 20% of species of flowering plants, show their specific alkaloid pattern o Numerous alkaloids are toxic and deterrent to insects Pyridine
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  o Before theadvent of synthetic insecticides Nicotine and Nor- nicotine were popular as botanical insecticides o A great number of structurally unrelated alkaloids are feeding deterrent to many insects such as:
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  o A potentinhibitore of alpha- glucosidase from insects o Prensent in Derris and Lanchocarpus. o At 0.03 per cent DMDP killed seed beetle, Callosobruchus maculatus (Evans et al., 1985) o DMDP also acts as feeding deterrent in young nymphs of Locusta migratorianb at 0.001 per cent concentration DMDP Derris scandens Lonchocarpus sericeus Callosobruchus maculatus Locusta migratorianb
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  o A smallgroup of about 100 sulphur or nitrogen containing distinctive secondary compounds o Act as precursors of mustard oils o Glucosinolate appear to contribute to effective chemical defences against a majority of non-adapted phytophagous insects o Capparales,Cruciferae are good examples Cruciferae
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  o A smallminority of adapted (crucifer-feeding) insects are able to utilize glucosinolates in host seeking and host recognition behavior. o Specific cocentrations of different glucosinolates also stimulate larval feeding by adapted species. o Damage by herbivorous insects tend to decline as the concentration of glucosinolates increase. o Furthermore, the occurrence of species of adapted insects decline as total glucosinolates concentration increased. o volatile hydrolysis products, are also used as cues by parasitoids of crucifer-feeding insects.