Glandular trichomes produce a wide variety of secondary metabolites that are considered as major defensive chemicals against herbivore attack.The morphology and secondary metabolites of the peltate glandular trichomes...Glandular trichomes produce a wide variety of secondary metabolites that are considered as major defensive chemicals against herbivore attack.The morphology and secondary metabolites of the peltate glandular trichomes of a lianoid Labiatae,Colquhounia seguinii Vaniot,were investigated.Three new clerodane diterpenoids,seguiniilactones A-C（1-3）,were identified through precise trichome collection with laser microdissection,metabolic analysis with ultra performance liquid chromatography-tandem mass spectrometer,target compound isolation with classical phytochemical techniques,structure elucidation with spectroscopic methods.All compounds showed significant antifeedant activity against a generalist plant-feeding insect Spodoptera exigua.Seguiniilactone A（1） was approximately 17-fold more potent than the commercial neem oil.a-Substituted α,β-unsaturated γ-lactone functionality was found to be crucial for strong antifeedant activity of this class of compounds.Quantitative results indicated that the levels of these compounds in the peltate glandular trichomes and leaves were sufficiently high to deter the feeding by generalist insects.Moderate antifungal activity was observed for seguiniilactone C（3） against six predominant fungal species isolated from the diseased leaves of C seguinii,while seguiniilactones A and B were generally inactive.These findings suggested that seguiniilactones A-C might be specialized secondary metabolites in peltate glandular trichomes for the plant defense against insect herbivores and pathogens.展开更多
基金supported financially by the NSFC-Yunnan Joint Fund(U1202263)the National Basic Research Program of China(973 Program) on Biological Control of Key Crop Pathogenic Nematodes(2013CB127505)+1 种基金the National Natural Science Foundation of China(31070320,31470395 and 31100222)the "Hundred Talents Program" of the Chinese Academy of Sciences(awarded to SH Li)
文摘Glandular trichomes produce a wide variety of secondary metabolites that are considered as major defensive chemicals against herbivore attack.The morphology and secondary metabolites of the peltate glandular trichomes of a lianoid Labiatae,Colquhounia seguinii Vaniot,were investigated.Three new clerodane diterpenoids,seguiniilactones A-C（1-3）,were identified through precise trichome collection with laser microdissection,metabolic analysis with ultra performance liquid chromatography-tandem mass spectrometer,target compound isolation with classical phytochemical techniques,structure elucidation with spectroscopic methods.All compounds showed significant antifeedant activity against a generalist plant-feeding insect Spodoptera exigua.Seguiniilactone A（1） was approximately 17-fold more potent than the commercial neem oil.a-Substituted α,β-unsaturated γ-lactone functionality was found to be crucial for strong antifeedant activity of this class of compounds.Quantitative results indicated that the levels of these compounds in the peltate glandular trichomes and leaves were sufficiently high to deter the feeding by generalist insects.Moderate antifungal activity was observed for seguiniilactone C（3） against six predominant fungal species isolated from the diseased leaves of C seguinii,while seguiniilactones A and B were generally inactive.These findings suggested that seguiniilactones A-C might be specialized secondary metabolites in peltate glandular trichomes for the plant defense against insect herbivores and pathogens.
