The outer wall of pollen and spores,namely the exine,is composed of sporopollenin,which is highly resistant to chemical reagents and enzymes.In this study,we demonstrated that phenylpropanoid pathway derivatives are e...The outer wall of pollen and spores,namely the exine,is composed of sporopollenin,which is highly resistant to chemical reagents and enzymes.In this study,we demonstrated that phenylpropanoid pathway derivatives are essential components of sporopollenin in seed plants.Spectral analyses showed that the autofluorescence of Lilium and Arabidopsis sporopollenin is similar to that of lignin.Thioacidolysis and NMR analyses of pollen from Lilium and Cryptomeria further revealed that the sporopollenin of seed plants contains phenylpropanoid derivatives,including p-hydroxybenzoate(p-BA),p-coumarate(p-CA),ferulate(FA),and lignin guaiacyl(G)units.The phenylpropanoid pathway is expressed in the tapetum in Arabidopsis,consistent with the fact that the sporopollenin precursor originates from the tapetum.Further germination and comet assays showed that this pathway plays an important role in protection of pollen against UV radiation.In the pteridophyte plant species Ophioglossum vulgatum and Lycopodium clavata,phenylpropanoid derivatives including p-BA and p-CA were also detected,but G units were not.Taken together,our results indicate that phenylpropanoid derivatives are essential for sporopollenin synthesis in vascular plants.In addition,sporopollenin autofluorescence spectra of bryophytes,such as Physcomitrella and Haplocladium,exhibit distinct characteristics compared with those of vascular plants,indicating the diversity of sporopollenin among land plants.展开更多
基金grants from the National Key Research and Development Program of China(2016YFD0100902)the National Natural Science Foundation of China(31900165,31870296,31700277)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB27020104)the Program from Shanghai Municipal Education Com mission[2019-01-07-00-02-E00006]the China Postdoctoral Science Foundation(2017M61159)Jiangsu Collaborative Innovation Center for Modern Crop Production(to H.D.Z.).
文摘The outer wall of pollen and spores,namely the exine,is composed of sporopollenin,which is highly resistant to chemical reagents and enzymes.In this study,we demonstrated that phenylpropanoid pathway derivatives are essential components of sporopollenin in seed plants.Spectral analyses showed that the autofluorescence of Lilium and Arabidopsis sporopollenin is similar to that of lignin.Thioacidolysis and NMR analyses of pollen from Lilium and Cryptomeria further revealed that the sporopollenin of seed plants contains phenylpropanoid derivatives,including p-hydroxybenzoate(p-BA),p-coumarate(p-CA),ferulate(FA),and lignin guaiacyl(G)units.The phenylpropanoid pathway is expressed in the tapetum in Arabidopsis,consistent with the fact that the sporopollenin precursor originates from the tapetum.Further germination and comet assays showed that this pathway plays an important role in protection of pollen against UV radiation.In the pteridophyte plant species Ophioglossum vulgatum and Lycopodium clavata,phenylpropanoid derivatives including p-BA and p-CA were also detected,but G units were not.Taken together,our results indicate that phenylpropanoid derivatives are essential for sporopollenin synthesis in vascular plants.In addition,sporopollenin autofluorescence spectra of bryophytes,such as Physcomitrella and Haplocladium,exhibit distinct characteristics compared with those of vascular plants,indicating the diversity of sporopollenin among land plants.
