Phenylpropanoid Derivatives Are Essential Components of Sporopollenin in Vascular Plants

• 作者: Jing-Shi Xue Baocai Zhang HuaDong Zhan Yong-Lin Lv Xin-Lei Jia TianHua Wang Nai-Ying Yang Yu-Xia Lou Zai-Bao Zhang Wen-Jing Hu Jinshan Gui Jianguo Cao Ping Xu Yihua Zhou Jin-Feng Hu Laigeng Li Zhong-Nan Yang
• 来源期刊: 分子植物（英文版）
• 年，卷（期）: 2020,（11）
• 所属期刊栏目: Research Reports
• 页码范围: 1644-1653
• 页数: 10页
• 语种: 英文

摘要

The outerwallof pollen and spores,namely the exine,is composed of sporopollenin,which is highly resistantto chemicalreagents and enzymes.In this study,we demonstrated that phenylpropanoid pathway derivatives are essentialcomponents 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 phenylpropa-noid derivatives are essential for sporopollenin synthesis in vascular plants.In addition,sporopollenin auto-fluorescence 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.