Phenylpropanoid Derivatives Are Essential Components of Sporopollenin in Vascular Plants

The plant cell wall: Biosynthesis, construction, and functions

“…Many plant tissues that are exposed to UV, including stems, leaves, and pollen grains, often contain phenylpropanoid derivatives, but these components vary (Torabinejad et al, 1998). Several phenolic compounds were recently identified in sporopollenin, a structural layer covering pollen grains, using pyrolysis gas chromatography-mass spectrometry and liquid-state NMR (Li et al, 2019;Xue et al, 2020). These studies revealed the importance of lignin biosynthesis in plant adaptation to UV and provided important insights into plant evolution in terrestrial environments.…”

“…These regulators are in turn positively or negatively regulated via interactions with WRKY12, MYB26, XND1, VNI2, E2Fc, KNAT7, HB15, and MYC2/4, which integrate cell wall biosynthesis with other physiological processes (Wang et al, 2010; Yamaguchi et al, 2010; Taylor‐Teeples et al, 2015; Zhang et al, 2018a, 2018b; Wang et al, 2019). The interaction between rice NAC31/NAC29 and the DELLA protein Slender rice1 represents an interconnected nexus that inputs gibberellin signaling into cell wall formation (Huang et al, 2015).…”

Cross-Species Metabolic Profiling of Floral Specialized Metabolism Facilitates Understanding of Evolutional Aspects of Metabolism Among Brassicaceae Species

“…With few exceptions flowers in angiosperms are responsible for producing the next generation, therefore specialized metabolites in flowers serve the purpose of attracting pollinators, playing protective roles to against biotic or abiotic stress such as UV-irradiation or herbivory, and being an important constitution allowing the maintenance of normal fertility (Tohge et al, 2018;Borghi et al, 2019;Borghi and Fernie, 2020). Successful fertilization involves certain metabolite groups, for example, phenolic acids derivatives and flavonols function as important UV-absorbing compounds, some of which are essential to maintain pollen activity (Xue et al, 2020), phenolamides play unique role for fertility (Bassard et al, 2010), and glucosinolates are involve in plant-insect interaction (Liu et al, 2020). In this study, specialized metabolites from flowers of 20 Brassicaceae genotypes were investigated in order to study the metabolite evolutionary changes concomitant to the divergence of the different clades and the underlying different reproductive recognition systems.…”

The evolution of the phenylpropanoid pathway entailed pronounced radiations and divergences of enzyme families

“…Another prominent facet is that these metabolites act as UV-protecting substances. While some of the best-known UV screens are flavonoids, various other compounds stemming from the phenylpropanoid pathway are equally potent UV protectants (Sheahan, 1996; Booij James et al, 2000; Sytar et al 2018; Xue et al, 2020). The list of links between phenylpropanoid-derived compounds and the response to environmental challenges could be continued; in fact, the response to almost any abiotic stressor that plants face in the terrestrial habitat involves the action of phenylpropanoid-derived compounds (for comprehensive reviews see, e.g., Dixon and Paiva, 1995; Vogt, 2010).…”