This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: sporopollenin monomer biosynthesis
|Superclasses:||Biosynthesis → Cell Structures Biosynthesis → Plant Cell Structures|
Some taxa known to possess this pathway include : Arabidopsis thaliana col
Expected Taxonomic Range: Embryophyta
Sporopollenin is a complex polymer that constitutes the outer (exine) layer of spores and pollen wall. The sporopollenin polymer confers on the exine physical strength, chemical inertness and elasticity. The chemical composition of sporopollenin remains poorly characterized due to its extreme resistance to chemical and biological degradations. However limited data indicates the presence of aliphatic polyhydroxy compounds and phenolic hydroxyl groups [Ahlers]. Several genes and their encoded enzymes involved in sporopollenin biosynthesis have been identified in the recent years [Grienenberger10, Dobritsa09, Kim10f, Morant07, deAzevedo09]. The genetic and biochemical data further suggest that sporopollenin components include hydroxylated fatty acids and their derived tetraketide α-pyrones. The sporopollenin components are presumably coupled with ester and ether linkages. Nonetheless, the exact chemical nature of the sporopollenin polymer and its components still remains to be elucidated. For example, although in vitro enzyme characterization supports the presence of tetraketide α-pyrones but their occurrence in Arabidopsis has not been reported.
CYP704B1, CYP703A2, ACOS5, PKSA, PKSB, TKPR1 and TKPR2 are tightly co-expressed.
deAzevedo09: de Azevedo Souza C, Kim SS, Koch S, Kienow L, Schneider K, McKim SM, Haughn GW, Kombrink E, Douglas CJ (2009). "A novel fatty Acyl-CoA Synthetase is required for pollen development and sporopollenin biosynthesis in Arabidopsis." Plant Cell 21(2);507-25. PMID: 19218397
Dobritsa09: Dobritsa AA, Shrestha J, Morant M, Pinot F, Matsuno M, Swanson R, Moller BL, Preuss D (2009). "CYP704B1 is a long-chain fatty acid omega-hydroxylase essential for sporopollenin synthesis in pollen of Arabidopsis." Plant Physiol 151(2);574-89. PMID: 19700560
Grienenberger10: Grienenberger E, Kim SS, Lallemand B, Geoffroy P, Heintz D, Souza Cde A, Heitz T, Douglas CJ, Legrand M (2010). "Analysis of TETRAKETIDE α-PYRONE REDUCTASE function in Arabidopsis thaliana reveals a previously unknown, but conserved, biochemical pathway in sporopollenin monomer biosynthesis." Plant Cell 22(12);4067-83. PMID: 21193572
Kim10f: Kim SS, Grienenberger E, Lallemand B, Colpitts CC, Kim SY, Souza Cde A, Geoffroy P, Heintz D, Krahn D, Kaiser M, Kombrink E, Heitz T, Suh DY, Legrand M, Douglas CJ (2010). "LAP6/POLYKETIDE SYNTHASE A and LAP5/POLYKETIDE SYNTHASE B encode hydroxyalkyl α-pyrone synthases required for pollen development and sporopollenin biosynthesis in Arabidopsis thaliana." Plant Cell 22(12);4045-66. PMID: 21193570
Morant07: Morant M, Jorgensen K, Schaller H, Pinot F, Moller BL, Werck-Reichhart D, Bak S (2007). "CYP703 is an ancient cytochrome P450 in land plants catalyzing in-chain hydroxylation of lauric acid to provide building blocks for sporopollenin synthesis in pollen." Plant Cell 19(5);1473-87. PMID: 17496121
Huang14a: Huang FC, Peter A, Schwab W (2014). "Expression and characterization of CYP52 genes involved in the biosynthesis of sophorolipid and alkane metabolism from Starmerella bombicola." Appl Environ Microbiol 80(2);766-76. PMID: 24242247
Rubio06: Rubio S, Larson TR, Gonzalez-Guzman M, Alejandro S, Graham IA, Serrano R, Rodriguez PL (2006). "An Arabidopsis mutant impaired in coenzyme A biosynthesis is sugar dependent for seedling establishment." Plant Physiol 140(3);830-43. PMID: 16415216
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