Evolutionary origin of O‐acetyltransferases responsible for glucomannan acetylation in land plants

Abstract

Summary Mannans are an abundant cell wall polysaccharide in bryophytes, seedless vascular plants and gymnosperms. A previous study has shown that mannan acetylation in Arabidopsis and konjac is mediated by mannan O‐acetyltransferases belonging to the Domain of Unknown Function (DUF) 231 family. However, little is known about the acetylation patterns of mannans in bryophytes and seedless vascular plants, and the evolutionary origin of mannan O‐acetyltransferases in land plants has not yet been studied. Phylogenetic analysis of the DUF231 family revealed that DUF231 members were present in the charophycean green algae and evolved to form overlapped and divergent phylogenetic groups in different taxa of land plants. Acetyltransferase activity assays of recombinant proteins demonstrated that a number of group II DUF231 members from moss, Selaginella, pine, spruce, rice and poplar were mannan 2‐O‐ and 3‐O‐acetyltransferases, whereas the two group I DUF231 members from the alga Klebsormidium nitens were not. Structural analysis of mannans from moss and Selaginella showed they were composed of mannosyl and glucosyl residues and the mannosyl residues were acetylated at O‐2 and O‐3. These findings indicate that although the DUF231 genes originated in algae, their recruitment as mannan O‐acetyltransferases probably occurred in bryophytes, and the biochemical functions of these O‐acetyltransferases are evolutionarily conserved throughout land plants.

Balanced Xylan Acetylation is the Key Regulator of Plant Growth and Development, and Cell Wall Structure and for Industrial Utilization

“…More than 1100 members of the GDSL family are reported so far from twelve different fully sequenced plant genomes [ 76 ]. The specific role of GDSL lipases/esterases in xylan deacetylation was reported by [ 63 , 77 ]. A study of the rice ( Oryza sativa ) brittle leaf sheath1 ( bs1 ) mutant revealed that it has a defect in Golgi localization of the GDSL esterase and thus confirms the role of GDSL esterase in xylan acetylation.…”

“…The degree of xylan acetylation is regulated by a Golgi-localized BS1 (BRITTLE LEAF SHEATH1) protein as the BS1 mutant lacks specific xylan acetylation patterns [ 62 ]. The search for BS1 orthologues in plants is on its way to understand occurrence and mechanisms of xylan deacetylation in the Golgi [ 63 ].…”

“…A study of the rice ( Oryza sativa ) brittle leaf sheath1 ( bs1 ) mutant revealed that it has a defect in Golgi localization of the GDSL esterase and thus confirms the role of GDSL esterase in xylan acetylation. They also concluded that proper functioning of the BS1 gene is necessary for proper xylan acetylation and secondary wall formation and patterning [ 63 , 78 ]. A rice brittle leaf sheath1 mutant defective in GDSL esterase was found to have the ability to deacetylate xylan backbone.…”

Modular biosynthesis of plant hemicellulose and its impact on yeast cells

“…Of these polymers, HMs have the simplest structures since they can be found as linear β-1,4-linked mannans (defined as containing > 90% mannose, Man), or as glucomannans that also contain β-1,4-linked glucose (Glc) units [ 8 ]. (Gluco)mannans can be decorated with galactose side chains [ 9 , 10 ] or O -acetylated [ 11 , 12 ], which increases their solubility [ 13 ]. HM is abundant in the endosperms of most legume seeds [ 14 ], and to a lesser extent in cereal grains [ 15 ], which confer important physiological properties, such as stabilizing the extracellular matrix.…”

Modular biosynthesis of plant hemicellulose and its impact on yeast cells

“…Of these polymers, HMs have the simplest structures since they can be found as linear β-1,4-linked mannans (defined as containing >90% mannose, Man), or as glucomannans that also contain β-1,4-linked glucose (Glc) units [8]. (Gluco)mannans can be decorated with galactose side chains [9,10] or O -acetylated [11,12], which increases their solubility [13]. HM is abundant in the endosperms of most legume seeds [14], and to a lesser extent in cereal grains [15], which confer important physiological properties, such as stabilizing the extracellular matrix.…”