Outlining the roles of glycosyltransferase-related modules in cell wall synthesis

Hee Sung Kang1, Edwin R. Lampugnani1, Alex Tong1, Pawel Gluza1, Eduardo Flores-Sandoval2, John L. Bowman2, Staffan Persson1.

(1,5)-α-Arabinans are a type of pectic polysaccharide that play an important role in maintaining cell wall elasticity in plants. Past studies have shown that arabinan is synthesised in the Golgi-apparatus by Arabinosyl transferases (AraTs) from Carbohydrate-Active Enzyme (CAZy) family 47, clade B. Two homologs of Marchantia polymorpha related to previously identified Arabidopsis thaliana ARABINAN DEFICIENT1 (AtARAD1) and Nicotiana alata (NaARAD-LIKE1) genes that encode AraTs have been identified by comparing sequence similarity. M. polymorpha is a member of phylum Bryophyta, an ancient lineage of plants that diverged around 450 mya. It has a haploid dominant lifecycle, a highly conserved genome and is easy to manipulate genetically, making it an excellent organism to study gene function. Strikingly, M. polymorpha has very high levels of arabinan (up to 15%) suggesting that this polysaccharide plays a critical role in Marchantia plant growth. Here I describe the spatial and subcellular localisation patterns of MpARADL1 and MpARADL2 using C-terminally fused fluorescent proteins and GUS reporter constructs. Further, the effect of disrupting AraT activity is explored by examining CRISPR knock out mutant plants as is the effect of overexpressing these genes in planta. Finally, potential members of the arabinan biosynthetic pathway are examined using split-ubiquitin assays.

Presenting Author:  Hee Sung Kang

Author Affiliation: 

1. School of BioSciences, The University of Melbourne, Australia

2. School of Biological Sciences, Monash University, Australia