biostudies-literatureYang BNatural Sciences and Engineering Research Council of CanadaChina Scholarship CouncilDeutsche ForschungsgemeinschaftDFGMinistry of Innovation, Science and Research of North-Rhine Westphalia881-895https://www.ebi.ac.uk/biostudies/studies/S-EPMC6585848biostudies-literatureUnknown221(2)The differentiation of the seed coat epidermal (SCE) cells in Arabidopsis thaliana leads to the production of a large amount of pectin-rich mucilage and a thick cellulosic secondary cell wall. The mechanisms by which cortical microtubules are involved in the formation of these pectinaceous and cellulosic cell walls are still largely unknown. Using a reverse genetic approach, we found that TONNEAU1 (TON1) recruiting motif 4 (TRM4) is implicated in cortical microtubule organization in SCE cells, and functions as a novel player in the establishment of mucilage structure. TRM4 is preferentially accumulated in the SCE cells at the stage of mucilage biosynthesis. The loss of TRM4 results in compact seed mucilage capsules, aberrant mucilage cellulosic structure, short cellulosic rays and disorganThe New phytologistTRM4 is essential for cellulose deposition in Arabidopsis seed mucilage by maintaining cortical microtubule organization and interacting with CESA3.PMC6585848PGS-D3CASOM US98/13-1CASOM US98/13‐1201206350178PGS‐D3201206760005313/323-400-00213Klose HVoiniciuc CYang BFu LDieluweit SUsadel BfalseTRM4 is essential for cellulose deposition in Arabidopsis seed mucilage by maintaining cortical microtubule organization and interacting with CESA3.The differentiation of the seed coat epidermal (SCE) cells in Arabidopsis thaliana leads to the production of a large amount of pectin-rich mucilage and a thick cellulosic secondary cell wall. The mechanisms by which cortical microtubules are involved in the formation of these pectinaceous and cellulosic cell walls are still largely unknown. Using a reverse genetic approach, we found that TONNEAU1 (TON1) recruiting motif 4 (TRM4) is implicated in cortical microtubule organization in SCE cells, and functions as a novel player in the establishment of mucilage structure. TRM4 is preferentially accumulated in the SCE cells at the stage of mucilage biosynthesis. The loss of TRM4 results in compact seed mucilage capsules, aberrant mucilage cellulosic structure, short cellulosic rays and disorgan2019-01-01T00:00:00Z2019 Jan2026-05-06T20:57:20.059Z2019-07-24T07:24:14ZS-EPMC65858483027757810.1111/nph.15442