Mutation of an arabidopsis golgi membrane protein ELMO1 reduces cell adhesion

Abstract

Plant growth, morphogenesis and development involve cellular adhesion, a process dependent on the composition and structure of the extracellular matrix or cell wall. Pectin in the cell wall is thought to play an essential role in adhesion, and its modification and cleavage are suggested to be highly regulated so as to change adhesive properties. To increase our understanding of plant cell adhesion, a population of ethyl methanesulfonate-mutagenized Arabidopsis were screened for hypocotyl adhesion defects using the pectin binding dye Ruthenium Red that penetrates defective but not wild-type (WT) hypocotyl cell walls. Genomic sequencing was used to identify a mutant allele of ELMO1 which encodes a 20 kDa Golgi membrane protein that has no predicted enzymatic domains. ELMO1 colocalizes with several Golgi markers and elmo1−/− plants can be rescued by an ELMO1-GFP fusion. elmo1−/− exhibits reduced mannose content relative to WT but no other cell wall changes and can be rescued to WT phenotype by mutants in ESMERALDA1, which also suppresses other adhesion mutants. elmo1 describes a previously unidentified role for the ELMO1 protein in plant cell adhesion.

Polygalacturonase activity promotes aberrant cell separation in the quasimodo2 mutant of Arabidopsis thaliana

“…In Arabidopsis , several genes implicated in the synthesis and modification of HG are required for normal cell adhesion. These include the glycosyltransferase QUA1 , the putative O-fucosyltransferase FRIABLE1 ( Neumetzler et al, 2012 ), a newly identified Golgi membrane protein, ELMO1 ( Kohorn et al, 2021b ), and the focus of this work, QUASIMODO2 ( QUA2 ). Mutations in all of these genes have different effects on pectin synthesis or modification and can be rescued by the mutation of a putative O-fucosyltransferase gene, ESMERALDA1 ( Kohorn et al, 2021b , Verger et al, 2016 ).…”