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Disruption of glycosylphosphatidylinositol‐anchored lipid transfer protein 15 affects seed coat permeability in Arabidopsis
Author(s) -
Lee Saet B.,
Suh MiChung
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14101
Subject(s) - suberin , endodermis , apoplast , arabidopsis , biochemistry , endoplasmic reticulum , chemistry , cell wall , biophysics , microbiology and biotechnology , biology , mutant , gene
Summary The hydrophobic biopolymer suberin, which is deposited in the root endodermis and seed coats, functions as an extracellular barrier against uncontrolled water, gas, and ion loss. Suberin monomers synthesized in the endoplasmic reticulum ( ER) are exported through the plasma membrane to the apoplast. However, limited information is available about the molecular mechanisms underlying suberin monomer export and assembly. In this study, we investigated the in planta role of LTPG 15 encoding a glycosylphosphatidylinositol (GPI)‐anchored lipid transfer protein. LTPG 15 was predominantly expressed in the root endodermis and seed coat. Fluorescent signals from LTPG 15: eYFP were detected in the plasma membrane in tobacco epidermis. Disruption of LTPG 15 caused a significant decrease in the levels of fatty acids (C20–C24), primary alcohols (C20 and C22), ω‐hydroxy fatty acids (C22 and C24), and α,ω‐alkanediols (C20 and C22), but an increase in the amounts of primary alcohols and hydroxy fatty acids with C16 and C18 in seed coats. The mutant phenotype was restored to that of the wild type ( WT ) by the expression of LTPG 15 driven by its own promoter. Seed coats of ltpg15 had an increase in permeability to tetrazolium salts compared with WT seed coats. ltpg15 seeds were more sensitive than WT seeds to inhibition of germination and seedling establishment by salt and osmotic stress treatments. Taken together, our results indicate that LTPG 15 is involved in suberin monomer export in seed coats, and this highlights the role of Type G non‐specific lipid transfer proteins ( LTPG s) in very‐long‐chain fatty acids and their derivatives’ export for suberin polyester formation.