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Identification of tannic cell walls at the outer surface of the endosperm upon Arabidopsis seed coat rupture
Author(s) -
Demonsais Lara,
UtzPugin Anne,
Loubéry Sylvain,
LopezMolina Luis
Publication year - 2020
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.14994
Subject(s) - endosperm , coat , integument , cuticle (hair) , tannic acid , arabidopsis , cell wall , biology , botany , epidermis (zoology) , viral tegument , plant cuticle , trichome , mutant , microbiology and biotechnology , anatomy , biochemistry , gene , paleontology , virology , wax
SUMMARY The seed coat is specialized dead tissue protecting the plant embryo from mechanical and oxidative damage. Tannins, a type of flavonoids, are antioxidants known to accumulate in the Arabidopsis seed coat and transparent testa mutant seeds, deficient in flavonoid synthesis, exhibit low viability. However, their precise contribution to seed coat architecture and biophysics remains evasive. A seed coat cuticle, covering the endosperm outer surface and arising from the seed coat inner integument 1 cell layer was, intriguingly, previously shown to be more permeable in transparent testa mutants deficient not in cuticular component synthesis, but rather in flavonoid synthesis. Investigating the role of flavonoids in cuticle permeability led us to identify periclinal inner integument 1 tannic cell walls being attached, together with the cuticle, to the endosperm surface upon seed coat rupture. Hence, inner integument 1 tannic cell walls and the cuticle form two fused layers present at the surface of the exposed endosperm upon seed coat rupture, regulating its permeability. Their potential physiological role during seed germination is discussed.