期刊
PLANT PHYSIOLOGY AND BIOCHEMISTRY
卷 196, 期 -, 页码 712-723出版社
ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER
DOI: 10.1016/j.plaphy.2023.01.064
关键词
Ascorbate; Embryos; Gulono-1; 4?-lactone oxidase; Iron; Seeds; Suberin; Vitamin C
Plants synthesize ascorbate (ASC) via the D-mannose/L-galactose pathway, while animals produce ASC and H2O2 via the UDP-glucose pathway. A study investigated the role of GULLO2, an isoform of Gulono-1,4 gamma-lactone oxidases, in iron (Fe) nutrition in Arabidopsis thaliana. The findings suggest that GULLO2 is involved in ASC synthesis and Fe(III) reduction, which are crucial for Fe transport and suberin biosynthesis in developing seeds.
Plants synthesize ascorbate (ASC) via the D-mannose/L-galactose pathway whereas animals produce ASC and H2O2 via the UDP-glucose pathway, with Gulono-1,4 gamma-lactone oxidases (GULLO) as the last step. A. thaliana has seven isoforms, GULLO1-7; previous in silico analysis suggested that GULLO2, mostly expressed in developing seeds, might be involved in iron (Fe) nutrition. We isolated atgullo2-1 and atgullo2-2 mutants, quantified ASC and H2O2 in developing siliques, Fe(III) reduction in immature embryos and seed coats. Surfaces of mature seed coats were analysed via atomic force and electron microscopies; suberin monomer and elemental compositions of mature seeds, including Fe, were profiled via chromatography and inductively coupled plasma-mass spectrometry. Lower levels of ASC and H2O2 in atgullo2 immature siliques are accompanied by an impaired Fe(III) reduction in seed coats and lower Fe content in embryos and seeds; atgullo2 seeds displayed reduced permeability and higher levels of C18:2 and C18:3 omega-hydroxyacids, the two predominant suberin monomers in A. thaliana seeds. We propose that GULLO2 contributes to ASC synthesis, for Fe(III) reduction into Fe(II). This step is critical for Fe transport from endosperm into developing embryos. We also show that alterations in GULLO2 activity affect suberin biosynthesis and accumulation in the seed coat.
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