title: Higher endogenous methionine in transgenic Arabidopsis seeds affects the composition of storage proteins and lipids.
abstract: Previous in vitro studies demonstrate that exogenous application of the sulfur-containing amino acid methionine into cultured soybean cotyledons and seedlings reduces the level of methionine-poor storage proteins and elevates those that are methionine-rich. However, the effect of higher endogenous methionine in seeds on the composition of storage products in vivo is not studied yet. We have recently produced transgenic Arabidopsis seeds having significantly higher levels of methionine. In the present work we used these seeds as a model system and profiled them for changes in the abundances of 12S-globulins and 2S-albumins, the two major groups of storage proteins, using 2D-gels and MALDI-MS detection. The findings suggest that higher methionine affects from a certain threshold the accumulation of several subunits of 12S-globulins and 2S-albumins, regardless of their methionine contents, resulting in higher total protein contents. The mRNA abundances of most of the genes encoding these proteins were either correlated or not correlated with the abundances of these proteins, implying that methionine may regulate storage proteins at both transcriptional and post-transcriptional levels. The elevations in total protein contents resulted in reduction of total lipids and altered the fatty acid composition. Altogether, the data provide new insights into the regulatory roles of elevated methionine levels on seed composition.
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel.|Laboratory of Plant Science, Migal Galilee Technology Center, 12100, Kiryat Shmona, Israel.
authors.forename: Hagai
authors.initials: H
authors.lastname: Cohen
authors.affiliation: Genomics and Biotechnology, London Research and Development Centre, Agriculture and Agri-Food Canada, London, ON, Canada.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Pajak
authors.affiliation: Genomics and Biotechnology, London Research and Development Centre, Agriculture and Agri-Food Canada, London, ON, Canada.|Department of Biology, University of Western Ontario, London, ON, Canada.|Breeding and Agronomy, Brandon Research and Development Centre, Brandon, MB, Canada.
authors.forename: Sudhakar
authors.initials: S
authors.lastname: Pandurangan
authors.affiliation: Laboratory of Plant Science, Migal Galilee Technology Center, 12100, Kiryat Shmona, Israel. rachel@migal.org.il.|Tel-Hai College, 11016, Upper Galilee, Israel. rachel@migal.org.il.
authors.forename: Rachel
authors.initials: R
authors.lastname: Amir
authors.affiliation: Genomics and Biotechnology, London Research and Development Centre, Agriculture and Agri-Food Canada, London, ON, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Marsolais
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology*; D008715:Methionine / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D055314:Seed Storage Proteins / Q000096:biosynthesis / Q000235:genetics; D012639:Seeds / Q000235:genetics / Q000378:metabolism
chemical_list: D055314:Seed Storage Proteins; D008715:Methionine
keywords: 12S-globulins; 2S-albumins; Arabidopsis seeds; CYSTATHIONINE γ-SYNTHASE; Fatty acids; Methionine; Seed storage proteins