Scheler Claudia, Weitbrecht Karin, Pearce Simon P, Hampstead Anthony, Büttner-Mainik Annette, Lee Kieran J D, Voegele Antje, Oracz Krystyna, Dekkers Bas J W, Wang Xiaofeng, Wood Andrew T A, Bentsink Leónie, King John R, Knox J Paul, Holdsworth Michael J, Müller Kerstin, Leubner-Metzger Gerhard
Botany and Plant Physiology, Institute for Biology II, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany (C.S., K.W., A.B.-M., K.O., G.L.-M.);Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt, D-85764 Neuherberg, Germany (C.S.);Staatliches Weinbauinstitut Freiburg, D-79104 Freiburg, Germany (K.W.);Centre for Plant Integrative Biology (S.P.P., A.H., A.T.A.W., J.R.K., M.J.H.) and Division of Plant and Crop Science (S.P.P., M.J.H., K.M.), School of Biosciences, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, United Kingdom;School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom (S.P.P., A.H., A.T.A.W., J.R.K.)Agroscope, Institute for Plant Production Sciences, Seed Quality, CH-8046 Zurich, Switzerland (A.B.-M.);Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom (K.J.D.L., J.P.K.);National Institute for Health Research Trainees Coordinating Centre, Leeds Innovation Centre, Leeds LS2 9DF, United Kingdom (K.J.D.L.);School of Biological Sciences, Plant Molecular Science and Centre for Systems and Synthetic Biology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom (A.V., G.L.-M.);Department of Plant Physiology, Warsaw University of Life Sciences, 02-776, Warsaw, Poland (K.O.);Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research Centre, NL-6708 PB Wageningen, The Netherlands (B.J.W.D., L.B.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (X.W.); andLaboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany, CZ-783 71 Olomouc, Czech Republic (G.L.-M.).
Botany and Plant Physiology, Institute for Biology II, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany (C.S., K.W., A.B.-M., K.O., G.L.-M.);Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt, D-85764 Neuherberg, Germany (C.S.);Staatliches Weinbauinstitut Freiburg, D-79104 Freiburg, Germany (K.W.);Centre for Plant Integrative Biology (S.P.P., A.H., A.T.A.W., J.R.K., M.J.H.) and Division of Plant and Crop Science (S.P.P., M.J.H., K.M.), School of Biosciences, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire LE12 5RD, United Kingdom;School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom (S.P.P., A.H., A.T.A.W., J.R.K.)Agroscope, Institute for Plant Production Sciences, Seed Quality, CH-8046 Zurich, Switzerland (A.B.-M.);Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom (K.J.D.L., J.P.K.);National Institute for Health Research Trainees Coordinating Centre, Leeds Innovation Centre, Leeds LS2 9DF, United Kingdom (K.J.D.L.);School of Biological Sciences, Plant Molecular Science and Centre for Systems and Synthetic Biology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom (A.V., G.L.-M.);Department of Plant Physiology, Warsaw University of Life Sciences, 02-776, Warsaw, Poland (K.O.);Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research Centre, NL-6708 PB Wageningen, The Netherlands (B.J.W.D., L.B.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (X.W.); andLaboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany, CZ-783 71 Olomouc, Czech Republic (G.L.-M.)
Plant Physiol. 2015 Jan;167(1):200-15. doi: 10.1104/pp.114.247429. Epub 2014 Nov 26.
Pectin methylesterase (PME) controls the methylesterification status of pectins and thereby determines the biophysical properties of plant cell walls, which are important for tissue growth and weakening processes. We demonstrate here that tissue-specific and spatiotemporal alterations in cell wall pectin methylesterification occur during the germination of garden cress (Lepidium sativum). These cell wall changes are associated with characteristic expression patterns of PME genes and resultant enzyme activities in the key seed compartments CAP (micropylar endosperm) and RAD (radicle plus lower hypocotyl). Transcriptome and quantitative real-time reverse transcription-polymerase chain reaction analysis as well as PME enzyme activity measurements of separated seed compartments, including CAP and RAD, revealed distinct phases during germination. These were associated with hormonal and compartment-specific regulation of PME group 1, PME group 2, and PME inhibitor transcript expression and total PME activity. The regulatory patterns indicated a role for PME activity in testa rupture (TR). Consistent with a role for cell wall pectin methylesterification in TR, treatment of seeds with PME resulted in enhanced testa permeability and promoted TR. Mathematical modeling of transcript expression changes in germinating garden cress and Arabidopsis (Arabidopsis thaliana) seeds suggested that group 2 PMEs make a major contribution to the overall PME activity rather than acting as PME inhibitors. It is concluded that regulated changes in the degree of pectin methylesterification through CAP- and RAD-specific PME and PME inhibitor expression play a crucial role during Brassicaceae seed germination.
果胶甲酯酶（PME）控制果胶的甲酯化状态，从而决定植物细胞壁的生物物理特性，而这些特性对组织生长和弱化过程至关重要。我们在此证明，在水芹（独行菜）种子萌发过程中，细胞壁果胶甲酯化会发生组织特异性和时空变化。这些细胞壁变化与PME基因的特征性表达模式以及关键种子区室CAP（珠孔端胚乳）和RAD（胚根加下胚轴）中产生的酶活性相关。对包括CAP和RAD在内的分离种子区室进行转录组和定量实时逆转录-聚合酶链反应分析以及PME酶活性测量，揭示了萌发过程中的不同阶段。这些阶段与PME第1组、PME第2组和PME抑制剂转录本表达以及总PME活性的激素和区室特异性调节有关。调控模式表明PME活性在种皮破裂（TR）中起作用。与细胞壁果胶甲酯化在TR中的作用一致，用PME处理种子可提高种皮通透性并促进TR。对萌发的水芹和拟南芥种子中转录本表达变化的数学建模表明，第2组PME对总体PME活性起主要作用，而不是作为PME抑制剂。得出的结论是，通过CAP和RAD特异性PME以及PME抑制剂表达对果胶甲酯化程度进行的调控变化在十字花科种子萌发过程中起关键作用。
