title: Rice pectin methylesterase inhibitor28 (OsPMEI28) encodes a functional PMEI and its overexpression results in a dwarf phenotype through increased pectin methylesterification levels.
abstract: Pectin methylesterases (PMEs, EC 3.1.1.11) belonging to carbohydrate esterase family 8 cleave the ester bond between a galacturonic acid and an methyl group and the resulting change in methylesterification level plays an important role during the growth and development of plants. Optimal pectin methylesterification status in each cell type is determined by the balance between PME activity and post-translational PME inhibition by PME inhibitors (PMEIs). Rice contains 49 PMEIs and none of them are functionally characterized. Genomic sequence analysis led to the identification of rice PMEI28 (OsPMEI28). Recombinant OsPMEI28 exhibited inhibitory activity against commercial PME protein with the highest activities detected at pH 8.5. Overexpression of OsPMEI28 in rice resulted in an increased level of cell wall bound methylester groups and differential changes in the composition of cell wall neutral monosaccharides and lignin content in culm tissues. Consequently, transgenic plants overexpressing OsPMEI28 exhibited dwarf phenotypes and reduced culm diameter. Our data indicate that OsPMEI28 functions as a critical structural modulator by regulating the degree of pectin methylesterification and that an impaired status of pectin methylesterification affects physiochemical properties of the cell wall components and causes abnormal cell extensibility in rice culm tissues.
authors.affiliation: Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Hong Phuong
authors.initials: HP
authors.lastname: Nguyen
authors.affiliation: Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Jeong
authors.affiliation: Seed Research Center, Gyeongnam National University of Science and Technology, Jinju-Si 52725, Republic of Korea.
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Jeon
authors.affiliation: Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Donghyuk
authors.initials: D
authors.lastname: Kim
authors.affiliation: Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Republic of Korea; Department of Plant and Environmental New Resources, Kyung Hee University, Yongin 446-701, Republic of Korea. Electronic address: chan521@khu.ac.kr.
authors.forename: Chanhui
authors.initials: C
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism*; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D009928:Organ Specificity; D012275:Oryza / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D010368:Pectins / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004791:Enzyme Inhibitors; D010940:Plant Proteins; D011994:Recombinant Proteins; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
keywords: Cell wall modifications; Pectin; Pectin methylesterase inhibitors; Pectin methylesterases; Plant cell walls; Rice