title: EMPTY PERICARP16 is required for mitochondrial nad2 intron 4 cis-splicing, complex I assembly and seed development in maize.
abstract: In higher plants, chloroplast and mitochondrial transcripts contain a number of group II introns that need to be precisely spliced before translation into functional proteins. However, the mechanism of splicing and the factors involved in this process are not well understood. By analysing a seed mutant in maize, we report here the identification of Empty pericarp16 (Emp16) that is required for splicing of nad2 intron 4 in mitochondria. Disruption of Emp16 function causes developmental arrest in the embryo and endosperm, giving rise to an empty pericarp phenotype in maize. Differentiation of the basal endosperm transfer layer cells is severely affected. Molecular cloning indicates that Emp16 encodes a P-type pentatricopeptide repeat (PPR) protein with 11 PPR motifs and is localized in the mitochondrion. Transcript analysis revealed that mitochondrial nad2 intron 4 splicing is abolished in the emp16 mutants, leading to severely reduced assembly and activity of complex I. In response, the mutant dramatically increases the accumulation of mitochondrial complex III and the expression of alternative oxidase AOX2. These results imply that EMP16 is specifically required for mitochondrial nad2 intron 4 cis-splicing and is essential for complex I assembly and embryogenesis and development endosperm in maize.
authors.affiliation: State Key Lab of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, NT, Hong Kong, China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Xiu
authors.affiliation: Key Lab of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, 250100, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Sun
authors.affiliation: State Key Lab of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, NT, Hong Kong, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Key Lab of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, 250100, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Lab of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, 250100, China.
authors.forename: Ruicheng
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Institut de Biologie Moléculaire des Plantes CNRS, Associé à l'Université de Strasbourg, 12 Rue du Général Zimmer, 67084, Strasbourg, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Bonnard
authors.affiliation: State Key Lab of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, NT, Hong Kong, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Lab of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan, 250100, China.
authors.forename: Bao-Cai
authors.initials: BC
authors.lastname: Tan
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D042967:Electron Transport Complex I / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D056625:Endosperm / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D007438:Introns / Q000235:genetics; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing; D016415:Sequence Alignment; D003313:Zea mays / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D000099188:Alternative Oxidase
chemical_list: D042967:Electron Transport Complex I; D014450:Electron Transport Complex III; D024101:Mitochondrial Proteins; D009245:NADH Dehydrogenase; D010088:Oxidoreductases; D010940:Plant Proteins; D000099188:Alternative Oxidase
keywords: Emp16; Zea mays; mitochondrion; pentatricopeptide repeat protein; seed development