title: Elevation of Pollen Mitochondrial DNA Copy Number by WHIRLY2: Altered Respiration and Pollen Tube Growth in Arabidopsis.
abstract: In plants, the copy number of the mitochondrial DNA (mtDNA) can be much lower than the number of mitochondria. The biological significance and regulatory mechanisms of this phenomenon remain poorly understood. Here, using the pollen vegetative cell, we examined the role of the Arabidopsis (Arabidopsis thaliana) mtDNA-binding protein WHIRLY2 (AtWHY2). AtWHY2 decreases during pollen development, in parallel with the rapid degradation of mtDNA; to examine the importance of this decrease, we used the pollen vegetative cell-specific promoter Lat52 to express AtWHY2. The transgenic plants (LWHY2) had very high mtDNA levels in pollen, more than 10 times more than in the wild type (ecotype Columbia-0). LWHY2 plants were fertile, morphologically normal, and set seeds; however, reciprocal crosses with heterozygous plants showed reduced transmission of LWHY2-1 through the male and slower growth of LWHY2-1 pollen tubes. We found that LWHY2-1 pollen had significantly more reactive oxygen species and less ATP compared with the wild type, indicating an effect on mitochondrial respiration. These findings reveal that AtWHY2 affects mtDNA copy number in pollen and suggest that low mtDNA copy numbers might be the normal means by which plant cells maintain mitochondrial genetic information.
authors.affiliation: Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.).
authors.forename: Qiang
authors.identifier: http://orcid.org/0000-0001-5871-2519
authors.initials: Q
authors.lastname: Cai
authors.affiliation: Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.).
authors.forename: Liang
authors.identifier: http://orcid.org/0000-0002-1954-1179
authors.initials: L
authors.lastname: Guo
authors.affiliation: Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.).
authors.forename: Zhao-Rui
authors.initials: ZR
authors.lastname: Shen
authors.affiliation: Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.).
authors.forename: Dan-Yang
authors.identifier: http://orcid.org/0000-0001-8735-0422
authors.initials: DY
authors.lastname: Wang
authors.affiliation: Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.) zhang.q@water.pku.edu.cn sodmergn@pku.edu.cn.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.) zhang.q@water.pku.edu.cn sodmergn@pku.edu.cn.
authors.lastname: Sodmergen
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D019069:Cell Respiration; D020090:Chromosome Segregation; D003433:Crosses, Genetic; D004272:DNA, Mitochondrial / Q000235:genetics*; D018744:DNA, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D018628:Gene Dosage; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D030821:Plants, Genetically Modified; D053205:Pollen Tube / Q000166:cytology* / Q000254:growth & development*; D011485:Protein Binding; D021381:Protein Transport; D017382:Reactive Oxygen Species / Q000378:metabolism; D012639:Seeds / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D004272:DNA, Mitochondrial; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D017382:Reactive Oxygen Species; C503334:Whirly2 protein, Arabidopsis