The mitochondrial pentatricopeptide repeat protein PPR19 is involved in the stabilization of NADH dehydrogenase 1 transcripts and is crucial for mitochondrial function and Arabidopsis thaliana development.
Despite the importance of pentatricopeptide repeat (PPR) proteins in organellar RNA metabolism and plant development, the functions of many PPR proteins remain unknown. Here, we determined the role of a mitochondrial PPR protein (At1g52620) comprising 19 PPR motifs, thus named PPR19, in Arabidopsis thaliana. The ppr19 mutant displayed abnormal seed development, reduced seed yield, delayed seed germination, and retarded growth, indicating that PPR19 is indispensable for normal growth and development of Arabidopsis thaliana. Splicing pattern analysis of mitochondrial genes revealed that PPR19 specifically binds to the specific sequence in the 3'-terminus of the NADH dehydrogenase 1 (nad1) transcript and stabilizes transcripts containing the second and third exons of nad1. Loss of these transcripts in ppr19 leads to multiple secondary effects on accumulation and splicing of other nad1 transcripts, from which we can infer the order in which cis- and trans-spliced nad1 transcripts are normally processed. Improper splicing of nad1 transcripts leads to the absence of mitochondrial complex I and alteration of the nuclear transcriptome, notably influencing the alternative splicing of a variety of nuclear genes. Our results indicate that the mitochondrial PPR19 is an essential component in the splicing of nad1 transcripts, which is crucial for mitochondrial function and plant development.
Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 61186, Korea.
Kwanuk
K
Lee
Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 61186, Korea.
Ji Hoon
JH
Han
Department of Biological Sciences, Chungnam National University, Daejeon, 306-764, Korea.
Youn-Il
YI
Park
ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Catherine
C
Colas des Francs-Small
ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Ian
I
Small
Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 61186, Korea.
Hunseung
H
Kang
D017398:Alternative Splicing; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D042967:Electron Transport Complex I / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
D029681:Arabidopsis Proteins; C000623408:PDM2 protein, Arabidopsis; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D042967:Electron Transport Complex I

Arabidopsis thaliana
; development; intron splicing; mitochondria; pentatricopeptide; pentatricopeptide repeat (PPR)