The Mitochondrial Protein Import Component, TRANSLOCASE OF THE INNER MEMBRANE17-1, Plays a Role in Defining the Timing of Germination in Arabidopsis

Yan Wang, Simon Law, Aneta Ivanova, Olivier Van Aken, Szymon Kubiszewski-Jakubiak, Vindya Uggalla, Marna Van Der Merwe, Owen Duncan, Reena Narsai, James Whelan, Monika Murcha

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

In Arabidopsis (Arabidopsis thaliana), small gene families encode multiple isoforms for many of the components of the mitochondrial protein import apparatus. There are three isoforms of the TRANSLOCASE OF THE INNER MEMBRANE17 (Tim17). Transcriptome analysis indicates that AtTim17-1 is only detectable in dry seed. In this study, two independent transfer DNA insertional mutant lines of tim17-1 exhibited a germination-specific phenotype, showing a significant increase in the rate of germination. Microarray analyses revealed that Attim17-1 displayed alterations in the temporal sequence of transcriptomic events during germination, peaking earlier compared with the wild type. Promoter analysis of AtTim17-1 further identified an abscisic acid (ABA)-responsive element, which binds ABA-responsive transcription factors, acting to repress the expression of AtTim17-1. Attim17-1 dry seeds contained significantly increased levels of ABA and gibberellin, 2- and 5-fold, respectively. These results support the model that mitochondrial biogenesis is regulated in a tight temporal sequence of events during germination and that altering mitochondrial biogenesis feeds back to alter the germination rate, as evidenced by the altered levels of the master regulatory hormones that define germination.
Original languageEnglish
Pages (from-to)1420-1435
Number of pages16
JournalPlant Physiology
Volume166
Issue number3
Early online date24 Sept 2014
DOIs
Publication statusPublished - Nov 2014

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