Transcription factor AtTCP14 regulates embryonic growth potential during seed germination in Arabidopsis thaliana

Abstract

SummaryTo understand the molecular mechanisms underlying regulation of seed germination, we searched enriched cis elements in the upstream regions of Arabidopsis genes whose transcript levels increased during seed germination. Using available published microarray data, we found that two cis elements, Up1 or Up2, which regulate outgrowth of Arabidopsis axillary shoots, were significantly over-represented. Classification of Up1-and Up2-containing genes by gene ontology revealed that protein synthesis-related genes, especially ribosomal protein genes, were highly over-represented. Expression analysis using a reporter gene driven by a synthetic promoter regulated by these elements showed that the Up1 is necessary and sufficient for germination-associated gene induction, whereas Up2 acts as an enhancer of Up1. Up1-mediated gene expression was suppressed by treatments that blocked germination. Up1 is almost identical to the site II motif, which is the predicted target of TCP transcription factors. Of 24 AtTCP genes, AtTCP14, which showed the highest transcript level just prior to germination, was functionally characterized to test its involvement in the regulation of seed germination. Transposon-tagged lines for AtTCP14 showed delayed germination. In addition, germination of attcp14 mutants exhibited hypersensitivity to exogenously applied abscisic acid and paclobutrazol, an inhibitor of gibberellin biosynthesis. AtTCP14 was predominantly expressed in the vascular tissues of the embryo, and affected gene expression in radicles in a non-cell-autonomous manner. Taken together, these results indicate that AtTCP14 regulates the activation of embryonic growth potential in Arabidopsis seeds.

The Arabidopsis RING Finger E3 Ligase RHA2a Is a Novel Positive Regulator of Abscisic Acid Signaling during Seed Germination and Early Seedling Development

“…From publicly available microarray data, we noticed that the expression level of RHA2a (At1g15100), a gene that encodes a C3H2C3-type RING finger protein, is relatively high in dry seeds and undergoes significant reduction after imbibition (Nakabayashi et al, 2005;Tatematsu et al, 2008). We examined the expression pattern of RHA2a following stratification as well as during the early stages of seed germination with or without ABA.…”

The Cotton Transcription Factor TCP14 Functions in Auxin-Mediated Epidermal Cell Differentiation and Elongation

“…The cellular functions of class I TCPs are less well explored, but several previous studies indicated that they are involved in a number of cellular or developmental processes. For example, Arabidopsis AtTCP14 and AtTCP16 participate in regulation of seed germination and pollen development, respectively (Takeda et al, 2006;Tatematsu et al, 2008a), and AtTCP20 and AtTCP15 are involved in the regulation of cell division, expansion, and differentiation (Hervé et al, 2009;Kieffer et al, 2011). In addition, several lines of evidence have demonstrated that the functions of class I TCP proteins are associated with phytohormone signaling, such as auxin, jasmonic acid (JA), and cytokinin (Kosugi and Ohashi, 2002;Danisman et al, 2012;Steiner et al, 2012;Uberti-Manassero et al, 2012).…”

Antagonistic Action of Strigolactone and Cytokinin in Bud Outgrowth Control

“…The TCP family of transcription factors is implicated in many different plant development and morphogenic processes (Doebley et al, 1997;Nath et al, 2003;Aguilar-Martínez et al, 2007;Schommer et al, 2008;Tatematsu et al, 2008;Pruneda-Paz et al, 2009). Several TCP family members control cell proliferation through regulation of the cell cycle, but few TCP targets have been identified (for review, see Martín-Trillo and Cubas, 2010).…”