A Glycine Soja 14-3-3 Protein GsGF14o Participates in Stomatal and Root Hair Development and Drought Tolerance in Arabidopsis thaliana

Abstract

It is well established that 14-3-3 proteins are key regulators of multiple stress signal transduction cascades. However, the biological functions of soybean 14-3-3 proteins, especially in plant drought response, are not yet known. In this study, we characterized a Glycine soja 14-3-3 gene, GsGF14o, which is involved in plant development and drought response. GsGF14o expression was greatly induced by drought stress, as evidenced by the quantitative real-time PCR and β-glucuronidase (GUS) activity analysis. GsGF14o overexpression in Arabidopsis thaliana resulted in decreased drought tolerance during seed germination and seedling growth. Furthermore, silencing of AtGF14µ, the most homologous 14-3-3 gene of GsGF14o, led to enhanced drought tolerance at both the seed germination and seedling stage. Unexpectedly, GsGF14o transgenic lines showed reduced water loss and transpiration rates compared with wild-type plants, which was demonstrated to be the consequence of the decreased stomatal size. At the same time, the smaller stomata due to GsGF14o overexpression led to a relatively slow net photosynthesis rate, which led to a growth penalty under drought stress. We further demonstrated that GsGF14o overexpression caused deficits in root hair formation and development, and thereby reduced the water intake capacity of the transgenic root system. In addition, GsGF14o overexpression down-regulated the transcript levels of drought-responsive marker genes. Finally, we also investigated the tissue-specific accumulation of GsGF14o by using a GUS activity assay. Collectively, the results presented here confirm that GsGF14o plays a dual role in drought stress responses through its involvement in the regulation of stomatal size and root hair development.

Drought-Responsive Mechanisms in Plant Leaves Revealed by Proteomics

“…It has been reported that drought stress can directly alter the abundance of 14-3-3 proteins [94,95,96]. In addition, overexpression or silencing of the 14-3-3 protein genes can modulate drought tolerance of transgenic plants (e.g., Gossypium hirsutum and Arabidopsis ) [97,98]. These results imply that 14-3-3 proteins may have diverse regulatory roles in leaves under drought stress, and the involvement of each 14-3-3 protein in drought-response needs to be further elucidated.…”

Auxin and Cellular Elongation

“…1C, module 3). In agreement, overexpressors of GsGF14o (a Glycine soja 14-3-3 protein) induce shorter root hairs in Arabidopsis (Sun et al, 2014), but it was not elucidated whether this affects AHA activity. Other proteins also modify AHA protein activity by phosphorylation (e.g.…”

A Member of the 14-3-3 Gene Family in Brachypodium distachyon, BdGF14d, Confers Salt Tolerance in Transgenic Tobacco Plants

“…However, since reversible phosphorylation of a protein alone is insufficient to complete the interaction directly, 14-3-3s, as crucial adaptor proteins are of great importance in plants because they bind phosphorylated peptides in the regulation of a diversity of processes (Denison et al, 2011), notably primary metabolism (Comparot et al, 2003; Diaz et al, 2011) and light (Sullivan et al, 2009; Taoka et al, 2011) and hormone signaling pathways (Ishida et al, 2004; Schoonheim et al, 2007; Gokirmak et al, 2010; Wang H. et al, 2011). In recent years, an increasing number of studies have shown that 14-3-3s also play important roles in how plants respond to a variety of biotic (Li et al, 2014; Teper et al, 2014) and abiotic (Chen et al, 2006; Sun et al, 2014; Zhou et al, 2014; He et al, 2015) stresses via the binding of the phosphorylated target proteins (Obsil and Obsilova, 2011). …”