Talk abstracts
Talk on Tuesday 03:00-03:15pm submitted by Alecia Biel
Establishing the role of SINE proteins in regulating stomatal dynamics during environmental stress in Arabidopsis thaliana
Alecia Biel (Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210), Iris Meier (Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH 43210)
Abstract:
Drought is the main contributor to agricultural losses worldwide. The consequences of drought on plants are exacerbated by water loss through epidermal pore openings: stomata (1). Stomata are pairs of specialized plant cells: guard cells (GCs). In response to drought, abscisic acid (ABA) is upregulated, inducing a signaling cascade in GCs to promote stomatal closure, preventing dehydration (1,2). ABA signaling increases hydrogen peroxide (H2O2) and calcium (Ca2+) levels and induces filamentous actin (F-actin) reorganization. The mechanism of and connection between these events is unclear (3-5). SINE1, a nuclear envelope transmembrane protein, associates with F-actin and is, along with SINE2, expressed in GCs (6). Utilizing sine1-1 and sine2-1 null mutants, we show that drought increased water loss and wilting during transpiration assays while confocal imaging of ABA- or H2O2-exposed epidermal peels resulted in impaired GC closure in both mutants. However, Ca2+ was able to rescue this closure defect. SINE1 and SINE2 are involved in actin organization during ABA-induced stomatal closure: actin depolymerization partially rescued the closure defect of sine mutants; and F-actin stabilization in the presence of ABA induced closure in sine1-1, indicating misregulation of F-actin in the absence of SINE1 or SINE2. Stomatal closure is also induced by pathogens to prevent invasion, often utilizing flg22. ABA and flg22 are mediated by similar downstream effectors (1,7,8). Lack of either SINE1 or SINE2 did not affect stomatal closure in response to flg22. We demonstrate a novel role for SINE proteins: regulating stomatal dynamics during abiotic stress. Additionally, SINE1 and SINE2 may bifurcate the ABA and flg22 pathways. This research will help clarify how plants use cytoskeletal reorganization to regulate stomatal dynamics, with likely relevance for plant drought tolerance and adaptation to environmental stresses.
References:
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2. Sah SK et al. Front Plant Sci. 2016;7:571.
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9. Montillet JL et al. PLoS Biol. 2013;11:e1001513.
Keywords: Environmental stress, Abscisic acid, stomata