Glycine‐rich RNA‐binding protein7 affects abiotic stress responses by regulating stomata opening and closing inArabidopsis thaliana

Abstract

SummaryDespite the fact that glycine-rich RNA-binding proteins (GRPs) have been implicated in the responses of plants to environmental stresses, their physiological functions and mechanisms of action in stress responses remain largely unknown. Here, we assessed the functional roles of GRP7, one of the eight GRP family members in Arabidopsis thaliana, on seed germination, seedling growth, and stress tolerance under high salinity, drought, or cold stress conditions. The transgenic Arabidopsis plants overexpressing GRP7 under the control of the cauliflower mosaic virus 35S promoter displayed retarded germination and poorer seedling growth compared with the wild-type plants and T-DNA insertional mutant lines under high salinity or dehydration stress conditions. By contrast, GRP7 overexpression conferred freezing tolerance in Arabidopsis plants. GRP7 is expressed abundantly in the guard cells, and has been shown to influence the opening and closing of the stomata, in accordance with the prevailing stress conditions. GRP7 is localized to both the nucleus and the cytoplasm, and is involved in the export of mRNAs from the nucleus to the cytoplasm under cold stress conditions. Collectively, these results provide compelling evidence that GRP7 affects the growth and stress tolerance of Arabidopsis plants under high salt and dehydration stress conditions, and also confers freezing tolerance, particularly via the regulation of stomatal opening and closing in the guard cells.

Molecular, anatomical and physiological properties of a genetically modified soybean line transformed with rd29A:AtDREB1A for the improvement of drought tolerance

“…These proteins are expressed abundantly in the guard cells and have been implicated in the control of stomata opening and closing (Kim et al, 2008). AtGR-RBP expression is induced by DREB1A (Maruyama et al, 2004).…”

Alternative Splicing at the Intersection of Biological Timing, Development, and Stress Responses

“…ABH1/CBP80 and CBP20 contribute to the regulation of AS and preferentially affect AS of the first intron, particularly at the 59 splice site (Laubinger et al, 2008;Raczynska et al, 2010). The hnRNP-like At-GRP7 (for glycine-rich RNA binding protein 7) that is upregulated by cold and oxidative stress has also been associated with ABA responses (Carpenter et al, 1994;Cao et al, 2006;Kim et al, 2008;Schöning et al, 2008;Schmidt et al, 2010;Streitner et al, 2010). GRP7 regulates a number of AS events, in particular those involving alternative 59 splice sites.…”

Lights, Rhythms, Infection: The Role of Light and the Circadian Clock in Determining the Outcome of Plant–Pathogen Interactions

“…Glycine-rich RNA binding protein 7 (GRP7) is modulated by the circadian clock and in response to various environmental stresses, including cold (Heintzen et al, 1997;Kim et al, 2008). Interestingly, this protein is highly expressed in guard cells, regulates stomatal opening and closing in response to stress (Kim et al, 2008), and was recently shown to be an ADPribosylation target for a type III Pst DC3000 effector, hopU1 (Fu et al, 2007).…”

“…Interestingly, this protein is highly expressed in guard cells, regulates stomatal opening and closing in response to stress (Kim et al, 2008), and was recently shown to be an ADPribosylation target for a type III Pst DC3000 effector, hopU1 (Fu et al, 2007). Arabidopsis plants deficient in GRP7 due to insertional mutagenesis were more susceptible to Pst DC3000 infection that wild-type plants (Fu et al, 2007).…”

“…The RNA binding on GRP7 is thought to be impaired due to hopU1 ADP-ribosylation of Arg residues in the RRM domain. GRP7 is thought to play a role in mRNA export from the nucleus under stress conditions (Kim et al, 2008), and ADP-ribosylation of GRP7 may affect the expression of plant defense transcripts (Fu et al, 2007).…”