Functional characterization of a glycine-rich RNA-binding protein 2 in Arabidopsis thaliana under abiotic stress conditions.
Although glycine-rich RNA-binding protein 2 (GRP2) has been implicated in plant responses to environmental stresses, the function and importance of GRP2 in stress responses are largely unknown. Here, we examined the functional roles of GRP2 in Arabidopsis thaliana under high-salinity, cold or osmotic stress. GRP2 affects seed germination of Arabidopsis plants under salt stress, but does not influence seed germination and seedling growth of Arabidopsis plants under osmotic stress. GRP2 accelerates seed germination and seedling growth in Arabidopsis plants under cold stress, and contributes to enhancement of cold and freezing tolerance in Arabidopsis plants. No differences in germination between the wild-type and transgenic plants were observed following addition of abscisic acid (ABA) or glucose, implying that GRP2 affects germination through an ABA-independent pathway. GRP2 complements the cold sensitivity of an Escherichia coli BX04 mutant and exhibits transcription anti-termination activity, suggesting that it has an RNA chaperone activity during the cold adaptation process. Mitochondrial respiration and catalase and peroxidase activities were affected by expression of mitochondrial-localized GRP2 in Arabidopsis plants under cold stress. Proteome analysis revealed that expression of several mitochondrial-encoded genes was modulated by GRP2 under cold stress. These results provide new evidence indicating that GRP2 plays important roles in seed germination, seedling growth and freezing tolerance of Arabidopsis under stress conditions, and that GRP2 exerts its function by modulating the expression and activity of various classes of genes.
Kim
Joo Y
JY
Department of Plant Biotechnology, Agricultural Plant Stress Research Center and Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonam National University, Gwangju 500-757, Korea.
Park
Su J
SJ
Jang
Boseung
B
Jung
Che-Hun
CH
Ahn
Sung J
SJ
Goh
Chang-Hyo
CH
Cho
Kyoungwon
K
Han
Oksoo
O
Kang
Hunseung
H
D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D004926:Escherichia coli / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000235:genetics / Q000502:physiology; D005998:Glycine / Q000032:analysis*; D010101:Oxygen Consumption / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development; D012965:Sodium Chloride; D014158:Transcription, Genetic; D014867:Water
D000975:Antioxidants; D029681:Arabidopsis Proteins; C521041:GRP2 protein, Arabidopsis; D016601:RNA-Binding Proteins; D014867:Water; D012965:Sodium Chloride; D005998:Glycine