Trehalose 6-Phosphate Is Required for the Onset of Leaf Senescence Associated with High Carbon Availability

• Published in: Plant physiology (Bethesda) Vol. 158; no. 3; pp. 1241 - 1251
• Main Authors: Wingler, Astrid, Delatte, Thierry L., O'Hara, Liam E., Primavesi, Lucia F., Jhurreea, Deveraj, Paul, Matthew J., Schluepmann, Henriette
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01-03-2012
• Subjects: Anthocyanins - genetics; Anthocyanins - metabolism; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biological and medical sciences; Carbohydrate Metabolism; Carbon - metabolism; Cellular senescence; Culture Media - metabolism; DEVELOPMENT AND HORMONE ACTION; Developmental biology; Enzyme Activation; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - metabolism; Flowers - physiology; Fundamental and applied biological sciences. Psychology; Gene expression; Genes; Glucose - metabolism; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Leaves; Nitrogen; Phenotype; Plant growth; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Leaves - physiology; Plant physiology and development; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Plants, Genetically Modified - physiology; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Senescence and abscission; Signal Transduction; Sugar Phosphates - metabolism; Sugars; Transgenic plants; Trehalose - analogs & derivatives; Trehalose - metabolism; Vegetative apparatus, growth and morphogenesis. Senescence; Phosphates; Senescence; Plant leaf; Trehalose; Plant physiology; Carbon
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.111.191908

Trehalose 6-phosphate (T6P) is an important regulator of plant metabolism and development. T6P content increases when carbon availability is high, and in young growing tissue, T6P inhibits the activity of Snf1-related protein kinase (SnRK1). Here, strong accumulation of T6P was found in senescing leaves of Arabidopsis (Arabidopsis thaliana), in parallel with a rise in sugar contents. To determine the role of T6P in senescence, T6P content was altered by expressing the bacterial T6P synthase gene, otsA (to increase T6P), or the T6P phosphatase gene, otsB (to decrease T6P). In ofsB-expressing plants, T6P accumulated less strongly during senescence than in wild-type plants, while ofsA-expressing plants contained more T6P throughout. Mature ofsB-expressing plants showed a similar phenotype as described for plants overexpressing the SnRK1 gene, KIN10, including reduced anthocyanin accumulation and delayed senescence. This was confirmed by quantitative reverse transcriptionpolymer ase chain reaction analysis of senescence-associated genes and genes involved in anthocyanin synthesis. To analyze if the senescence phenotype was due to decreased sugar sensitivity, the response to sugars was determined. In combination with low nitrogen supply, metabolizable sugars (glucose, fructose, or sucrose) induced senescence in wild-type and otsA-expressing plants but to a smaller extent in ofsB-expressing plants. The sugar analog 3-O-methyl glucose, on the other hand, did not induce senescence in any of the lines. Transfer of plants to and from glucose-containing medium suggested that glucose determines senescence during late development but that the effects of T6P on senescence are established by the sugar response of young plants.