Water stress-induced ABA accumulation plays a key role in the root to shoot communication and/or the cell to cell signaling under the soil stresses. The signaling of the water stress itself that leads to the accumulat...Water stress-induced ABA accumulation plays a key role in the root to shoot communication and/or the cell to cell signaling under the soil stresses. The signaling of the water stress itself that leads to the accumulation, however, is less known. In this study, we subjected the roots of Malus hupehensis seedlings to water stress treatment and investigated the ABA accumulation in relation to protein phos-phorylation. Our results showed that ABA accumulation could be substantially triggered in 40 min and reached 4 folds in 100 min after treatment with 30% PEG 6000 (polyethylene glycol). The water stress treatment also led to a substantial enhancement of total kinase activity, assessed with histone-111 as substrate, in 15 min and a maximum enhancement in 30 min before it declined to initial level. The Ca2+-dependent kinase activity showed a similar, if not more sensitive, trend. When the roots were fed with labeled 32P-ATP, water stress enhanced the labeling of proteins, which showed a maximum labeling at展开更多
Water stress-induced ABA accumulation is a cellular signaling process from water stress perception to activation of genes encoding key enzymes of ABA biosynthesis, of which the water stress-signal perception by cells ...Water stress-induced ABA accumulation is a cellular signaling process from water stress perception to activation of genes encoding key enzymes of ABA biosynthesis, of which the water stress-signal perception by cells or triggering mechanism of the ABA accumulation is the center in the whole process of ABA related-stress signaling in plants. The cell biological mechanism for triggering of ABA accumulation under water stress was studied in leaves of Vicia faba. Mannitol at 890 mmol· kg-1 osmotic concentration induced an increase of more than 5 times in ABA concentra-tion in detached leaf tissues, but the same concentration of mannitol only induced an increase of less than 40 % in ABA concentration in protoplasts. Like in detached leaf tissues, ABA concentra-tion in isolated cells increased more than 10 times under the treatment of mannitol at 890 mmol·kg-1 concentration, suggesting that the interaction between plasmalemma and cell wall was essential to triggering of the water stress-induced ABA accumulation. Neither Ca2+-che- lating agent EGTA nor Ca2+ channel activator A23187 nor the two cytoskeleton inhibitors, colchicine and cyto-chalasin B, had any effect on water stress-induced ABA accumulation. Interestingly water stress-induced ABA accumulation was effectively inhibited by a non-plasmalemma-perme- able sulfhy-dryl-modifier PCMBS (p-chloromercuriphenyl-sulfonic acid), suggesting that plasmalemma pro-tein(s) may be involved in the triggering of water stress-induced ABA accumulation, and the protein may contain sulfhydryl group at its function domain.展开更多
基金This work was supported by a Key Project (Grant No. 39730340) from the National Natural Science Foundation of China and the National Key Basic Research Project (Grant No. G1999011700).
文摘Water stress-induced ABA accumulation plays a key role in the root to shoot communication and/or the cell to cell signaling under the soil stresses. The signaling of the water stress itself that leads to the accumulation, however, is less known. In this study, we subjected the roots of Malus hupehensis seedlings to water stress treatment and investigated the ABA accumulation in relation to protein phos-phorylation. Our results showed that ABA accumulation could be substantially triggered in 40 min and reached 4 folds in 100 min after treatment with 30% PEG 6000 (polyethylene glycol). The water stress treatment also led to a substantial enhancement of total kinase activity, assessed with histone-111 as substrate, in 15 min and a maximum enhancement in 30 min before it declined to initial level. The Ca2+-dependent kinase activity showed a similar, if not more sensitive, trend. When the roots were fed with labeled 32P-ATP, water stress enhanced the labeling of proteins, which showed a maximum labeling at
基金the National Natural Science Foundation of China (Grant Nos. 39730340 & 30070071 and the National Key Basic Research Project (Grant No. G1999011700).
文摘Water stress-induced ABA accumulation is a cellular signaling process from water stress perception to activation of genes encoding key enzymes of ABA biosynthesis, of which the water stress-signal perception by cells or triggering mechanism of the ABA accumulation is the center in the whole process of ABA related-stress signaling in plants. The cell biological mechanism for triggering of ABA accumulation under water stress was studied in leaves of Vicia faba. Mannitol at 890 mmol· kg-1 osmotic concentration induced an increase of more than 5 times in ABA concentra-tion in detached leaf tissues, but the same concentration of mannitol only induced an increase of less than 40 % in ABA concentration in protoplasts. Like in detached leaf tissues, ABA concentra-tion in isolated cells increased more than 10 times under the treatment of mannitol at 890 mmol·kg-1 concentration, suggesting that the interaction between plasmalemma and cell wall was essential to triggering of the water stress-induced ABA accumulation. Neither Ca2+-che- lating agent EGTA nor Ca2+ channel activator A23187 nor the two cytoskeleton inhibitors, colchicine and cyto-chalasin B, had any effect on water stress-induced ABA accumulation. Interestingly water stress-induced ABA accumulation was effectively inhibited by a non-plasmalemma-perme- able sulfhy-dryl-modifier PCMBS (p-chloromercuriphenyl-sulfonic acid), suggesting that plasmalemma pro-tein(s) may be involved in the triggering of water stress-induced ABA accumulation, and the protein may contain sulfhydryl group at its function domain.
