Type 2C protein phosphatases(PP2Cs)are the largest protein phosphatase family.PP2Cs dephosphorylate substrates for signaling in Arabidopsis,but the functions of most PP2 Cs remain unknown.Here,we characterized PP2 C49...Type 2C protein phosphatases(PP2Cs)are the largest protein phosphatase family.PP2Cs dephosphorylate substrates for signaling in Arabidopsis,but the functions of most PP2 Cs remain unknown.Here,we characterized PP2 C49(AT3G62260,a Group G PP2C),which regulates Na^(+)distribution under salt stress and is localized to the cytoplasm and nucleus.PP2C49 was highly expressed in root vascular tissues and its disruption enhanced plant tolerance to salt stress.Compared with wild type,the pp2c49 mutant contained more Na^(+)in roots but less Na^(+)in shoots and xylem sap,suggesting that PP2C49 regulates shoot Na^(+)extrusion.Reciprocal grafting revealed a root-based mechanism underlying the salt tolerance of pp2 c49.Systemic Na+distribution largely depends on AtHKT1;1 and loss of function of AtHKT1;1 in the pp2c49 background overrode the salt tolerance of pp2c49,resulting in salt sensitivity.Furthermore,compared with plants overexpressing PP2C49 in the wild-type background,plants overexpressing PP2C49 in the athtk1;1 mutant background were sensitive to salt,like the athtk1;1 mutants.Moreover,protein-protein interaction and two-voltage clamping assays demonstrated that PP2C49 physically interacts with AtHKT1;1 and inhibits the Na^(+)permeability of AtHKT1;1.This study reveals that PP2C49 negatively regulates AtHKT1;1 activity and thus determines systemic Na^(+)allocation during salt stress.展开更多
A total of 222 surface soil samples and 40 plant samples were collected to investigate the spatial distribution and possible sources of soil heavy metals and to know the uptake and translocation of heavy metals from r...A total of 222 surface soil samples and 40 plant samples were collected to investigate the spatial distribution and possible sources of soil heavy metals and to know the uptake and translocation of heavy metals from roots to different plant parts in a representative vegetable production area in the Baguazhou Island, a suburb of Nanjing City, East China. The arithmetic mean values of total Cd, Cr,Cu, Ni, Pb, and Zn concentrations in the soils were 0.314, 133, 41.0, 58.0, 31.8, and 114 mg kg-1, respectively. All of these values were above the topsoil background values in the Nanjing area. Multivariate and geostatistical analyses showed that soil Cd contamination was derived mainly from agricultural practices. In contrast, Cu and Zn were derived mainly from soil parent materials and Pb from atmospheric deposition from highway gasoline stations. Artemisia selengensis, a locally important specialty vegetable, accumulated heavy metals primarily in the edible leaves. The general distribution of heavy metal concentrations in this plant species showed that the highest occurred in the leaves, intermediate in the stems and lowest in the roots. Cd had the highest concentration factor(root-to-soil ratio) and may pose increased health risks in the future to the local population through the consumption of contaminated vegetables.展开更多
基金supported by the Doctoral Fund of Ministry of Education of China(20130091110038)。
文摘Type 2C protein phosphatases(PP2Cs)are the largest protein phosphatase family.PP2Cs dephosphorylate substrates for signaling in Arabidopsis,but the functions of most PP2 Cs remain unknown.Here,we characterized PP2 C49(AT3G62260,a Group G PP2C),which regulates Na^(+)distribution under salt stress and is localized to the cytoplasm and nucleus.PP2C49 was highly expressed in root vascular tissues and its disruption enhanced plant tolerance to salt stress.Compared with wild type,the pp2c49 mutant contained more Na^(+)in roots but less Na^(+)in shoots and xylem sap,suggesting that PP2C49 regulates shoot Na^(+)extrusion.Reciprocal grafting revealed a root-based mechanism underlying the salt tolerance of pp2 c49.Systemic Na+distribution largely depends on AtHKT1;1 and loss of function of AtHKT1;1 in the pp2c49 background overrode the salt tolerance of pp2c49,resulting in salt sensitivity.Furthermore,compared with plants overexpressing PP2C49 in the wild-type background,plants overexpressing PP2C49 in the athtk1;1 mutant background were sensitive to salt,like the athtk1;1 mutants.Moreover,protein-protein interaction and two-voltage clamping assays demonstrated that PP2C49 physically interacts with AtHKT1;1 and inhibits the Na^(+)permeability of AtHKT1;1.This study reveals that PP2C49 negatively regulates AtHKT1;1 activity and thus determines systemic Na^(+)allocation during salt stress.
基金supported by the National High Technology Research and Development Program (863 Program) of China (No. 2012AA101402-2)
文摘A total of 222 surface soil samples and 40 plant samples were collected to investigate the spatial distribution and possible sources of soil heavy metals and to know the uptake and translocation of heavy metals from roots to different plant parts in a representative vegetable production area in the Baguazhou Island, a suburb of Nanjing City, East China. The arithmetic mean values of total Cd, Cr,Cu, Ni, Pb, and Zn concentrations in the soils were 0.314, 133, 41.0, 58.0, 31.8, and 114 mg kg-1, respectively. All of these values were above the topsoil background values in the Nanjing area. Multivariate and geostatistical analyses showed that soil Cd contamination was derived mainly from agricultural practices. In contrast, Cu and Zn were derived mainly from soil parent materials and Pb from atmospheric deposition from highway gasoline stations. Artemisia selengensis, a locally important specialty vegetable, accumulated heavy metals primarily in the edible leaves. The general distribution of heavy metal concentrations in this plant species showed that the highest occurred in the leaves, intermediate in the stems and lowest in the roots. Cd had the highest concentration factor(root-to-soil ratio) and may pose increased health risks in the future to the local population through the consumption of contaminated vegetables.
