The βC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby βC1 functions in pathogenicity, ...The βC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby βC1 functions in pathogenicity, a yeast two-hybrid screen of a tobacco cDNA library was carried out using βC1 as the bait. The screen revealed that βC1 interacts with a tobacco RING-finger protein designated NtRFP1, which was further confirmed by the bimolecular fluorescence complementation and co-immunoprecipitation assays in Nicotiana benthamiana cells. Expression of NtRFP1 was induced by βC1, and in vitro ubiquiti- nation assays showed that NtRFP1 is a functional E3 ubiquiUn ligase that mediates βC1 ubiquitination. In addition, βC1 was shown to be ubiquitinated in vivo and degraded by the plant 26S proteasome. After viral infection, plants overexpressing NtRFP1 developed attenuated symptoms, whereas plants with silenced expression of NtRFP1 showed severe symptoms. Other lines of evidence showed that NtRFP1 attenuates βC1-induced symptoms through promoting its degradation by the 26S proteasome. Taken together, our results suggest that tobacco RING E3 ligase NtRFP1 attenuates disease symptoms by interacting with βC1 to mediate its ubiquitination and degradation via the ubiquitin/26S proteasome system.展开更多
Accumulation of heavy metals in agricultural soils tends to increase crop uptake of heavy metals,and can adversely impact human health through food chains.This study assessed the heavy metal pollution status and the p...Accumulation of heavy metals in agricultural soils tends to increase crop uptake of heavy metals,and can adversely impact human health through food chains.This study assessed the heavy metal pollution status and the potential ecological risk of tea plantation soils in southern Shaanxi Province,China.A total of 330 topsoil samples were collected to analyze the concentrations of seven heavy metals(Pb,Zn,Cu,Cr,Hg,As and Cd)and the pH level.The Hakanson potential ecological risk index was used based on the background levels of soil heavy metals in Shaanxi.Results showed that the averaged concentrations of soil Pb,Zn,Cu,Cr,Hg,As,and Cd were 10.0,87.6,16.4,12.4,0.2,6.9 and 0.1 mg/kg,respectively.Cd and Hg concentrations exceeded level II of China’s Soil Environment Quality Standard(GB 15618-2009)in 9.3%and 7.0%of the total samples,respectively.The coefficient of variation ranged from 29.2%to 52.2%for different elements,and was 49.3%for Cd and 48.6%for Hg.The averaged comprehensive potential ecological risk index was 95.4,and the overall potential ecological risk was low,with 82.4%of the total samples at a low level of potential ecological risk.Cd and Hg contributed most to the potential ecological risk(35.5%and 46.5%,respectively),and the risks associated with other elements were relatively minor.This study suggested that soil Cd and Hg pollution should be controlled to ensure the safe production of tea in the study area.展开更多
文摘The βC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby βC1 functions in pathogenicity, a yeast two-hybrid screen of a tobacco cDNA library was carried out using βC1 as the bait. The screen revealed that βC1 interacts with a tobacco RING-finger protein designated NtRFP1, which was further confirmed by the bimolecular fluorescence complementation and co-immunoprecipitation assays in Nicotiana benthamiana cells. Expression of NtRFP1 was induced by βC1, and in vitro ubiquiti- nation assays showed that NtRFP1 is a functional E3 ubiquiUn ligase that mediates βC1 ubiquitination. In addition, βC1 was shown to be ubiquitinated in vivo and degraded by the plant 26S proteasome. After viral infection, plants overexpressing NtRFP1 developed attenuated symptoms, whereas plants with silenced expression of NtRFP1 showed severe symptoms. Other lines of evidence showed that NtRFP1 attenuates βC1-induced symptoms through promoting its degradation by the 26S proteasome. Taken together, our results suggest that tobacco RING E3 ligase NtRFP1 attenuates disease symptoms by interacting with βC1 to mediate its ubiquitination and degradation via the ubiquitin/26S proteasome system.
基金This work was financially supported by Key Research and Development Program of Shaanxi Province,China(No.2019NY-202)the Key Laboratory for Agricultural Environment,Ministry of Agriculture Open Foundation(No.2015)+1 种基金Research Foundation of Education Bureau of Shaanxi Province,China(No.19JS012)the Shaanxi Province Key Laboratory of Bio-resources(2015SZS-15-04/09).
文摘Accumulation of heavy metals in agricultural soils tends to increase crop uptake of heavy metals,and can adversely impact human health through food chains.This study assessed the heavy metal pollution status and the potential ecological risk of tea plantation soils in southern Shaanxi Province,China.A total of 330 topsoil samples were collected to analyze the concentrations of seven heavy metals(Pb,Zn,Cu,Cr,Hg,As and Cd)and the pH level.The Hakanson potential ecological risk index was used based on the background levels of soil heavy metals in Shaanxi.Results showed that the averaged concentrations of soil Pb,Zn,Cu,Cr,Hg,As,and Cd were 10.0,87.6,16.4,12.4,0.2,6.9 and 0.1 mg/kg,respectively.Cd and Hg concentrations exceeded level II of China’s Soil Environment Quality Standard(GB 15618-2009)in 9.3%and 7.0%of the total samples,respectively.The coefficient of variation ranged from 29.2%to 52.2%for different elements,and was 49.3%for Cd and 48.6%for Hg.The averaged comprehensive potential ecological risk index was 95.4,and the overall potential ecological risk was low,with 82.4%of the total samples at a low level of potential ecological risk.Cd and Hg contributed most to the potential ecological risk(35.5%and 46.5%,respectively),and the risks associated with other elements were relatively minor.This study suggested that soil Cd and Hg pollution should be controlled to ensure the safe production of tea in the study area.
