In an attempt to isolate and identify the target genes relevant to salt tolerance in a mangrove plant （Sesuvium portulacastrum L.）, a subtracted cDNA library was constructed via suppressive subtractive hybridization...In an attempt to isolate and identify the target genes relevant to salt tolerance in a mangrove plant （Sesuvium portulacastrum L.）, a subtracted cDNA library was constructed via suppressive subtractive hybridization （SSH）, in which the poly（A）＋RNA isolated from salt-tolerant S. portulacastrum leaves was used as a tester, whereas the driver was poly（A）＋RNA, derived from salt-sensitive S. portulacastrum leaves. Screening of this subtracted cDNA library revealed five clones, of which the expression levels in the salt-tolerant plant were markedly higher than those observed in the salt-sensitive plant, indicating that these candidate clones may be involved in salt-tolerance pathways. Among the clones isolated, P66, P175, and P233 are novel because no significant similarity was obtained upon alignment with the GenBank database. Clone P89 demonstrated high homology with NADPH of Arabidopsis thaliana, whereas clone P152 was highly homologous with the gene encoding late embryogenesis abundant （LEA） protein of A. thaliana. The full-length gene of clone P152, with a predicated 344 amino acid residues, was shown to bear LEA-2 domains, a signature motif for proteins that have been enriched under salty and drought conditions. It is thus implied that clone P152 would be a salt-tolerance gene of S. portulacastrum. In addition, we have also developed a strategy for the extraction of total RNA from mangrove plants.展开更多
Many coastal seas are severely eutrophic and required to reduce nutrient concentrations to meet a certain water quality standard.We proposed a method for nutrient removal by planting Sesuvium portulacastrum at the wat...Many coastal seas are severely eutrophic and required to reduce nutrient concentrations to meet a certain water quality standard.We proposed a method for nutrient removal by planting Sesuvium portulacastrum at the water surface using the floating beds in the aquaculture area of the Dongshan Bay as an example,which is an important net-cage culture base in China and where dissolved inorganic nitrogen(DIN)and dissolved inorganic phosphate(DIP)reach 0.75 mg/L and 0.097 mg/L,respectively far exceeding China’s Grade IV water quality standards.Numerical simulations were taken using the ecological model,field observations and field plantation experimental results to assess the environmental restoration effects of planting S.portulacastrum at some certain spatial scales.Our field experiments suggested that the herbs can absorb 377 g/m^2 nitrogen and 22.9 g/m^2 phosphorus in eight months with an inserting density of^60 shoot/m^2.The numerical experiments show that the greater the plantation area is,the more nutrient removal.Plantation in^12%of the study area could lower nutrients to the required Grade II standards,i.e.,0.2 mg/L<DIN≤0.3 mg/L and 0.015 mg/L<DIP≤0.03 mg/L.Here the phytoremediation method and results provide helpful references for environmental restoration in other eutrophic seas.展开更多
Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol ...Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol agents was accomplished through in vitro epidemic study to control weed populations. The foliar disease symptoms on infected weed plants caused by fungal pathogens represented as round to irregular maroon spots with dark borders and the epidemic was identified as leaf spot disease. The pathogen allied with the infection of horse purslane was isolated from infectious propagules by inoculation of leaf bites on a nutrient medium, potato dextrose agar （PDA）. The causal agent of leaf spot was confirmed as Gibbago trianthemae Simmons by Koch＇s postulates. The mycoherbicide ability of G. trianthemae has been examined through visual （standard area diagram） and statistical methods （analysis of variance using the Microsoft Office Excel-Data Analysis Tool Pack 2007）. The results revealed that the pathogen causes significantly （P 〈 0.05） severe infection on host weed and destructs the weed population by leaf spot diseases. The findings of the research suggested that the isolate G. trianthemae is highly virulent and host-specific, and recommended for further studies as a promising biocontrol agent against horse purslane weed.展开更多
Objective:To identify the larvicidal activity of the volatile oil from Sesuvium portulacastrum(S.portulacastrum)against Anopheles stephensi and Aedes aegypti.Methods:Volatile oil extract of S.portulacastrum was prepar...Objective:To identify the larvicidal activity of the volatile oil from Sesuvium portulacastrum(S.portulacastrum)against Anopheles stephensi and Aedes aegypti.Methods:Volatile oil extract of S.portulacastrum was prepared in a graded series of concentration.The test for the larvicidal effect of volatile oil against mosquitos larvae was conducted in accordance with the WHO standard method.Batches of 25 early 4th instar larvae of two mosquitoes were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts.Each experiment was conducted with triplicate with concurrent a control group.Results:Volatile oil extract of S.portulacastrum showed toxicity against 4th instar larvae of Aedes aegypti and Anopheles stephensi with equivalent LC50 value[(63±7.8)μL/mL,LCL-UCL=55.2-64.0]and LC90 value[(94.2±3.9)μL/mL]in maximum activity with minimum concentration(200μL/mL)of volatile oil and followed by maximum activity of 250μL concentration showed LC50 value=(68.0±8.2)μL/mL,LCL-UCL=66.26-69.2 and LC50 value of(55.2±2.8)μL/mL,LCL-UCL=53.7-56.9,LC90=(95.2±1.25)μL/mL and followed by 250μL of oil extract against 4th instar larvae of Aedes aegypti respectively.Conclusions:It is inferred from the present study that,the extracts from salt marsh mangrove plan of S.portulacastum are identified as a potential source of safe and efficacious mosquito control agents for the management of vector borne diseases of malaria and dengue.展开更多
文摘In an attempt to isolate and identify the target genes relevant to salt tolerance in a mangrove plant （Sesuvium portulacastrum L.）, a subtracted cDNA library was constructed via suppressive subtractive hybridization （SSH）, in which the poly（A）＋RNA isolated from salt-tolerant S. portulacastrum leaves was used as a tester, whereas the driver was poly（A）＋RNA, derived from salt-sensitive S. portulacastrum leaves. Screening of this subtracted cDNA library revealed five clones, of which the expression levels in the salt-tolerant plant were markedly higher than those observed in the salt-sensitive plant, indicating that these candidate clones may be involved in salt-tolerance pathways. Among the clones isolated, P66, P175, and P233 are novel because no significant similarity was obtained upon alignment with the GenBank database. Clone P89 demonstrated high homology with NADPH of Arabidopsis thaliana, whereas clone P152 was highly homologous with the gene encoding late embryogenesis abundant （LEA） protein of A. thaliana. The full-length gene of clone P152, with a predicated 344 amino acid residues, was shown to bear LEA-2 domains, a signature motif for proteins that have been enriched under salty and drought conditions. It is thus implied that clone P152 would be a salt-tolerance gene of S. portulacastrum. In addition, we have also developed a strategy for the extraction of total RNA from mangrove plants.
基金The Public Science and Technology Research Funds Projects of Ocean under contract Nos 201305043 and 201205009the National Basic Research Program(973 Program)of China under contract No.2015CB755904the National Natural Science Foundation of China under contract No.41276036
文摘Many coastal seas are severely eutrophic and required to reduce nutrient concentrations to meet a certain water quality standard.We proposed a method for nutrient removal by planting Sesuvium portulacastrum at the water surface using the floating beds in the aquaculture area of the Dongshan Bay as an example,which is an important net-cage culture base in China and where dissolved inorganic nitrogen(DIN)and dissolved inorganic phosphate(DIP)reach 0.75 mg/L and 0.097 mg/L,respectively far exceeding China’s Grade IV water quality standards.Numerical simulations were taken using the ecological model,field observations and field plantation experimental results to assess the environmental restoration effects of planting S.portulacastrum at some certain spatial scales.Our field experiments suggested that the herbs can absorb 377 g/m^2 nitrogen and 22.9 g/m^2 phosphorus in eight months with an inserting density of^60 shoot/m^2.The numerical experiments show that the greater the plantation area is,the more nutrient removal.Plantation in^12%of the study area could lower nutrients to the required Grade II standards,i.e.,0.2 mg/L<DIN≤0.3 mg/L and 0.015 mg/L<DIP≤0.03 mg/L.Here the phytoremediation method and results provide helpful references for environmental restoration in other eutrophic seas.
文摘Trianthema portulacastrum L. （commonly known as horse purslane） is a noxious weed of several economically important field crops in tropical regions of the world. An intensive work on the screening of the biocontrol agents was accomplished through in vitro epidemic study to control weed populations. The foliar disease symptoms on infected weed plants caused by fungal pathogens represented as round to irregular maroon spots with dark borders and the epidemic was identified as leaf spot disease. The pathogen allied with the infection of horse purslane was isolated from infectious propagules by inoculation of leaf bites on a nutrient medium, potato dextrose agar （PDA）. The causal agent of leaf spot was confirmed as Gibbago trianthemae Simmons by Koch＇s postulates. The mycoherbicide ability of G. trianthemae has been examined through visual （standard area diagram） and statistical methods （analysis of variance using the Microsoft Office Excel-Data Analysis Tool Pack 2007）. The results revealed that the pathogen causes significantly （P 〈 0.05） severe infection on host weed and destructs the weed population by leaf spot diseases. The findings of the research suggested that the isolate G. trianthemae is highly virulent and host-specific, and recommended for further studies as a promising biocontrol agent against horse purslane weed.
基金Supported by Ministry of Environment and Forest with Grant Number:DD.N.3/2/2004CS(M)-11.12.2006.
文摘Objective:To identify the larvicidal activity of the volatile oil from Sesuvium portulacastrum(S.portulacastrum)against Anopheles stephensi and Aedes aegypti.Methods:Volatile oil extract of S.portulacastrum was prepared in a graded series of concentration.The test for the larvicidal effect of volatile oil against mosquitos larvae was conducted in accordance with the WHO standard method.Batches of 25 early 4th instar larvae of two mosquitoes were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts.Each experiment was conducted with triplicate with concurrent a control group.Results:Volatile oil extract of S.portulacastrum showed toxicity against 4th instar larvae of Aedes aegypti and Anopheles stephensi with equivalent LC50 value[(63±7.8)μL/mL,LCL-UCL=55.2-64.0]and LC90 value[(94.2±3.9)μL/mL]in maximum activity with minimum concentration(200μL/mL)of volatile oil and followed by maximum activity of 250μL concentration showed LC50 value=(68.0±8.2)μL/mL,LCL-UCL=66.26-69.2 and LC50 value of(55.2±2.8)μL/mL,LCL-UCL=53.7-56.9,LC90=(95.2±1.25)μL/mL and followed by 250μL of oil extract against 4th instar larvae of Aedes aegypti respectively.Conclusions:It is inferred from the present study that,the extracts from salt marsh mangrove plan of S.portulacastum are identified as a potential source of safe and efficacious mosquito control agents for the management of vector borne diseases of malaria and dengue.
