Two forms of A. halimus shrubs: erect habit (A. halimus) and bushy habit shrub (A. schweinfurthii) are used naturally isolated by a considerable distance from each other and occupy the same area. To explore the effect...Two forms of A. halimus shrubs: erect habit (A. halimus) and bushy habit shrub (A. schweinfurthii) are used naturally isolated by a considerable distance from each other and occupy the same area. To explore the effect of natural isolation on the genetic basis of the two forms, Start Codon Targeted (SCoT) and the phylogenetic relationships of A. halimus by sequencing ITS1-5.8S-ITS2 regions of the ribosomal DNA are used. Significant isolation-by-distance relationship was found (r = 0.62, P = 0.001). Soil factors did not influence molecular variations. The natural isolation of A. halimus habitats restricts gene flow among the populations and the observed high within-population genetic diversity (74.19%) in this species is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. The UPGMA analysis of the SCoT results showed that all the studied populations were divided into two discrete genetic groups with significant separation of the two forms in Burg El-Arab area (Populations 1 and 2) and insignificant separation between two forms in El-Hammam area (population 5 and 6). The sequencing of the ITS1-5.8S-ITS2 rDNA regions also showed the insignificant separation of the two A. halimus forms. We conclude that gene flow depending on habitat fragmentation was the main factor affecting the population genetic differentiation. We suggest that the two forms do not merit specific rank in presence of interference between the two forms and absence of a breeding barrier fail to separate the different populations when they become sympatric.展开更多
Endophytes are hypothesized to be transferred across the soil-plant continuum, suggesting both the transfers of endophytes from environment to plant and from plant to soil. To verify this hypothesis and to assess the ...Endophytes are hypothesized to be transferred across the soil-plant continuum, suggesting both the transfers of endophytes from environment to plant and from plant to soil. To verify this hypothesis and to assess the role of locality, we evaluated the similarity of microbial communities commonly found both in soils and endophytic communities in three arid regions, i.e. the Jornada LTER （Long Term Ecological Research） site in New Mexico, USA, and the research station of Jordan University of Science and Technology （JUST） and Khanasd research station in Badia region of Jordan. Rhizosphere and non-rhizosphere soils, leaves and seeds of Atriplex spp. were sampled. Diversity and distribution of bacteria and fungi across the soil-plant continuums were assessed by tag-encoded FLX amplicon pyrosequencing and sequence alignment. Of the total bacterial OTUs （operational taxonomic units）, 0.17% in Khanasri research station, 0.16% in research station of JUST, and 0.42% in Jornada LTER site were commonly found across all the plant and soil compartments. The same was true for fungi in two regions, i.e. 1.56% in research station of JUST and 0.86% in Jornada LTER site. However, in Khanasri research station, 12.08% of total fungi OTUs were found in at least one soil compartment and one plant compartment. Putative Arthrobacter, Sporosarcina, Cladosporium and members of Proteobacteria and Actinobacteria were found across all the soil-plant continuums. Ascomycota, mainly including Didymellaceae, Pleosporaceae and Davidiellaceae were present across all the soil-plant continuums. Microbial communities in two regions of Jordan were similar to each other, but both of them were different from the Jornada LTER site of USA. SIMPER （similarity percentage） analysis of bacterial and fungal taxa for both soil and endophyte communities revealed that dissimilarities of two bacterial genera （Arthrobacter and Sporosarcina） and two fungal genera （Cladosporium and Alternaria） are very high, so they play key roles in the soil-plant continuums. A weighed Pearson correlation analysis for the specific bacterial OTUs in the soil-plant continuums only showed high similarity between the two regions of Jordan. However, fungal groups showed higher similarities among all regions. This research supports the hypothesis of continuity of certain bacterial and fungal communities across the soil-plant continuums, and also explores the influences of plant species and geographic specificity on diversity and distribution of bacteria and fungi.展开更多
This paper focused on the water relations of two halophytes differing in photosynthetic pathway, phe- notype, and life cycle： Karelinia caspica （Pall.） Less. （C3, deep-rooted perennial Asteraceae grass） and Atrip...This paper focused on the water relations of two halophytes differing in photosynthetic pathway, phe- notype, and life cycle： Karelinia caspica （Pall.） Less. （C3, deep-rooted perennial Asteraceae grass） and Atriplex tatarica L. （C4, shallow-rooted annual Chenopodiaceae grass）. Gas exchange, leaf water potential, and growth characteristics were investigated in two growing seasons in an arid area of Xinjiang to explore the physiological adaptability of the two halophytes. Both K. caspica and A. tatarica showed midday depression of transpiration, in- dicating that they were strong xerophytes and weak midday depression types. The roots of A. tatarica were con- centrated mainly in the 0-60 cm soil layer, and the leaf water potential （~L） increased sharply in the 0-20 cm layer due to high soil water content, suggesting that the upper soil was the main water source. On the other hand, K. caspica had a rooting depth of about 1.5 m and a larger root/shoot ratio, which confirmed that this species uptakes water mainly from deeper soil layer. Although A. tatarica had lower transpiration water consumption, higher water use efficiency （WUE）, and less water demand at the same leaf water potential, it showed larger water stress impact than K. caspica, indicating that the growth of A. tatarica was restricted more than that of K. caspica when there was no rainfall recharge. As a shallow-rooted C4 species, A. tatarica displayed lower stomatal conductance, which could to some extent reduce transpiration water loss and maintain leaf water potential steadily. In contrast, the deep-rooted C3 species K. caspica had a larger root/shoot ratio that was in favor of exploiting groundwater. We concluded that C3 species （K. caspica） tapes water and C4 species （A. tatarica） reduces water loss to survive in the arid and saline conditions. The results provided a case for the phenotype theory of Schwinning and Ehleringer on halophytic plants.展开更多
Salinity is a major stress that adversely affects growth and productivity in plants. There are species that tolerate this stresswithin the genus Atriplex. Four species, A. lampa, A. crenatifolia, A. nummularia and A. ...Salinity is a major stress that adversely affects growth and productivity in plants. There are species that tolerate this stresswithin the genus Atriplex. Four species, A. lampa, A. crenatifolia, A. nummularia and A. argentina were compared for their ionaccumulation and water relations under saline conditions. A greenhouse study was conducted by irrigating the four species with NaCIsolutions at concentrations 0%, 1%, 2% and 4% starting when plants were six months old. Plants were harvested 45 d after startingthe salinity treatments and analyzed for their ion contents. In the four Atriplex species, Na^＋ and Cl^- contents in plants increased, whileCa^2＋ and Mg^2＋ decreased with the increase of salinity in the irrigation solution. The results suggested that A. argentina and A.nummularia were able to maintain a higher leaf relative water content （RWC） at low leaf water potential, which was associated witha greater capacity of osmotic adjustment. A. lampa showed lower ion accumulation and minor osmotic adjustment than the otherspecies. It can be concluded that the accumulation of ions favors the lower osmotic potential and contributes to osmotic adjustment inthese halophytes.展开更多
OBJECTIVE: To investigate saponins and various solvent extracts from Atriplex laciniata(A. laciniata)against human parasites and various pests.METHODS: The samples from A. laciniata used in the activities were crude s...OBJECTIVE: To investigate saponins and various solvent extracts from Atriplex laciniata(A. laciniata)against human parasites and various pests.METHODS: The samples from A. laciniata used in the activities were crude saponins(Al.Sp F) and solvent samples including methanolic extract(Al.Me F), ethyl acetate(Al.Ea F), choloroform(Al.Cf F),n-hexane(Al.Hx F) and water residual(Al.Wt F). Anthelmintic potentials of the samples were analyzed against Pheretima posthuma(earthworms) and Ascaridia galli(round worms) using contact toxicity method. Insecticidal activities were performed against Heterotermes indicola(termite), Monomorium pharaonis(pharaoh ant), Tribolium castaneum(flour beetle) and Rhyzopertha dominica(grain borer) using standard protocols.RESULTS: In anthelmintic assay, Al.Cf F and Al.Sp F were most effective against P. posthuma and A. gal-li with average death times of 25.62 and 29.65 min respectively. Likewise the anthelmintic assay, Al.Sp F and Al.Cf F were most effective against H. indicola causing 90.36% and 73.24% lethality respectively. Furthermore, in anti-Pharaoh activity Al.Sp F, Al.Wt F, Al.Cf F, Al.Me F and Al.Cf F exhibited highest activity with LD50 of 78, 220, 260, 330 and > 800 mg/m L respectively. Al.Sp F and Al.Cf F were highly effective against R. dominica causing 80.11% and71.30% lethality respectively. Al.Sp F was found most active against T. castaneum.CONCLUSION: Our findings suggest that the Al.Sp F, Al.Cf F and Al.Wt F extracted from A.laciniata L.may be the best options for the isolation of anthelmintic and bio-insecticidal compounds.展开更多
Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Me...Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Metabolism of proline has been elucidated in many plant species. However, transport of proline was poorly characterized although transport system plays an important role in proline distribution in different tissues. We isolated one full_length cDNA encoding proline transporter from the typical halophyte: Atriplex hortensis L. through cDNA library screening and 5′_RACE. The deduced amino acid sequence had eleven transmembrane domains, showed 60%-69% similarities to other ProTs and the gene was designated AhProT1. In the phylogenetic tree, higher plants' ProTs, e.g. AhProT1, showed more similar to ProP from microorganisms than ProT from mammalians. AhProT1 gene was transformed into Arabidopsis thaliana under 35S promoter. In MS medium containing [U_ 14 C] proline, AhProT1 + plants were able to accumulate much more radiolabeled proline in the roots than control plants. In MS medium containing different concentrations of NaCl, AhProT1 + plants could endure 200 mmol/L NaCl and keep development and biomass increase with proline supply, whereas control plants died back at 150 mmol/L NaCl.展开更多
EREBP/AP2-type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respec...EREBP/AP2-type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respectively. To characterize transcription factors involved in plant responses to salt stress, we constructed cDNA library from salt-treated halophyte (Atriplex hortensis) and isolated a novel gene encoding EREBP/AP2-type protein from this library. This cDNA contained an ORF of 723 bp and a long 3'-Untranslated-Region (UTR) of 655 bp. The deduced amino acid sequence showed one conserved DNA binding domain of EREBP/AP2, thus the corresponding gene was named AhDREB1 with a calculated molecular mass of 26.1 kD. AhDREB1 under the control of CaMV 35S promoter was then transformed into tobacco and nine independent transgenic lines were obtained and subjected to long term salt stress. The results suggested that overexpression of AhDREB1 improved the salt tolerance in transgenic tobacco through functioning as a regulatory molecule in response to salt stress. Analysis of Arabidopsis genome in database resulted in dozens of EREBP/AP2-type homologous proteins, of which seven members showed high similarity to AhDREB1. Secondary structure analysis predicted similar arrangement of a-helix in their DNA binding domains.展开更多
文摘Two forms of A. halimus shrubs: erect habit (A. halimus) and bushy habit shrub (A. schweinfurthii) are used naturally isolated by a considerable distance from each other and occupy the same area. To explore the effect of natural isolation on the genetic basis of the two forms, Start Codon Targeted (SCoT) and the phylogenetic relationships of A. halimus by sequencing ITS1-5.8S-ITS2 regions of the ribosomal DNA are used. Significant isolation-by-distance relationship was found (r = 0.62, P = 0.001). Soil factors did not influence molecular variations. The natural isolation of A. halimus habitats restricts gene flow among the populations and the observed high within-population genetic diversity (74.19%) in this species is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. The UPGMA analysis of the SCoT results showed that all the studied populations were divided into two discrete genetic groups with significant separation of the two forms in Burg El-Arab area (Populations 1 and 2) and insignificant separation between two forms in El-Hammam area (population 5 and 6). The sequencing of the ITS1-5.8S-ITS2 rDNA regions also showed the insignificant separation of the two A. halimus forms. We conclude that gene flow depending on habitat fragmentation was the main factor affecting the population genetic differentiation. We suggest that the two forms do not merit specific rank in presence of interference between the two forms and absence of a breeding barrier fail to separate the different populations when they become sympatric.
文摘Endophytes are hypothesized to be transferred across the soil-plant continuum, suggesting both the transfers of endophytes from environment to plant and from plant to soil. To verify this hypothesis and to assess the role of locality, we evaluated the similarity of microbial communities commonly found both in soils and endophytic communities in three arid regions, i.e. the Jornada LTER （Long Term Ecological Research） site in New Mexico, USA, and the research station of Jordan University of Science and Technology （JUST） and Khanasd research station in Badia region of Jordan. Rhizosphere and non-rhizosphere soils, leaves and seeds of Atriplex spp. were sampled. Diversity and distribution of bacteria and fungi across the soil-plant continuums were assessed by tag-encoded FLX amplicon pyrosequencing and sequence alignment. Of the total bacterial OTUs （operational taxonomic units）, 0.17% in Khanasri research station, 0.16% in research station of JUST, and 0.42% in Jornada LTER site were commonly found across all the plant and soil compartments. The same was true for fungi in two regions, i.e. 1.56% in research station of JUST and 0.86% in Jornada LTER site. However, in Khanasri research station, 12.08% of total fungi OTUs were found in at least one soil compartment and one plant compartment. Putative Arthrobacter, Sporosarcina, Cladosporium and members of Proteobacteria and Actinobacteria were found across all the soil-plant continuums. Ascomycota, mainly including Didymellaceae, Pleosporaceae and Davidiellaceae were present across all the soil-plant continuums. Microbial communities in two regions of Jordan were similar to each other, but both of them were different from the Jornada LTER site of USA. SIMPER （similarity percentage） analysis of bacterial and fungal taxa for both soil and endophyte communities revealed that dissimilarities of two bacterial genera （Arthrobacter and Sporosarcina） and two fungal genera （Cladosporium and Alternaria） are very high, so they play key roles in the soil-plant continuums. A weighed Pearson correlation analysis for the specific bacterial OTUs in the soil-plant continuums only showed high similarity between the two regions of Jordan. However, fungal groups showed higher similarities among all regions. This research supports the hypothesis of continuity of certain bacterial and fungal communities across the soil-plant continuums, and also explores the influences of plant species and geographic specificity on diversity and distribution of bacteria and fungi.
基金supported by the National Basic Research Program of China(2009CB825101)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20110008110035)
文摘This paper focused on the water relations of two halophytes differing in photosynthetic pathway, phe- notype, and life cycle： Karelinia caspica （Pall.） Less. （C3, deep-rooted perennial Asteraceae grass） and Atriplex tatarica L. （C4, shallow-rooted annual Chenopodiaceae grass）. Gas exchange, leaf water potential, and growth characteristics were investigated in two growing seasons in an arid area of Xinjiang to explore the physiological adaptability of the two halophytes. Both K. caspica and A. tatarica showed midday depression of transpiration, in- dicating that they were strong xerophytes and weak midday depression types. The roots of A. tatarica were con- centrated mainly in the 0-60 cm soil layer, and the leaf water potential （~L） increased sharply in the 0-20 cm layer due to high soil water content, suggesting that the upper soil was the main water source. On the other hand, K. caspica had a rooting depth of about 1.5 m and a larger root/shoot ratio, which confirmed that this species uptakes water mainly from deeper soil layer. Although A. tatarica had lower transpiration water consumption, higher water use efficiency （WUE）, and less water demand at the same leaf water potential, it showed larger water stress impact than K. caspica, indicating that the growth of A. tatarica was restricted more than that of K. caspica when there was no rainfall recharge. As a shallow-rooted C4 species, A. tatarica displayed lower stomatal conductance, which could to some extent reduce transpiration water loss and maintain leaf water potential steadily. In contrast, the deep-rooted C3 species K. caspica had a larger root/shoot ratio that was in favor of exploiting groundwater. We concluded that C3 species （K. caspica） tapes water and C4 species （A. tatarica） reduces water loss to survive in the arid and saline conditions. The results provided a case for the phenotype theory of Schwinning and Ehleringer on halophytic plants.
文摘Salinity is a major stress that adversely affects growth and productivity in plants. There are species that tolerate this stresswithin the genus Atriplex. Four species, A. lampa, A. crenatifolia, A. nummularia and A. argentina were compared for their ionaccumulation and water relations under saline conditions. A greenhouse study was conducted by irrigating the four species with NaCIsolutions at concentrations 0%, 1%, 2% and 4% starting when plants were six months old. Plants were harvested 45 d after startingthe salinity treatments and analyzed for their ion contents. In the four Atriplex species, Na^＋ and Cl^- contents in plants increased, whileCa^2＋ and Mg^2＋ decreased with the increase of salinity in the irrigation solution. The results suggested that A. argentina and A.nummularia were able to maintain a higher leaf relative water content （RWC） at low leaf water potential, which was associated witha greater capacity of osmotic adjustment. A. lampa showed lower ion accumulation and minor osmotic adjustment than the otherspecies. It can be concluded that the accumulation of ions favors the lower osmotic potential and contributes to osmotic adjustment inthese halophytes.
文摘利用超高效液相色谱-三重四极杆串联质谱联用法(ultra-high performance liquid chromatography-triple quadrupole mass spectrometry, UPLC-QQQ-MS)比较2种寄主肉苁蓉经过不同干燥处理后的10种苯乙醇苷类成分含量。将肉苁蓉干燥品粉碎,粉末过60目筛,用50%(体积分数)甲醇溶解后超声提取,用Agilent Eclipse Plus C18柱(2.1 mm×150 mm, 1.8μm)分离,以A相(0.1%甲酸水溶液)-B(乙腈)相作为流动相进行梯度洗脱,利用电喷雾离子源,在UPLC-QQQ-MS的动态多反应模式下检测。结果表明,不同干燥处理的寄主肉苁蓉苯乙醇苷类成分含量具有明显差异,冷冻干燥处理所得的肉苁蓉中10种苯乙醇苷类含量最高,其次为80℃烘干样品。虽然冷冻干燥对于肉苁蓉所保留10种苯乙醇苷类成分最高,但基于大规模生产考虑,80℃烘干更具有经济效益。
文摘OBJECTIVE: To investigate saponins and various solvent extracts from Atriplex laciniata(A. laciniata)against human parasites and various pests.METHODS: The samples from A. laciniata used in the activities were crude saponins(Al.Sp F) and solvent samples including methanolic extract(Al.Me F), ethyl acetate(Al.Ea F), choloroform(Al.Cf F),n-hexane(Al.Hx F) and water residual(Al.Wt F). Anthelmintic potentials of the samples were analyzed against Pheretima posthuma(earthworms) and Ascaridia galli(round worms) using contact toxicity method. Insecticidal activities were performed against Heterotermes indicola(termite), Monomorium pharaonis(pharaoh ant), Tribolium castaneum(flour beetle) and Rhyzopertha dominica(grain borer) using standard protocols.RESULTS: In anthelmintic assay, Al.Cf F and Al.Sp F were most effective against P. posthuma and A. gal-li with average death times of 25.62 and 29.65 min respectively. Likewise the anthelmintic assay, Al.Sp F and Al.Cf F were most effective against H. indicola causing 90.36% and 73.24% lethality respectively. Furthermore, in anti-Pharaoh activity Al.Sp F, Al.Wt F, Al.Cf F, Al.Me F and Al.Cf F exhibited highest activity with LD50 of 78, 220, 260, 330 and > 800 mg/m L respectively. Al.Sp F and Al.Cf F were highly effective against R. dominica causing 80.11% and71.30% lethality respectively. Al.Sp F was found most active against T. castaneum.CONCLUSION: Our findings suggest that the Al.Sp F, Al.Cf F and Al.Wt F extracted from A.laciniata L.may be the best options for the isolation of anthelmintic and bio-insecticidal compounds.
文摘Proline is one of the most important and widespread osmolyte which functions in adaptation to adverse environmental stresses in many organisms. Also it is an important carbon and nitrogen resource in higher plants. Metabolism of proline has been elucidated in many plant species. However, transport of proline was poorly characterized although transport system plays an important role in proline distribution in different tissues. We isolated one full_length cDNA encoding proline transporter from the typical halophyte: Atriplex hortensis L. through cDNA library screening and 5′_RACE. The deduced amino acid sequence had eleven transmembrane domains, showed 60%-69% similarities to other ProTs and the gene was designated AhProT1. In the phylogenetic tree, higher plants' ProTs, e.g. AhProT1, showed more similar to ProP from microorganisms than ProT from mammalians. AhProT1 gene was transformed into Arabidopsis thaliana under 35S promoter. In MS medium containing [U_ 14 C] proline, AhProT1 + plants were able to accumulate much more radiolabeled proline in the roots than control plants. In MS medium containing different concentrations of NaCl, AhProT1 + plants could endure 200 mmol/L NaCl and keep development and biomass increase with proline supply, whereas control plants died back at 150 mmol/L NaCl.
文摘EREBP/AP2-type proteins are members of a large DNA binding protein (DBP) family found in plants. Some members like APETALA2 and AtDREB/CBF can regulate flower development and response to environmental stresses, respectively. To characterize transcription factors involved in plant responses to salt stress, we constructed cDNA library from salt-treated halophyte (Atriplex hortensis) and isolated a novel gene encoding EREBP/AP2-type protein from this library. This cDNA contained an ORF of 723 bp and a long 3'-Untranslated-Region (UTR) of 655 bp. The deduced amino acid sequence showed one conserved DNA binding domain of EREBP/AP2, thus the corresponding gene was named AhDREB1 with a calculated molecular mass of 26.1 kD. AhDREB1 under the control of CaMV 35S promoter was then transformed into tobacco and nine independent transgenic lines were obtained and subjected to long term salt stress. The results suggested that overexpression of AhDREB1 improved the salt tolerance in transgenic tobacco through functioning as a regulatory molecule in response to salt stress. Analysis of Arabidopsis genome in database resulted in dozens of EREBP/AP2-type homologous proteins, of which seven members showed high similarity to AhDREB1. Secondary structure analysis predicted similar arrangement of a-helix in their DNA binding domains.
