Understanding genetic variation is important for efficiently selecting excellent clones and utilizing genetic resources during tree breeding. We investigated 16 growth traits of 50 32-year-old Pinus koraiensis clones....Understanding genetic variation is important for efficiently selecting excellent clones and utilizing genetic resources during tree breeding. We investigated 16 growth traits of 50 32-year-old Pinus koraiensis clones. Analyses of variance showed that all the test traits differed significantly among clones. Average height, diameter at breast height(DBH), and volume of all clones were 10.41 m, 21.30 cm,and 0.148 m3, respectively. Phenotypic coefficients of variation and repeatabilities of traits ranged from 4.37 to48.03% and from 0.013 to 0.900, respectively. There exists significant positive correlations among heights, diameter at different heights(1.3, 3.0, 5.0 m), and volumes; genetic correlation was close to phenotype correlation. Using four growth traits(height, DBH, volume, average crown width)as indices for a comprehensive evaluation, five clones(PK11, PK 19, PK 04, PK 14, and PK 28), whose traits scored in the top 10%, were selected as elite clones. For these clones,genetic gains in height, DBH, volume and crown height were 8.58, 13.02, 32.72 and 3.83%, respectively. These results provide important information for improving P.koraiensis breeding programs.展开更多
To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume)and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted wit...To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume)and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted with four levels of spacing(2 m 92 m,3 m 93 m,4 m 94 m,and 5 m 95 m)in a semi-arid area in northeastern China were examined.The results of ANOVA showed significant differences(P\0.01)for all the investigated growth traits and wood properties under different plantation densities,except for the chemical composition of wood.The repeatability and phenotypic variations of all the traits varied from 0.34 to 0.99 and from 13.45 to 59.65%,respectively.Except for wood density,which was significantly negatively correlated with the growth traits,a positive correlation was observed between the growth traits and all the other wood mechanical properties.However,most of the correlations between the growth traits and the chemical composition of the wood were not significant.The path analysis for the wood mechanical characteristics and the growth in the prediction of volume were significant and ranged from 0.18 to 0.72 for wood density and diameter at breast height,respectively,while those for the chemical composition of wood ranged from 0.001 to 0.336,which showed a low impact on the volume.The highest stand volume(610 m3)per hectare was observed with the 2 m 92 m spacing,which consequently provided a high total price and income,while a high individual volume growth per tree was observed with the 5 m 95 m spacing.The results suggested that for the poplar trees younger than 40 years in a semi-arid area in China,2 m 92 m spacing is suitable for obtaining a high volume per hectare,while 5 m 95 m spacing is best for obtaining a high individual volume per tree.展开更多
It is important to evaluate nitrogen use efficiency and nitrogen tolerance of trees in order to improve their productivity.In this study,both were evaluated for 338 Populus deltoides genotypes from six provenances.The...It is important to evaluate nitrogen use efficiency and nitrogen tolerance of trees in order to improve their productivity.In this study,both were evaluated for 338 Populus deltoides genotypes from six provenances.The plants were cultured under normal nitrogen(750μM NH_4 NO_3)and low nitrogen(5μM NH_4 NO_3)conditions for 3 months.Growth,chlorophyll content and glutamine synthetase activity of each genotype were measured.Under low nitrogen,heights,ground diameter,leaf area,leaf and root biomass,and chlorophyll contents were significantly lower than those under normal nitrogen level.Correlation analysis showed that nutrient distribution changed under different nitrogen treatments.There was a negative correlation between leaf traits and root biomass under normal nitrogen level,however,the correlation became positive in low nitrogen treatment.Moreover,with the decrease of nitrogen level,the negative correlation between leaf morphology and chlorophyll levels became weakened.The growth of the genotypes under the two treatments was evaluated by combining principal component analysis with a fuzzy mathematical membership function;the results showed that leaf traits accounted for a large proportion of the variation in the evaluation model.According to the results of comprehensive evaluation of plants under the two treatments,the 338 P.deltoides genotypes could be divided into nine categories,with wide genotypic diversity in nitrogen use efficiency and low nitrogen tolerance.As a result,26 N-efficient genotypes and 24 N-inefficient genotypes were selected.By comparative analysis of their morphological and physiological traits under the two treatments,leaf traits could be significant indicators for nitrogen use efficiency and nitrogen tolerance,which is of considerable significance for breeding poplar varieties with high nitrogen use efficiencies.展开更多
The growth and wood properties of 240 individual Populus×euramericana cv.’74/76’(hereafter poplar 107)trees planted in Hebei Plain,China was evaluated.Mean annual increments in height,breast height diameter and...The growth and wood properties of 240 individual Populus×euramericana cv.’74/76’(hereafter poplar 107)trees planted in Hebei Plain,China was evaluated.Mean annual increments in height,breast height diameter and volume,as well as cellulose,hemicellulose and lignin contents,shrinkage,density,bending strength and modulus of elasticity in the heart wood and sap wood.Environmental factors influencing growth and wood properties were analyzed using correlation and stepwise regres sion.The results show that the coefficients of variation(CVs)of growth traits ranged from 10.6 to 22.4%.The CVs of the chemical properties of heartwood ranged from 4.3 to 30.2%,and for sap wood from 3.2 to 27.5%.The CVs of the physical and mechanical properties of heartwood ranged from 8.6 to 31.7%,and for sapwood from 6.4 to 29.9%.The results of one-way ANOVA showed that there were significant differences in growth traits and wood properties among sites.Soil pH,total and available phosphorus,total potassium,and soil organic matter were key soil factors affecting growth and wood properties of poplar 107,whereas mean annual ground temperatures and precipitation were the main climatic factors.To better cultivate poplar 107,area with less annual rainfall,slightly higher temperature and soil pH value close to neutral should be selected.展开更多
Branch phenotypic traits determine tree crown architecture,which in turn governs leaf display,light interception,and biomass production.Sylleptic and proleptic branches are the obviously different branch phenotypes in...Branch phenotypic traits determine tree crown architecture,which in turn governs leaf display,light interception,and biomass production.Sylleptic and proleptic branches are the obviously different branch phenotypes in the poplar crown.Many studies have focused on the influence of sylleptic branch numbers(SBN)on biomass production,but the research on the influence of proleptic branch phenotypes was only a few.To explore the relationship between proleptic branch traits and biomass generation production in a high-density poplar plantation,we investigated the branch phenotypic traits of three poplar genotypes,all of which have high survival rates in forests(>95%)and significantly different crown architecture and biomass performance in the high-density plantations(1667 stems ha−1).The plantation site was established in 2007.A terrestrial laser scanner was used to measure branch characteristics such as length,angle of origin and termination,and azi-muth angle.A hierarchical cluster analysis performed on branch characteristics showed that SBN,crown depth,and proleptic branch curvature(PBC)were clustered with bio-mass production and leaf area index(LAI).Among all of the monitored traits,PBC played the second most important role in biomass production after SBN and was significantly correlated with SBN,LAI,and biomass production.The positive correlation between PBC and SBN indicated that a larger PBC was associated with more sylleptic branches within the monitored genotypes planted in the high-density plantation,providing greater leaf area and biomass produc-tion.The results of this study will improve the identification of high-production poplar varieties for cultivation in high-density plantations for biofuel production.展开更多
The European black poplar(Populus nigra L.)has been used as a germplasm resource for the breeding of new poplar varieties around the world.The identification and screening of its high nitrogen use efficiency genotypes...The European black poplar(Populus nigra L.)has been used as a germplasm resource for the breeding of new poplar varieties around the world.The identification and screening of its high nitrogen use efficiency genotypes could enable the breeding of new resource-efficient poplar varieties.The accessions were screened using MALDI-TOF MS genotyping technology for ammonium transporter(AMT)and nitrate transporters(NRT)genes against phenotypic data for seedling height and ground diameter traits,in both low and high nitrogen environments.Allele re-sequencing of seven genes related to root development was carried out using the minisequencing method.By cluster analysis,101 accessions of black poplar were divided into 4 populations,and it was concluded that Central Europe is the origin of the evolution of low-nitrogen and high-efficiency populations of European black poplar.Association study between SNP typing and seedling height and ground diameter traits showed that there were significant correlations between four SNP loci and growth traits under the contrasting N levels.We found that SNP3 and SNP4 in the PttAMT1;3 gene were significantly associated with seedling height traits,and that SNP2 and SNP7 in the PttAMT1;2 and PttAMT1;5 genes,respectively,were significantly associated with ground diameter traits.Thus,considerable allelic diversity is present within the candidate genes studied and can be utilized to develop functional markers to select for poplars with improved growth under N stress conditions.展开更多
Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified（GM） plants, especial for tree species. We used the ampl...Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified（GM） plants, especial for tree species. We used the amplitude sequencing method to analyze the V4 regions of the 16 S r RNA gene to identify changes in bacterial diversity and community structure in two GM lines（D520 and D521）, one non-genetically modified（nonGM） line and in uncultivated soil. After chimera filtering,468.133 sequences in the domain Bacteria remained. There were ten dominant taxonomic groups（with [1 % of all sequences） across the samples. 241 of 551 genera（representing a ratio of 97.33 %） were common to all samples.A Venn diagram showed that 1.926 operational taxonomic units（OTUs） were shared by all samples. We found a specific change, a reduction in Chloroflexi, in the microorganisms in the rhizosphere soil planted with poplars. Taken together, the results showed few statistical differences in the bacterial diversity and community structure between the GM line and non-GM line, this suggests that there was no or very limited impact of this genetic modification on the bacterial communities in the rhizosphere.展开更多
Molecular biological research into wood development and formation has been the focus in recent years, but the pace of discovery of related genes and their functions in the control of wood properties has been slow. The...Molecular biological research into wood development and formation has been the focus in recent years, but the pace of discovery of related genes and their functions in the control of wood properties has been slow. The microarray technique--with its advantages of high throughput capacity, sensitivity, and reliability over other tools developed for investigating genes expression patterns-is capable of rapidly assaying thousands of genes. In this study, a cDNA microarray prepared from two cDNA libraries of developing poplar xylem tissues was used to assay gene expression patterns in immature xylem tissues at different heights from the main stem of Populus deltoides （15 years old）, which was confirmed to have distinct wood properties （microfibrillar angle, woody density） by X-ray. Two hundred seventy-four transcripts with differ- ential expression profles between the chips were screened out, and the individual clones were subjected to 5＇ sequencing. Using bioinformatic analysis, we identified candidate genes that may influence poplar wood properties, many of which belong to various regulatory and signal transduction gene families, such as zinc finger protein transcription factor, DNA-binding transcription factor, ethylene response factors, and so on. The results suggest that these genes may regulate enzymes involved in wood formation. Further work will be performed to clone these genes and determine how they influence poplar wood properties.展开更多
DNA methylation, an epigenetic mechanism used by cells to control gene expression, has an important biological role in plant development and environmental fitness. Since plant DNA methylation is closely related to env...DNA methylation, an epigenetic mechanism used by cells to control gene expression, has an important biological role in plant development and environmental fitness. Since plant DNA methylation is closely related to environmental conditions, variation during the day is expected. Here, in genetically identical plants of Populus nigra clone N46, DNA methylation changes in leaves over a 24 h period were detected using the methylation-sensitive amplification polymorphism method. The results showed different DNA methylation patterns in mature poplar leaves: not only in individuals at the same time, but also in samples at each of the six time during the day. In addition, night samples had a higher percentage of methylation than in morning samples. However, no statistically significant differences were found among the samples gathered at different times. Similar results were obtained for three other P. nigra clones with different genetic backgrounds. Real time qPCR showed that the DNA methyltransferase genes Pt-MET1 and Pt-SOM1 involved in CG DNA methylation in poplar were stable over a 24 h period in leaves of P. nigra N46 compared with circadian-controlled genes. That could be part of the reason that methylation of CCGG sites is stable in those leaves. That DNA methylation differed even in genetically identical plants indicates the specificity of DNA methylation changes in their genomes. No statistically significant differences in methylation changes were found between day and night, suggesting that DNA methylation is more stable than expected and is unlikely to be involved in circadian regulation in plants.展开更多
Bamboos are one of the most beautiful and useful plants on Earth.The genetic background and population structure of bamboos are well known,which helps accelerate the process of artificial domestication of bamboo.Parti...Bamboos are one of the most beautiful and useful plants on Earth.The genetic background and population structure of bamboos are well known,which helps accelerate the process of artificial domestication of bamboo.Partial sequences of six genes involved in nitrogen use efficiency in 32 different bamboo species were analyzed for occurrence of single nucleotide polymorphisms(SNPs).The nucleotide diversityθw and total nucleotide polymorphismsπT of the sequenced DNA regions was 0.05137 and 0.03332,respectively.Bothπnonsyn/πsyn and Ka/Ks values were<1.The nucleotide sequences of these six genes were inferred to be relatively conserved,and the haplotype diversity was relatively high.The results of evolutionary neutrality tests showed that the six genes were in line with neutral evolution,and that the NRT2.1 and AMT2.1 gene sequences may have experienced negative selection.An inter-SNP recombination event at the NRT2.1 gene in the all pooled sample,of all 32 bamboo species was the lowest at 0.0645,whereas the AMT gene recombination events were all>0.1.Estimation and analysis of linkage disequilibrium of five genes revealed that with the increase in nucleotide sequence length,the degree of SNP linkage disequilibrium decreased rapidly.We inferred the population genetic structure of 32 bamboo species based on the SNP loci of six genes with frequencies>18%.32 bamboo species were divided into five categories,which indicated that the combined population of all bamboo species had obvious multivariate characteristics and was heterogeneous;red(Group 1)and green(Group 2)were the main groups.展开更多
基金financially supported by the Innovation Project of State Key Laboratory of Tree Genetics and Breeding(Northeast Forestry University)(No.C02)the Fundamental Research Funds for the Central Universities(2572015EA03)+1 种基金China Postdoctoral Science Foundation(2014M561315)the National Natural Science Fund(31500549)
文摘Understanding genetic variation is important for efficiently selecting excellent clones and utilizing genetic resources during tree breeding. We investigated 16 growth traits of 50 32-year-old Pinus koraiensis clones. Analyses of variance showed that all the test traits differed significantly among clones. Average height, diameter at breast height(DBH), and volume of all clones were 10.41 m, 21.30 cm,and 0.148 m3, respectively. Phenotypic coefficients of variation and repeatabilities of traits ranged from 4.37 to48.03% and from 0.013 to 0.900, respectively. There exists significant positive correlations among heights, diameter at different heights(1.3, 3.0, 5.0 m), and volumes; genetic correlation was close to phenotype correlation. Using four growth traits(height, DBH, volume, average crown width)as indices for a comprehensive evaluation, five clones(PK11, PK 19, PK 04, PK 14, and PK 28), whose traits scored in the top 10%, were selected as elite clones. For these clones,genetic gains in height, DBH, volume and crown height were 8.58, 13.02, 32.72 and 3.83%, respectively. These results provide important information for improving P.koraiensis breeding programs.
文摘To characterize the effects of plantation densities on the growth characteristics(diameter at breast level,tree height and volume)and the common wood properties,38-year-old Populus simonii 9 P.nigra clones planted with four levels of spacing(2 m 92 m,3 m 93 m,4 m 94 m,and 5 m 95 m)in a semi-arid area in northeastern China were examined.The results of ANOVA showed significant differences(P\0.01)for all the investigated growth traits and wood properties under different plantation densities,except for the chemical composition of wood.The repeatability and phenotypic variations of all the traits varied from 0.34 to 0.99 and from 13.45 to 59.65%,respectively.Except for wood density,which was significantly negatively correlated with the growth traits,a positive correlation was observed between the growth traits and all the other wood mechanical properties.However,most of the correlations between the growth traits and the chemical composition of the wood were not significant.The path analysis for the wood mechanical characteristics and the growth in the prediction of volume were significant and ranged from 0.18 to 0.72 for wood density and diameter at breast height,respectively,while those for the chemical composition of wood ranged from 0.001 to 0.336,which showed a low impact on the volume.The highest stand volume(610 m3)per hectare was observed with the 2 m 92 m spacing,which consequently provided a high total price and income,while a high individual volume growth per tree was observed with the 5 m 95 m spacing.The results suggested that for the poplar trees younger than 40 years in a semi-arid area in China,2 m 92 m spacing is suitable for obtaining a high volume per hectare,while 5 m 95 m spacing is best for obtaining a high individual volume per tree.
基金financial support this research and the State Key Laboratory of Tree Genetics and Breeding,Research Institute of Forestry,Chinese Academy of Forestry for the instrument support。
文摘It is important to evaluate nitrogen use efficiency and nitrogen tolerance of trees in order to improve their productivity.In this study,both were evaluated for 338 Populus deltoides genotypes from six provenances.The plants were cultured under normal nitrogen(750μM NH_4 NO_3)and low nitrogen(5μM NH_4 NO_3)conditions for 3 months.Growth,chlorophyll content and glutamine synthetase activity of each genotype were measured.Under low nitrogen,heights,ground diameter,leaf area,leaf and root biomass,and chlorophyll contents were significantly lower than those under normal nitrogen level.Correlation analysis showed that nutrient distribution changed under different nitrogen treatments.There was a negative correlation between leaf traits and root biomass under normal nitrogen level,however,the correlation became positive in low nitrogen treatment.Moreover,with the decrease of nitrogen level,the negative correlation between leaf morphology and chlorophyll levels became weakened.The growth of the genotypes under the two treatments was evaluated by combining principal component analysis with a fuzzy mathematical membership function;the results showed that leaf traits accounted for a large proportion of the variation in the evaluation model.According to the results of comprehensive evaluation of plants under the two treatments,the 338 P.deltoides genotypes could be divided into nine categories,with wide genotypic diversity in nitrogen use efficiency and low nitrogen tolerance.As a result,26 N-efficient genotypes and 24 N-inefficient genotypes were selected.By comparative analysis of their morphological and physiological traits under the two treatments,leaf traits could be significant indicators for nitrogen use efficiency and nitrogen tolerance,which is of considerable significance for breeding poplar varieties with high nitrogen use efficiencies.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFD22012052016YFD0600400)。
文摘The growth and wood properties of 240 individual Populus×euramericana cv.’74/76’(hereafter poplar 107)trees planted in Hebei Plain,China was evaluated.Mean annual increments in height,breast height diameter and volume,as well as cellulose,hemicellulose and lignin contents,shrinkage,density,bending strength and modulus of elasticity in the heart wood and sap wood.Environmental factors influencing growth and wood properties were analyzed using correlation and stepwise regres sion.The results show that the coefficients of variation(CVs)of growth traits ranged from 10.6 to 22.4%.The CVs of the chemical properties of heartwood ranged from 4.3 to 30.2%,and for sap wood from 3.2 to 27.5%.The CVs of the physical and mechanical properties of heartwood ranged from 8.6 to 31.7%,and for sapwood from 6.4 to 29.9%.The results of one-way ANOVA showed that there were significant differences in growth traits and wood properties among sites.Soil pH,total and available phosphorus,total potassium,and soil organic matter were key soil factors affecting growth and wood properties of poplar 107,whereas mean annual ground temperatures and precipitation were the main climatic factors.To better cultivate poplar 107,area with less annual rainfall,slightly higher temperature and soil pH value close to neutral should be selected.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2016YFD0600401)the Basic Research Fund of RIF(Grant No.CAFYBB2017ZA001-3)the 12th 5-Year National Science and Technology Support Program(2012BAD01B03).
文摘Branch phenotypic traits determine tree crown architecture,which in turn governs leaf display,light interception,and biomass production.Sylleptic and proleptic branches are the obviously different branch phenotypes in the poplar crown.Many studies have focused on the influence of sylleptic branch numbers(SBN)on biomass production,but the research on the influence of proleptic branch phenotypes was only a few.To explore the relationship between proleptic branch traits and biomass generation production in a high-density poplar plantation,we investigated the branch phenotypic traits of three poplar genotypes,all of which have high survival rates in forests(>95%)and significantly different crown architecture and biomass performance in the high-density plantations(1667 stems ha−1).The plantation site was established in 2007.A terrestrial laser scanner was used to measure branch characteristics such as length,angle of origin and termination,and azi-muth angle.A hierarchical cluster analysis performed on branch characteristics showed that SBN,crown depth,and proleptic branch curvature(PBC)were clustered with bio-mass production and leaf area index(LAI).Among all of the monitored traits,PBC played the second most important role in biomass production after SBN and was significantly correlated with SBN,LAI,and biomass production.The positive correlation between PBC and SBN indicated that a larger PBC was associated with more sylleptic branches within the monitored genotypes planted in the high-density plantation,providing greater leaf area and biomass produc-tion.The results of this study will improve the identification of high-production poplar varieties for cultivation in high-density plantations for biofuel production.
基金This study was financially supported by the national key research and development program of China(Grant No.2016YFD060040)the National Natural Science Foundation of China(31870662)the Natural Science Foundation of key University of Fujian Province(JZ160477).
文摘The European black poplar(Populus nigra L.)has been used as a germplasm resource for the breeding of new poplar varieties around the world.The identification and screening of its high nitrogen use efficiency genotypes could enable the breeding of new resource-efficient poplar varieties.The accessions were screened using MALDI-TOF MS genotyping technology for ammonium transporter(AMT)and nitrate transporters(NRT)genes against phenotypic data for seedling height and ground diameter traits,in both low and high nitrogen environments.Allele re-sequencing of seven genes related to root development was carried out using the minisequencing method.By cluster analysis,101 accessions of black poplar were divided into 4 populations,and it was concluded that Central Europe is the origin of the evolution of low-nitrogen and high-efficiency populations of European black poplar.Association study between SNP typing and seedling height and ground diameter traits showed that there were significant correlations between four SNP loci and growth traits under the contrasting N levels.We found that SNP3 and SNP4 in the PttAMT1;3 gene were significantly associated with seedling height traits,and that SNP2 and SNP7 in the PttAMT1;2 and PttAMT1;5 genes,respectively,were significantly associated with ground diameter traits.Thus,considerable allelic diversity is present within the candidate genes studied and can be utilized to develop functional markers to select for poplars with improved growth under N stress conditions.
基金financially supported by the National High-Tech Research and Development Program of China,863Program(Grant No.2011AA100201)the National Forestry Public Welfare Research Project of China(Grant No.201004004)
文摘Microbe communities in rhizosphere ecosystems are important for plant health but there is limited knowledge of them in the rhizospheres of genetically modified（GM） plants, especial for tree species. We used the amplitude sequencing method to analyze the V4 regions of the 16 S r RNA gene to identify changes in bacterial diversity and community structure in two GM lines（D520 and D521）, one non-genetically modified（nonGM） line and in uncultivated soil. After chimera filtering,468.133 sequences in the domain Bacteria remained. There were ten dominant taxonomic groups（with [1 % of all sequences） across the samples. 241 of 551 genera（representing a ratio of 97.33 %） were common to all samples.A Venn diagram showed that 1.926 operational taxonomic units（OTUs） were shared by all samples. We found a specific change, a reduction in Chloroflexi, in the microorganisms in the rhizosphere soil planted with poplars. Taken together, the results showed few statistical differences in the bacterial diversity and community structure between the GM line and non-GM line, this suggests that there was no or very limited impact of this genetic modification on the bacterial communities in the rhizosphere.
基金supported by the State Key Basic Research Program of China(No.2012CB114506)
文摘Molecular biological research into wood development and formation has been the focus in recent years, but the pace of discovery of related genes and their functions in the control of wood properties has been slow. The microarray technique--with its advantages of high throughput capacity, sensitivity, and reliability over other tools developed for investigating genes expression patterns-is capable of rapidly assaying thousands of genes. In this study, a cDNA microarray prepared from two cDNA libraries of developing poplar xylem tissues was used to assay gene expression patterns in immature xylem tissues at different heights from the main stem of Populus deltoides （15 years old）, which was confirmed to have distinct wood properties （microfibrillar angle, woody density） by X-ray. Two hundred seventy-four transcripts with differ- ential expression profles between the chips were screened out, and the individual clones were subjected to 5＇ sequencing. Using bioinformatic analysis, we identified candidate genes that may influence poplar wood properties, many of which belong to various regulatory and signal transduction gene families, such as zinc finger protein transcription factor, DNA-binding transcription factor, ethylene response factors, and so on. The results suggest that these genes may regulate enzymes involved in wood formation. Further work will be performed to clone these genes and determine how they influence poplar wood properties.
基金supported by National Nonprofit Institute Research Grant of Chinese Academy of Forestry(TGB2013010)
文摘DNA methylation, an epigenetic mechanism used by cells to control gene expression, has an important biological role in plant development and environmental fitness. Since plant DNA methylation is closely related to environmental conditions, variation during the day is expected. Here, in genetically identical plants of Populus nigra clone N46, DNA methylation changes in leaves over a 24 h period were detected using the methylation-sensitive amplification polymorphism method. The results showed different DNA methylation patterns in mature poplar leaves: not only in individuals at the same time, but also in samples at each of the six time during the day. In addition, night samples had a higher percentage of methylation than in morning samples. However, no statistically significant differences were found among the samples gathered at different times. Similar results were obtained for three other P. nigra clones with different genetic backgrounds. Real time qPCR showed that the DNA methyltransferase genes Pt-MET1 and Pt-SOM1 involved in CG DNA methylation in poplar were stable over a 24 h period in leaves of P. nigra N46 compared with circadian-controlled genes. That could be part of the reason that methylation of CCGG sites is stable in those leaves. That DNA methylation differed even in genetically identical plants indicates the specificity of DNA methylation changes in their genomes. No statistically significant differences in methylation changes were found between day and night, suggesting that DNA methylation is more stable than expected and is unlikely to be involved in circadian regulation in plants.
基金This study was financially supported by the National Natural Science Foundation of China(41301346)the Natural Science Foundation of Fujian Province(2020J01375)the Natural Science Foundation of Fujian Province(2015N0034).
文摘Bamboos are one of the most beautiful and useful plants on Earth.The genetic background and population structure of bamboos are well known,which helps accelerate the process of artificial domestication of bamboo.Partial sequences of six genes involved in nitrogen use efficiency in 32 different bamboo species were analyzed for occurrence of single nucleotide polymorphisms(SNPs).The nucleotide diversityθw and total nucleotide polymorphismsπT of the sequenced DNA regions was 0.05137 and 0.03332,respectively.Bothπnonsyn/πsyn and Ka/Ks values were<1.The nucleotide sequences of these six genes were inferred to be relatively conserved,and the haplotype diversity was relatively high.The results of evolutionary neutrality tests showed that the six genes were in line with neutral evolution,and that the NRT2.1 and AMT2.1 gene sequences may have experienced negative selection.An inter-SNP recombination event at the NRT2.1 gene in the all pooled sample,of all 32 bamboo species was the lowest at 0.0645,whereas the AMT gene recombination events were all>0.1.Estimation and analysis of linkage disequilibrium of five genes revealed that with the increase in nucleotide sequence length,the degree of SNP linkage disequilibrium decreased rapidly.We inferred the population genetic structure of 32 bamboo species based on the SNP loci of six genes with frequencies>18%.32 bamboo species were divided into five categories,which indicated that the combined population of all bamboo species had obvious multivariate characteristics and was heterogeneous;red(Group 1)and green(Group 2)were the main groups.
