Bailian Li
NC State University, Forestry, Faculty Member
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Research Interests: Genetics, Energy Conservation, Molecular Genetics, Gene expression, Functional Genomics, and 13 moreGenetic Testing, Genetic Map, General Combining Ability, Specific Combining Ability, Analytical Method, Microarray Analysis, Pulp and Paper Industry, Molecular Marker, Wood properties, Genetic variation, Loblolly Pine, Physical Properties, and Genetic Correlation
ABSTRACT Abstract: Two intra-provenance [Atlantic Coastal (C�C), Piedmont (P�P)] and two inter-provenance [Atlantic Coastal � Piedmont (C�P), Piedmont � Atlantic Coastal (P�C)] loblolly pine (Pinus taeda L.) populations, represented by 80... more
ABSTRACT Abstract: Two intra-provenance [Atlantic Coastal (C�C), Piedmont (P�P)] and two inter-provenance [Atlantic Coastal � Piedmont (C�P), Piedmont � Atlantic Coastal (P�C)] loblolly pine (Pinus taeda L.) populations, represented by 80 polycross families, were assessed for height, volume, and survival in five Piedmont regions at four years of age. The hybrid populations (C�P, P�C) were intermediate among the pure opulations (C�C, P�P). Across and within regions the C�P hybrids were significantly taller and more productive in volume than the pure P�P, with performance comparable to that of C�C. The C�P hybrids exhibited stronger additive genetic control for both height and volume across and within regions, except for the two inland egions, where the P�C hybrids’ genetic control for height was stronger. Stability of performance in height and volume varied among families within populations. These early results suggest that the C�P hybrids will perform better in milder Piedmont environments, while the P�C hybrids could be suitable for more inland and northern Piedmont sites. Long-term evaluation of population performance and adaptability is essential before implementing such a plan in the Piedmont.
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ABSTRACT: Early growth and fusiform rust resistance of loblolly pine (Pinus taeda L. ) rooted cuttings and seedlings from the same nine full-sib families established on two sites (Nassau Co., FL and Monroe Co., AL) were compared. Although... more
ABSTRACT: Early growth and fusiform rust resistance of loblolly pine (Pinus taeda L. ) rooted cuttings and seedlings from the same nine full-sib families established on two sites (Nassau Co., FL and Monroe Co., AL) were compared. Although site effects on growth were large, ...
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Biomass of stem, needles, and roots were determined for seedlings of 23 open-pollinated loblolly pine families alter 20 weeks' growth in a greenhouse under two nitrogen (N) levels (5 and 50 ppm). Allometric analysis was used to... more
Biomass of stem, needles, and roots were determined for seedlings of 23 open-pollinated loblolly pine families alter 20 weeks' growth in a greenhouse under two nitrogen (N) levels (5 and 50 ppm). Allometric analysis was used to determine the N and family effects on the biomass allocation. Nitrogen had significant effects on seedling growth and biomass allocation to stem, needles, and roots. Low N resulted in smaller seedling size, but relatively more biomass was allocated to roots than under the high N condition. N stress generally favored biomass allocation to roots at the expense of needles or both needles and stem. Relative allocation of biomass to roots was significantly different among families with low N but not with high N. Larger seedlings exhibited greater allocation to roots possibly as a result of greater N stress. Different patterns of biomass allocation among loblolly pine families were related to their stem weight and height. Families with superior stem weight and ...
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Populus simonii Carr. is an important ecological and commercial breeding species in northern China; however, human interference during the last few centuries has led to the reduction and fragmentation of natural populations. To evaluate... more
Populus simonii Carr. is an important ecological and commercial breeding species in northern China; however, human interference during the last few centuries has led to the reduction and fragmentation of natural populations. To evaluate genetic diversity and differentiation within and among existing populations, we used 20 microsatellite markers to examine the genetic variation and structure of 16 natural populations. Our results indicated that the level of genetic diversity differed among populations, with average number of alleles per locus (AR) and expected heterozygosity (H e) ranging from 3.7 to 6.11 and 0.589 to 0.731, respectively. A marginal population from Qilian in the Qinghai–Tibetan Plateau showed the highest values (AR = 6.11, H e = 0.731), and the Zhangjiakou and Yishui populations showed the lowest values (AR = 4.08, H e = 0.589 and AR = 3.7, H e = 0.604). The inbreeding coefficient (F IS) values for all populations were positive, which indicated an excess of homozygo...
Despite the significance of actin in plant growth and development, little is known of the structure, expression and evolution of the actin gene family in woody plants. In this study, we systematically examined the diversification of the... more
Despite the significance of actin in plant growth and development, little is known of the structure, expression and evolution of the actin gene family in woody plants. In this study, we systematically examined the diversification of the actin gene family in Populus by integrating genomic organization, expression, and phylogeny data. Genome-wide analysis of the Populus genome indicated that actin is a multigene family consisting of eight members, all predicted to encode 377-amino acid polypeptides that share high sequence homology ranging from 94.2 to 100% identity. Microarray and real-time PCR expression analysis showed that the PtrACT family members are differentially expressed in different tissues, exhibiting overlapping and unique expression patterns. Of particular interest, all PtrACT genes have been found to be preferentially expressed in the stem phloem and xylem, suggesting that poplar PtrACTs are involved in the wood formation. Gene structural and phylogenetic analyses revea...
Research Interests: Genetics, Functional Genomics, real time PCR, Phylogeny, Populus, and 13 moreWood, Plant growth, Plants, Phylogenetic analysis, Plant Molecular Genetics and Functional Genomics, Gene Structure, Tree growth, Genome Organization, Woody Plants, Amino Acid Profile, Gene Family, Expression analysis, and Differential expression
In woody crop plants, the oligosaccharide components of the cell wall are essential for important traits such as bioenergy content, growth, and structural wood properties. UDP-glucuronate decarboxylase (UXS) is a key enzyme in the... more
In woody crop plants, the oligosaccharide components of the cell wall are essential for important traits such as bioenergy content, growth, and structural wood properties. UDP-glucuronate decarboxylase (UXS) is a key enzyme in the synthesis of UDP-xylose for the formation of xylans during cell wall biosynthesis. Here, we isolated a multigene family of seven members (PtUXS1-7) encoding UXS from Populus tomentosa, the first investigation of UXSs in a tree species. Analysis of gene structure and phylogeny showed that the PtUXS family could be divided into three groups (PtUXS1/4, PtUXS2/5, and PtUXS3/6/7), consistent with the tissue-specific expression patterns of each PtUXS. We further evaluated the functional consequences of nucleotide polymorphisms in PtUXS1. In total, 243 single-nucleotide polymorphisms (SNPs) were identified, with a high frequency of SNPs (1/18 bp) and nucleotide diversity (πT = 0.01033, θw = 0.01280). Linkage disequilibrium (LD) analysis showed that LD did not ext...
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Chinese white poplar (Populus tomentosa), an important commercial tree species for timber and pulp production in northern China, has been used to examine the individual genes and allelic diversity responsible for complex traits... more
Chinese white poplar (Populus tomentosa), an important commercial tree species for timber and pulp production in northern China, has been used to examine the individual genes and allelic diversity responsible for complex traits controlling growth and lignocellulosic biosynthesis. Taking advantage of the low degree of linkage disequilibrium (LD) within P. tomentosa association populations, we examined associations between 15 cellulose synthase (PtoCesA) genes and traits including growth and wood properties. Thirty-six novel simple sequence repeat (SSR) markers within PtoCesA genes were detected by re-sequencing and genotyped in an association population (460 individuals). Single-marker and haplotype-based LD approaches were used to identify significant marker-trait associations. Family-based linkage studies and real-time PCR testing were conducted to validate the functional significance of SSR variation. Fifteen single-marker associations from seven PtoCesA genes and nine haplotype-b...
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To optimize marker-assisted selection programs, knowledge of the genetic architecture of phenotypic traits is very important for breeders. Generally, most phenotypes, e.g. morphological and physiological traits, are quantitatively... more
To optimize marker-assisted selection programs, knowledge of the genetic architecture of phenotypic traits is very important for breeders. Generally, most phenotypes, e.g. morphological and physiological traits, are quantitatively inherited, and thus detection of the genes underlying variation for these traits is difficult. Association mapping based on linkage disequilibrium has recently become a powerful approach to map genes or quantitative trait loci (QTL) in plants. In this study, association analysis using 20 simple sequence repeat (SSR) markers was performed to detect the marker loci linked to 13 morphological traits and 10 physiological traits in a wild P. simonii population that consisted of 528 individuals sampled from 16 sites along the Yellow River in China. Based on a model controlling for both population structure (Q) and relative kinship (K), three SSR markers (GCPM_616-1 in 31.2 Mb on LG I, GCPM_4055-2 in 5.7 Mb on LG XV, and GCPM_3142 of unknown location) were identi...
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MicroRNAs (miRNAs) play important roles in the regulation of gene expression in various biological processes. However, the interactions between miRNAs and their targets are largely unknown in plants. As a powerful tool for identification... more
MicroRNAs (miRNAs) play important roles in the regulation of gene expression in various biological processes. However, the interactions between miRNAs and their targets are largely unknown in plants. As a powerful tool for identification of variation associated with traits, association genetics provides another strategy for exploration of interactions between miRNAs and their targets. Here, we conducted expression analysis and association mapping to evaluate the interaction between Pto-miR160a and its target Pto-ARF16 in Populus tomentosa. By examining the expression patterns of Pto-MIR160a and Pto-ARF16, we identified a significant, negative correlation between their expression levels, indicating that Pto-miR160a may affect the expression of Pto-ARF16. Among the single nucleotide polymorphisms (SNPs) identified in this study, one common SNP in the pre-miRNA region of Pto-miR160a altered its predicted secondary structure while another common SNP in the predicted miRNA target site changed the binding affinity of Pto-miR160a. Linkage disequilibrium (LD) analysis revealed low LD levels of Pto-MIR160a and Pto-ARF16, indicating that they are suitable for candidate gene-based association analysis. Single SNP-based association analysis identified 19 SNPs (false discovery rate Q < 0.05) in Pto-MIR160a and Pto-ARF16 associated with three phenotypic traits. Epistasis analysis further identified 36 SNP-SNP interactions between SNPs in Pto-MIR160a and SNPs in Pto-ARF16, reflecting the possible genetic interaction of Pto-miR160a and Pto-ARF16. Taking these results together, our study identified SNPs in Pto-MIR160a and Pto-ARF16 associated with tree growth and wood properties, providing SNPs with potential applications in marker-assisted breeding and evidence for the genetic interaction of Pto-miR160a and Pto-ARF16.
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The distributions of genetic variance components and their ratios (heritability and type-B genetic correlation) from 105 pairs of six-parent disconnected half-diallels of a breeding population of loblolly pine (Pinus taeda L.) were... more
The distributions of genetic variance components and their ratios (heritability and type-B genetic correlation) from 105 pairs of six-parent disconnected half-diallels of a breeding population of loblolly pine (Pinus taeda L.) were examined. A series of simulations based on these estimates were carried out to study the coverage accuracy of confidence intervals based on the usual t-method and several other alternative methods. Genetic variance estimates fluctuated greatly from one experiment to another. Both general combining ability variance (sigma(2) (g)) and specific combining ability variance (sigma(2) (s)) had a large positive skewness. For sigma(2) (g) and sigma(2) (s), a skewness-adjusted t-method proposed by Boos and Hughes-Oliver (Am Stat 54:121-128, 2000) provided better upper endpoint confidence intervals than t-intervals, whereas they were similar for the lower endpoint. Bootstrap BCa-intervals (Efron and Tibshirani, An introduction to the bootstrap. Chapman & Hall, London 436 p, 1993) and Hall's transformation methods (Zhou and Gao, Am Stat 54:100-104, 2000) had poor coverages. Coverage accuracy of Fieller's interval endpoint(J R Stat Soc Ser B 16:175-185, 1954) and t-interval endpoint were similar for both h(2) and r(B) for sample sizes n</=10, but for n=30 the Fieller's method is much better.
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ABSTRACT Fifteen provenance/progeny tests of Pinus tecunumanii (Schw.) Eguiluz et Perry were assessed for upper-crown stem breakage at 5 to 8 years of age in Brazil, Colombia and South Africa. Five year results indicated that the mean... more
ABSTRACT Fifteen provenance/progeny tests of Pinus tecunumanii (Schw.) Eguiluz et Perry were assessed for upper-crown stem breakage at 5 to 8 years of age in Brazil, Colombia and South Africa. Five year results indicated that the mean percent stem breakage was moderate in Colombia (14% to 21%), low in South Africa (2% to 6%) and very low in Brazil (P. tecunumanii exhibited 13% stem breakage. Family variation in stem breakage ranged from 0 to 44% in Colombia and 0 to 33% in South Africa at 5 years of age and were highly significant. The Spearman rank correlations in stem breakage of 36 half-sib families common to tests in Colombia and South Africa were r=0.13 and not significant. Family heritabilities for stem breakage at 5 and 8 years of age ranged from 0.17 to 0.63. Results indicate that stem breakage was more common on trees with branches of large diameter and was not strongly related to growth rate.
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We present a novel adaptive radial basis function network to reconstruct smooth closed surfaces and complete meshes from non-uniformly sampled noisy range data. The network is established using a heuristic learning strategy. Neurons can... more
We present a novel adaptive radial basis function network to reconstruct smooth closed surfaces and complete meshes from non-uniformly sampled noisy range data. The network is established using a heuristic learning strategy. Neurons can be inserted, removed or updated iteratively, adapting to the complexity and distribution of the underlying data. This flexibility is particularly suited to highly variable spatial frequencies,
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The objectives of characterization of subsurface contamination are to provide information for the evaluation of: (1) the environmental effects of these contaminants; and (2) alternate remediation measures. However, the procedure is very... more
The objectives of characterization of subsurface contamination are to provide information for the evaluation of: (1) the environmental effects of these contaminants; and (2) alternate remediation measures. However, the procedure is very complex. Complete characterization is very time consuming and costly if not impossible. In this paper, we propose an adaptive fuzzy modeling framework for the characterization of potentially contaminated sites when there is a lack of complete knowledge and detailed information
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Research Interests: Evolutionary Biology, Genetics, Reproduction, Heredity, Pollen, and 3 moreCell nucleus, Seeds, and Cytoplasm
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Human immunodeficiency virus (HIV) infection yields a high level of non-integrated viral DNA in the infected cells and up to 99% of total viral DNA can be capable of transcription. This capability of non-integrated viral DNA is reducing... more
Human immunodeficiency virus (HIV) infection yields a high level of non-integrated viral DNA in the infected cells and up to 99% of total viral DNA can be capable of transcription. This capability of non-integrated viral DNA is reducing the efficacy of anti-HIV drug development approaches that solely focus on the integration reactions of viral replication. Using kinetic modeling, we show the transient coordinated regulation of viral DNA production by retrovirus-encoded interacting enzymes reverse transcriptase (RT) and integrase (IN), and thus we identify a possible mechanism for reducing overall efficiency of viral replication. The results indicate that both IN·RT and IN·DNA complexes and their formation rates affect RT processivity and thereby the viral DNA expression level within the pre-integration complex.
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As the economic and financial center of China, Shanghai has experienced an extensive urban expansion since the early 1980s, with an attendant cost in environmental degradation. We use an integrated pollution index to study the temporal... more
As the economic and financial center of China, Shanghai has experienced an extensive urban expansion since the early 1980s, with an attendant cost in environmental degradation. We use an integrated pollution index to study the temporal variations of surface water quality in urban, suburban and rural areas between 1982 and 2005. Data on monitored cross-sections were collected from the Shanghai Environmental Monitoring Center. The results indicated that the spatial pattern of surface water quality was determined by the level of urbanization. Surface water qualities in urban and suburban areas were improved by strengthening the environmental policies and management, but were worsening in rural areas. The relationship between economic growth and surface water quality in Shanghai showed an inversed-U-shaped curve, which reflected a similar pattern in most developed countries. This research suggests that decision makers and city officials should be more aware of the recent pollution increases in Shanghai.
Research Interests: Environmental policy, Economic Growth, Economic Development, Population Dynamics, Environmental Monitoring, and 22 moreChina, Rivers, Urbanization, Water Pollution, Environmental Pollution, Multidisciplinary, TIME, Urbanisation, Water Supply, Developing Country, Surface Water, Environmental degradation, Sanitation, Spatial Pattern, Chine, Cross Section, Spatial Variation, Time, Rural Area, Indexation, Decision Maker, and Water Movements(China, Rivers, Urbanization, Water Pollution, Environmental Pollution, Multidisciplinary, TIME, Urbanisation, Water Supply, Developing Country, Surface Water, Environmental degradation, Sanitation, Spatial Pattern, Chine, Cross Section, Spatial Variation, Time, Rural Area, Indexation, Decision Maker, and Water Movements)
(China, Rivers, Urbanization, Water Pollution, Environmental Pollution, Multidisciplinary, TIME, Urbanisation, Water Supply, Developing Country, Surface Water, Environmental degradation, Sanitation, Spatial Pattern, Chine, Cross Section, Spatial Variation, Time, Rural Area, Indexation, Decision Maker, and Water Movements)
To use fractal models for ecological and geologic data, the statistical properties of fractals need to be clarified. No sampling or estimation theory for fractals currently exists. Several concrete steps in this direction are taken here.... more
To use fractal models for ecological and geologic data, the statistical properties of fractals need to be clarified. No sampling or estimation theory for fractals currently exists. Several concrete steps in this direction are taken here. First, the information fractal dimension is ...