Time-specific and pleiotropic quantitative trait loci coordinately modulate stem growth in Populus.

In perennial woody plants, the coordinated increase of stem height and diameter during juvenile growth improves competitiveness (i.e. access to light); however, the factors underlying variation in stem growth remain unknown in trees. Here, we used linkage-linkage disequilibrium (linkage-LD) mapping to decipher the genetic architecture underlying three growth traits during juvenile stem growth. We used two Populus populations: a linkage mapping population comprising a full-sib family of 1,200 progeny and an association mapping panel comprising 435 unrelated individuals from nearly the entire natural range of Populus tomentosa. We mapped 311 quantitative trait loci (QTL) for three growth traits at 12 timepoints to 42 regions in 17 linkage groups. Of these, 28 regions encompassing 233 QTL were annotated as 27 segmental homology regions (SHRs). Using SNPs identified by whole-genome re-sequencing of the 435-member association mapping panel, we identified significant SNPs (P ≤ 9.4 × 10-7 ) within 27 SHRs that affect stem growth at nine timepoints with diverse additive and dominance patterns, and these SNPs exhibited complex allelic epistasis over the juvenile growth period. Nineteen genes linked to potential causative alleles that have time-specific or pleiotropic effects, and mostly overlapped with significant signatures of selection within SHRs between climatic regions represented by the association mapping panel. Five genes with potential time-specific effects showed species-specific temporal expression profiles during the juvenile stages of stem growth in five representative Populus species. Our observations revealed the importance of considering temporal genetic basis of complex traits, which will facilitate the molecular design of tree ideotypes.

[Correlation between dietary protein intake and metabolic syndrome in Hubei Province adult residents in 2010-2012].

OBJECTIVE: To explore the correlation between dietary protein intake and metabolic syndrome( MS) among the men and women of Hubei Province. METHODS: Data were obtained from the 2010-2012 Chinese National Nutrition and Health Survey in Hubei Province. Cross-sectional data on 1827 men and women aged l8 years and above was gathered from 6 monitoring sites by multi-stage stratified and Probability Proportionate to Size( PPS) cluster random sampling method. All subjects took the dietary survey with the 24-hour recall method for 3 consecutive days, medical examination and blood assay. Prevalence of MS was defined under the diagnostic criteria of Joint Interim Statement( JIS2009), and the logistic regression was used to explore the possible relationships between dietary protein intake and MS among 18 years old and above adults, when calculating the OR and its 95% CI of MS. RESULTS: After adjusting for covariates, increased risks of MS were related with percentage of energy from protein( OR = 1. 44, 95% CI 1. 19-2. 03) and percentage of protein from animal foods( OR = 1. 16, 95% CI2. 02-2. 08) among men. Meanwhile, no significant correlations were shown betweendietary protein intake and MS among women. CONCLUSION: There are gender differences at the correlation between dietary protein intake and MS. Percentage of energy from protein and percentage of protein from animal foods could possibly be the risk factors of MS among men.

Genetic architecture of growth traits in Populus revealed by integrated quantitative trait locus (QTL) analysis and association studies.

Deciphering the genetic architecture underlying polygenic traits in perennial species can inform molecular marker-assisted breeding. Recent advances in high-throughput sequencing have enabled strategies that integrate linkage-linkage disequilibrium (LD) mapping in Populus. We used an integrated method of quantitative trait locus (QTL) dissection with a high-resolution linkage map and multi-gene association mapping to decipher the nature of genetic architecture (additive, dominant, and epistatic effects) of potential QTLs for growth traits in a Populus linkage population (1200 progeny) and a natural population (435 individuals). Seventeen QTLs for tree height, diameter at breast height, and stem volume mapped to 11 linkage groups (logarithm of odds (LOD) ≥ 2.5), and explained 2.7-18.5% of the phenotypic variance. After comparative mapping and transcriptome analysis, 187 expressed genes (10 046 common single nucleotide polymorphisms (SNPs)) were selected from the segmental homology regions (SHRs) of 13 QTLs. Using multi-gene association models, we observed 202 significant SNPs in 63 promising genes from 10 QTLs (P ≤ 0.0001; FDR ≤ 0.10) that exhibited reproducible associations with additive/dominant effects, and further determined 11 top-ranked genes tightly linked to the QTLs. Epistasis analysis uncovered a uniquely interconnected gene-gene network for each trait. This study opens up opportunities to uncover the causal networks of interacting genes in plants using an integrated linkage-LD mapping approach.

Populus endo-ß-1,4-glucanases gene family: genomic organization, phylogenetic analysis, expression profiles and association mapping.

MAIN CONCLUSION: Extensive characterization of the poplar GH9 gene family provides new insights into GH9 function and evolution in woody species, and may drive novel progress for molecular breeding in trees. In higher plants, endo-ß-1,4-glucanases (cellulases) belonging to the glycosyl hydrolase family 9 (GH9) have roles in cell wall synthesis, remodeling and degradation. To increase the understanding of the GH9 family in perennial woody species, we conducted an extensive characterization of the GH9 family in the model tree species, Populus. We characterized 25 putative GH9 members in Populus with three subclasses (A, B, and C), using structures and bioinformatic analysis. Phylogenetic analyses of 114 GH9s from plant (dicot, monocot, and conifer) and bacterial species (outgroup) demonstrated that plant GH9s are monophyletic with respect to bacteria GH9s. Three subclasses, A, B, and C, of plant GH9 are formed before the divergence of angiosperms and gymnosperms. Chromosomal localization and duplications of GH9s in the Populus genome showed that eight paralogous pairs remained in conserved positions on segmental duplicated blocks, suggesting duplication of chromosomal segments has contributed to the family expansion. By examining tissue-specific expression profiles for all 25 members, we found that GH9 members exhibited distinct but partially overlapping expression patterns, while certain members have higher transcript abundance in mature or developing xylem. Based on our understanding of intraspecific variation and linkage disequilibrium of two KORRIGANs (PtoKOR1 and PtoKOR2) in natural population of Populus tomentosa, two non-synonymous SNPs in PtoKOR1 associated with fiber width and holocellulose content were obtained. Characterizations of the poplar GH9 family provide new insights into GH9 function and evolution in woody species, and may drive novel progress for molecular breeding in trees.

Single nucleotide polymorphisms in a cellulose synthase gene (PtoCesA3) are associated with growth and wood properties in Populus tomentosa.

In plants, the composition and organization of the cell wall determine cell shape, enable cell expansion, and affect the properties of woody tissues. Cellulose synthase (CesA) genes encode the enzymes involved in the synthesis of cellulose which is the major component of plant primary and secondary cell walls. Here, we isolated a full-length PtoCesA3 cDNA from the stem cambium tissue of Populus tomentosa. Tissue-specific expression profiling showed that PtoCesA3 is highly expressed during primary cell wall formation. Estimation of single nucleotide polymorphism (SNP) diversity and linkage disequilibrium (LD) revealed that PtoCesA3 harbors high SNP diversity (π(T) = 0.00995 and θ(w) = 0.0102) and low LD (r(2) ≥ 0.1, within 1,280 bp). Association analysis in a P. tomentosa association population (460 individuals) showed that seven SNPs (false discovery rate Q < 0.10) and five haplotypes (Q < 0.10) were significantly associated with growth and wood properties, explaining 4.09-7.02% of the phenotypic variance. All significant marker-trait associations were validated in at least one of the three smaller subsets (climatic regions) while five associations were repeated in the linkage population. Variation in RNA transcript abundance among genotypic classes of significant loci was also confirmed in the association or linkage populations. Identification of PtoCesA3 and examining its allelic polymorphisms using association studies open an avenue to understand the mechanism of cellulose synthesis in the primary cell wall and its effects on the properties of woody tissues.

Allelic variation within the S-adenosyl-L-homocysteine hydrolase gene family is associated with wood properties in Chinese white poplar (Populus tomentosa).

BACKGROUND: S-adenosyl-l-homocysteine hydrolase (SAHH) is the only eukaryotic enzyme capable of S-adenosyl-l-homocysteine (SAH) catabolism for the maintenance of cellular transmethylation potential. Recently, biochemical and genetic studies in herbaceous species have obtained important discoveries in the function of SAHH, and an extensive characterization of SAHH family in even one tree species is essential, but currently lacking. RESULTS: Here, we first identified the SAHH family from Populus tomentosa using molecular cloning method. Phylogenetic analyses of 28 SAHH proteins from dicotyledons, monocotyledons, and lower plants revealed that the sequences formed two monophyletic groups: the PtrSAHHA with PtoSAHHA and PtrSAHHB with PtoSAHHB. Examination of tissue-specific expression profiles of the PtoSAHH family revealed similar expression patterns; high levels of expression in xylem were found. Nucleotide diversity and linkage disequilibrium (LD) in the PtoSAHH family, sampled from P. tomentosa natural distribution, revealed that PtoSAHH harbors high single-nucleotide polymorphism (SNP) diversity (π = 0.01059 ± 0.00122 and 0.00930 ± 0.00079,respectively) and low LD (r2 > 0.1, within 800 bp and 2,200 bp, respectively). Using an LD-linkage analysis approach, two noncoding SNPs (PtoSAHHB_1065 and PtoSAHHA_2203) and the corresponding haplotypes were found to significantly associate with α-cellulose content, and a nonsynonymous SNP (PtoSAHHB_410) within the SAHH signature motifs showed significant association with fiber length, with an average of 3.14% of the phenotypic variance explained. CONCLUSIONS: The present study demonstrates that PtoSAHHs were split off prior to the divergence of interspecies in Populus, and SAHHs may play a key role promoting transmethylation reactions in the secondary cell walls biosynthesis in trees. Hence, our findings provide insights into SAHH function and evolution in woody species and also offer a theoretical basis for marker-aided selection breeding to improve the wood quality of Populus.

[Evaluation of the feeding status of infants and young children under 2 years old in rural areas of Hubei province].

OBJECTIVE: To evaluate the current feeding status of infants and young children under 2 years old in rural areas of Hubei province. METHODS: The study was conducted by cluster random sampling from September 2009 to march 2010. The data on breastfeeding and complementary food supplement of the 1 197 infants and young children aged 0-23 months in 8 counties of Hubei province were collected through questionnaires. The feeding status was analyzed according to the WHO 2008 edition of Indicators for assessing infant and young child feeding practices. RESULTS: A total of 1 197 children aged 0-23 months were investigated. The rate of ever breastfeeding of children aged 0-23 months reached up to 93.9% (1 124/1 197), while the percentage of early initiation of breastfeeding was only 22.0% (263/1 197). The rates of exclusive breastfeeding under 6 months, continued breastfeeding for 1 year, and continued breastfeeding for 2 years were 72.1% (277/384), 17.0% (26/153) and 4.9% (7/144), respectively. The median time of giving complementary food was the 6th month and the weaning time was the 9th month. The rate of complementary food supplemented from 6th-8th month in time was 61.8% (444/718) . The rates of minimum dietary diversity, minimum meal frequency, minimum acceptable diet, and consumption of iron-rich or iron-fortified foods among children aged 6-23 months were 61.7% (502/813), 81.5% (663/813), 54.4% (442/813) and 50.1% (407/813), respectively. CONCLUSION: Late initiation of breastfeeding, non-continued breastfeeding, giving complementary food too early or too late, inadequate category and frequency of complementary food, and the low rate of consumption of iron-rich or iron-fortified foods were the main issues to be concerned on infant feeding in rural areas of Hubei province.

Preparation and Characterization of Soybean Protein Adhesives Modified with an Environmental-Friendly Tannin-Based Resin.

Soybean protein-based adhesives are limited in their application due to their poor wet bonding strength and poor water resistance. Herein, we prepared a novel, environmentally friendly soybean protein-based adhesive by adding tannin-based resin (TR) to improve the performance of water resistance and wet bonding strength. The active sites of TR reacted with the soybean protein and its functional groups and formed strong cross-linked network structures, which improved the cross-link density of the adhesives and then improved the water resistance. The residual rate increased to 81.06% when 20 wt%TR was added, and the water resistance bonding strength reached 1.07 MPa, which fully met the Chinese national requirements for plywood (Class II, ≥0.7 MPa). SEM observations were performed on the fracture surfaces of all modified SPI adhesives after curing. The modified adhesive has a denser and smooth cross-section. Based on the TG and DTG plots, the thermal stability performance of the TR-modified SPI adhesive was improved when TR was added. The total weight loss of the adhesive decreased from 65.13% to 58.87%. This study provides a method for preparing low-cost and high-performance, environmentally friendly adhesives.

Better adherence to the Chinese Healthy Eating Index is associated with a lower prevalence of metabolic syndrome and its components.

The Chinese Healthy Eating Index (CHEI) was built on Dietary Guidelines for Chinese-2016 and has been confirmed as a valid measuring instrument to evaluate the diet quality of the Chinese population. Studies have shown that healthy dietary patterns were associated with reduced metabolic syndrome (MS) risk. Here, we hypothesized a better adherence to CHEI was effective in preventing MS. Therefore, we performed a cross-sectional study (n = 704; 298 males and 406 females) in Hubei. Dietary data were collected by 3-day 24-hour dietary recalls. MS was diagnosed using Guidelines for the Prevention and Control of type 2 Diabetes in China (2017 edition). Logistic regression and propensity and restricted cubic splines analysis were used to evaluate the associations of CHEI with MS and its components. In a comparison of the adjusted risk of MS in participants in the third and first tertile of CHEI, a 47% lower risk was observed for MS in females, especially for those who were middle-aged. However, no significant association of CHEI was exhibited with MS in males. Propensity analysis validated the findings in females, presenting a 58% lower MS risk and 71% lower risk of central obesity. It exhibited a linear association of CHEI score with MS and abdominal obesity. The associations were consistent after excluding those with prior hypertension or diabetes mellitus. In conclusion, a negative linear association was identified between CHEI score and MS and central obesity, which was pronounced in females.

[The influence of the nutrient supplement for children on the nutrition and health status and intelligence of children of schooling age in the countryside of children of schooling age during 2 years].

OBJECTIVE: To analyze the effect of complex nutrients on growth and development, intelligence and nutrition state of 6-12 years old children in two continuous years. METHODS: According to the rural school's similar condition, such as social economical statement, education condition and proportion of students entering schools, 6 rural schools were respectively selected in Xishui County of Hubei Province as the experimental group and control group. In the former, middle and later periods (2004, 2005, 2006 ), growth and development, nutrition state and intelligence were analyzed and compared. RESULTS: The increase of height and weight in experimental group were higher than those of the control group. In 2 years, height in experimental group increased 12.9 cm, while the control group increased 11.5 cm. Weights increased in experimental group were 6.6 kg, while the control group increased 5.2 kg. Girl's bone density in experimental group increased from 0.236 g/cm in 2004 to 0.280 g/cm in 2006. The hemoglobin contents of 4 age group's children in experimental group increased significantly (P < 0.05) . While the anemia prevalence decreased 25 .8% in 2 years, the control group decreased 7.2%. Moreover, other results showed that the complex nutrients also have some effect on the intelligence in experiment group. CONCLUSIONS: The complex nutrients supplement could improve the rural school children's growth and development, bone and intelligence.

Dissection of Insertion-Deletion Variants within Differentially Expressed Genes Involved in Wood Formation in Populus.

Short insertions and deletions (InDels) are one of the major genetic variants and are distributed widely across the genome; however, few investigations of InDels have been conducted in long-lived perennial plants. Here, we employed a combination of RNA-seq and population resequencing to identify InDels within differentially expressed (DE) genes underlying wood formation in a natural population of Populus tomentosa (435 individuals) and utilized InDel-based association mapping to detect the causal variants under additive, dominance, and epistasis underlying growth and wood properties. In the present paper, 5,482 InDels detected from 629 DE genes showed uneven distributions throughout all 19 chromosomes, and 95.9% of these loci were diallelic InDels. Seventy-four InDels (positive false discovery rate q ≤ 0.10) from 68 genes exhibited significant additive/dominant effects on 10 growth and wood-properties, with an average of 14.7% phenotypic variance explained. Potential pleiotropy was observed in one-third of the InDels (representing 24 genes). Seven genes exhibited significantly differential expression among the genotypic classes of associated InDels, indicating possible important roles for these InDels. Epistasis analysis showed that overlapping interacting genes formed unique interconnected networks for each trait, supporting the putative biochemical links that control quantitative traits. Therefore, the identification and utilization of InDels in trees will be recognized as an effective marker system for molecular marker-assisted breeding applications, and further facilitate our understanding of quantitative genomics.

[Protection of tooth protecting spray against dental carries].

OBJECTIVE: To investigate the growth, adherence and soul production of streptococcus mutans incubated with olitin tooth protecting spray and the effect of specific sample against dental caries. METHODS: Streptococcus mutans were cultured with the sample of Olitin tooth protecting spray. After culturing, S. mutans were observed by Gram stain and by spectrophotometer, and the percentages of the adherent S. mutans were calculated. 40 Wistar rats were divided into 4 groups: group A was control group; group B,C,D was low, middle, high test group respectively. All test groups received samples. The sum of the caries scores was assessed by the Keyes' procedure. RESULTS: The sample did not inhibit the growth of S. mutans, but the long chain was occurred. The adherence of S. mutans cells on the glass was decrease, the pH value was increase to above 6.0. There was a significant lower mean of caries score of test group than control group. CONCLUSION: The sample can prevent the development of dental caries in this experiment. The mechanism may relate with the decrease of adherence of S. mutans.

Development and application of microsatellites in candidate genes related to wood properties in the Chinese white poplar (Populus tomentosa Carr.).

Gene-derived simple sequence repeats (genic SSRs), also known as functional markers, are often preferred over random genomic markers because they represent variation in gene coding and/or regulatory regions. We characterized 544 genic SSR loci derived from 138 candidate genes involved in wood formation, distributed throughout the genome of Populus tomentosa, a key ecological and cultivated wood production species. Of these SSRs, three-quarters were located in the promoter or intron regions, and dinucleotide (59.7%) and trinucleotide repeat motifs (26.5%) predominated. By screening 15 wild P. tomentosa ecotypes, we identified 188 polymorphic genic SSRs with 861 alleles, 2-7 alleles for each marker. Transferability analysis of 30 random genic SSRs, testing whether these SSRs work in 26 genotypes of five genus Populus sections (outgroup, Salix matsudana), showed that 72% of the SSRs could be amplified in Turanga and 100% could be amplified in Leuce. Based on genotyping of these 26 genotypes, a neighbour-joining analysis showed the expected six phylogenetic groupings. In silico analysis of SSR variation in 220 sequences that are homologous between P. tomentosa and Populus trichocarpa suggested that genic SSR variations between relatives were predominantly affected by repeat motif variations or flanking sequence mutations. Inheritance tests and single-marker associations demonstrated the power of genic SSRs in family-based linkage mapping and candidate gene-based association studies, as well as marker-assisted selection and comparative genomic studies of P. tomentosa and related species.

Allelic variation in a cellulose synthase gene (PtoCesA4) associated with growth and wood properties in Populus tomentosa.

Lignocellulosic biomass from trees provides a renewable feedstock for biofuels, lumber, pulp, paper, and other uses. Dissecting the mechanism underlying natural variation of the complex traits controlling growth and lignocellulose biosynthesis in trees can enable marker-assisted breeding to improve wood quality and yield. Here, we combined linkage disequilibrium (LD)-based association analysis with traditional linkage analysis to detect the genetic effect of a Populus tomentosa cellulose synthase gene, PtoCesA4. PtoCesA4 is strongly expressed in developing xylem and leaves. Nucleotide diversity and LD in PtoCesA4, sampled from the P. tomentosa natural distribution, revealed that PtoCesA4 harbors high single nucleotide polymorphism (SNP) diversity (πT = 0.0080 and θw = 0.0098) and low LD (r(2) ≥ 0.1, within 1400 bp), demonstrating that the potential of a candidate-gene-based LD approach in understanding the molecular basis underlying quantitative variation in this species. By combining single SNP, multi-SNP, and haplotype-based associations in an association population of 460 individuals with single SNP linkage analysis in a family-based linkage populations (1200 individuals), we identified three strong associations (false discovery rate Q < 0.05) in both populations. These include two nonsynonymous markers (SNP49 associated with α-cellulose content and SNP59 associated with fiber width) and a noncoding marker (SNP18 associated with α-cellulose content). Variation in RNA transcript abundance among genotypic classes of SNP49 was confirmed in these two populations. Therefore, combining different methods allowed us to examine functional PtoCesA4 allelic variation underlying natural variation in complex quantitative traits related to growth and lignocellulosic biosynthesis.