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Zhou P.,Shanghai JiaoTong University | Zhu Q.,National Engineering Laboratory for Tree Breeding | Zhu Q.,Beijing Forestry University | Xu J.,National Engineering Laboratory for Tree Breeding | And 3 more authors.
Crop Science | Year: 2011

Expansin proteins play a role in regulating cell growth and plant adaptation to various environmental stresses. The objectives of this study were to clone and characterize the expression and promoter activity of a gene in creeping bentgrass (Agrostis stolonifera L.) encoding an expansin protein, AsEXP1, in response to heat stress and plant hormones. The AsEXP1 cloned from the genome of heat-tolerant genotype 'Penn A-4' spans a 2659 bp DNA sequence and consists of three coding sequences, two introns, a 962 bp 5'-noncoding region, and a 483 bp 3'-noncoding region. Several putative abscisic acid (ABA)-response cis-elements and gibberellic acid (GA)-response cis-elements were found nearby TATA box in the promoter region through the search of PlantCARE database and PLACE database search. AsEXP1 transcripts were detected by reverse transcription polymerase chain reaction (RT-PCR) in Penn A-4 leaves treated with ABA and GA, while no transcripts were detected in untreated plants. The AsEXP1 promoter was cloned into a binary vector fused to a β-glucuronidase (GUS) marker gene (pAsEXP1-GUS) and introduced into rice (Oryza sativa L.) callus ('Kassalatha'). Reverse transcription polymerase chain reaction confi rmed that the expression of pAsEXP1 in A. stolonifera was inducible by heat stress and exogenous applications of GA and ABA. Our results demonstrate that the AsEXP1 gene may be involved in the signal pathway of hormone regulation of plant responses to heat stress. © Crop Science Society of America.


Chao N.,Beijing Forestry University | Liu S.-X.,Beijing Forestry University | Liu B.-M.,Beijing Forestry University | Li N.,Beijing Forestry University | And 5 more authors.
Planta | Year: 2014

Main conclusion: Nine CAD/CAD-like genes inP. tomentosawere classified into four classes based on expression patterns, phylogenetic analysis and biochemical properties with modification for the previous claim of SAD.Cinnamyl alcohol dehydrogenase (CAD) functions in monolignol biosynthesis and plays a critical role in wood development and defense. In this study, we isolated and cloned nine CAD/CAD-like genes in the Populus tomentosa genome. We investigated differential expression using microarray chips and found that PtoCAD1 was highly expressed in bud, root and vascular tissues (xylem and phloem) with the greatest expression in the root. Differential expression in tissues was demonstrated for PtoCAD3, PtoCAD6 and PtoCAD9. Biochemical analysis of purified PtoCADs in vitro indicated PtoCAD1, PtoCAD2 and PtoCAD8 had detectable activity against both coniferaldehyde and sinapaldehyde. PtoCAD1 used both substrates with high efficiency. PtoCAD2 showed no specific requirement for sinapaldehyde in spite of its high identity with so-called PtrSAD (sinapyl alcohol dehydrogenase). In addition, the enzymatic activity of PtoCAD1 and PtoCAD2 was affected by temperature. We classified these nine CAD/CAD-like genes into four classes: class I included PtoCAD1, which was a bone fide CAD with the highest activity; class II included PtoCAD2, -5, -7, -8, which might function in monolignol biosynthesis and defense; class III genes included PtoCAD3, -6, -9, which have a distinct expression pattern; class IV included PtoCAD12, which has a distinct structure. These data suggest divergence of the PtoCADs and its homologs, related to their functions. We propose genes in class II are a subset of CAD genes that evolved before angiosperms appeared. These results suggest CAD/CAD-like genes in classes I and II play a role in monolignol biosynthesis and contribute to our knowledge of lignin biosynthesis in P. tomentosa. © 2014, Springer-Verlag Berlin Heidelberg.


Zhang D.,National Engineering Laboratory for Tree Breeding | Zhang D.,Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants | Yang X.,National Engineering Laboratory for Tree Breeding | Yang X.,Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants | And 5 more authors.
Tree Genetics and Genomes | Year: 2010

The COBRA gene encodes a putative glycosyl-phosphatidylinositol-anchored protein that regulates cellulose deposition and oriented cell expansion in the plant cell wall. This study reports the identification of PtCOBL4, a first COBRA gene from the tree Populus tomentosa. The full-length cDNA of PtCOBL4 was isolated from a xylem cDNA library. The deduced protein sequence shares 72. 7% identity with Arabidopsis AtCOBL4 protein involved in secondary cell wall deposition. Analysis of differential tissue expression by real-time polymerase chain reaction (PCR) indicated that PtCOBL4 is expressed predominantly in the mature xylem zone. By using the sequenced whole genome and DNA microarray data of Populus, we demonstrated that COBRA is a multigene family of 11 members, each of which exhibit different tissue-specific expression patterns. To evaluate the functional consequences of nucleotide polymorphisms in the PtCOBL4 locus, the patterns of variation in a 2,002-bp region of the gene were surveyed in 40 unrelated individuals representative of almost the entire natural range of P. tomentosa. Sixty-one single-nucleotide polymorphisms (SNPs) were identified at a frequency of one SNP per 32. 8 bp of sequence, giving an estimated nucleotide diversity of πT = 0. 00800 and Θw = 0. 00716. Within coding regions, nonsynonymous diversity (πnonsyn = 0. 00285) was markedly lower than synonymous diversity (πsyn = 0. 02128); the πnonsyn/πsyn ratio was 0. 13, significantly less than 1, indicating that the synonymous sites were subject to strong purifying selection. These results provide the necessary foundation for improving the quantity and quality of cellulose via genetic engineering or by candidate-gene-based association genetics in P. tomentosa. © Springer-Verlag 2009.


Gao H.,Beijing Forestry University | Gao H.,National Engineering Laboratory for Tree Breeding | Gao H.,Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education | Gao F.,Beijing Forestry University
Frontiers in Biology | Year: 2011

Chloroplasts are photosynthetic organelles derived from endosymbiotic cyanobacteria during evolution. Dramatic changes occurred during the process of the formation and evolution of chloroplasts, including the large-scale gene transfer from chloroplast to nucleus. However, there are still many essential characters remaining. For the chloroplast division machinery, FtsZ proteins, Ftn2, SulA and part of the division site positioning system-MinD and MinE are still conserved. New or at least partially new proteins, such as FtsZ family proteins FtsZ1 and ARC3, ARC6H, ARC5, PDV1, PDV2 and MCD1, were introduced for the division of chloroplasts during evolution. Some bacterial cell division proteins, such as FtsA, MreB, Ftn6, FtsW and FtsI, probably lost their function or were gradually lost. Thus, the chloroplast division machinery is a dynamically evolving structure with both conservation and innovation. © 2011 Higher Education Press and Springer-Verlag Berlin Heidelberg.


Song Y.,National Engineering Laboratory for Tree Breeding | Jiang X.,National Engineering Laboratory for Tree Breeding | Zhang M.,Northwest Agriculture and Forestry University | Wang Z.,National Engineering Laboratory for Tree Breeding | And 4 more authors.
Forestry Studies in China | Year: 2012

We analyzed the genetic differences of 16 poplar clones between genomic-SSR and EST-SSR markers. The statistical results show that the average number of alleles detected by genomic-SSR was 4. 1, Shannon's index 1. 0646, observed heterozygosity 0. 4427 and expected heterozygosity 0. 5523, while for the EST-SSR, the average number of alleles was 2. 8, Shannon's index 0. 6985, observed heterozygosity 0. 2330 and expected heterozygosity 0. 4684. Cluster analysis indicated that the EST-SSR capacity of genotypic identification was more precise than that of genomic-SSR. These results reveal that EST-SSR and genomic-SSR have statistically significant genetic differences in polymorphism detection and genotypic identification. These differences could provide a theoretical basis for the rational use of SSR markers in species diversity and other related research. © 2012 Beijing Forestry University and Springer-Verlag Berlin Heidelberg.


Chen J.,National Engineering Laboratory for Tree Breeding | Chen J.,Beijing Forestry University | Tian Q.,Beijing Forestry University | Pang T.,National Engineering Laboratory for Tree Breeding | And 7 more authors.
BMC Genomics | Year: 2014

Background: Compared with other Populus species, Populus euphratica Oliv. exhibits better tolerance to abiotic stress, especially those involving extreme temperatures. However, little is known about gene regulation and signaling pathways involved in low temperature stress responses in this species. Recent development of Illumina/Solexa-based deep-sequencing technologies has accelerated the study of global transcription profiling under specific conditions. To understand the gene network controlling low temperature perception in P. euphratica, we performed transcriptome sequencing using Solexa sequence analysis to generate a leaf transcriptome at a depth of 10 gigabases for each sample.Results: Using the Trinity method, 52,081,238 high-quality trimmed reads were assembled into a non-redundant set and 108,502 unigenes with an average length of 1,047 bp were generated. After performing functional annotations by aligning all-unigenes with public protein databases, 85,584 unigenes were annotated. Differentially expressed genes were investigated using the FPKM method by applying the Benjamini and Hochberg corrections. Overall, 2,858 transcripts were identified as differentially expressed unigenes in at least two samples and 131 were assigned as unigenes expressed differently in all three samples. In 4°C-treated sample and -4°C-treated sample, 1,661 and 866 differently expressed unigenes were detected at an estimated absolute log2-fold change of > 1, respectively. Among them, the respective number of up-regulated unigenes in C4 and F4 sample was 1,113 and 630, while the respective number of down-regulated ungenes is 548 and 236. To increase our understanding of these differentially expressed genes, we performed gene ontology enrichment and metabolic pathway enrichment analyses. A large number of early cold (below or above freezing temperature)-responsive genes were identified, suggesting that a multitude of transcriptional cascades function in cold perception. Analyses of multiple cold-responsive genes, transcription factors, and some key transduction components involved in ABA and calcium signaling revealed their potential function in low temperature responses in P. euphratica.Conclusions: Our results provide a global transcriptome picture of P. euphratica under low temperature stress. The potential cold stress related transcripts identified in this study provide valuable information for further understanding the molecular mechanisms of low temperature perception in P. euphratica. © 2014 Chen et al.; licensee BioMed Central Ltd.


Pan X.,Beijing Forestry University | Li H.,Beijing Forestry University | Wei H.,Beijing Forestry University | Su W.,Beijing Forestry University | And 5 more authors.
Molecular Biology Reports | Year: 2013

4-Coumarate:CoA ligase (4CL) is a key enzyme in the phenylpropanoid synthesis pathway. The Pto4CL2 promoter was cloned from Populus tomentosa Carr. and fused to the reporter gene encoding β-glucuronidase (GUS); the complex expression patterns directed by the Pto4CL2 promoter were then characterized in Nicotiana tabacum Xanthi by histochemical assays. The promoter 5′-deletion and histochemical assay conducted on transformants indicated that the -317 to -292 nt region supports Pto4CL2 expression in the epidermis and petals and the deletion of the -266 to -252 nt region resulted in the loss of tissue specificity and a dramatic reduction in GUS activity. Furthermore, electrophoretic mobility shift assays testified that an adenine and cytosine-rich element (-264 to -255 nt) and an abscisic acid-responsive element (-242 to -235 nt) in the Pto4CL2 promoter would have functions for the complex expression profiling and efficient basal expression, respectively. These results further clarify the mode of the regulatory expression of class II 4CL promoters in higher plants. © 2012 Springer Science+Business Media Dordrecht.


Gao Y.,Beijing Forestry University | Liu H.,Beijing Forestry University | An C.,Beijing Forestry University | Shi Y.,Beijing Forestry University | And 7 more authors.
Plant Journal | Year: 2013

ARC5 is a dynamin-related GTPase essential for the division of chloroplasts in plants. The arc5 mutant frequently exhibits enlarged, dumbbell-shaped chloroplasts, indicating a role for ARC5 in the constriction of the chloroplast division site. In a screen for chloroplast division mutants with a phenotype similar to arc5, two mutants, cpd25 and cpd45, were obtained. CPD45 was identified as being the same gene as FHY3, a key regulator of far-red light signaling recently shown to be involved in the regulation of ARC5. CPD25 was previously named FRS4 and is homologous to FHY3. We found that CPD25 is also required for the expression of ARC5, suggesting that its function is not redundant to that of FHY3. Moreover, cpd25 does not have the far-red light-sensing defect present in fhy3 and far1. Both FRS4/CPD25 and FHY3/CPD45 could bind to the FBS-like 'ACGCGC' motifs in the promoter region of ARC5, and the binding efficiency of FRS4/CPD25 was much higher than that of FHY3/CPD45. Unlike FHY3/CPD45, FRS4/CPD25 has no ARC5 activation activity. Our data suggest that FRS4/CPD25 and FHY3/CPD45 function as a heterodimer that cooperatively activates ARC5, that FRS4/CPD25 plays the major role in promoter binding, and that FHY3/CPD45 is largely responsible for the gene activation. This study not only provides insight into the mechanisms underlying the regulation of chloroplast division in higher plants, but also suggests a model that shows how members of a transcription factor family can evolve to have different DNA-binding and gene activation features. © 2013 John Wiley & Sons Ltd.


Chen J.,National Engineering Laboratory for Tree Breeding | Chen J.,Beijing Forestry University | Xue B.,National Engineering Laboratory for Tree Breeding | Xue B.,Beijing Forestry University | And 4 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

Populus species are the most important timber trees over the Northern hemisphere. Most of them are cold- and drought-sensitive except the Populus euphratica Oliv. Here, a calcium-dependent protein kinase (CDPK) gene cloned from P. euphratica, designated as PeCPK10, was rapidly induced by salt, cold, and drought stresses. The protein encoded by PeCPK10 was localized within the nucleus and cytosol, which may be important for its specific regulation in cellular functions. To elucidate the physiological functions of PeCPK10, we generated transgenic Arabidopsis plants overexpressing PeCPK10. The results showed that PeCPK10-transgenic lines experienced better growth than vector control plants when treated with drought. Stronger abscisic acid-induced promotion of stomatal closing has been showed in transgenic lines. Particularly, overexpression of PeCPK10 showed enhanced freezing tolerance. Constitutive expression of PeCPK10 enhanced the expression of several abscisic acid-responsive genes and multiple abiotic stress-responsive genes such as RD29B and COR15A. Accordingly, a positive regulator responsive to cold and drought stresses in P. euphratica is proposed. © 2013.


Zheng H.,National Engineering Laboratory for Tree Breeding | Lin S.,National Engineering Laboratory for Tree Breeding | Zhang Q.,National Engineering Laboratory for Tree Breeding | Zhang Q.,Guangdong Academy of Forestry | And 3 more authors.
Plant Cell Reports | Year: 2010

The PtDrl02 gene belongs to the TIR-NBS gene family in triploid white poplar (Populus tomentosa × P. bolleana) × P. tomentosa. Its expression pattern displays tissue-specificity, and the transcript level can be induced by wounding, methyl jasmonate (MeJA), and salicylic acid (SA). To understand the regulatory mechanism controlling PtDrl02 gene expression, we functionally characterized the PtDrl02 promoter region. Using the β-glucuronidase as a reporter, we found that the PtDrl02 promoter directed gene expression mainly in the aerial parts of the plants and was confined to the cortex tissues of leaf veins, petioles, stems, and stem piths, showing a typical tissue-specific expression pattern. Deletion analysis revealed two positive regulatory regions (-985 to -669 and -669 to -467) responsible for the basal activity of the PtDrl02 promoter. Impressively, the sequence from -669 to -467 was shown to contain cis-element (s) responding to wounding and MeJA, while the promoter region between -244 and 0 could individually display wounding-responsiveness, and the fragment from -467 to -244 was required for SA- and NaCl-inducible expression of the PtDrl02 promoter. Additionally, it was found that the -985 to -669 sequence was the ABA-responding promoter fragment. These results suggested that the PtDrl02 promoter was modulated by multiple cis-regulatory elements in distinct and complex patterns to regulate PtDrl02 gene expression. Our study also suggested that the PtDrl02 gene 5′ untranslated region, as well as a Populus WRKY transcription factor, PtWRKY1, was involved in the regulation of PtDrl02 promoter activities. © 2010 Springer-Verlag.

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