title: Characterization of the Transcriptome of the Xerophyte Ammopiptanthus mongolicus Leaves under Drought Stress by 454 Pyrosequencing.
abstract: BACKGROUND
  Ammopiptanthus mongolicus (Maxim. Ex Kom.) Cheng f., an endangered ancient legume species, endemic to the Gobi desert in north-western China. As the only evergreen broadleaf shrub in this area, A. mongolicus plays an important role in the region's ecological-environmental stability. Despite the strong potential of A. mongolicus in providing new insights on drought tolerance, sequence information on the species in public databases remains scarce. To both learn about the role of gene expression in drought stress tolerance in A. mongolicus and to expand genomic resources for the species, transcriptome sequencing of stress-treated A. mongolicus plants was performed.
  
  
  RESULTS
  Using 454 pyrosequencing technology, 8,480 and 7,474 contigs were generated after de novo assembly of RNA sequences from leaves of untreated and drought-treated plants, respectively. After clustering using TGICL and CAP3 programs, a combined assembly of all reads produced a total of 11,357 putative unique transcripts (PUTs). Functional annotation and classification of the transcripts were conducted by aligning the 11,357 PUTs against the public protein databases and nucleotide database (Nt). Between control and drought-treated plants, 1,620 differentially expressed genes (DEGs) were identified, of which 1,106 were up-regulated and 514 were down-regulated. The differential expression of twenty candidate genes in metabolic pathways and transcription factors families related to stress-response were confirmed by quantitative real-time PCR. Representatives of several large gene families, such as WRKY and P5CS, were identified and verified in A. mongolicus for the first time.
  
  
  CONCLUSIONS
  The additional transcriptome resources, gene expression profiles, functional annotations, and candidate genes provide a more comprehensive understanding of the stress response pathways in xeric-adapted plant species such as A. mongolicus.
authors: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Key Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, People's Republic of China.
authors: Tao
authors: T
authors: Pang
authors: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Key Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, People's Republic of China; College of Agricultural, Henan University of Science and Technology, Luoyang, People's Republic of China.
authors: Lili
authors: L
authors: Guo
authors: The Schatz Center for Tree Molecular Genetics, Department Ecosystem Science and Management, Pennsylvania State University, University Park, Pennsylvania, United States of America; Department of Forest Genetic Resources, Korea Forest Research Institute, Suwon 441-350, Korea.
authors: Donghwan
authors: D
authors: Shim
authors: The Schatz Center for Tree Molecular Genetics, Department Ecosystem Science and Management, Pennsylvania State University, University Park, Pennsylvania, United States of America.
authors: Nathaniel
authors: N
authors: Cannon
authors: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Key Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, People's Republic of China.
authors: Sha
authors: S
authors: Tang
authors: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Key Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, People's Republic of China.
authors: Jinhuan
authors: J
authors: Chen
authors: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Key Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, People's Republic of China.
authors: Xinli
authors: X
authors: Xia
authors: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Key Laboratory for Silviculture and Conservation, Beijing Forestry University, Beijing, People's Republic of China.
authors: Weilun
authors: W
authors: Yin
authors: The Schatz Center for Tree Molecular Genetics, Department Ecosystem Science and Management, Pennsylvania State University, University Park, Pennsylvania, United States of America.
authors: John E
authors: JE
authors: Carlson
mesh_terms: D002681:China; D030541:Databases, Genetic; D007887:Fabaceae / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D059014:High-Throughput Nucleotide Sequencing; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000096:biosynthesis / Q000235:genetics; D012984:Software; D013312:Stress, Physiological / Q000502:physiology*; D059467:Transcriptome / Q000502:physiology*
chemical_list: D018749:RNA, Plant