title: Abundance and genetic diversity of microbial polygalacturonase and pectate lyase in the sheep rumen ecosystem.
abstract: BACKGROUND
  Efficient degradation of pectin in the rumen is necessary for plant-based feed utilization. The objective of this study was to characterize the diversity, abundance, and functions of pectinases from microorganisms in the sheep rumen.
  
  
  RESULTS
  A total of 103 unique fragments of polygalacturonase (PF00295) and pectate lyase (PF00544 and PF09492) genes were retrieved from microbial DNA in the rumen of a Small Tail Han sheep, and 66% of the sequences of these fragments had low identities (<65%) with known sequences. Phylogenetic tree building separated the PF00295, PF00544, and PF09492 sequences into five, three, and three clades, respectively. Cellulolytic and noncellulolytic Butyrivibrio, Prevotella, and Fibrobacter species were the major sources of the pectinases. The two most abundant pectate lyase genes were cloned, and their protein products, expressed in Escherichia coli, were characterized. Both enzymes probably act extracellularly as their nucleotide sequences contained signal sequences, and they had optimal activities at the ruminal physiological temperature and complementary pH-dependent activity profiles.
  
  
  CONCLUSIONS
  This study reveals the specificity, diversity, and abundance of pectinases in the rumen ecosystem and provides two additional ruminal pectinases for potential industrial use under physiological conditions.
authors: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors: Peng
authors: P
authors: Yuan
authors: Kun
authors: K
authors: Meng
authors: Yaru
authors: Y
authors: Wang
authors: Huiying
authors: H
authors: Luo
authors: Huoqing
authors: H
authors: Huang
authors: Pengjun
authors: P
authors: Shi
authors: Yingguo
authors: Y
authors: Bai
authors: Peilong
authors: P
authors: Yang
authors: Bin
authors: B
authors: Yao
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D004926:Escherichia coli / Q000378:metabolism; D014644:Genetic Variation; D006863:Hydrogen-Ion Concentration; D008957:Models, Genetic; D010368:Pectins / Q000378:metabolism; D010802:Phylogeny; D011096:Polygalacturonase / Q000235:genetics*; D011133:Polysaccharide-Lyases / Q000235:genetics*; D012417:Rumen / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012756:Sheep; D034561:Sheep, Domestic / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D010368:Pectins; D011096:Polygalacturonase; D011133:Polysaccharide-Lyases; C023911:pectate lyase