关键词: 瘤胃；D-塔格糖；阿拉伯糖异构酶；基因多样性

Abstract:

L-arabinose isomerase catalyzes the isomerization reaction from D-galactose to D-tagatose, and has attracted more attention due to its importance in animal nutrition and food applied research. Animal rumen is a special anaerobic environment, and ruminal microorganisms contain large amounts of novel genes that code for polysaccharide-degrading enzymes. This study primarily analyzed the genetic diversity of L-arabinose isomerase in sheep rumen bacteria. Using the metagenome of rumen content extracted 4 h after feeding as template, 61 L-arabinose isomerase gene fragments with 68%~98% identities and known sequences were obtained by PCR amplification with specific degenerate primers and restriction enzyme digest. Of them, 38 distinct sequences (<95% identity) were subjected to clustering analysis. The results showed that the L-arabinose isomerase genes from Prevotella ruminicola were found to be predominant (36/38) in sheep rumen, and those from Catonella morbid and Marinilabilia salmonicolor (2/38) were minor. This study has not only enriched the genetic resources of L-arabinose isomerase, but also determined the importance of Prevotella in sheep rumen.

Key words: rumen, D-tagatose, L-arabinose isomerase, genetic diversity