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木聚糖酶是半纤维素酶系的重要组成部分,能够分解水稻、小麦等农作物秸秆中的半纤维素。研究探讨木聚糖酶相关基因及其功能,为进一步探讨木聚糖酶与草菇生物转化率之间的关系提供理论依据。首先通过生物信息学手段构建了草菇2个木聚糖酶基因xyn1和xynII编码氨基酸序列的系统进化树,然后从生物转化率不同的草菇菌株分别提取各自的RNA,反转录为cDNA后,采用实时荧光定量PCR技术分析了xyn1和xynII基因的转录表达情况;最后应用DNS法对这些菌株中的木聚糖酶活性进行了测定。研究结果表明,xyn1编码的氨基酸序列与草腐菌相似性较高,而xynII编码的氨基酸序列与木腐菌遗传差异较小。在木聚糖酶活性测定和实时荧光定量PCR结果中,不同菌株的木聚糖酶活性趋势与xynII的转录表达趋势相似,均呈现依次递减。草菇的木聚糖酶活性与其生物转化率之间存在正相关性,推测草菇不同菌株木聚糖酶活性差异可能表现在转录水平上的差异。
Xylanase is an important part of the hemicellulase system and can decompose hemicellulose in crop straw such as rice and wheat. To investigate the xylanase-related genes and their functions, provide a theoretical basis for further exploring the relationship between xylanase and straw mushroom bioconversion rate. The phylogenetic tree of two xylanase gene xyn1 and xynII coding amino acid sequences was constructed by means of bioinformatics. Then RNA was extracted from each strain of Agrobacterium with different biotransformation rate and then transcribed into cDNA . The transcriptional expression of xyn1 and xynII genes was analyzed by real-time fluorescence quantitative PCR. Finally, the activity of xylanase in these strains was determined by DNS. The results showed that the amino acid sequence of xyn1 was highly similar to that of the grass-rot fungi, while the genetic diversity of the xynll-encoded amino acid sequence was less than that of the wood rot. In xylanase activity assay and real-time fluorescence quantitative PCR results, the trend of xylanase activity of different strains was similar to that of xynII, showing decreasing sequence in turn. There is a positive correlation between the xylanase activity and the bioconversion rate of the mushrooms. It is speculated that the differences in the xylanase activity of different strains of straw mushrooms may be at the transcriptional level.