草菇多糖单加氧酶基因Vv-lpmo 1的序列分析及其表达规律

Sequence Characterization and Expression Pattern of Lytic Polysaccharide Monooxygenase Encoding Gene(Vv-lpmo 1)in Volvariella volvacea

依据草菇（Volvariella volvacea）基因组和转录组数据,采用ZOOM软件将转录组Reads定位到基因组的分析方法,从草菇中鉴定了一个多糖单加氧酶基因Vv-lpmo1,对其进行生物信息学分析,并对其高效诱导物进行筛选,采用定量PCR方法研究其在降解稻草时表达量的变化规律。结果表明：草菇Vv-lpmo1基因DNA序列长1432bp,有9个内含子,预测编码305个氨基酸的蛋白质;生物信息学分析表明该蛋白质有分泌信号肽,且含有两个完整的保守结构域：N端的glycoside hydrolase family 61（GH61）结构域和C端的cellulose-binding domain（CBD）结构域。通过对葡萄糖、无碳源（饥饿诱导）、微晶纤维素、滤纸、稻草和木屑6种不同基质诱导草菇菌丝的定量PCR,结果筛选出稻草对Vv-lpmo1基因有最强的诱导作用。进一步研究稻草诱导不同时间的变化过程中,该基因的表达规律为0~4h先下调;4~12h恢复到初始水平;12h以后开始迅速上调并维持较高水平。本研究表明草菇多糖单加氧酶基因Vvlpmo1属于诱导表达型基因,可能在草菇降解稻草基质中起着重要作用。

Using available whole genome and transcriptome data, a lytic polysaccharide monooxygenase- encoding gene （Vv-lpmol） was identified in Volvariella volvacea by mapping transcriptome sequencing reads on the genome reference sequence with ZOOM software. The Vv-lpmol gene consisted of 1432 bp, contained nine introns, and encoded a protein comprised of 305 amino acids. Bioinformatic analysis performed on both Vv-lpmol and the encoded protein indicated that the Vv-LPMO1 sequence contained a secretory signal peptide, and two conserved domains （glycoside hydrolase family 61 and family 1 cellulose- binding domains）. Relative Vv-lpmol expression levels in V. volvacea mycelium grown on glucose, avicel, filter paper, rice straw, sawdust and in the absence of a carbon source were determined using quantitative PCR （Q-PCR） ： Highest gene expression levels were induced in mycelium grown on rice straw, and Vv-lpmol may play an important role in straw degradation by this fungus. Time-course experiments revealed that Vv- lpmol was expressed at relative low levels during the first 12 h of mycelial growth, at sharply higher levels （～10-fold） after 12 h, and at relatively high levels thereafter until the experiment was terminated at 240 h.