| Corn stalk biomass in agricultural and forestry waste are the most abundant renewable resource on earth,which are extremely important for solving the energy crisis and sustainable economic development.However,the utilization rate of corn stalks in China is low,and there is still a large amount of straw waste or even pollution.Therefore,how to use straw resources more effectively has become a top priority.The complex structure of corn stalk lignocellulose biomass is difficult to be degraded,which has become a key factor restricting the development and utilization of corn stalk biomass.Therefore,the protoplast regenerated strains of Pleurotus djamor obtained by protoplast complex mutagenesis which could grow on solid corn stalk medium in previous research are used as the research objects,mainly carrying out screening and identification by IT-PCR of the strain with high growth rate and high lignocellulose activities.The ability in degradation of lignocellulose was determined when mutant strain was cultured in pure corn stalk powder liquid medium.And RNA-Seq was performed to extract functional genes related to lignocellulose-degrading enzymes.On the one hand,it lays a foundation for revealing the molecular mechanism of lignin degradation of corn stalks,and on the other hand,provides candidate genes for cultivating engineering bacteria by genetically engineered techniques that efficiently utilize corn stalk lignocellulose and lays a foundation for the development and utilization of corn straw biomass resources.The main results are as follows:1.A mutant strain CM13 with high production of lignocellulase in pure corn stalk powder liquid medium was screened and identified by antagonistic experiment,growth rate measurement experiment and ITS-PCR technique.The laccase,manganese peroxidase,xylanase and cellulase activities were increased by 13.07%,12.90%,19.93% and 30.22%,respectively.2.The liquid fermentation of pure corn stalk powder showed that the xylanase and cellulase activities peaked at the 16 th day.On the 4th day,manganese peroxidase and laccase activity peaked.When the corn stalk powder was cultured for 16 days,the total quality decline rate of corn straw lignin,cellulose and hemicellulose were 68.86%,14.04% and 28.71%,respectively.The results of FTIR and SEM showed that lignin,cellulose and hemicellulose in corn stalk were all degraded.3.The mycelium cultured in the corn stalk powder medium for 12 d was used as the treatment group(T1),and the control group(CK)was used as the control group(CK)at 0d,and RNA-Seq was carried out,respectively.The results of RT-qPCR experiment showed that the results of RNA-Seq were right.A total of 17207 Unigenes were obtained by de novo assembly.Through Nr,Swiss-Prot,KEGG/COG and KEGG annotations,11054 Unigenes were obtained.Through differential expression analysis,3322 genes with a significant differentially expression was screened,and 1913 genes were significantly up-regulated,and 1409 genes were significantly down-regulated.4.There are 675 CAZymes DEGs related to the biotransformation of corn stalk.there are 89 CAZymes DEGs related to the degradation of corn stalk cellulose,hemicellulose and lignin.70 DEGs are an up-regulated genes. |
