Transcription Analysis Of Two Trichoderma Species Response To Copper Stress

Trichoderma spp. is widely used as biological fertilizer and pesticide to prevent disease as one of the most important biocontrol fungi. Cupric pesticides were widely used which have the characteristic of good effect on disease prevention, wide antibacterial spectrum and low cost. Analyzing the variation of Trichoderma transcriptome response to copper stress are of great significance for revealling the mechasnism of copper resisitance and improving the effect of prevention plant diseases. In this study, the biological characteristics of four Trichoderma under copper stress were analysed, and two of them were choosed for further research. By comparison and analysis the transcriptome sequencing results of the two strains, we found that Trichodema with different resistance to copper stress had different responses to copper stress at transcriptional level. This study laid the foundation for further research on the mechanism copper resistance of Trichoderma. The results of this study were as follows:1. The tolerance of Trichoderma harzianum Th-33 is the weakest and T. asperellum1888 is the strongest among the four tested Trichoderma strains by compring the growth and spore production of them under copper stress.2. The transcriptome of Th-33 under copper stress was sequenced by Hiseq 2500 high-throughput sequencing platform, 891 genes were identified to differentially expressed genes(DEGs) comparing to the contrast, including 570 up-regulated and 321 down-regulated genes. GO analysis suggested that total of 438 differentially expressed genes were categorized into 673 functional groups. KEGG analysis revealed that total of 254 genes were annotated in 167 individual pathways and these unigenes were significantly enriched in various known aminobenzoate degradation and chloroalkane degradation. Pathways of reducing of copper ions and Ctr transporting were inhibited by copper stress and part of copper may enter Th-33 cells by endocytosis. It was speculated that copper transferred in Th-33 by combining with glutathione, or on the other hand, transported to the plasma membrane by P-type ATPase.3. The transcriptome of 1888 under copper stress were sequenced by using Hiseq2500 high-throughput sequencing. There were 1011 DEGs between 1888 and 1888-Cu including 447 up-regulated and 564 down-regulated expressed genes. GO functional enrichment analysis showed that a total of 637 differentially expressed genes were categorized into 1275 functional groups. KEGG analysis revealed that the genes were significantly enriched in various known bisphenol degradation and aminobenzoate degradation pathways. The result inferred that copper may transfer into 1888 cells mainly through low affinity transport channel. Copper ion transferred into vacuole may combining with GSH and copper chaperones Sod1 combine with copper ion was restrained, there were no differentially expressed in pathways of CCS to Sod1, and if there have other pathways of CCS1 to Sod1 is still unknown4. The transcriptome data of Th-33 and 1888 showed that the patterns of antioxidase to copper stress genes expression of Th-33 were consistent with 1888, copper stress may damage the enzyme activities of both Th-33 and 1888. There were differences in channels of the copper enter the cell which causes different stress response. In the Trichoderma of different copper resistance which expression of some genes coding chitinase, cell wall protein, hydrophobin and glutathione in Th-33 were not consistent with 1888, which were speculated to be the key genes related to copper tolerance of Trichoderma and need further study.