Study Of Cloning And Expression Of Funyional Genes From Chaetomium Globosum

Chaetomium globosum, an important plant biocontrol fungus with wide application, can prevent many diseases of plants including many kinds of vegetables, trees and crops. C. globosum also can degrade some compounds which not easily degraded, such as lignin, and possess many important enzymes genes, having a tremendous value in research.Seventeen genes were cloned from C. globosum using molecular biology technique, and the function of these genes involved in biocontrol and stress response etc. All these genes are analyzed by using bioinformatics approach, and gene expression and functional analysis of some important genes were also carried out in this study.The DNA and cDNA sequences of a 46kD endochitinase gene (chi46) were cloned from C. globosum using degenerate primer PCR combined with RACE approach. The DNA and cDNA sequences of chi46 were 1466bp and 1 350bp in length, respectively, which encoded 449 amino acid residues with molecular weight of 46.2kD and the isoelectric point of 5.38. The DNA sequence of chi46 was composed of 2 exons and 1 intron, the 2 exons were 528bp and 822bp in length respectively, and the intron length was 73bp. The splice sites between exons and introns was following GT/AG splicing rule. BlastP search revealed that the chi46 share the highest identities with chitinase from Neurospora crassa(XP₃23907), the identity was 85%. SignalP analysis showed that there was a signal peptide of 31 amino acid residues at N-terminal of chi46, demonstrating this gene was secret enzyme.The 5'-and 3'-terminal region of cDNA sequence of C-4 sterol methyl oxidase (sterol) gene were obtained from C. globosum EST collection using bioinformatics approach. Then the DNA and cDNA sequences of sterol gene were amplified from C. globosum using PCR based on sequence of the two obtained ESTs . The DNA and cDNA sequences of sterol gene were 1 268bp and 1151bp in length, respectively, encoding 306 amino acid residues with molecular weight of 35.5kD and the isoelectric point of 6.73. The DNA sequence of sterol gene was composed of 4 exons and 3 introns. The splice sites between exons and introns was following GT/AG splicing rule. BlastP search revealed that the deduced amino acid sequence of sterol...