【摘要】 选用三类典型重组子3a、3b、A7-1和双亲本菌株AspersillusnigerAMSH、TrichodermareeseiQM9414为材料，按照所设计的纤维素酶系基因的通用序列和同工酶分型方法，进行基因组DNA指纹和酶系同工酶多态性比较分析。旨在提供重组子中基因重组的分子证据，阐明远缘双亲本基因组间的遗传表达相容性，并讨论其杂种优势的分子基础。结果发现重组子中基因组DNA指纹的重组特征稳定遗传，并能够相容性增强表达重组后的羧甲基纤维素酶（CMCase）和β-葡萄糖苷酶（βGLase）同工酶组分。纤维素酶系杂种优势的分子基础多样性包括：（1）3b中来自于双亲本部分编码βGLase的基因的杂合迭加和增强表达；（2）3a和A7-1中对应继承双亲本部分编码CMCase和βGLase的基因间协调性增强表达，并导致相应酶组分蛋白合成量的显著增加。由此综合提出了一个由βGLase介导的纤维素酶系活性调节和诱导合成调控的“双重协同增效”模型。此外还建立了考察重组子中杂种优势分子基础及其遗传稳定性的可行方法。更多还原

【Abstract】 By using the developed display techniques of cellulase isozymes and the RAPD-PCR analysis guided by a deduced diversal sequence of cellulase genes, the polymorphisms of genomic DNA fingerprints and cellulase isozymes were compared among three typical stable recombinants (3a. 3b, A7-1) and their tWo parents(ASpergillus niger AMS11, Trichoderma reesei QM9414) in order tO provide the molecular evidence of gene recombination, to demonstrate the compatibility of heredity and expression of intergeneric genomes, and to assay on the molecular fundamentals of hybridizahon dominance. The results showed that in these recombinant sabins the recombinantal fingerprints of genomic DNA could be stablly hereditary and the expression of recombinantal CMCase (carboxymethylcellulase) and β GLase (β -glucosidase) could be compatibly enhanced. The diversity of molecular fundamentals of cellulase hybridization dominance were (1) the compatible co-existence and enhanced expression of some hereditary β GLase-coding genes from two parents in recombinant 3b; and (2) the compatibly enhancement of expression between the hereditary genes encoding βGLase and CMCase from two parents, resulting in the dramatic increase of proteins of cormsponding isozymes in recombinants 3a and A7-1,Based on these, a proposal model for the double synergism on cellulase activity in vitro and on its biosynthesis in vivo mediated by βGLase was suggested. A practical method for assaying on the molecular fundamentals and the stability of hybridization dominance of recombinants was thereby established in this study.更多还原