| 1 | Simultaneously down-regulation of multiplex branch pathways using CRISPRi and fermentation optimization for enhancingβ-amyrin production in Saccharomyces cerevisiae显示文摘The production ofβ-amyrin in Saccharomyces cerevisiae is still low due to the inability of effectively regulating the endogenous metabolic pathway for competitive synthesis ofβ-amyrin precursors.In this study,we focused on two branches ofβ-amyrin synthetics pathway that consumeβ-amyrin precursors(2,3-oxidosqualene and cytosolic acetyl-CoA)and regulated related genes(ADH1,ADH4,ADH5,ADH6,CIT2,MLS2 and ERG7).We developed a CRISPRi method by constructing a multi-gRNA plasmid to down-regulate the seven genes simultaneously,which is reported for the first time in S.cerevisiae.The average transcription inhibition efficiency of the seven genes reached as high as 75.5%.Furthermore,by optimizing the fermentation condition(including pH,inoculum size,initial glucose concentration and feed of glucose or ethanol)and increasing extracellular transportation via supplying methyl-β-cyclodextrin,β-amyrin concentration of engineered strain SGibSdCg increased by 44.3%compared with the parent strain SGib,achieving 156.7 mg/L which was the highest concentration ofβ-amyrin reported in yeast.The one-step down-regulation of multiple genes using CRISPRi showed high efficiency and promising future in improving the yields of natural products. | Jiangping Ni Genlin Zhang Lei Qin Jun Li Chun Li | 2019 | Synthetic and Systems Biotechnology2019，4，2： | 4 |
| 2 | Insights into genetic diversity and phenotypic variations in domestic geese through comprehensive population and pan-genome analysis显示文摘Background Domestic goose breeds are descended from either the Swan goose(Anser cygnoides)or the Greylag goose(Anser anser),exhibiting variations in body size,reproductive performance,egg production,feather color,and other phenotypic traits.Constructing a pan-genome facilitates a thorough identification of genetic variations,thereby deepening our comprehension of the molecular mechanisms underlying genetic diversity and phenotypic variability.Results To comprehensively facilitate population genomic and pan-genomic analyses in geese,we embarked on the task of 659 geese whole genome resequencing data and compiling a database of 155 RNA-seq samples.By constructing the pan-genome for geese,we generated non-reference contigs totaling 612 Mb,unveiling a collection of 2,813 novel genes and pinpointing 15,567 core genes,1,324 softcore genes,2,734 shell genes,and 878 cloud genes in goose genomes.Furthermore,we detected an 81.97 Mb genomic region showing signs of genome selection,encompassing the TGFBR2 gene correlated with variations in body weight among geese.Genome-wide association studies utilizing single nucleotide polymorphisms(SNPs)and presence-absence variation revealed significant genomic associations with various goose meat quality,reproductive,and body composition traits.For instance,a gene encoding the SVEP1 protein was linked to carcass oblique length,and a distinct gene-CDS haplotype of the SVEP1 gene exhibited an association with carcass oblique length.Notably,the pan-genome analysis revealed enrichment of variable genes in the“hair follicle maturation”Gene Ontology term,potentially linked to the selection of feather-related traits in geese.A gene presence-absence variation analysis suggested a reduced frequency of genes associated with“regulation of heart contraction”in domesticated geese compared to their wild counterparts.Our study provided novel insights into gene expression features and functions by integrating gene expression patterns across multiple organs and tissues in geese and analyzing population variation.Conclusion This accomplishment originates from the discernment of a multitude of selection signals and candidate genes associated with a wide array of traits,thereby markedly enhancing our understanding of the processes underlying domestication and breeding in geese.Moreover,assembling the pan-genome for geese has yielded a comprehensive apprehension of the goose genome,establishing it as an indispensable asset poised to offer innovative viewpoints and make substantial contributions to future geese breeding initiatives. | Guangliang Gao Hongmei Zhang Jiangping Ni Xianzhi Zhao Keshan Zhang Jian Wang Xiangdong Kong Qigui Wang | 2024 | Journal of Animal Science and Biotechnology2024，15，1： | 0 |
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