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【bio-news】首例植物共生菌宏基因组文库

Enriching plant microbiota for a metagenomic library construction

ABSTRACT

Plant microbiota (the microorganisms that live in any associations with plant tissues) represents a rather unexplored area of metagenomic research compared with soils and oceans. Constructing a metagenomic library for plant microbiota is technically challenging. Using all the biomass without pre-enrichment could lead to vast proportions of the host plant DNA in the metagenomic library, doubtless obliterating the microbial contribution. Therefore, the first and essential step is to enrich for the constituent microorganisms from plant tissues. Here, a strong enrichment for plant microbiota was achieved by coupling SDS (sodium dodecyl sulfate) with NaCl, creating a predominantly microbial metagenomic library that contains 88% bacterial inserts. 16S rDNA sequence analysis revealed that the metagenomic DNA of enrichments originates from very diverse microorganisms. At least 74 distinct ribotypes (at a 97% threshold) from seven different bacterial phyla were identified and mainly distributed among Actinobacteria and Proteobacteria. Additionally, a simplified version of Amplified Ribosomal DNA Restriction Analysis (ARDRA) was developed for a quick and efficient assessment of the enriching procedures. This work opens further insight into the great biotechnical potential of plant microbiota, holding more potential for drug discovery through a metagenomic strategy, and paving the way for recovery and biochemical characterization of functional gene repertoire from plant microbiota.

对于目前尚未成功培养的微生物包括为数众多的植物共生菌,运用宏基因组的研究策略发掘其基因资源,可为医药和工业生物技术等领域带来创新成果。

中科院昆明植物研究所曾英研究员等专家,在国家自然科学基金重点项目“通过进化生物学途径从植物共生放线菌中寻找强生理活性化合物”等支持下,经过三年多的努力,完成了植物共生菌的富集和植物共生菌宏基因组文库构建研究工作。

与宿主植物相比,共生菌的基因组和生物量非常微小。因此,构建植物共生菌宏基因组文库必须首先突破共生菌富集的技术瓶颈,专家们经过努力,在植物共生菌的富集方法上取得突破和创新,相关技术已申请发明专利并公开;同时依托共生菌富集方法的独特创新,构建了国际上首例植物共生菌宏基因组文库,相关研究成果陆续发表在微生物学重要学术期刊《应用微生物学杂志》(Journal of Applied Microbiology)和《环境微生物学》(Environmental Microbiology)上。构建的滑桃树共生菌宏基因组文库极具开发潜力,不仅库容量大(1.37×106个克隆,相当于5000个链霉菌基因组拷贝),而且蕴含丰富的微生物种类多样性,文库的基因组来源涵盖七个门类两百种以上的微生物,其中以放线菌和变形菌的种类最为丰富,而且有相当一部分属于未可培养微生物或新种来源。与此同时,还发现了一个与美登素类化合物(maytansinoids)合成有关的基因簇,目前正在用KS、AHBA以及相关基因对文库进行高通量筛选,充分挖掘宏基因组文库的基因资源。

新基因和新酶资源是生物技术和工业催化发展的驱动力。不依赖培养的微生物宏基因组作为新颖的基因资源,既是生物技术发展的源泉,也是发现新酶和开发生物催化剂的新途径。生物催化剂被视为21世纪化学工业可持续发展的必要工具,植物共生菌宏基因组文库这一崭新的基因资源,极有可能为生物催化剂的研制提供源头上的创新。(来源:中科院昆明植物研究所)

(《环境微生物学》(Environmental Microbiology),DOI: 10.1111/j.1462-2920.2008.01689.x,Hao-Xin Wang,Yue-Mao Shen)
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作者:admin@医学,生命科学    2011-02-15 05:11
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