Recent Advances in Function-based Metagenomic Screening

Metagenomes from uncultured microorganisms are rich resources for novel enzyme genes. The methods used to screen the metagenomic libraries fall into two categories, which are based on sequence or function of the enzymes. The sequence-based approaches rely on the known sequences of the target gene families. In contrast, the function-based approaches do not involve the incorporation of metagenomic sequencing data and, therefore, may lead to the discovery of novel gene sequences with desired functions. In this review, we discuss the function-based screening strategies that have been used in the identi?cation of enzymes from metagenomes. Because of its simplicity, agar plate screening is most commonly used in the identi?cation of novel enzymes with diverse functions. Other screening methods with higher sensitivity are also employed, such as microtiter plate screening. Furthermore, several ultra-high-throughput methods were developed to deal with large metagenomic libraries. Among these are the FACS-based screening, droplet-based screening,and the in vivo reporter-based screening methods. The application of these novel screening strategies has increased the chance for the discovery of novel enzyme genes.

The Tara Oceans Project:New Opportunities and Greater Challenges Ahead

In the May 22, 2015 issue of Science magazine, several articles （including the editorial, research papers, and perspectives） were published on the Tara Oceans Project and studies related to ocean microbes [1-8]. This represents truly a milestone for studies in both ocean ecology and microbial communities. As stated on the European Molecular Biology Laboratory （EMBL） website （http：//www.embl.de/tara-oceans/start/）： ＂Tara Oceans results reveal climate change insights, and a treasure trove of novel species and genes.＂