Streptomycetes are a complex group of actinomycetes that produce diverse bioactive metabolites of commercial significance. Systematics can provide a useful framework for identifying species that may produce novel metabolites. However, previously proposed approaches to the systematics of Streptomyces have suffered from either poor interlaboratory comparability or insufficient resolution. In particular, the Streptomyces griseus 16S rRNA gene clade is the most challenging and least defined group within the genus Streptomyces in terms of phylogeny. Here we report the results of a multilocus sequence analysis scheme developed to address the phylogeny of this clade. Sequence fragments of six housekeeping genes, atpD, gyrB, recA, rpoB, trpB and 16S rRNA, were obtained for 53 reference strains that represent 45 valid species and subspecies. Analysis of each individual locus confirmed the suitability of loci and the congruence of single-gene trees for concatenation. Concatenated trees of three, four, five and all six genes were constructed, and the stability of the topology and discriminatory power of each tree were analysed. It can be concluded from the results that phylogenetic analysis based on multilocus sequences is more accurate and robust for species delineation within Streptomyces. A multilocus phylogeny of six genes proved to be optimal for elucidating the interspecies relationships within the S. griseus 16S rRNA gene clade. Our multilocus sequence analysis scheme provides a valuable tool that can be applied to other Streptomyces clades for refining the systematic framework of this genus.

BackgroundSweet potato (Ipomoea batatas L. [Lam.]) ranks among the top six most important food crops in the world. It is widely grown throughout the world with high and stable yield, strong adaptability, rich nutrient content, and multiple uses. However, little is known about the molecular biology of this important non-model organism due to lack of genomic resources. Hence, studies based on high-throughput sequencing technologies are needed to get a comprehensive and integrated genomic resource and better understanding of gene expression patterns in different tissues and at various developmental stages.Methodology/Principal FindingsIllumina paired-end (PE) RNA-Sequencing was performed, and generated 48.7 million of 75 bp PE reads. These reads were de novo assembled into 128,052 transcripts (≥100 bp), which correspond to 41.1 million base pairs, by using a combined assembly strategy. Transcripts were annotated by Blast2GO and 51,763 transcripts got BLASTX hits, in which 39,677 transcripts have GO terms and 14,117 have ECs that are associated with 147 KEGG pathways. Furthermore, transcriptome differences of seven tissues were analyzed by using Illumina digital gene expression (DGE) tag profiling and numerous differentially and specifically expressed transcripts were identified. Moreover, the expression characteristics of genes involved in viral genomes, starch metabolism and potential stress tolerance and insect resistance were also identified.Conclusions/SignificanceThe combined de novo transcriptome assembly strategy can be applied to other organisms whose reference genomes are not available. The data provided here represent the most comprehensive and integrated genomic resources for cloning and identifying genes of interest in sweet potato. Characterization of sweet potato transcriptome provides an effective tool for better understanding the molecular mechanisms of cellular processes including development of leaves and storage roots, tissue-specific gene expression, potential biotic and abiotic stress response in sweet potato.

Antimicrobial peptides (AMPs) represent a class of natural peptides that form a part of the innate immune system, and this kind of ‘nature's antibiotics’ is quite promising for solving the problem of increasing antibiotic resistance. In view of this, it is highly desired to develop an effective computational method for accurately predicting novel AMPs because it can provide us with more candidates and useful insights for drug design. In this study, a new method for predicting AMPs was implemented by integrating the sequence alignment method and the feature selection method. It was observed that, the overall jackknife success rate by the new predictor on a newly constructed benchmark dataset was over 80.23%, and the Mathews correlation coefficient is 0.73, indicating a good prediction. Moreover, it is indicated by an in-depth feature analysis that the results are quite consistent with the previously known knowledge that some amino acids are preferential in AMPs and that these amino acids do play an important role for the antimicrobial activity. For the convenience of most experimental scientists who want to use the prediction method without the interest to follow the mathematical details, a user-friendly web-server is provided at http://amp.biosino.org/.

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A high-G+C-content, Gram-positive bacterium, strain D10 T , was isolated from the root of Oroxylum indicum, a Chinese medicinal plant. Based on 16S rRNA gene sequence analysis, strain D10T was a member of the genus Pseudonocardia and was most closely related, albeit loosely, to

Actinoalloteichus hymeniacidonis sp. nov., an actinomycete isolated from the marine sponge Hymeniacidon perleve A polyphasic study was undertaken to establish the taxonomic status of a Gram-positive, aerobic actinomycete, strain HPA177 T , isolated from a marine sponge, Hymeniacidon perleve. The organism formed branching, non-fragmenting vegetative hyphae and produced black pigment. Chemotaxonomic characteristics were consistent with its assignment to the genus Actinoalloteichus. Analysis of the 16S rRNA gene sequence showed that strain HPA177 T formed a robust clade with type strains of the genus Actinoalloteichus, but was distinct from them. A number of phenotypic characteristics also readily distinguished strain HPA177 T from species of the genus Actinoalloteichus with validly published names. On the basis of the above data, it is proposed that strain HPA177 T represents a novel species, Actinoalloteichus hymeniacidonis sp. nov. The type strain of Actinoalloteichus hymeniacidonis is HPA177 T (=CGMCC 4.2500 T =JCM 13436 T ).

4Escuela Nacional de Ciencias Bioló gicas, Instituto Polité cnico Nacional, 11340 Mé xico D. F., Mexico Four rhizobia-like strains, isolated from root nodules of Pisum sativum and Vicia faba grown in Anhui and Jiangxi Provinces of China, were grouped into the genus Rhizobium but were distinct from all recognized species of the genus Rhizobium by phylogenetic analysis of 16S rRNA and housekeeping genes. The combined sequences of the housekeeping genes atpD, recA and glnII for strain CCBAU 23252 T showed 86.9 to 95 % similarity to those of known species of the genus Rhizobium. All four strains had nodC and nifH genes and could form effective nodules with Pisum sativum and Vicia faba, and ineffective nodules with Phaseolus vulgaris, but did not nodulate Glycine max, Arachis hypogaea, Medicago sativa, Trifolium repens or Lablab purpureus in crossnodulation tests. Fatty acid composition, DNA-DNA relatedness and a series of phenotypic tests also separated these strains from members of closely related species. Based on all the evidence, we propose a novel species, Rhizobium anhuiense sp. nov., and designate CCBAU 23252 Leguminous plants pea (Pisum sativum) and broad bean (Vicia faba) were originally domesticated in the Middle East (Bond, 1976). They are essential foods, vegetables and raw materials for other bean products. V. faba has been cultivated for around 6000 years and is currently grown in 57 countries (George, 1999). Both V. faba and P. sativum are plants introduced to and widely grown in China. Mutualisms between Rhizobium leguminosarum symbiovar viciae and P. sativum or V. faba have been widely studied. Plants of V. faba strongly select rhizobia with a specific nodD type, while P. sativum plants are more promiscuous in selection of their symbionts (Laguerre et al., 2003;Mutch & Young, 2004). In addition to R. leguminosarum, three related species Rhizobium pisi, Rhizobium fabae and Rhizobium laguerreae have been described as broad bean rhizobia (Ramírez-Bahena et al., 2008; Saïdi et al., 2014;Tian et al., 2008), demonstrating the existence of diverse rhizobial species associated with this plant.In the present study, root nodules of V. faba and P. sativum were collected from the fields of Anhui and Jiangxi Provinces in China and 23 fast-growing, acid-producing 3Present address: Beijing Century Kingdo

An actinomycete, designated strain E71T, was isolated from the stem of Sambucus adnata Wall, a Chinese medicinal plant, and subjected to a polyphasic taxonomic study. Phylogenetic analyses based on the 16S rRNA gene sequence showed that the organism was a member of the genus Glycomyces, and formed a distinct phyletic line distantly related to recognized species of the genus Glycomyces. Morphological and chemotaxonomic data supported the affiliation of strain E71T to the genus Glycomyces. A number of physiological properties and a unique menaquinone profile allowed differentiation of the strain from related Glycomyces species. It is therefore proposed that strain E71T represents a novel species of the genus Glycomyces, for which the name Glycomyces sambucus sp. nov. is proposed. The type strain is E71T (=CGMCC 4.3147T=DSM 45047T).