Poly(A) polymerase I participates in the indole regulatory pathway of Pantoea agglomerans YS19.

Pantoea agglomerans YS19 is a preponderant endophytic bacterium isolated from rice. It is characterized by the formation of symplasmata, a type of multicellular aggregate structure, contributing to a strong stress resistance and specific adaptation of YS19 in endophyte-host associations. Indole is an important signal molecule in intra- or interspecies relationships, regulating a variety of bacterial behaviours such as cell aggregation and stress resistance; however, the regulatory mechanism remains an ongoing area of investigation. This study selected YS19 as a model strain to construct a mutant library, utilizing the mTn5 transposon mutagenesis method, thus obtaining a positive mutant with an indole-inhibited mutation gene. Via thermal asymmetric interlaced PCR, the mutational site was identified as the gene of pcnB, which encodes the poly(A) polymerase I to catalyse the polyadenylation of RNAs. The full length of the pcnB sequence was 1332 bp, and phylogenetic analysis revealed that pcnB is extremely conserved among strains of P. agglomerans. The expression of the gene was significantly inhibited (by 36.6 % as detected via quantitative PCR) by indole (0.5 mM). Many physiological behaviours of YS19 were affected by this mutation: the cell decay rate in the post-stationary growth phase was promoted, symplasmata formation and motility were inhibited in the late stationary growth phase and the colonization ability and growth-promoting effect of YS19 on the host plant were also inhibited. This study discusses the indole regulatory pathways from the point of RNA post-transcriptional modification, thus enriching our knowledge of polyadenylation and expanding current research ideas of indole regulation.

Complete genome sequence of Paenibacillus mucilaginosus 3016, a bacterium functional as microbial fertilizer.

Paenibacillus mucilaginosus is a ubiquitous functional bacterium in microbial fertilizer. Here we report the complete sequence of P. mucilaginosus 3016. Multiple sets of functional genes have been found in the genome. To the best of our knowledge, this is the first announcement about the complete genome sequence of a P. mucilaginosus strain.

Complete genome sequence of Paenibacillus polymyxa SC2, a strain of plant growth-promoting Rhizobacterium with broad-spectrum antimicrobial activity.

Paenibacillus polymyxa SC2 is an important plant growth-promoting rhizobacterium (PGPR). Here, we report the complete genome sequence of P. polymyxa SC2. Multiple sets of functional genes have been found in the genome. As far as we know, this is the first complete genome sequence of Paenibacillus polymyxa.

4-Methyl-N-[(2-oxo-1,3-thia-zolidin-3-yl)carbon-yl]benzene-sulfonamide.

The asymmetric unit of the title compound, C(11)H(12)N(2)O(4)S(2), contains two independent mol-ecules with similar dihedral angles of 76.7 (1) and 77.3 (1)° between the mean planes of the five- and six-membered rings. In both mol-ecules, the amino groups are involved in intra-molecular N-H⋯O hydrogen bonds. In the crystal structure, weak inter-molecular C-H⋯O hydrogen bonds link mol-ecules into ribbons extended along the a axis.

In vitro adsorption revealing an apparent strong interaction between endophyte Pantoea agglomerans YS19 and host rice.

Pantoea (formerly Enterobacter) agglomerans YS19 is a dominant diazotrophic endophyte isolated from rice (Oryza sativa cv. Yuefu) grown in a temperate-climate region in west Beijing, China. In vitro adsorption and invasion of YS19 on host plant root were studied in this research. Adsorption of YS19 on rice seedling roots closely resembled the Langmuir adsorption and showed a higher adsorption quantity than the control strains Paenibacillus polymyxa WY110 (a rhizospheric bacterium from the same rice cultivar) and Escherichia coli HB101 (a general model bacterium). Adsorption dynamics study revealed high rates and a long duration of the YS19-rice root adsorption process. Adsorption of YS19 was mainly observed on the root hair, though which it enters the plant. This in vitro adsorption study revealed an apparent strong interaction between YS19 and rice at the early endophyte-host recognition stage.

[Multiplex-PCR approach to identify Bacillus species applied in microbial fertilizers].

OBJECTIVE: To discriminate the strains of Bacillus subtilis group including B. subtilis, B. amyloliquefaciens, B. licheniformis, and B. pumilus, a rapid and accurate distinguishing method is essential for the identification of the target strains to ensure the quality and safety of microbial fertilizers. METHODS: By analyzing unique nucleotide sequences of the rpoA, gyrA and 16S rDNA genes, 4 pairs of species-specific primers were optimized and the multiplex PCR was developed to discriminate and identify B. subtilis, B. amyloliquefaciens, B. licheniformis and B. pumilus. RESULTS: Thirty-three reference strains belonging to three genera of Bacillus, Paenibacillus and Brevibacillus were tested and the anticipated results appeared except for four species with cross amplification results with the primers of B. pumilus. However, the four species can be easily discriminated by morphology characters. In addition, the multiplex-PCR results of 23 strains of B. subtilis group isolated from MF products were identical with the biochemical assay. CONCLUSION: The newly constructed multiplex-PCR assay is species-specific and effective. This method can be used to detect and identify the strains of B. subtilis group from microbial fertilizers products.

Rice endophyte Pantoea agglomerans YS19 forms multicellular symplasmata via cell aggregation.

Pantoea agglomerans is characterized by the formation of multicellular symplasmata. One unanswered question regarding this bacterium is how these structures are formed. In this study, the rice diazotrophic endophyte P. agglomerans YS19 was selected for exploration of this theme. YS19 was labeled with green fluorescent protein and the resulting recombinant YS19::gfp was observed to grow only slightly more slowly (a decrease of 5.5%) than the wild-type strain, and to show high GFP label stability (label loss rate 8.9218 x 10(-6) per generation, nearly reaching the generally accepted spontaneous mutation rate for most bacteria). YS19::gfp resembled the wild-type YS19 in symplasmata formation and growth profiles. Based on associated cultivation of both strains by mixing their individually cultivated single cells, symplasmata were formed and composed of both YS19::gfp and YS19, suggesting that YS19 formed symplasmata via aggregation, not proliferation, of the original single cells.

Consistent effects of nitrogen fertilization on soil bacterial communities in black soils for two crop seasons in China.

Long-term use of inorganic nitrogen (N) fertilization has greatly influenced the bacterial community in black soil of northeast China. It is unclear how N affects the bacterial community in two successive crop seasons in the same field for this soil type. We sampled soils from a long-term fertilizer experimental field in Harbin city with three N gradients. We applied sequencing and quantitative PCR targeting at the 16S rRNA gene to examine shifts in bacterial communities and test consistent shifts and driving-factors bacterial responses to elevated N additions. N addition decreased soil pH and bacterial 16S rDNA copy numbers, and increased soil N and crop yield. N addition consistently decreased bacterial diversity and altered bacterial community composition, by increasing the relative abundance of Proteobacteria, and decreasing that of Acidobacteria and Nitrospirae in both seasons. Consistent changes in the abundant classes and genera, and the structure of the bacterial communities across both seasons were observed. Our results suggest that increases in N inputs had consistent effects on the richness, diversity and composition of soil bacterial communities across the crop seasons in two continuous years, and the N addition and the subsequent edaphic changes were important factors in shaping bacterial community structures.

Indole affects the formation of multicellular aggregate structures in Pantoea agglomerans YS19.

Pantoea agglomerans YS19 is an endophytic diazotrophic bacterium isolated from rice. As well as having the ability to form a biofilm, as do most bacteria, it is characterized by the formation of a unique multicellular aggregate structure called symplasmata. Indole is traditionally known as a metabolite of the amino acid tryptophan, which, however, has recently been shown to participate in various regulations of bacterial physiological processes, including stress resistance, quorum sensing and biofilm formation. Here, an indole signal was found to promote symplasmata formation, yet inhibit biofilm formation, indicating different regulatory pathways of indole in the construction of the two structures. However, symplasmata showed almost an equivalent stress-resistant capability, as compared with biofilms, for YS19 to confront acids, heavy metals (Cu(2+)), and UV treatments. Moreover, indole was tested to show a promoting effect on exopolysaccharides (EPS) production and an inhibition effect on the expression of an outer membrane protein OmpW. These results provide evidence for understanding the regulatory mechanisms of indole on such multicellular aggregates.

Research on the rheological properties of pesticide suspension concentrate.

This study reports research on pesticide suspension rheology and a new rheological parameter, the relative value of approach, which has great advantage for judging the physical stability of a pesticide suspension concentrate. Experiments showed that the system can form stable dispersions when the value of the relative value of approach (S(r)) is less than 0.1.

Analysis of volatile compounds emitted from fresh Syringa oblata flowers in different florescence by headspace solid-phase microextraction-gas chromatography-mass spectrometry.

In this study, a simple and solvent-free method was developed for determination of the volatile compounds from fresh flowers of Syringa oblata using headspace solid-phase microextraction and gas chromatography-mass spectrometry. The SPME parameters were studied, the optimum conditions of a 65mum polydimethylsiloxan/divinylbenezene (PDMS/DVB), extraction temperature of 25 degrees C and extraction time of 30 min were obtained and applied to extraction of the volatile compounds emitted from fresh flowers of S. oblata. The volatile compounds released from fresh flowers of S. oblata were separated and identified by GC-MS. Lilac aldehyde A, lilac aldehyde B, lilac aldehyde C, lilac aldehyde D, lilac alcohol A, lilac alcohol B, lilac alcohol C, lilac alcohol D, alpha-pinene, sabinene, beta-pinene, myrcene, d-limonene, eucalyptol, cis-ocimene, benzaldehyde, terpinolene, linalool, benzene acetaldehyde, alpha-terpineol, p-methoxyanisole, p-anisaldehyde, (Z,E)-alpha-farnesene and (E,E)-alpha-farnesene were the most abundant volatiles released from fresh flowers of S. oblata var. alba. The relative contents of main volatile fragrance were found to be different in emissions from two varieties of S. oblata flowers (white or purple in color). The four isomers of lilac alcohol and four isomer lilac aldehyde were the characteristic components of the scent of fresh flowers of S. oblata. The main volatile fragrance from fresh flowers of S. oblata var. alba in different florescence ((A) flower buds; (B) at the early stage of flower blooming; (C) during the flower blooming; (D) at the end of flower blooming; (E) senescence) were studied in this paper. The results demonstrated that headspace SPME-GC-MS is a simple, rapid and solvent-free method suitable for analysis of volatile compounds emitted from fresh flowers of S. oblata in different florescence.