The apoplast of plant cells, which carries out multiple functions in plant metabolism and signaling, is not only a barrier but also the linker between the environment and the protoplast. To investigate the role of apoplastic proteins in the salt stress response, 10-d-old rice (Oryza sativa) plants were treated with 200 mM NaCl for 1, 3, or 6 h, and the soluble apoplast proteins were extracted for differential analysis compared with untreated controls using two-dimensional electrophoresis. Ten protein spots that increased or decreased significantly in abundance were identified by mass spectrometry. These proteins included some well-known biotic and abiotic stress-related proteins. Among them, an apoplastic protein, with extracellular domain-like cysteine-rich motifs (DUF26), O. sativa root meander curling (OsRMC), has shown drastically increased abundance in response to salt stress during the initial phase. OsRMC RNA interference transgenic rice has been generated to assess the function of OsRMC in the salt stress response. The results show that knocking down the expression level of OsRMC in transgenic rice led to insensitive seed germination, enhanced growth inhibition, and improved salt stress tolerance to NaCl than in untransgenic plants. These results indicate that plant apoplastic proteins may have important roles in the plant salt stress response.

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Two Gram-negative, rod-shaped, gliding and pink-pigmented bacterial strains, X14-1 T and X19-1, were isolated from a mixture of sand samples collected from the desert of Xinjiang, China, and characterized by using a polyphasic taxonomic approach. Strains X14-1 T and X19-1 contained MK-7 as the predominant menaquinone. The major cellular fatty acids included iso-C 15 : 0 , iso-C 17 : 0 3-OH, summed feature 3 and summed feature 4.

Taxol is currently a valuable anticancer drug; however, the accumulated mixture of taxoids can vary greatly among Taxus species. So far, there is very little genomic information for the genus Taxus, except for Taxus baccata. Transcriptome analysis is a powerful approach to explore the different regulatory mechanisms underlying the taxoid biosynthesis pathway in Taxus species. First, we quantified the variation in the taxoid contents between Taxus media and Taxus mairei. The contents of paclitaxel and 10-deacetylpaclitaxel in T. media are higher than that in T. mairei. Then, the transcriptome profiles of T. media and T. mairei were analyzed to investigate the altered expressions. A total of 20,704 significantly differentially expressed genes (DEGs), including 9865 unigenes predominantly expressed in T. media and 10,839 unigenes predominantly expressed in T. mairei, were identified. In total, 120 jasmonic acid-related DEGs were analyzed, suggesting variations in 'response to JA stimulus' and 'JA biosynthetic process' pathways between T. media and T. mairei. Furthermore, a number of genes related to the precursor supply, taxane skeleton formation and hydroxylation, and C13-side chain assembly were also identified. The differential expression of the candidate genes involved in taxoid biosynthetic pathways may explain the variation in the taxoid contents between T. media and T. mairei.

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Taxus species are well-known for paclitaxel, which exhibits antitumor activities and is used for treating various cancers. Although most Taxus species are widespread in many areas, few studies have characterized the variation in metabolism among different Taxus species. Using an integrated approach involving 'tandem mass tag' labeling and liquid chromatography-tandem mass spectrometry (HPLC-MS), proteomes of T. media and T. mairei were investigated and 4078 proteins were quantified. Screening and classification of differentially expressed proteins revealed many metabolism-associated proteins. In detail, four enzymes involved in the flavonoid biosynthesis pathway were predominantly expressed in T. mairei. Four enzymes associated with supplying precursors for paclitaxel biosynthesis and three cytochrome P450 taxoid oxygenases were preferentially expressed in T. media compared with T. mairei. Furthermore, variations in taxoid contents between T. media and T. mairei were determined using HPLC-MS analysis. Variations in flavonoid contents between T. media and T. mairei were determined by HPLC analysis. A number of differentially expressed proteins may provide an explanation for the variation in metabolisms of different Taxus species.

A novel strain, designated 311-10 T , isolated from soil of Xinjiang, China, was characterized by using a polyphasic taxonomic approach. The isolate was Gram-negative, aerobic, rod-shaped, non-motile, oxidase-negative and catalase-positive. The predominant menaquinone of strain 311-10 T was MK-7 and the genomic DNA G+C content was 47.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate formed a cluster with the genera Pontibacter and [Effluviibacter] in the phylum 'Bacteroidetes', with sequence similarities of 93.9-95.6 %. Phylogenetic evidence and the results of phenotypic, genotypic and chemotaxonomic analyses support the reclassification of [Effluviibacter] roseus as Pontibacter roseus comb. nov. (type strain, SRC-1 T 5MTCC 7260 T 5DSM 17521 T ) and the establishment of a novel species, Pontibacter xinjiangensis sp. nov., with strain 311-10 T (5CCTCC AB 207200 T 5NRRL B-51335 T ) as the type strain.The genus Pontibacter, a member of the phylum 'Bacteroidetes' with menaquinone 7 (MK-7) as the main respiratory quinone, accommodates heterotrophic, aerobic, rod-shaped, Gram-negative and pink-pigmented bacteria. At the time of writing, Pontibacter species with validly published names comprise Pontibacter actiniarum, isolated from marine actinians (Nedashkovskaya et al., 2005), and Pontibacter akesuensis (Zhou et al., 2007) During the course of studying the bacterial communities associated with soil in Xinjiang, China, bacterial strain 311-10 T was isolated. The strain appeared as pinkpigmented, circular, convex, shiny colonies with a smooth surface after 48 h cultivation at 30 uC on 0.36 marine agar 2216 (MA; Difco). After primary isolation and purification, the novel strain was cultivated at 30 u C for 2 days on 0.36 MA and cellular morphology was observed by phasecontrast microscopy (Olympus). Except where indicated, the isolate was routinely grown aerobically on 0.36 MA for 2 days at 30 u C.The gliding-motility test was performed as described by Bowman (2000). Oxidase activity was evaluated via the oxidation of 1 % p-aminodimethylaniline oxalate. Catalase activity was determined by measurements of bubble production after the application of 3 % (v/v) hydrogen peroxide solution. Tests were also made for hydrolysis of starch (1 %, w/v), cellulose (0.1 %, w/v), chitin from crab shells (1 %, w/v), casein (5 %, w/v) and tyrosine (0.5 %, w/v) as described by Smibert & Krieg (1994). Tolerance of NaCl concentrations (0-6 %, w/v) was determined at 1 % NaCl increments. Growth was examined at different temperatures (4, 10, 20, 28, 30, 37 and 42 u C) and pH values (5.0-11.0 at 1.0 pH unit increments).Carbon-source oxidation was investigated by using the Biolog GN2 Microplate system as recommended by the manufacturer. Additional enzyme activities and biochemical features were determined by API kits (API 20NE, API 20E and API ZYM) according to the manufacturer's instructions (bioMérieux).Isoprenoid quinones were extracted from lyophilized cells and analysed by HPLC (UltiMate 3000; Dionex...

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