Increasing evidence has confirmed the importance of plant-associated bacteria for plant growth and productivity, and thus it is hypothesized that interactions between bacteria and alien plants might play an important role in plant invasions. However, the diversity of the bacterial communities associated with invasive plants is poorly understood. We therefore investigated the diversity of rhizospheric and endophytic bacteria associated with the invasive annual plant Senecio vulgaris L. (Asteraceae) based on 16S rRNA gene data obtained from 57 samples of four Senecio vulgaris populations in a subtropical mountainous area in central China. Significant differences in diversity were observed between plant compartments. Specifically, the rhizosphere harbored many more bacterial operational taxonomic units and showed higher alpha diversity than the leaf and root endospheres. The relative abundance profiles of the bacterial community composition differed substantially between the compartments and populations, especially at the phylum and family levels. However, the top five phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Acidobacteria) accounted for more than 90% of all the bacterial communities. Moreover, similar endophytic communities with a shared core set of bacteria were observed from different Senecio vulgaris populations. Heavy-metal-resistant, phosphate-solubilizing bacteria (Brevundimonas diminuta), nitrogen-fixing bacteria (Rhizobium leguminosarum), and cold-resistant bacteria (Exiguobacterium sibiricum) were present in the endosphere at relatively high abundance. This study, which reveals the structure of bacterial communities and their putative function in invasive Senecio vulgaris plants, is the first step in investigating the role of plant–bacteria interactions in the invasion of this species in China.

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The salt-anhydrite formation has a highly negative impact on well construction, which can cause various drilling accidents upon drilling. In combination to salt-anhydrite characteristics of Missan Oilfields, a novel type of brine-based frilling fluid was established. The weighting manner of fixed salinity was evaluated, and key additives, viscosifier and filtrate reducer, were determined by single-factor experiments. The formula of brine-based drilling fluid was constructed as: fresh water + 0.6wt.% VIS + 2wt.% S-FLO+ (25wt.% NaCl + 5wt.% KCl + 8wt.% HCOONa) fixed salinity, which will be essential for further developing multifunctional high-density drilling fluids.

Predicting potential distribution for alien plants by species distribution model (SDM, or Ecological Niche Model) using occurrence data and habitat environmental variables plays an important role in management of the invasive risk by an alien plant. Common groundsels (Senecio vulgaris, Asteracea), native in Eurasia and North Africa, has been a cosmopolitan weed in temperature and also listed as one of invasive plants in China. We predict the potential distribution of this species in the world and in China particularly in Maxent (maximum entropy) models by using global occurrence records of S. vulgaris and the associated climate variables. The occurrence data were collected from the online databases, Global Biodiversity Information Facility database (GBIF), Chinese Virtual Herbarium database (CVH), and also from field work in China. The climate variables were download from WorldClim (http://www.worldclim.org). The occurrence records showed that S. vulgaris is present in 16 provinces or regions in north – eastern, south – western, central and north China, and almost not present in south – eastern, north – western China. The mapping of S. vulgaris potential distribution is diagonally across China, including the north – eastern, south – western China, and the cool area between the two regions. Analysis of the contribution and importance of climatic factors in the prediction model indicated that S. vulgaris adapts to the climate in humid and cool area in China (annual mean temperature ranges 2.4 ~ 17.5 ℃, and annual precipitation ranges 550 ~ 1500 mm). It is suggested that special attention should be paid to the plain in NE China and Shandong Peninsula, Yungui Plateau, the cool mountain area around Sichuan basin, in western Hubei, southern Shaanxi, Shanxi and around Beijing in order to manage the invasion risk by S. vulgaris. The better performance of the model built by using occurrence data in China than that by using the global data in relation the predict outcome in China imply that it is might be better to use regional data than the global data when predict potential distribution for an alien plant with long invasive history in study area.

Because increasing evidence has confirmed the importance of plant-associated bacteria for plant growth and productivity, it is believed that interactions between bacteria and alien plants play an important role in plant invasions. However, the diversity of bacterial communities associated with invasive plants is poorly understood. Therefore, we investigated the diversity of rhizo- and endophytic bacteria associated with the invasive annual plant Senecio vulgaris L (Asteraceae) based on bacterial 16S rRNA gene data obtained from 57 samples of four S. vulgaris populations in a subtropical mountainous area in central China. Significant differences in diversity were observed between plant compartments. Rhizosphere harbored much more bacterial OTUs and showed higher alpha diversity than the leaf and root endosphere. Bacterial community composition differed substantially between compartments and locations in relative abundance profiles, especially at phyla and family level. However, the top five phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Acidobacteria) comprised more than 90% of abundance in all the bacterial communities. And similar endophytic communities with a shared core set of bacteria were observed from different S. vulgaris populations. According to the function prediction based on the identification and abundance information of the OTU, bacteria characterized as plant pathogens, as well as those involved in ureolysis and nitrate reduction, were rich in endophytic communities. This study reveals the microbiomes and their putative function in the invasive S. vulgaris plants and is also the first step for future studies on the role of interactions between bacteria and alien plants in plant invasions.