Tea gray blight disease and its existing control measures have had a negative impact on the sustainable development of tea gardens. However, our knowledge of safe and effective biological control measures is limited. It is critical to explore beneficial microbial communities in the tea rhizosphere for the control of tea gray blight. In this study, we prepared conditioned soil by inoculating Pseudopestalotiopsis camelliae-sinensis on tea seedling leaves. Thereafter, we examined the growth performance and disease resistance of fresh tea seedlings grown in conditioned and control soils. Next, the rhizosphere microbial community and root exudates of tea seedlings infected by the pathogen were analyzed. In addition, we also evaluated the effects of the rhizosphere microbial community and root exudates induced by pathogens on the performance of tea seedlings. The results showed that tea seedlings grown in conditioned soil had lower disease index values and higher growth vigor. Soil microbiome analysis revealed that the fungal and bacterial communities of the rhizosphere were altered upon infection with Ps. camelliae-sinensis. Genus-level analysis showed that the abundance of the fungi Trichoderma, Penicillium, and Gliocladiopsis and the bacteria Pseudomonas, Streptomyces, Bacillus, and Burkholderia were significantly (p < 0.05) increased in the conditioned soil. Through isolation, culture, and inoculation tests, we found that most isolates from the induced microbial genera could inhibit the infection of tea gray blight pathogen and promote tea seedling growth. The results of root exudate analysis showed that infected tea seedlings exhibited significantly higher exudate levels of phenolic acids and flavonoids and lower exudate levels of amino acids and organic acids. Exogenously applied phenolic acids and flavonoids suppressed gray blight disease by regulating the rhizosphere microbial community. In summary, our findings suggest that tea plants with gray blight can recruit beneficial rhizosphere microorganisms by altering their root exudates, thereby improving the disease resistance of tea plants growing in the same soil.

A natural tea seed saponin detergent with good safety and decontamination ability was successfully developed. This can make better use of the tea seed cake, thereby creating added value in the tea seed oil industry. © 2017 Society of Chemical Industry.

Monodisperse polystyrene (PS) nanoparticles with widely tunable sizes (30–930 nm) were prepared by soap-free emulsion polymerization with the assistance of crown ethers. The effects of crown ether species and concentrations, initiator species, and monomer contents on the sizes of PS nanoparticles were investigated in detail. The presence of 18-crown-6 and 15-crown-5 in the reaction system will facilitate the polymerization rate of styrene and produce larger PS nanoparticles in comparison with the control group (without crown ethers), whereas the system with 12-crown-4 retards the polymerization rate significantly and brings the smallest PS nanoparticles. As the interface of monomer/water is the main locus of initial reaction for the thermally initiated emulsion polymerization, the crown ether/alkali complexes accumulated around the styrene/water phase play both catalyst and molecular fence roles in the styrene soap-free emulsion polymerization. The former promotes and the latter inhibits the growth of PS nanoparticles. The relative contribution of these functions ultimately determines the final particle size. The results indicate that particle nucleation in styrene soap-free emulsion polymerization in the presence/absence of crown ethers occurs via an aggregative nucleation mechanism. This study provides a facile method to synthesize nanoparticles with widely tunable sizes via soap-free emulsion polymerization with the help of crown ethers, which has great potentials in biomedical and electronic fields.

A Gram-reaction-negative, yellow-pigmented, non-spore-forming rod, aerobic, motile bacterium, designated SJY3T, was isolated from soil samples collected from a Pu-erh tea cellar in Bolian Pu-erh tea estate Co. Ltd. in Pu'er city, Yunnan, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belonged to the genus Massilia . The closest phylogenetic relative was Massilia arenae CICC 24458T (99.5 %), followed by M. timonae CCUG45783T (97.9 %), M. oculi CCUG43427AT (97.8 %), and M. aurea DSM 18055T (97.8 %). The major fatty acids were C16 : 0 and C16 : 1  ω7c and/or C16 : 1  ω6c. The major respiratory quinone was ubiquinone Q-8 and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Genome sequencing revealed a genome size of 5.97 M bp and a G+C content of 65.4 mol%. Pairwise determined whole genome average nucleotide identity (gANI) values and digital DNA–DNA hybridization (dDDH) values were all below the threshold. Although the 16S rRNA gene similarity of stain SJY3T and Massilia arenae CICC 24458T was more than 99 %, the gANI, dDDH values and genomic tree clearly indicated that they were not of the same species. In summary, strain SJY3T represents a new species, for which we propose the name Massilia puerhi sp. nov. with the type strain SJY3T (=CGMCC 1.17158T=KCTC 82193T).