Probing active microbes involved in Bt-containing rice straw decomposition.

Transgenic Bacillus thuringiensis (Bt) rice extends significant protection against insect pests and meets the increasing demands for food and energy. Many studies have been conducted investigating the impacts of Bt rice to the agricultural ecosystem, but much less attention has been given to efforts attempting to determine how the presence of Bt rice influences and shapes the microbial community, especially the active microbes. Stable isotope probing and high-throughput sequencing were employed to explore the active microbes involved in Bt-containing straw decomposition. Compared to its near isoline, the Bt straw contained higher contents of total N, total P, total K, lignin, cellulose, and Cry1Ab toxin protein. These chemical differences did not affect the decomposition rate but significantly changed the active microbial decomposer communities. During the decomposition of Bt-containing straw, fungi were more affected than bacteria. Agromyces, Terrabacter, Microbacterium, Glycomyces, and Kribbella were the most representative unique (existed only in the Bt treatments and appeared at the early stage) bacterial genera, and Trichoderma was the most representative unique fungal genus in the Bt straw decomposition. By using similarity index calculation and function prediction, the significant differences between Bt straw and non-Bt straw treatments were found to be transient for both microbial taxa and functional traits. These results suggested that Bt rice has a significant but transient impact on soil microbes in terms of microbial straw decomposition.

Three new species of Tomocerus from tropical zone of China (Collembola, Tomoceridae).

Tomocerids are world-widely distributed, but were seldom reported from tropics. In the present paper, three new species of Tomocerus Nicolet are described from Hainan and Yunnan Provinces, tropical zone of China. All three species have compound-type dental spines and belong to Tomocerus ocreatus species-group. Tomocerus tropicus sp. nov. resembles Tomocerus pseudocreatus Yu, but differs from the latter in mesothoracic macrochaetotaxy, manubrial dorsal scales and denticles on the dental spines. Tomocerus nan sp. nov. resembles Tomocerus virgatus Yu, but differs from the latter in colour pattern, cephalic dorsal macrochaetotaxy, manubrial dorsal scales and denticles on the dental spines. Tomocerus nabanensis sp. nov. resembles T. postantennalis Yu, Zhang Deharveng, Tomocerus dong Yu Li and Tomocerus deharvengi Yu Li, but differs from the three species in PAO, cephalic and tergal dorsal macrochaetotaxy and tenent hairs. Our studies including the present work indicate the importance of future survey on Tomocerinae in and near tropics where diversity of this group was historically underestimated.

Changes in tetracycline partitioning and bacteria/phage-comediated ARGs in microplastic-contaminated greenhouse soil facilitated by sophorolipid.

The emerging mixed contamination of antibiotics and microplastics in greenhouse soil has made the control of antibiotic resistant gene (ARG) transmission a novel challenge. In this work, surfactant sophorolipid was applied to enhance the dissipation of tetracycline (TC) and tet genes in the presence of microplastics in greenhouse soil. During 49days of incubation, soil bacteria and phages were both found to be the crucial reservoirs of ARGs. Meanwhile, microplastic's presence significantly inhibited the dissipation of TC and ARGs in the soil. However, sophorolipid application was proved to outweigh the negative impact caused by microplastic existence, and lead to the highest dissipation of soil TC and ARGs. Significant positive correlation was detected between the dissipation rate of water-soluble and exchangeable TC content and bacteria/phage co-mediated ARG levels. This also held true between the two fractions of soil TC and the ratio of ARG level in the bacteria to that in the phages (BARGs/PARGs). The opposite impacts of microplastic presence and sophorolipid amendment on the TC/ARG dissipation found in this work provides new information for understanding ARG transmission between bacteria and phages in the mixed contaminated greenhouse soil.

New cave-dwelling species of Tomoceridae from China, with a study on the pattern of mesothoracic bothriotricha in Tomocerinae (Collembola, Entomobryomorpha).

Two new troglobitic species of Tomoceridae are described from Guizhou and Guangxi provinces, China. Tomocerus tiani sp. n. resembles Tomocerus kinoshitai Yosii, 1954, Tomocerus caecus Yu & Deharveng, 2015 and Tomocerus similis Chen & Ma, 1997 but differs from them mainly in the body colour, the cephalic chaetotaxy and the number of manubrial pseudopores. Monodontocerus cinereus sp. n. is similar to Monodontocerus mulunensis Yu, Deharveng & Zhang, 2014 but is different from the latter in the body colour, the length of antennae, the number of ungual teeth and the chaetotaxy on Abd. III and Abd. IV. Special remarks are made on the mesothoracic bothriotricha in Tomocerinae.