This study investigated the beneficial effect of molybdenum (Mo) application on rape plants (Brassica napus L.) grown in a soil polluted by cadmium (Cd). A pot experiment was conducted to determine how different concentrations of exogenous Mo (0, 50, 100, and 200 mg/kg) affect plant physiology, biomass, photosynthesis, cation uptake, and Cd translocation and enrichment in rape plants under Cd stress (0.5 and 6.0 mg/kg). Under single Cd treatment, plant physiological and biochemical parameters, biomass parameters, leaf chlorophyll fluorescence parameters, and macroelement uptake of rape plants decreased, while their malonaldehyde content, proline content, non-photochemical quenching coefficient, and Cd uptake significantly increased, compared to those of the control group (p-values < 0.05). High-Cd treatment resulted in much larger changes in these parameters than low-Cd treatment. Following Mo application, the accumulation of malondialdehyde and proline decreased in the leaves of Cd-stressed plants; reversely, the contents of soluble protein, soluble sugar, and chlorophyll, and the activities of superoxide dismutase and glutathione peroxidase, all increased compared to those of single Cd treatment (p-values < 0.05). Exogenous Mo application promoted shoot and root growth of Cd-stressed plants in terms of their length, fresh weight, and dry weight. The negative effect of Cd stress on leaf chlorophyll fluorescence was substantially mitigated by applying Mo. Exogenous Mo also improved the uptake of inorganic cations, especially potassium (K⁺), in Cd-stressed plants. After Mo application, Cd uptake and accumulation were inhibited and Cd tolerance was enhanced, but Cd translocation was less affected in Cd-stressed plants. The mitigation effect of Mo on Cd stress in rape was achieved through the immobilization of soil Cd to reduce plant uptake, and improvement of plant physiological properties to enhance Cd tolerance. In conclusion, exogenous Mo can effectively reduce Cd toxicity to rape and the optimal Mo concentration was 100 mg/kg under the experimental conditions.

A novel actinobacterium, designated strain YIM 100590^T, was isolated from Panthera tigris amoyensis faeces collected from Yunnan Wild Animal Park in Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequence data showed that strain YIM 100590^T is a member of the family Micrococcaceae . Cells were coccoid to oval (0.7–1.5 µm in diameter) occurring singly or in clusters. Growth was observed at 10–37 °C (optimum 28 °C) and at pH 7.0–11.0 (optimum pH 8.0). The major fatty acids were iso-C_15 : 0 (32.22 %), anteiso-C_15 : 0 (31.64 %) and iso-C_16 : 0 (17.38 %). The peptidoglycan was of A4α type (l-Lys–Gly–l-Glu). The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, dimannosyl diacylglycerol, an unknown glycolipid and two unknown phospholipids. The quinone system comprised menaquinones MK-7 (91.9 %) and MK-8 (8.3 %). The DNA G+C content of strain YIM 100590^T was 56.2 mol%. Chemotaxonomic data indicated that the strain belongs to the family Micrococcaceae . On the basis of morphological and chemotaxonomic data and phylogenetic analysis, strain YIM 100590^T is considered to represent a novel species of a new genus within the family Micrococcaceae , for which the name Enteractinococcus coprophilus gen. nov., sp. nov. is proposed. The type strain of Enteractinococcus coprophilus is YIM 100590^T ( = DSM 24083^T = JCM 17352^T). Yaniella fodinae DSM 22966^T was transferred to the new genus as Enteractinococcus fodinae comb. nov. (type strain G5^T = DSM 22966^T = JCM 17931^T = MTCC 9846^T).