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bZIP transcription factors play important roles in regulating plant development and stress responses. Although bZIPs have been identified in many plant species, there is little information on the bZIPs in Chrysanthemum. In this study, bZIP TFs were identified from the leaf transcriptome of C. mongolicum, a plant naturally tolerant to drought. A total of 28 full-length bZIP family members were identified from the leaf transcriptome of C. mongolicum and were divided into five subfamilies based on their phylogenetic relationships with the bZIPs from Arabidopsis. Ten conserved motifs were detected among the bZIP proteins of C. mongolicum. Subcellular localization assays revealed that most of the CmbZIPs were predicted to be localized in the nucleus. A novel bZIP gene, designated as CmbZIP9, was cloned based on a sequence of the data of the C. mongolicum transcriptome and was overexpressed in tobacco. The results indicated that the overexpression of CmbZIP9 reduced the malondialdehyde (MDA) content and increased the peroxidase (POD) and superoxide dismutase (SOD) activities as well as the expression levels of stress-related genes under drought stress, thus enhancing the drought tolerance of transgenic tobacco lines. These results provide a theoretical basis for further exploring the functions of the bZIP family genes and lay a foundation for stress resistance improvement in chrysanthemums in the future. [ABSTRACT FROM AUTHOR]

Moso bamboo (Phyllostachys edulis), a high‐value bamboo used to produce food (young shoots), building, and industrial goods. To explore key candidate genes regulating signal transduction and metabolic processes during the initiation of stem elongation in moso bamboo, a transcriptome analysis of the shoots during three successive early elongation stages was performed. From cluster and differential expression analyses, 2984 differentially expressed genes (DEGs) were selected for an enrichment analysis. The DEGs were significantly enriched in the plant hormone signal transduction, sugar and starch metabolism, and energy metabolism pathways. Consequently, the DEG expression patterns of these pathways were analyzed, and the plant endogenous hormone and carbon metabolite (including sucrose, total soluble sugar, and starch) contents for each growth stage, of the shoot, were determined. The cytokinin‐signaling pathway was continuously active in the three successive elongation stages, in which several cytokinin‐signaling genes played indispensable roles. Additionally, many key DEGs regulating sugar, starch metabolism, and energy conversion, which are actively involved in energy production and substrate synthesis during the continuous growth of the shoots, were found. In summary, our study lays a foundation for understanding the mechanisms of moso bamboo growth and provides useful gene resources for breeding through genetic engineering. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in the soil of farmland is regarded as serious threats to agricultural production environment in China. Zihu River is located in Nanjing, Jiangsu, China. The source of Zihu River is the purple mountain, a famous local mountain. The pollution problem of Zihu River has aroused public concerns because of heavy metal contamination caused by sewage. To investigate and assess the situation of heavy metal pollution of Zihu River region, concentrations of heavy metals including As, Cd, Cr, Cu, Mn, Ni, Pb and Zn were determined and analyzed for brook water, the soil from river silt and riverbank, as well as for the riverbank plants of nine species. These species include Trifolium repens, Alternanthera philoxeroides, Chenopodium glaucum, Commelina communis, Ranunculus ternatus, Poa annua, Ligustrum lucidum, Lycium chinense, Broussonetia papyrifera. An assessment of heavy-metal contamination was conducted by means of pollution index (Pi). Such data may provide information for screening of heavy metal accumulator, and for phytoremediation of heavy metals. The results indicated that serious contamination of Cd and Mn was found in the brook water, the concentrations for Cd and Mn were 0.003 mg/L and 0.124 mg/L, respectively. Among the heavy metals in the soil from the river silt, contamination of Zn, Cd and Cu was serious based on the Pi values (18.89, 8.53 and 6.25, respectively), with the order of potential ecological risk as: Zn>Cd>Cu>Pb>As>Ni> Cr>Mn. Pearson correlation analysis showed a significantly (p < 0.05) positive correlation among concentrations of heavy metals in the riparian soil, which indicated that they were mainly polluted by sewage and silt. High concentrations of Cd, Zn and Cu were investigated from the soil of the riverbank based on the Pi values (3.68, 3.61 and 3.41, respectively). The bioconcentration factor (BFs) to Cd, Cr and Pb were quite lower among all the nine species due probably to the selective absorption of the plants. Because Pb is toxic to all plants, the transfer factors (TF) to Pb for all the nine species were typically less than 1. This meant that they were all compartment types to Pb. Plants growing on the sites with heavy metal pollution can gradually evolve into differentiated ecotypes based on the survey of plant population and the result of heavy metal concentration. Wetland ecotypes, Alternanthera philoxeroides and Ranunculus ternatus, have an advantage for accumulating of heavy metals. Poa annua, Chenopodium glaucum and Lycium chinense can resistant to absorption heavy metals. Broussonetia papyrifera, a species of woody plants, will play a great function in the field of phytoremediation for soils contaminated by heavy metals in the future due to its higher bioconcentration factor and transfer factor to some heavy metals, as well as its huge biomass. This case study also provided useful information for monitoring of heavy metals and phytoremediation of river systems contaminated among other cities. [ABSTRACT FROM AUTHOR]