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In higher plants, heavy metal transporters are responsible for metal uptake, translocation and homeostasis. These metals include essential metals such as zinc (Zn) or manganese (Mn) and non-essential metals like cadmium (Cd) or lead (Pb). Although a few heavy metal transporters have been well identified in model plants (e.g. Arabidopsis and rice), little is known about their functionality in rapeseed (Brassica napus). B. napus is an important oil crop ranking the third largest sources of vegetable oil over the world. Importantly, B. napus has long been considered as a desirable candidate for phytoremediation owning to its massive dry weight productivity and moderate to high Cd accumulation. In this study, 270 metal transporter genes (MTGs) from B. napus genome were identified and annotated using bioinformatics and high-throughput sequencing. Most of the MTGs (74.8%, 202/270) were validated by RNA-sequencing (RNA-seq) the seedling libraries. Based on the sequence identity, nine superfamilies including YSL, OPT, NRAMP, COPT, ZIP, CDF/MTP, HMA, MRP and PDR have been classified. RNA-sequencing profiled 202 non-redundant MTGs from B. napus seedlings, of which, 108 MTGs were differentially expressed and 62 genes were significantly induced under Cd stress. These differentially expressed genes (DEGs) are dispersed in the rapeseed genome. Some of the genes were well confirmed by qRT-PCR. Analysis of the genomic distribution of MTGs on B. napus chromosomes revealed that their evolutional expansion was probably through localized allele duplications.

In plants, metal transporters are responsible for metal uptake, translocation and homeostasis. These metals include essential nutrients such as zinc (Zn) and manganese (Mn) or non-essential metals like cadmium (Cd) and lead (Pb). Although a few metal transporters have been well characterized in model plants, little is known about their functionality in rapeseed (Brassica napus). In the study, 22 NRAMP transporter genes from B. napus genome were identified and annotated using bioinformatics and high-throughput RNA-sequencing (RNA-seq). Based on the sequence identity, these NRAMP transporters can be classified into 6 subfamilies. RNA-seq analysis revealed that 19 NRAMP transporters were detected and some of the genes were well confirmed by qRT-PCR. Ten NRAMP transporters (45.5%, 10/22) were found to be differentially expressed (> 2 fold change, p < 0.05) under Cd exposure. As an example, we specified expression of BnNRAMP1b under Cd exposure. BnNRAMP1b is a constitutive gene expressing throughout all development stages including seedlings, vegetative tissue, flowers and siliques. Expression of BnNRAMP1b can be strongly induced in seedlings exposed to 80, 160 and 240 μM Cd. To define whether BnNRAMP1b was specific for Cd transport, a yeast (wild-type, BY4741) system with its mutants (ycf1, zrc1, and smf1) defective in transport activity of Cd, Zn and Mn, respectively were tested. Compared to empty vectors (pYES2), cells carrying BnNRAMP1b can rescue the transport functions. As a consequence, excess Cd, Zn and Mn were taken in the cells, which led to metal toxicity, suggesting that BnNRAMP1b is responsible for transport of these metals in B. napus. Using our previously created degradome datasets, we found that BnNRAMP1b could be cleaved by miR167, suggesting that BnNRAMP1b is a target of miR167 in B. napus. The contrasting expression pattern of BnNRAMP1b and miR167 under Cd stress supported the post-transcriptional regulation of BnNRAMP1b by miR167.

There is increasing evidence of long non-coding RNA (lncRNA) involvement in a variety of biological responses to environmental stresses. The toxic heavy metal cadmium (Cd) is one of the major inorganic contaminants in environments. How lncRNAs are involved in Cd stress-induced response and regulatory mechanism in dicot plants is unknown. The present study performed strand-specific RNA-sequencing (RNA-Seq) to profile lncRNAs in Cd-exposed rapeseed (Brassica napus). More than 60 million clean reads corresponding to 5038 unique B. napus lncRNAs were identified, in which 2546 lncRNAs were generated from the sense strand and 2492 were generated from natural antisense transcripts (lncNATs). A combinational analysis resulted in identification of 301 lncRNAs responding to Cd stress. Cd-induced expression of lncRNAs appeared to be associated with their nearby protein-coding genes. Many coding genes flanking lncRNA loci were involved in Cd uptake, translocation and stress-responses, suggesting that the associated lncRNAs might have similar functions. Four lncRNAs were identified as precursors of miR824, miR167d, miR156d and miR156e. Sixty-seven lncRNAs acted as competing endogenous target mimics (eTMs) for 36 miRNAs potentially involved in Cd stress response. The functional mimics were validated by transient transformation of three lncRNAs into B. napus protoplasts under control of double 35S promoter with a decoy lncRNA (d35S-lncRNAs-pAN580). These results suggest that a set of putative lncRNAs were involved in response to Cd stress in B. napus.

WRKY transcription factors play crucial roles in plant response to environmental stresses. This study aimed to investigate an uncharacterized gene (At2g30590) encoding AtWRKY21 in mediating an adaptive response to osmotic stress in Arabidopsis. AtWRKY21expressed at various development stages and was substantially induced by drought stress but not salinity. Confocal scanning detection shows that AtWRKY21 resides in the nucleus. Two AtWRKY21 knockout mutant lines displayed drought tolerance phenotype by increasing plant biomass, chlorophyll accumulation, survival rate, and leafy water retention, whereas transgenic lines overexpressing AtWRKY21 show drought supersensitive phenotype. The wrky21 mutant lines had a lower degree of drought-induced cellular damage, with reduced electrolyte leakage and peroxides. In contrast, the AtWRKY21 OE lines exhibited adverse tolerant responses. We performed a genome-wide RNA sequencing of wrky21 and its wild-type rice exposed to osmotic stress to identify differentially expressed genes relevant to AtWRKY21-mediated drought stress response. We profiled 291 upregulated and 607 downregulated genes. Gene Ontology analysis showed pathways closely related to the drought stress response and expression of numerous genes such as protein binding transcription factors and drought-stress tolerance was changed. A set of genes were possibly working on the downstream of AtWRKY21. The results suggest that AtWRKY21 functions as a negative regulator of plant response to drought stress.

The plant ATP binding cassette (ABC) transporters are one of the integral membrane proteins responsible for uptake and allocation of a wide range of metabolites and xenobiotics including heavy metals (e.g. zinc, manganese and cadmium). They play multiple roles in plant growth, development and environmental stress responses. Although the ABC transporters have been identified in model plants such as Arabidopsis and rice, they are have not been annotated and identified in rapeseed (Brassica napus) and also, little is known about functionality of these metal transporters. B. napus is an important oil crop ranking the third largest source of vegetable oil worldwide. Importantly, it is long considered as a desirable candidate for phytoremediation owning to its massive dry weight productivity and moderate Cd accumulation. In this study, we identified 314 ABC protein genes from B. napus using bioinformatics and high-throughput sequencing. Eight subfamilies including ABCA-G and ABCI have been categorized. The ABCG proteins constitute the largest subfamily with 116 members, and the ABCB and ABCC subfamilies ranks second and third with 69 and 47 members, respectively. Analyses of ABCs in B. napus genome reveal that their evolutional expansion was through localized allele duplications. Most of the ABC genes (74.2%, 233/314) were validated by RNA-sequencing rapeseed seedlings. Among the 233 profiled BnaABCs, 132 genes were differentially expressed (1.5 fold change, p 0.05) and 84 genes were significantly induced under Cd stress. Analyses of specific cis-elements in the upstream of eight representative genes show diverse motifs, which potentially respond to environmental stress, hormone responsiveness and other development signals.

With the in-depth development of smart grid, renewable energy, such as wind power, will be an important source of electrical energy, the proportion of renewable resources increase rapidly. Serious problems emerged with large-scale wind power integrating to power grid. The integration of wind generation imports variability and uncertainty to system operation and control. Control center must consider this variability and uncertainty to dispatch economically. Fortunately, there will be many electric vehicles in smart grid. With the popularization of electric vehicles, charging stations and electric vehicle battery swap stations will be increasing rapidly. Battery swap stations can be regarded as energy storage power stations, which can be used to stabilize the wind power output variability and uncertainty. In this paper, new economic dispatch model considering wind power and electric vehicle battery swap stations is proposed, the Particle Swarm Optimization (PSO) method and prior priority way are adopted to solve this model. The algorithm based on MATLAB 6.5 is developed. The correctness and effectiveness of the model and algorithm are verified using test system.