Brassica campestris L., a cadmium (Cd) hyperaccumulating herbaceous plant, is considered as a promising candidate for the bioremediation of Cd pollution. However, the molecular mechanisms regulating these processes remain unclear. The present work, using proteome studies combined with a transcriptome analysis, was carried out to reveal the response mechanisms of the hairy roots of Brassica campestris L. under Cd stress. Significant tissue necrosis and cellular damage occurred, and Cd accumulation was observed in the cell walls and vacuoles of the hairy roots. Through quantitative proteomic profiling, a total of 1424 differentially expressed proteins (DEPs) were identified, and are known to be enriched in processes including phenylalanine metabolism, plant hormone signal transduction, cysteine and methionine metabolism, protein export, isoquinoline alkaloid biosynthesis and flavone biosynthesis. Further studies combined with a transcriptome analysis found that 118 differentially expressed genes (DEGs) and their corresponding proteins were simultaneously up- or downregulated. Further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of the 118 shared DEGs and DEPs indicated their involvement in calcium, ROS and hormone signaling-mediated response, including regulation of carbohydrate and energy metabolism, biosynthesis of GSH, PCs and phenylpropanoid compounds that play vital roles in the Cd tolerance of Brassica campestris L. Our findings contribute to a better understanding of the regulatory networks of Brassica campestris L. under Cd stress, as well as provide valuable information on candidate genes (e.g., BrPAL, BrTAT, Br4CL, BrCDPK, BrRBOH, BrCALM, BrABCG1/2, BrVIP, BrGCLC, BrilvE, BrGST12/13/25). These results are of particular importance to the subsequent development of promising transgenic plants that will hyperaccumulate heavy metals and efficient phytoremediation processes.

Brassica campestris L., a hyperaccumulator of cadmium (Cd), is considered a candidate plant for efficient phytoremediation. The hairy roots of Brassica campestris L are chosen here as a model plant system to investigate the response mechanism of Brassica campestris L. to Cd stress. High-throughput sequencing technology is used to identify genes related to Cd tolerance. A total of 2394 differentially expressed genes (DEGs) are identified by RNA-Seq analysis, among which 1564 genes are up-regulated, and 830 genes are down-regulated. Data from the gene ontology (GO) analysis indicate that DEGs are mainly involved in metabolic processes. Glutathione metabolism, in which glutathione synthetase and glutathione S-transferase are closely related to Cd stress, is identified in the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. A Western blot shows that glutathione synthetase and glutathione S-transferase are involved in Cd tolerance. These results provide a preliminary understanding of the Cd tolerance mechanism of Brassica campestris L. and are, hence, of particular importance to the future development of an efficient phytoremediation process based on hairy root cultures, genetic modification, and the subsequent regeneration of the whole plant.

Solanum nigrum L., a hyperaccumulator of cadmium (Cd), is regarded as a promising candidate for phytoremediation of heavy metal pollution. In the present study, the hairy roots of Solanum nigrum L. were selected as a model plant system to study the potential application of Iron-regulated Transporter Gene (IRT1) for the efficient phytoremediation of Cd pollution. The transgenic hairy roots of Solanum nigrum L. expressing the IRT1 gene from Arabidopsis thaliana were successfully obtained via the Agrobacterium tumegaciens-mediated method. Expression of IRT1 reduced Cd stress-induced phytotoxic effects. Significantly superior root growth, increased antioxidant enzyme activities, decreased reactive oxygen species (ROS) levels, and less cell apoptosis were observed in the transgenic hairy roots of Solanum nigrum L. compared to the wild-type lines under Cd stress. Enhanced Cd accumulation was also carried out in the transgenic hairy roots compared to the control (886.8 μg/g vs. 745.0 μg/g). These results provide an important understanding of the Cd tolerance mechanism of transgenic IRT1 hairy roots of Solanum nigrum L., and are of particular importance to the development of a transgenic candidate for efficient phytoremediation process.

Surfactants play a vital role in the delignification and saccharification of lignocellulosic biomass. A strategy for coupling surfactant-assisted alkaline pretreatment (SAP) with surfactant-assisted enzymatic hydrolysis (SEH) has been proposed for improving sugar recovery from a potential energy crop, Miscanthus sinensis. Poly (ethylene glycol) 2000 (PEG 2000) was found to be more efficient in SAP than in other tested surfactants. Compositional and structural analysis revealed that the SAP process with 1% of PEG 2000 produced more efficient lignin removal and microstructure disruption of the pretreated sample, thus indicating much higher reducing sugar yields of 544.4–601.2 mg/g compared to the samples that were untreated or pretreated by alkali alone. Moreover, SEH with 1% Tween 80, which could block the lignin-enzyme interactions, produced a substantial reduction of 33.3% in the enzyme loading to achieve a higher sugar recovery from the SAP sample.

In this study, effects of different pretreatment methods on the enzymatic digestibility of Pennisetum alopecuroides, a ubiquitous wild grass in China, were investigated to evaluate its potential as a feedstock for biofuel production. The stalk samples were separately pretreated with H₂SO₄, NaOH and FeCl₃ solutions of different concentrations at 120 °C for 30 min, after which enzymatic hydrolysis was conducted to measure the digestibility of pretreated samples. Results demonstrated that different pretreatments were effective at removing hemicellulose, among which ferric chloride pretreatment (FCP) gave the highest soluble sugar recovery (200.2 mg/g raw stalk) from the pretreatment stage. In comparison with FCP and dilute acid pretreatment (DAP), dilute alkaline pretreatment (DALP) induced much higher delignification and stronger morphological changes of the biomass, making it more accessible to hydrolysis enzymes. As a result, DALP using 1.2% NaOH showed the highest total soluble sugar yield through the whole process from pretreatment to enzymatic hydrolysis (508.5 mg/g raw stalk). The present work indicates that DALP and FCP have the potential to enhance the effective bioconversion of lignocellulosic biomass like P. alopecuroides, hence making this material a valuable and promising energy plant.

In this work, a novel MXene-copolymeric molecularly imprinted hydrogel (FMMIH) with temperature/pH dual response and photothermal conversion performance for selective recognition of cis-diol compounds is successfully prepared. Functionalized MXene becomes an important part of the hydrogel’s skeleton by participating in the free radical polymerization reaction. Therefore, FMMIH exhibits improved mechanical properties and great photothermal conversion performance. Furthermore, based on the temperature/pH dual response, FMMIH can realize the controllable capture and release of ginsenoside Rb1 with cis diol structures through dual recognitions of functional groups and geometric space. Under the conditions of pH 8.5 and 25 °C, the adsorption capacity of FMMIH is 26.3 mg·g⁻¹ and the imprinting factor is 16.4, showing a good imprinting effect. It is worth noting that the volume shrinkage caused by photothermal conversion of the hydrogel is conducive to the elution of template molecules and greatly saves the time of desorption (the desorption efficiency is as high as 89.4% under light conditions for 30 min, which is 3.7 times in dark conditions). These excellent properties make it possible to have broad prospects in many fields such as separation of cis-diol compounds, drug delivery systems, and biosensors.