Heavy metal pollution of agricultural soils, especially from cadmium (Cd) contaminationcaused serious problems in both food security and economy. Sorghum bicolor (L.) showed a great potential in phytoremediation of Cd contamination due to its fast growth, high yield and easy harvesting. However, the growth of S. bicolor plants tends to be inhibited under Cd exposure, which limited its application for Cd remediation. Plant growth-promoting rhizobacteria may enhance the Cd resistance of S. bicolor and thus improve its Cd removal efficiency. In this study, three Cd-resistant bacteria were screened based on Cd and acid tolerance and identified as Bacillus velezensis QZG6, Enterobacter cloacae QZS3 and Bacillus cereus QZS8, by 16S rRNA sequencing. Inoculation of hydroponic plants with strains QZG6, QZS3 or QZS8 significantly promoted the biomass of sorghum plants by 31.52%, 50.20% and 26.93%, respectively, compared with those of uninoculated plants under Cd exposure. The activity of SOD, POD and MDA content in Cd-stressed S. bicolor plants were reduced of 65.74%, 31.52%, and 80.91%, respectively, when inoculated with the strains QZS3. For pot experiment, strains QZG6, QZS3 and QZS8 significantly promoted the biomass of sorghum plants by 47.30%, 19.27% and 58.47%, compared with those of uninoculated plants under Cd exposure. The activity of SOD, POD and MDA content in Cd-stressed S. bicolor plants were reduced of 67.20%, 22.40%, and 40.65%, respectively, when inoculated with the strains QZS3. All these three strains significantly increased the Cd removal efficiency of the plants by 42.16% (QZG6), 18.76% (QZS3) and 21.06% (QZS8). To investigate the bacterial characteristics associated with growth promotion of S. bicolor plants, the ability on nitrogen fixation, phosphorus solubilization, siderophores production, and phytohormones production were determined. All the strains were able to fix nitrogen. Phosphorus release was observed for strains QZG6 (inorganic or organic phosphorus) and QZS3 (inorganic phosphorus). Both QZG6 and QZS8 were able to produce siderophores, while only QZG6 was positive for ACC deaminase. All the strains produced IAA, SA and GA. These results indicated that the three strains promoted the plant growth under Cd stress, probably through Cd detoxification by siderophores, as well as through growth regulation by N/P nutrient supply and phytohormone. The present study showed a great potential of the three Cd-resistant strains combined with S. bicolor plants in the remediation of Cd-polluted soils, which may provide a new insight into combining the advantages of microbes and plants to improve the remediation of Cd-contaminated soils.

Coptis chinensis Franch is a perennial herb from the Ranunculaceae family with a long history of medicinal use. As the medicinal part, the rhizome of coptis often accumulates excessive cadmium (Cd) even at low concentrations in the soil, which not only compromises its medicinal safety but also raises concerns about adverse effects on human health. Therefore, effective strategies are needed to mitigate this accumulation and ensure its safe use in traditional medicine. This study utilized transcriptome profiling and physiological analysis to explore molecular mechanisms associated with ecological significance and the active accumulation of Cd in C. chinensis. The response to Cd in C. chinensis was assessed through RNA sequencing, Cd determination and isoquinoline alkaloid measurement using its roots, stems, and leaves. The transcriptome revealed, a total of 2667, 2998, or 2815 up-regulated deferentially expressed genes in roots, stems or leaves in response to Cd exposure. Furthermore, we identified phenylpropanoid and isoquinoline alkaloid biosynthesis as the key pathways response to Cd exposure, which suggests that C. chinensis may improve its tolerance to Cd through regulating the phenylpropanoid biosynthesis pathway. Under Cd exposure, plant-pathogen interaction in leaves was identified as the key pathway, which indicates that upregulation of genes involved in plant-pathogen interaction could enhance disease resistance in C. chinensis. WGCNA analysis identified WRKY8 (Cluster-55763.31419) and WRKY47 (Cluster-55763.221590) as potential regulators of secondary metabolic synthesis and plant-pathogen interaction pathway in C. chinensis triggered by Cd. The measurement of berberine, coptisine, palmatine, and epiberberine also demonstrated that Cd simulated the four isoquinoline alkaloids in roots. Therefore, our study not only presented a transcriptome expression profiles that revealed significant upregulation of genes involved in metal transport and detoxification pathways but also suggested a possible mechanism to cope with Cd accumulation. This knowledge provides a new insight into gene manipulation for controlling Cd accumulation, enhancing resistance and promoting synthesis of secondary metabolites with potential medicinal properties in other medicinal plant species.

Uncaria macrophylla (Rubiaceae) is a medicinal vine plant of the Rubiaceae family that was distributed in East Asia and Southeast Asia. The first complete chloroplast genome of Uncaria macrophylla was sequenced and assembled in this study. The genome is 155,138 bp in length and contained 129 encoded genes in total, including 79 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. The phylogenomic analysis showed that U. macrophylla was closely related to Uncaria rhynchophylla according to the current sampling extent.

Camellia shells are the main by-product of camellia seed processing and are usually incinerated or disposed of as agricultural waste. In this study, camellia shells were employed in the Pleurotus pulmonarius cultivation process using five distinct formulae substituting for cottonseed shells. Our results show that as the substitution rate of camellia shells increased from 0% to 35%, the protein content in P. pulmonarius significantly increased from 34.05% to 53.35%. The polysaccharide content reached a peak value of 5.62% at 30% substitution of camellia shells. The DPPH free radical scavenging rate reached its maximum of 82.70% at 20% substitution of camellia shells. Furthermore, increases in the total amino acid contents in P. pulmonarius were positively correlated with the substitution rate of camellia shells. Considering the yield characteristics, the formula of 20% camellia shell substitution tested in this study appears to be optimal for P. pulmonarius cultivation. These findings not only provide a substrate to enhance the nutritional quality of P. pulmonarius but also demonstrate a novel approach for the ecological utilization of camellia shells.

To improve the cadmium (Cd) resistance and the remediation ability of Sorghum bicolor (L.) Moench, fourteen Cd-resistant bacteria were screened from cadmium-contaminated soil, together with two strains preserved in the laboratory. It was found that 3 strains (ZR451, ZR452, and ZJSH1) significantly promoted the growth of Cd-stressed S. bicolor in hydroponics and mitigated Cd toxicity to plants, and SR8, ZRK1, and ZR211 promoted sorghum growth lightly. Further studies indicated that strains SR8, ZR211, and ZJSH1 were Cd-resistant and acid-resistant strains. Strains ZR211and ZR121 significantly produced two hormones (SA and GA), ZJSH1 significantly produced IAA and SA, and strains SR8, ZR451 and ZR452 produced one hormone. Strains SR8, ZR451, ZR452, and ZJSH1 produced siderophores. In addition, strain ZJSH1fixed nitrogen and produced ACC deaminase, while ZR451 and ZJSH1 solubilized phosphorus Correlation analysis showed that the Cd resistance of the strains was significantly and positively correlated with their IAA and GA production. The screening of the three cadmium resistant strains ZJSH1 (Sphingomonas paucimobilis), ZR451 (Bacillus cereus) and ZR452 (Bacillus cereus) provided bacterial resources for the efficient remediation of Cd-contaminated soils by bacterial - S. bicolor combination.