The earthworm -based vermiremediation facilitated with benign chemicals such as nano zero-valent iron (nZVI) is a promising approach for the remediation of a variety of soil contaminants including cyanotoxins. As the most toxic cyanotoxin, microcystin-LR (MC-LR) enter soil via runoff, irrigated surface water and sewage, and the application of cyanobacterial biofertilizers as part of the sustainable agricultural practice. Earthworms in such remediation systems must sustain the potential risk from both nZVI and MC-LR. In the present study, earthworms (Eisenia fetida) were exposed up to 14 days to MC-LR and nZVI (individually and in mixture), and the toxicity was investigated at both the organismal and metabolic levels, including growth, tissue damage, oxidative stress, metabolic response and gut microbiota. Results showed that co -exposure of MC-LR and nZVI is less potent to earthworms than that of separate exposure. Histological observations in the co -exposure group revealed only minor epidermal brokenness, and KEGG enrichment analysis showed that co -exposure induced earthworms to regulate glutathione biosynthesis for detoxification and reduced adverse effects from MC-LR. The combined use of nZVI promoted the growth and reproduction of soil and earthworm gut bacteria (e.g., Sphingobacterium and Acinetobacter) responsible for the degradation of MC-LR, which might explain the observed antagonism between nZVI and MC-LR in earthworm microcosm. Our study suggests the beneficial use of nZVI to detoxify pollutants in earthworm -based vermiremediation systems where freshwater containing cyanobacterial blooms is frequently used to irrigate soil and supply water for the growth and metabolism of earthworms. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Sophora tonkinensis is a significant medicinal plant indigenous to China and Vietnam. In China, S. tonkinensis is mainly grown naturally on limestone mountains or is cultivated artificially in arable land. Heavy metal contamination in agricultural soil, particularly cadmium (Cd), poses serious threats to soil health, as well as the growth and productivity of S. tonkinensis. However, information regarding the physiological and metabolic mechanism of S. tonkinensis under Cd toxicity conditions remains limited. In this study, a hydroponic experiment was conducted to investigate the physiological and metabolic responses of S. tonkinensis to varying concentrations of Cd (0, 20, 40, 60, 80 mu M), designated as T0, T1, T2, T3, and T4 respectively. The results indicated that the Cd stress significantly impaired the growth and physiological activity of S. tonkinensis. Specifically, reductions were observed in plant height (15.3% to 37.1%) along with shoot fresh weight (9.6% to 36.3%), shoot dry weight (8.2% to 34.1%), root fresh weight (6.7% to 38.2%) and root dry weight (5.1% to 51.3%). This impairment was attributed to a higher uptake and accumulation of Cd in the roots. The decrease in growth was closely linked to the increased production of reactive oxygen species (ROS), which led to cellular damage under Cd toxicity; however, increased antioxidant enzyme activities improved the stress tolerance of S. tonkinensis's stress to Cd toxicity. Non-targeted metabolomic analyses identified 380 differential metabolites (DMs) in the roots of S. tonkinensis subjected to varying level of Cd stress, including amino acids, organic acids, fatty acids, ketones, and others compounds. Further KEGG pathway enrichment analysis revealed that several pathways, such as ABC transporters, isoflavonoid biosynthesis, and pyrimidine metabolism were involved in the response to Cd. Notably, the isoflavonoid biosynthesis pathway was significantly enriched in both T0 vs. T2 and T0 vs. the higher level (80 mu M) of Cd stress, highlighting its significance in the plant responses to Cd stress. In conclusion, the identification of key pathways and metabolites is crucial for understanding Cd stress tolerance in S. tonkinensis.

Strigolactones (SLs), the newest group of phytohormones, are involved in a wide range of functions, including the regulation of plant growth and physiology. Besides, emerging evidence suggests that SLs also participate in the promotion of plant environmental stress resilience through mediation of different metabolic genes/pathways. However, thus far little is known about SL-mediated transcriptional changes in rice (Oryza sativa), compared to other model plants. To meet this objective, we analyzed the RNA-seq-based comparative transcriptome data sets of rice SL-deficient dwarf l7 (d17) mutant line and its respective wild-type (WT), obtained from the National Center for Biotechnology Information GenBank. Both, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, in order to identify genes/pathways which function downstream of SLs. With respect to the WT, a large number of functional GO terms, mainly stress-associated terms such as 'response to stress', 'response to stimulus', 'response to chemical', 'response to oxidative stress' and 'reactive oxygen species metabolic process' were significantly suppressed in the d17 mutant plants. In addition, KEGG metabolic pathways such as cvaline, leucine and isoleucine degradation', 'plant hormone signal transduction', 'galactose metabolism', 'fatty acid degradation' and 'phenylalanine metabolism' were also remarkably undermined in the d17 lines relative to the WT. These results imply a possible involvement of rice SLs in the regulation of distinct stress-related metabolic genes/pathways, which may function in environmental stress tolerance of plants. Taken together, the study provides new opportunities to broaden our limited understanding of SL-regulated downstream pathways, especially in rice.