Integrated physiological, transcriptomic and metabolomic analyses provide insights into phosphorus-mediated cadmium detoxification in Salix caprea roots.

Phosphorus (P) plays a crucial role in facilitating plant adaptation to cadmium (Cd) stress. However, the molecular mechanisms underlying P-mediated responses to Cd stress in roots remain elusive. This study investigates the effects of P on the growth, physiology, transcriptome, and metabolome of Salix caprea under Cd stress. The results indicate that Cd significantly inhibits plant growth, while sufficient P alleviates this inhibition. Under Cd exposure, P sufficiency resulted in increased Cd accumulation in roots, along with reduced oxidative stress levels (superoxide anion and hydrogen peroxide contents were reduced by 16.8% and 30.1%, respectively). This phenomenon can be attributed to the enhanced activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT), as well as increased levels of antioxidants including ascorbic acid (AsA) and flavonoids under sufficient P conditions. A total of 4208 differentially expressed genes (DEGs) and 552 differentially accumulated metabolites (DAMs) were identified in the transcriptomic and metabolomic analyses, with 2596 DEGs and 113 DAMs identified among treatments with different P levels under Cd stress, respectively. Further combined analyses reveal the potential roles of several pathways in P-mediated Cd detoxification, including flavonoid biosynthesis, ascorbate biosynthesis, and plant hormone signal transduction pathways. Notably, sufficient P upregulates the expression of genes including HMA, ZIP, NRAMP and CAX, all predicted to localize to the cell membrane. This may elucidate the heightened Cd accumulation under sufficient P conditions. These findings provide insights into the roles of P in enhancing plant resistance to Cd stress and improving of phytoremediation.

Phosphorus deficiency-induced cell wall pectin demethylesterification enhances cadmium accumulation in roots of Salix caprea.

Regions affected by heavy metal contamination frequently encounter phosphorus (P) deficiency. Numerous studies highlight crucial role of P in facilitating cadmium (Cd) accumulation in woody plants. However, the regulatory mechanism by which P affects Cd accumulation in roots remains ambiguous. This study aims to investigate the effects of phosphorus (P) deficiency on Cd accumulation, Cd subcellular distribution, and cell wall components in the roots of Salix caprea under Cd stress. The results revealed that under P deficiency conditions, there was a 35.4% elevation in Cd content in roots, coupled with a 60.1% reduction in Cd content in shoots, compared to the P sufficiency conditions. Under deficient P conditions, the predominant response of roots to Cd exposure was the increased sequestration of Cd in root cell walls. The sequestration of Cd in root cell walls increased from 37.1% under sufficient P conditions to 66.7% under P deficiency, with pectin identified as the primary Cd binding site under both P conditions. Among cell wall components, P deficiency led to a significant 31.7% increase in Cd content within pectin compared to P sufficiency conditions, but did not change the pectin content. Notably, P deficiency significantly increased pectin methylesterase (PME) activity by regulating the expression of PME and PMEI genes, leading to a 10.4% reduction in the degree of pectin methylesterification. This may elucidate the absence of significant changes in pectin content under P deficiency conditions and the concurrent increase in Cd accumulation in pectin. Fourier transform infrared spectroscopy (FTIR) results indicated an increase in carboxyl groups in the root cell walls under P deficiency compared to sufficient P treatment. The results provide deep insights into the mechanisms of higher Cd accumulation in root mediated by P deficiency.

Sexual differences in root growth and antioxidant characteristics in Salix viminalis exposed to cadmium stress.

NOVELTY STATEMENT: Salix viminalis, a dioecious shrub willow, has been widely used in phytoremediation, yet sexually differences in tolerance to cadmium of which remained unclear. This study focused on different responses to cadmium stress between roots of male and female S. viminalis. Results show that male plants of S. viminalis have stronger cadmium tolerance than female plants, which indicates male S. viminalis should be more considered to be applied for phytoremediation and ecological restoration of cadmium-accumulated soil considering cadmium tolerance characteristics. The findings can provide valuable evidence and insights for researches focused on phytoremediation with dioecious woody plants and sexual dimorphism under abiotic stress.

Identification and expression analysis of novel LAGE-1 alleles with single nucleotide polymorphisms in cancer patients.

OBJECTIVE: The purpose of this study is to identify single nucleotide polymorphisms (SNPs) in the coding region alleles of the X chromosomal LAGE-1 gene, and investigate the frequency of such SNPs in both cancer patients and healthy controls, and thus determine the potential significance of these SNPs with respect to cancer vaccine therapy. METHODS: In this study, different mRNAs transcribed from the LAGE-1 gene were identified by RT-PCR from healthy donors and cancer patients samples. RESULTS: A new LAGE-1 allele containing three coding region SNPs (69A/G, 317C/G, and 397T/G) were identified. The allele is highly expressed as the LAGE-1a mRNA variant AY679089 in some of the cancer patients. The three SNPs altered the LAGE-1 gene sequence to that of NYESO-1 at both the nucleotide and amino acid level. CONCLUSION: There is a high frequency of the LAGE-1 gene allele with SNPs in coding regions in cancer patients. There was a clear relationship between the variant AY679089 and gastric cancer. The SNPs may lead to accelerated progress of poorly differentiated gastric cancer. The SNPs found in these alleles may also alter the immunological characteristics of LAGE-1a and should be taken into account if this antigen is adopted as a cancer vaccine component.

[Identification and expression of non-coding RNAs NC28 and NC119 in human tumors].

OBJECTIVE: To explore and identify the non-coding RNAs related to tumors. METHODS: We used RT-PCR and Northern blot to analyze non-coding RNAs in tumor tissues and cell lines. RESULTS: Two predicted non-coding RNAs were confirmed to be expressed in cancer tissues and cell lines by RT-PCR and DNA sequencing. We detected the expression of two non-coding RNA transcripts by Northern blot. The length of NC28 was about 1800 nt, and that of NC119 was about 1200nt. CONCLUSIONS: NC28 and NC119 have a tumor-associated expression pattern. The non-coding RNAs may play a role in the development of tumors.

[The expression of 11 cancer/testis (CT) antigen genes in esophageal carcinoma].

OBJECTIVE: To investigate the expression status of 11 different cancer/testis (CT) antigen genes in esophageal carcinoma. METHODS: Esophageal carcinoma tissue and adjacent normal esophageal mucosa taken from 35 esophageal carcinoma patients were assayed for the expression of 11 different CT antigen genes by RT-PCR techniques. RESULTS: Of the 11 CT antigen genes analyzed, none of them was expressed in normal esophageal mucosa. MAGE-3 was found to be the most frequently expressed in esophageal carcinoma tissues (62.9%), followed, in the order of expression frequency, by MAGE4 (31.4%), LAGE-1 (28.6%), MAGE-1 (25.7%), CT10 (20.0%), NY-ESO-1 (20.0%), CT7 (5.7%) and SCP1 (2.9%). No expression of SSX-1, SSX-2 and SSX-4 was found. Among the 35 cases, 28 (80.0%) expressed at least one CT antigen gene, 21 (60.0%) expressed more than 2 CT antigen genes, and 4 of the 21 (19.0%) expressed more than 4 CT antigens, which accounted for 11.4% of total number of patients (4/35). No CT antigen expression was found in the tumor tissue in 7 cases, including 5 cases in stage II and 1 case each in stage I and IV, respectively. Of the 11 CT genes examined, expression of 5 genes (NY-ESO-1, LAGE-1, MAGE-1, MAGE-3 and MAGE-4) was correlated with tumor progression. SCP-1 and CT10 expression was found more frequently in early stage patients. With progression of the disease, the frequency of co-expression of multiple CT antigen genes was significantly increased reaching 28.6% in stage III patients. CONCLUSION: Of the 11 different CT antigen genes examined by RT-PCR in esophageal carcinoma, 8 genes were detected in various frequencies in 28 of the 35 esophageal cancer patients studied. They are candidate tumor-associated antigens in the preparation of tumor vaccines for immunotherapy in esophageal cancer patients.