Biochemical and proteomic insights revealed selenium priming induced phosphorus stress tolerance in common bean (Phaseolus vulgaris L.).

BACKGROUND: Mineral stress is one of the dominating abiotic stresses, which leads to decrease in crop production. Selenium (Se) seed priming is a recent approach to mitigate the plant's mineral deficiency stress. Although not an essential element, Se has beneficial effects on the plants in terms of growth, quality, yield and plant defense system thus, enhancing plant tolerance to mineral deficiency. METHODS AND RESULTS: The present research was accomplished to find out the effect of Se priming on common bean plant (SFB-1 variety) under phosphorus (P) stress. The seeds were grown invitro on four different MGRL media which are normal MGRL media as control with non-Se primed seeds (Se- P+), non -Se primed seeds grown on P deficient MGRL media (Se- P-), Se primed seeds grown on normal MGRL media (Se+P+) and Se primed seeds grown on P deficient MGRL media (Se+P -). The various morphological and biochemical parameters such as proline content, total sugar content, polyphenols and expression of proteins were analyzed under P stress. The results showed that Se priming has significantly (p ≤ 0.05) affected the morphological as well as biochemical parameters under normal and P stress conditions. The morphological parameters-length, weight, number of nodes and leaves of Se+P+, Se+P- root and shoot tissue showed significant increase as compared to Se-P+, Se-P-. Similarly various biochemical parameters such as total chlorophyll content, proline, total sugar content and polyphenols of Se+P+, Se+P- increased significantly as compared to Se-P+, Se-P-. The differential protein expression in both Se+P+, Se+P- and Se-P+, Se-P- plants were determined using MALDI-MS/MS. The differentially expressed proteins in Se+P+, Se+P- plants were identified as caffeic acid-3-O-methyltransferase (COMT) and SecA protein (a subunit of Protein Translocan transporter), and are found responsible for lignin synthesis in root cell walls and ATP dependent movement of thylakoid proteins across the membranes in shoot respectively. The differential expression of proteins in plant tissues, validated morphological and biochemical responses such as maintaining membrane integrity, enhanced modifications in cellular metabolism, improved polyphenol activities and expression of defensive proteins against mineral deficiency. CONCLUSIONS: The study provided an understanding of Se application as a potential approach increasing tolerance and yield in crop plants against mineral deficiency.

The microbiome-derived metabolite TMAO drives immune activation and boosts responses to immune checkpoint blockade in pancreatic cancer.

The composition of the gut microbiome can control innate and adaptive immunity and has emerged as a key regulator of tumor growth, especially in the context of immune checkpoint blockade (ICB) therapy. However, the underlying mechanisms for how the microbiome affects tumor growth remain unclear. Pancreatic ductal adenocarcinoma (PDAC) tends to be refractory to therapy, including ICB. Using a nontargeted, liquid chromatography-tandem mass spectrometry-based metabolomic screen, we identified the gut microbe-derived metabolite trimethylamine N-oxide (TMAO), which enhanced antitumor immunity to PDAC. Delivery of TMAO intraperitoneally or via a dietary choline supplement to orthotopic PDAC-bearing mice reduced tumor growth, associated with an immunostimulatory tumor-associated macrophage (TAM) phenotype, and activated effector T cell response in the tumor microenvironment. Mechanistically, TMAO potentiated the type I interferon (IFN) pathway and conferred antitumor effects in a type I IFN-dependent manner. Delivering TMAO-primed macrophages intravenously produced similar antitumor effects. Combining TMAO with ICB (anti-PD1 and/or anti-Tim3) in a mouse model of PDAC significantly reduced tumor burden and improved survival beyond TMAO or ICB alone. Last, the levels of bacteria containing CutC (an enzyme that generates trimethylamine, the TMAO precursor) correlated with long-term survival in patients with PDAC and improved response to anti-PD1 in patients with melanoma. Together, our study identifies the gut microbial metabolite TMAO as a driver of antitumor immunity and lays the groundwork for potential therapeutic strategies targeting TMAO.

Morphological, Biochemical, and Proteomic Studies Revealed Impact of Fe and P Crosstalk on Root Development in Phaseolus vulgaris L.

Mineral stress is one of the major abiotic stresses faced by crop plants. The present study was undertaken to investigate the impact of mineral stress (iron (Fe) and phosphorus (P)) on various morphological and biochemical responses of the shoot and root tissues and root architecture of common bean (Phaseolus vulgaris L.). This study also leads us to the identification of P stress responsive proteins. The study was conducted under in vitro conditions, in which seeds of Shalimar French Bean-1 (SFB-1) variety were cultured on four different MGRL medium (control (P1Fe1), iron deficient (P1Fe0), phosphorus deficient (P0Fe1), and phosphorus and iron deficient (P0Fe0)). Chlorophyll content of leaves, Fe/P content of root tissues, total sugars, proline, length, and weight of shoot and root tissues were assessed and compared within and between the treatments. The analyzed data revealed significant difference between control and other three treatments. Chlorophyll content of shoots was found significantly decreased under mineral stress treatments P0Fe1, P1Fe0, and P0Fe0 than control. Length and weight of shoot and root were also observed significantly decreased under P0Fe1, P1Fe0, and P0Fe0 as compared to control. Total sugar was significantly higher in P0Fe1 of roots in comparison to control. Proline content was significantly higher in both tissues of shoots and roots of plants grown under P1Fe0, P0Fe1, and P0Fe0 than control condition. Furthermore, we unexpectedly observed the recovery of roots (mainly primary roots) under P0Fe0 as compared to P1Fe0 and P0Fe1. Interestingly higher concentration of Fe was also observed in P0Fe1 compared to other treatments and also higher concentration of P was observed in P1Fe1. These findings suggested that there is a crosstalk between Fe and P and also revealed that there is a disruption in the ability of PR (primary root) to sense local P deficiency in the absence of Fe. Furthermore, proteomics analysis (SDS-PAGE followed by MALDI MS) helped in identification of defensive proteins in P stress condition compared to control.

Quality control, HPTLC analysis, antioxidant and antimicrobial activity of hydroalcoholic extract of roots of qust (Saussurea lappa, C.B Clarke).

OBJECTIVES: Saussurea lappa, CB Clarke (S.lappa) is a perennial herb of the Compositae family. The root of S.lappa has been used for the treatment of various diseases such as hepatitis, jaundice, intestinal worms, bronchial asthma, and a variety of skin diseases. The aim of the study was to ensure quality control of S.lappa and its preparation HAESL (hydroalcoholic extract of S.lappa) along with assessment of HAESL antimicrobial and antioxidant activities in vitro. METHODS: HAESL was prepared with 50% ethanol, (v/v). Physiochemical analysis of the root of S.lappa, and phytochemical screening, thin-layer chromatography (TLC), high-performance thin-layer chromatography (HPTLC), and in vitro antimicrobial and antioxidant activity of HAESL were performed using the standard protocol. RESULTS: Physiochemical and phytochemical assessments of S.lappa and HAESL showed the greater quality of the drug. HAESL showed the presence of many phytochemical constituents corresponding to colorful spots, peaks, area under the curve, and corresponding Rf values as evident in the TLC and HPTLC analysis. HAESL showed a concentration-dependent effect on radical scavenging activity against DPHH (2,2-diphenyl-1-picrylhydrazyl) and hydroxyl radical with IC50 value of 19.10 µg/mL and 82.23 µg/mL, respectively. HAESL exhibited antimicrobial activity against the growth of micro-organisms such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Aspergillus flavus, and Candida albicans. HASEL showed no antimicrobial activity against Aspergillus niger. CONCLUSIONS: The procured and an identified sample of Saussurea lappa was good in quality and the prepared HAESL contained many phytochemical compounds. HAESL substantiated significant antioxidant and antimicrobial activity in vitro.