Overexpression of AtMYB12 transcription factor simultaneously enhances quercetin-dependent metabolites in radish callus.

The study aimed to enhance quercetin production in radish by optimizing Agrobacterium tumefaciens-mediated in-planta transformation. This protocol involved infecting radish seed embryo axis with A. tumefaciens EHA105 strain carrying the 35S::AtMYB12. Radish seeds were infected with the Agrobacterium suspension (0.8 OD600) for 30 min, followed by sonication for 60 s and vacuum infiltration for 90 s at 100 mm Hg. A 3-day co-cultivation in Murashige and Skoog medium with 150 µM acetosyringone yielded a transformation efficiency of 59.6% and a transgenic callus induction rate of 32.3%. Transgenic plant and callus lines were confirmed by GUS histochemical assay, PCR, and qRT-PCR. The transgenic lines showed an increased expression of flavonoid pathway genes (AtMYB12, CHS, F3H, and FLS) and antioxidant genes (GPX, APX, CAT, and SOD) compared to WT plants. Overexpression of AtMYB12 in transgenic callus increased enzyme activity of phenylalanine ammonia lyase, catalase, and ascorbate peroxidase. In half-strength MS medium with 116.8 mM sucrose, the highest growth index (7.63) was achieved after 20 days. In AtMYB12 overexpressed callus lines, phenolic content (357.31 mg g-1 dry weight), flavonoid content (463 mg g-1 dry weight), and quercetin content (48.24 mg g-1 dry weight) increased significantly by 9.41-fold. Micro-wounding, sonication, and vacuum infiltration improved in-planta transformation in radishes. These high-quercetin-content transgenic callus lines hold promise as valuable sources of flavonoids.

Isotopic signatures, hydrochemical and multivariate statistical analysis of seawater intrusion in the coastal aquifers of Chennai and Tiruvallur District, Tamil Nadu, India.

In coastal aquifers, seawater intrusion is a significant groundwater issue. The research paper contributes to the understanding of the consequences of seawater intrusion in the Chennai coastal aquifer from Foreshore Estate to Thirunilai along the coastline. 110 groundwater samples were collected and analyzed for physicochemical parameters such as pH, (EC), (TDS), (TH), major anions (Cl-, NO3-, HCO32-, and SO42-), and cations (Ca2+, Mg2+, Na+, and K+) during the pre-monsoon (June 2014) and post-monsoon (January 2015) seasons. Stable isotopic analyses of 18O were performed on 24 groundwater samples collected from various locations throughout the research region based on EC, TDS, Na, and Cl- concentrations for both seasons. The stable isotopic composition of 18O and Deuterium in groundwater samples was determined for the study region. According to the Correlation matrix and Factor analysis, the main contributors to groundwater salinity as a result of seawater intrusion into the coastal aquifer are EC, TDS, Na+, and Cl-. GMWL exhibits a similar pattern, and the samples have been classified into various molar ratio diagrams to identify seawater intrusions for better evaluation. The result revealed that seasonal, geogenic, and anthropogenic factors always make a significant contribution to the heterogeneous chemistry of groundwater.

Elite hairy roots of Raphanus sativus (L.) as a source of antioxidants and flavonoids.

An efficient protocol for hairy root induction in radish was established by optimizing several parameters that affect the efficiency of Agrobacterium rhizogenes-mediated transformations. Explants wounded using sterile hypodermic needle, infected with Agrobacterium suspension (0.6 OD600) for 10 min and co-cultivated in 1/2 MS medium containing acetosyringone (100 µM) for 2 days displayed maximum percentage of hairy root induction using MTCC 2364 (77.6%) and MTCC 532 (67.6%). On further experiments with MTCC 2364 initiated hairy roots, maximum biomass accumulation (fresh weight = 9.50 g; dry weight = 1.48 g) was achieved in liquid 1/2 MS medium supplemented with 87.6 mM sucrose after 40 days of culture. Transgenic state of hairy roots of MTCC 2364 was confirmed by polymerase chain reaction using rolB- and rolC-specific primers. The MTCC 2364-induced hairy roots produced higher amount of phenolic (33.0 mg g-1), flavonoid (48.0 mg g-1), and quercetin (114.8 mg g-1) content compared to auxin-induced roots of non-transformed radish. Furthermore, the results of ferric reducing antioxidant power and 1,1-diphenyl-2-picrylhydrazyl assay confirmed that the antioxidant activity of MTCC 2364 root extracts was improved when compared to auxin-induced roots of non-transformed radish. The present study offers a new insight in radish for production of phenolics and flavonoids (quercetin) using A. rhizogenes-mediated hairy root induction.