Chickpea glutaredoxin (CaGrx) gene mitigates drought and salinity stress by modulating the physiological performance and antioxidant defense mechanisms.

Glutaredoxins (Grxs) are short, cysteine-rich glutathione (GSH)-mediated oxidoreductases. In this study, a chickpea (Cicer arietinum L.) glutaredoxin [LOC101493651 (CaGrx)] gene has been selected based on screening experiments with two contrasting varieties of chickpea, PUSA-362 (drought-tolerant) and ICC-1882 (drought-sensitive) under drought and salinity. The tolerant variety showed higher CaGrx gene expression, as compared to less in the sensitive variety, under both the stresses. The CaGrx gene was then over-expressed in Arabidopsis thaliana and were exposed to drought and salinity. The over-expression of CaGrx elevated the activity of glutaredoxin, which induced antioxidant enzymes (glutathione reductase; GR, glutathione peroxidase; GPX, catalase; CAT, ascorbate peroxidase; APX, glutathione-S-transferase; GST, superoxide dismutase; SOD, monodehydroascorbate reductase; MDHAR, and dehydroascorbate reductase; DHAR), antioxidants (GSH and ascorbate) and stress-responsive amino acids (cysteine and proline). Enhancement in the antioxidant defense system possibly administered tolerance in transgenics against both stresses. CaGrx reduced stress markers (H2O2, TBARS, and electrolyte leakage) and enhanced root growth, seed germination, and survival against both stresses. The physiological parameters (net photosynthesis; P N, water use efficiency; WUE, stomatal conductance; g s, transpiration; E, electron transport rate; ETR, and photochemical quenching; qP), chlorophylls and carotenoids, were improved in the transgenics during both stresses, that maintained the photosynthetic apparatus and protected the plants from damage. The enhanced activity of the cysteine biosynthesis enzyme, o-acetylserine (thiol) lyase (OAS-TL), increased the cysteine level in the transgenics, which elevated glutathione biosynthesis to maintain the ascorbate-glutathione cycle under both stresses. This investigation verified that the CaGrx gene provides tolerance against salinity and drought, maintaining physiological and morphological performances, and could be exploited for genetic engineering approaches to overcome both the stresses in various crops. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-00999-z.

Over-expression of chickpea metallothionein 1 gene confers tolerance against major toxic heavy metal stress in Arabidopsis.

Heavy metals are ubiquitously present in nature, including soil, water, and thus in plants, thereby causing a potential health risk. This study has investigated the role and efficiency of the chickpea metallothionein 1 (MT1) gene against the major toxic heavy metals, i.e., As [As(III) and As(V)], Cr(VI), and Cd toxicity. MT1 over-expressing transgenic lines had reduced As(V) and Cr(VI) accumulation, whereas Cd accumulation was enhanced in the L3 line. The physiological responses (WUE, A, Gs, E, ETR, and qP) were noted to be enhanced in transgenic plants, whereas qN was decreased. Similarly, the antioxidant molecules and enzymatic activities (GSH/GSSG, Asc/DHA, APX, GPX, and GRX) were higher in the transgenic plants. The activity of antioxidant enzymes, i.e., SOD, APX, GPX, and POD, were highest in the Cd-treated lines, whereas higher CAT activity was observed in As(V)-L1 and GRX in Cr-L3 line. The stress markers TBARS, H2O2, and electrolyte leakage were lower in transgenic lines in comparison to WT, while RWC was enhanced in the transgenic lines, and the transcript of MT1 gene was accumulated in the transgenic lines. Similarly, the level of stress-responsive amino acid cysteine was higher in transgenic plants as compared to WT plants. Among all the heavy metals, MT1 over-expressing lines showed a highly increased accumulation of Cd, whereas a non-significant effect was observed with As(III) treatment. Overall, the results demonstrate that Arabidopsis thaliana transformed with the MT1 gene mitigates heavy metal stress by regulating the defense mechanisms in plants. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01103-1.

Genus Psoralea: A review of the traditional and modern uses, phytochemistry and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Psoralea (Fabaceae) harbours 105 accepted species that are extensively used by local peoples and medicinal practitioners of China, India, and other countries for treatment of tooth decay, psoriasis, leucoderma, leprosy, kidney problems, tuberculosis, indigestion, constipation and impotence. Presently, pharmacological research reports are available on only few species namely Bituminaria bituminosa (Syn: P. bituminosa), P. canescens, P. corylifolia, P. esculenta, P. plicata and P. glandulosa which are valued for their chemical constituents and traditional uses. AIM OF THE REVIEW: This review article provides explicit information on traditional uses, phytochemistry, and pharmacological activities of selected Psoralea species. The possible trends and perspectives for future research on these plants are also discussed. MATERIALS AND METHODS: An extensive and systematic review of the extant literature was carried out, and the data under various sections were identified using a computerized bibliographic search via the PubMed, Web of Science and Google Scholar, CAB Abstracts, MEDLINE, EMBASE, INMEDPLAN, NATTS as well as several websites. KEY FINDINGS: A total of 291 bioactive compounds from 06 species of genus Psoralea have been isolated and characterized. However, P. bituminosa alone possess nearly 150 compounds. These bioactive compounds belong to different chemical classes, including flavonoids, coumarins, furanocoumarins, chalcones, quinines, terpenoids and some others due to which these species exhibit significant anti-oxidant, anti-bacterial, anti-fungal, anti-viral, anti-helmintic, anti-diabetic, diuretic, hepatoprotective, anti-cancer and anti-tumor activities. P. corylifolia L. (Babchi), a Chinese traditional medicinal plant has been used in traditional medicine for many decades for its healing properties against numerous skin diseases such as leprosy, psoriasis and leucoderma. CONCLUSIONS: The in vitro studies and in vivo models have provided a simple bio-scientific justification for various ethnopharmacological uses of Psoralea species. From the toxicological perspective, the root, leaf, and seed extracts and their preparations have been proven to be safe when consumed in the recommended doses. But, meticulous studies on the pharmaceutical standardization, mode of action of the active constituents, and sustainable conservation of Psoralea species are needed, to meet the growing demands of the pharmaceutical industries, and to fully exploit their preventive and therapeutic potentials.