Hydrogen sulphide alleviates cadmium stress in Trigonella foenum-graecum by modulating antioxidant enzymes and polyamine content.

Cadmium (Cd) toxicity reduces growth and yield of crops grown in metal-polluted sites. Research was conducted to estimate the potential of hydrogen sulphide (H2 S) to mitigate toxicity caused by Cd in fenugreek seedlings (Trigonella foenum-graecum L.). Different concentrations of CdCl2 (Cd1-1 mM, Cd2-1.5 mM, Cd3-2mM) and H2 S (HS1-100 µM, HS2-150 µM, HS3-200 µM) were assessed. Seeds of fenugreek were primed with sodium hydrosulphide (NaHS), as H2 S donor. Seedlings growing in Cd-spiked media treated with H2 S were harvested after 2 weeks. Cd stress affected growth of fenugreek seedlings. Cd toxicity decreased leaf relative water content (LRWC), intercellular CO2 concentration, net photosynthesis, stomatal conductance and transpiration. However, application of H2 S significantly improved seedling morphological attributes by increasing the activity of antioxidant enzymes, i.e. APX, CAT and SOD, in Cd-contaminated soil. H2 S treatment also regulated phenolic and flavonoid content. H2 S-induced biosynthesis of spermidine (Spd) and putrescine (Put) could account for the enhancement of growth and physiological performance of fenugreek seedlings under Cd stress. H2 S treatment also reduced H2 O2 production (38%) and electrolyte leakage (EL, 51%) in seedlings grown in different concentrations of Cd. It is recommended to evaluate the efficacy of H2 S in alleviating Cd toxicity in other crop plants.

Hydrogen sulphide and salicylic acid regulate antioxidant pathway and nutrient balance in mustard plants under cadmium stress.

Cadmium (Cd), a pervasive noxious heavy metal, is a key threat to agricultural system. It is rapidly translocated and has detrimental effects on plant growth and development. Hydrogen sulphide (H2 S) is emerging as a potential messenger molecule for modulating plant tolerance to Cd. Salicylic acid (SA), a phenolic signalling molecule, can alleviate Cd toxicity in plants. The present study investigated the mediatory role of H2 S (100 µM) and SA (0.5 mM), individually and in combination, in modulating antioxidant defence machinery and nutrient balance to impart Cd (50 µM) resistance to mustard. Accumulation of Cd resulted in oxidative stress (TBARS and H2 O2 ), mineral nutrient imbalance (N, P, K, Ca), decreased leaf gas exchange and PSII efficiency, ultimately reducing plant growth. Both H2 S and SA independently attenuated phytotoxic effects of Cd by triggering antioxidant systems, enhancing the nutrient pool, eventually leading to improved photosynthesis and biomass of mustard plants. The positive effects were more pronounced under combined application of H2 S and SA, indicating a synergistic relationship between these two signalling molecules in mitigating the detrimental effects of Cd on nutrient homeostasis and overall health of mustard, primarily by boosting antioxidant pathway. Our findings provide new insights into H2 S- and SA-induced protective mechanisms in mustard plants subjected to Cd stress and suggest their combined use as a feasible strategy to confer Cd tolerance.

Genetic linkage between protein and DNA polymorphisms and antioxidant capacity of Cuminum cyminum L. accessions.

This study aimed to link the genetic variation observed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and random amplified polymorphic DNA (RAPD) analysis among 11 Cuminum cyminum L. accessions, collected from diverse ecogeographical areas in Saudi Arabia, with their antioxidant capacity to better identify potential genotypes for breeding programs for this medicinal spice. SDS-PAGE analysis revealed genetic variation among cumin germplasms and distinct polymorphisms (100%). Protein polymorphisms were identified based on the number of polypeptide bands (288) with molecular weights ranging from 13.85 to 350 kDa, band intensity, the appearance of new bands, and the absence of other bands. RAPD analysis revealed 363 amplified DNA products with a high polymorphism value (98.88%) based on DNA band type (unique, non-unique, and monomorphic), DNA 90 to 1085-bp long, and band intensity. The unweighted pair group method with arithmetic mean clustering based on SDS-PAGE or RAPD and Jaccard's similarity coefficient divided cumin accessions into similar but distinct clusters with respect to their location of collection. The antioxidant potential of cumin accessions based on 1, 1-diphenyl-2-picrylhydrazyl radical scavenging activity, the ß-carotene-linoleate model system, and total phenolic and flavonoid contents revealed distinct variability. These data indicate that cumin is a valuable genetic resource with high antioxidant activity. Additionally, clustering based on antioxidant activity was not identical to that based on SDS-PAGE and RAPD. Data and clustering of SDS-PAGE and RAPD, combined with the high antioxidant capacity of cumin accessions, are important for the efficient use of genetic resources of cumin in breeding strategies and genetic improvement programs.

Induction of Osmoregulation and Modulation of Salt Stress in Acacia gerrardii Benth. by Arbuscular Mycorrhizal Fungi and Bacillus subtilis (BERA 71).

The role of soil microbiota in plant stress management, though speculated a lot, is still far from being completely understood. We conducted a greenhouse experiment to examine synergistic impact of plant growth promoting rhizobacterium, Bacillus subtilis (BERA 71), and arbuscular mycorrhizal fungi (AMF) (Claroideoglomus etunicatum; Rhizophagus intraradices; and Funneliformis mosseae) to induce acquired systemic resistance in Talh tree (Acacia gerrardii Benth.) against adverse impact of salt stress. Compared to the control, the BERA 71 treatment significantly enhanced root colonization intensity by AMF, in both presence and absence of salt. We also found positive synergistic interaction between B. subtilis and AMF vis-a-vis improvement in the nutritional value in terms of increase in total lipids, phenols, and fiber content. The AMF and BERA 71 inoculated plants showed increased content of osmoprotectants such as glycine, betaine, and proline, though lipid peroxidation was reduced probably as a mechanism of salt tolerance. Furthermore, the application of bioinoculants to Talh tree turned out to be potentially beneficial in ameliorating the deleterious impact of salinity on plant metabolism, probably by modulating the osmoregulatory system (glycine betaine, proline, and phenols) and antioxidant enzymes system (SOD, CAT, POD, GR, APX, DHAR, MDAHR, and GSNOR).

Correlation of genetic variation among wild Trigonella foenum-graecum L. accessions with their antioxidant potential status.

In this study, we analyzed the correlation between genetic variation based on random amplified polymorphic DNA (RAPD), acid phosphatase, and glutamate-oxaloacetate transaminase isozymes, and amino acid composition with the antioxidant potential status of 7 wild Trigonella foenum-graecum L. accessions collected from diverse ecogeographical regions. RAPD revealed that 90 DNA products had highly polymorphism value (94.12%) based on band numbers, with sizes ranging from 50-2100 base pairs, and band intensity. Of 49 DNA polymorphic bands, 31 unique and 3 monomorphic bands were scored. Acid phosphatase and glutamate-oxaloacetate transaminase showed total polymorphism values of 90.00 and 93.75%, respectively, based on zymogram number, relative front (Rf), and optical intensity. Because isozymes are composed of amino acids, they were analyzed using high-performance liquid chromatography, which revealed the presences of 16 amino acids of variable content ranging from 13.21-15.35%, 9 of which are essential amino acids in humans. RAPD and isozymes showed similarly high estimates of genetic variability. Genetic relationships revealed by unweighted pair group method with arithmetic mean clustering analysis based on data obtained from all primers of RAPD and each isozyme were very similar. The antioxidant potential based on free radical scavenging, 2, 2-diphenyl-1-picrylhydrazyl, b-carotene-linoleate, total phenolic, and flavonoid contents values were variable among accessions. We found that fenugreek is a valuable genetic resource with high antioxidant activity. Their genotypes, based on data and clustering of RAPD, isozymes, and variable amino acid contents, combined with their antioxidant potential statues are important in fenugreek breeding and improvement programs.

Comparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and restricted fragment length polymorphism among fenugreek accessions.

Protein and DNA polymorphismswere surveyed among seven accessions of wild fenugreek (Trigonellafoenum-graecum L.) to estimate their genetic diversity and relationships. Samples were obtained from diverse ecogeographical areas in Saudi Arabia and Yemen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of seed storage protein showed genetic variations among fenugreek germplasms, both quantitatively and qualitatively, generating a total of 168 polypeptide bands with different molecular weights ranging from 4.5 to 300 kDa. Twenty-six of these bands were polymorphic, with a considerable polymorphism value (80.00%). Furthermore, restriction fragment length polymorphism (RFLP) analysis was also employed, which was based on the ability of four restriction enzymes (EagI, EcoRI, FspI, and HindIII) to cleave genomic DNA of the plant materials at specific target nucleotide sequences into different numbers of DNA fragments. RFLP analysis revealed 166 fragments with known sequences and variable lengths ranging from 80 to 4000 bp with a highly degree of polymorphism (88.71%). Data derived from SDS-PAGE or RFLP analyses were used to produce dendrograms, which clustered the studied fenugreek accessions into different groups based on the unweighted pair group method with arithmetic mean (UPGMA). The resulting relationships indicated that these two marker techniques were nearly equivalent, but not identical, with respect to phylogenetic information. In conclusion, SDS-PAGE analysis of seed proteins should be augmented with RFLP analysis of DNA for reliable estimates of genetic diversity among fenugreek germplasms.