Seed biopriming with Ochrobactrum ciceri mediated defense responses in Zea mays (L.) against Fusarium rot.

Seed bio-priming is a simple and friendly technique to improve stress resilience against fungal diseases in plants. An integrated approach of maize seeds biopriming with Ochrobactrum ciceri was applied in Zn-amended soil to observe the response against Fusarium rot disease of Zea mays (L.) caused by Fusarium verticillioides. Initially, the pathogen isolated from the infected corn was identified as F. verticillioides based on morphology and sequences of the internally transcribed spacer region of the ribosomal RNA gene. Re-inoculation of maize seed with the isolated pathogen confirmed the pathogenicity of the fungus on the maize seeds. In vitro, the inhibitory potential of O. ciceri assessed on Zn-amended/un-amended growth medium revealed that antifungal potential of O. ciceri significantly improved in the Zn-amended medium, leading to 88% inhibition in fungal growth. Further assays with different concentrations (25, 50, and 75%) of cell pellet and the cultural filtrate of O. ciceri (with/without the Zn-amendment) showed a dose-dependent inhibitory effect on mycelial growth of the pathogen that also led to discoloration, fragmentation, and complete disintegration of the fungus hyphae and spores at 75% dose. In planta, biopriming of maize seeds with O. ciceri significantly managed disease, improved the growth and biochemical attributes (up to two-fold), and accelerated accumulation of lignin, polyphenols, and starch, especially in the presence of basal Zn. The results indicated that bioprimed seeds along with Zn as the most promising treatment for managing disease and improving plant growth traits through the enhanced accumulation of lignin, polyphenols, and starch, respectively.

Farmyard manure, a potential organic additive to reclaim copper and Macrophomina phaseolina stress responses in mash bean plants.

In the era of global warming, stress combinations instead of individual stress are realistic threats faced by plants that can alter or trigger a wide range of plant responses. In the current study, the cumulative effect of charcoal rot disease caused by notorious fungal pathogen viz., Macrophomina phaseolina was investigated under toxic levels of copper (Cu) in mash bean, and farmyard manure (FYM) was employed to manage stress. Therefore, Cu-spiked soil (50 and 100 mg/kg) was inoculated with the pathogen, and amended with 2% FYM, to assess the effect of intricate interactions on mash bean plants through pot experiments. Results demonstrated that the individual stress of the pathogen or Cu was more severe for morpho-growth, physio-biochemical, and expression profiles of stress-related genes and total protein in mash bean plants as compared to stress combinations. Under single Cu stress, a significant amount of Cu accumulated in plant tissues, particularly in roots than in upper ground tissues, while, under stress combination less Cu accumulated in the plants. Nonetheless, 2% FYM in soil encountered the negative effect of stress responses provoked by the pathogen, Cu, or both by improving health markers (photosynthetic pigments, reducing sugar, total phenolics) and oxidative stress markers (catalase, peroxidase, and polyphenol oxidase), together with regulating the expression of stress-related genes (catalase, ascorbate peroxidase, and cytokinin-resistant genes), and proteins, besides decreasing Cu uptake in the plants. FYM worked better at lower concentrations (50 mg/kg) of Cu than at higher ones (100 mg/kg), hence could be used as a suitable option for better growth, yield, and crop performance under charcoal rot disease stress in Cu-contaminated soils.

Cloncurry buffel grass mitigated Cr(III) and Cr(VI) toxicity in tomato plant.

Contamination of agricultural soil with chromium (Cr) ions has threatened global crop, human and ecosystem health. Its two oxidation states viz. Cr(III) and Cr(VI) are most stable and readily available to the plants. The study explored the impact of increasing exposure (up to 500 ppm) of Cr(III) and Cr(VI) on bio-physical traits of 15-day-old seedlings (in vitro) as well as 60-day-old tomato plant (in vivo), and highlighted the importance of buffel grass (Cenchrus pennisetiformis) in mitigating Cr levels in the tomato plants. In vitro, Petri plate bioassays with 13 different concentrations (20-500 ppm) of Cr(III) and Cr(VI) depicted the highly toxic effect of metal ions ≥ 200 ppm on all bio-physical traits of tomato seedlings. In vivo, soil spiked with Cr(III) and Cr(VI) (200, 300, and 400 mg/kg) was amended with 1% and 2% dry biomass of buffel grass. Phytotoxicity was higher in Cr(VI)-spiked soil compared with Cr(III)-spiked soil. Cr was mainly accumulated in tomato roots, and more Cr was translocated from roots to shoots from Cr(VI)-spiked soil than Cr(III)-spiked soil. Soil amendments with 2% weed biomass reduced metal toxicity in plants, particularly at 200 and 300 mg/kg of Cr. Protein profiles through SDS-PAGE revealed 12-50 kDa (mainly PR proteins) as an important region in tomato leaf, where many new bands were expressed under different treatments, particularly in the treatments provided with buffel grass. PCA-based biplot clearly separated Cr tolerance treatments from highly sensitive treatments. For the cultivation of tomato plants in Cr(III) and Cr(VI) contaminated soil (200 and 300 mg/kg), the biomass of Cloncurry buffel grass should be considered an effective and easily available phyto-management option.

Integrated management of charcoal rot disease in susceptible genotypes of mungbean with soil application of micronutrient zinc and green manure (prickly sesban).

Charcoal rot disease is incited by the soil-borne fungus Macrophomina phaseolina (Tassi). Goid is a challenging disease due to long-term persistence of fungus sclerotia in the soil. This study assessed the potential of zinc (Zn: 1.25, 2.44, and 5 mg/kg) and green manure (GM: 1 and 2%) in solitary and bilateral combinations to alleviate infection stress incited by M. phaseolina on disease, growth, physiology, and yield attributes in mungbean. A completely randomized design experiment was conducted in potted soil, artificially inoculated with the pathogen, and sown with surface-sterilized seeds of mungbean genotypes (susceptible: MNUYT-107 and highly susceptible: MNUYT-105). Concealment of plant resistance by M. phaseolina in both genotypes resulted in 53-55% disease incidence and 40-50% plant mortality, which contributed in causing a significant reduction of 30-90% in attributes of growth, biomass, yield, photosynthetic pigment, and total protein content with an imbalance of production of antioxidant enzymes (polyphenol oxidase, superoxide dismutase, catalase, and peroxidase). Soil application with Zn-based fertilizer (ZnSO4: 33%) in combination with GM significantly managed up to 80% of the charcoal rot disease, hence improving growth (50-100%) and physiochemical (30-100%) attributes and sustainably enhancing grain average yield (300-600%), biological yield (100-200%), and harvest index (100-200%) in mungbean plants. The heat map and principal component analyses based on 19 measured attributes with 16 treatments separated Zn (2.44 or 5 mg/kg) combined with 2% GM as the best treatments for alleviating charcoal rot disease stress by improving growth, yield, and biological attributes to an extent to profitable farming in terms of harvest index (HI) and benefit-cost ratio (BCR).

Combining Biocontrol Agent With Plant Nutrients for Integrated Control of Tomato Early Blight Through the Modulation of Physio-Chemical Attributes and Key Antioxidants.

Early blight (EB) is one of the major fungal diseases caused by Alternaria solani that is responsible for destructive tomato production around the globe. Biocontrol agent/s can be adequately implemented in an integrated management framework by using it in combination with vital plant nutrients, e.g., nitrogen, phosphorus, and potassium (NPK) and zinc (Zn). The current study was aimed to assess the integrated effect of a biocontrol agent Bacillus subtilis (BS-01) and the selective plant nutrients (NPK and Zn) on EB disease management and tomato crop performance. A field experiment was conducted for the off-season tomato production (under walk-in tunnels) in Punjab, Pakistan. The trial was set in a randomized complete block design (RCBD) and comprised nine treatments of a biocontrol agent (BS-01) either alone or in combination with the plant nutrients, viz., NPK (64:46:50 kg acre-1) and Zn (10 kg acre-1) as sustainable disease managing approach against EB. In addition, the biocontrol efficacy of B. subtilis (BS-01) on a fungal load of A. solani was estimated by quantitative PCR assays, where the foliar application of BS-01 on tomato plants either alone or in combination with the plant nutrients was done as a preventive measure. Our results revealed that the interactive effect of BS-01 with plant nutrients conferred significantly a varying degree of resilience in the infected tomato plants against EB by effectively modifying the content of total chlorophyll, carotenoids, and total phenolics along with the activities of antioxidant enzymes (SOD, CAT, POX, PPO, and PAL). In addition, the integrative effect of BS-01 and plant nutrients proved significantly effective in reducing pathogen load on inoculated tomato foliage, displaying the desired level of protection against A. solani infection. Besides, the complementary interaction of BS-01 + Zn + NPK worked synergistically to improve crop productivity by providing the highest marketable yield (21.61 tons acre-1) and net profit (361,363 Pakistani rupees acre-1). This integrated approach is put forward as a way to reduce the fungicide doses to control EB that would act as a sustainable plant protection strategy to generate profitable tomato production.

Antifungal potential of volatiles produced by Bacillus subtilis BS-01 against Alternaria solani in Solanum lycopersicum.

Bacterial biocontrol agent/s (BCAs) against plant diseases are eco-friendly and sustainable options for profitable agricultural crop production. Specific beneficial strains of Bacillus subtilis are effective in controlling many fungal diseases including Alternaria blight caused by a notorious pathogen "Alternaria solani". In the present study, the biocontrol attributes of a newfangled strain of B. subtilis (BS-01) have been investigated and its bioactive compounds were also identified against A. solani. The volatile organic compounds (VOCs) produced by BS-01 in organic solvents viz., n-hexane, dichloromethane, and ethyl acetate were extracted and their antifungal efficacy has evaluated against A. solani. Also, the preventive and curative biocontrol method to reduce the fungal load of A. solani was estimated by both foliar and seed applications on infected tomato (Solanum lycopersicum) plants as determined by quantitative PCR assays. Growth chamber bioassay revealed that both foliar and seed application of BS-01 on tomato plants previously or subsequently infected by A. solani significantly reduced the pathogen load on inoculated tomato foliage. Results showed that antifungal bioassays with various concentrations (10-100 mg mL-1) of extracted metabolites produced by BS-01 in ethyl acetate fraction showed the highest inhibition in fungal biomass (extracellular metabolites: 69-98% and intracellular metabolites: 48-85%) followed by n-hexane (extracellular metabolites: 63-88% and intracellular metabolites: 35-62%) and dichloromethane (extracellular metabolites: 41-74% and intracellular metabolites: 42-70%), respectively. The extracted volatile compounds of BS-01 were identified via GC-MS analysis and were found in great proportions in the organic fractions as major potent antifungal constituents including triphenylphosphine oxide; pyrrolo[1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl); pyrrolo[1,2-a] pyrazine-1,4-dione, hexahydro-3-(phenylmethyl); n-hexadecanoic acid; n-tridecan-1-ol; octadecane; octadecanoic acid; eicosane and dodecyl acrylate. Separate or mixture of these bioactive VOCs had the potential to mitigate the tomato early blight disease severity in the field that would act as a sustainable plant protection strategy to generate profitable tomato production.

Modulation of salt-induced stress impact in Gladiolus grandiflorus L. by exogenous application of salicylic acid.

Salinity is challenging threats to the agricultural system and leading cause of crop loss. Salicylic acid (SA) is an important endogenous signal molecule, which by regulating growth and physiological processes improves the plant ability to tolerate salt stress. Considering the prime importance of Gladiolus grandiflorus (L.) in the world's cut-flower market, the research work was undertaken to elucidate salinity tolerance in G. grandiflorus by exogenous application of SA irrigated with saline water. Results revealed that increasing salinity (EC: 2, 4 and 6 dS m-1) considerably altered morpho-growth indices (corm morphology and plant biomass) in plants through increasing key antioxidants including proline content and enzymes activity (superoxide dismutase, catalase and peroxidase), while negatively affected the total phenolic along with activity of defense-related enzymes (phenylalanine ammonia lyase, and polyphenol oxidase activity). SA application (50-200 ppm) in non-saline control or saline conditions improved morpho-physiological traits in concentration-dependent manners. In saline conditions, SA minimized salt-stress by enhancing chlorophyll content, accumulating organic osmolytes (glycine betaine and proline content), total phenolic, and boosting activity of antioxidant and defense-related enzymes. Principle component analysis based on all 16 morphological and physiological variables generated useful information regarding the classification of salt tolerant treatment according to their response to SA. These results suggest SA (100 or 150 ppm) could be used as an effective, economic, easily available and safe phenolic agent against salinity stress in G. grandiflorus.

Antifungal potential of zinc against leaf spot disease in chili pepper caused by Alternaria alternata.

The fungal pathogen, Alternaria alternata is responsible for causing leaf spot disease in many plants, including chili pepper. Zinc (Zn) an essential micronutrient for plant growth, also increases resistance in plants against diseases, and also acts as an antifungal agent. Here, in vitro effects of ZnSO4 on the propagation of A. alternata were investigated, and also in vivo, the effect of foliar application of ZnSO4 was investigated in chili pepper plants under disease stress. In vitro, ZnSO4 inhibited fungal growth in a dose-dependent manner, with complete inhibition being observed at the concentration of 8.50 mM. Hyphae and conidial damage were observed along with abnormal activity of antioxidant enzymes, Fourier-transform infrared spectroscopy confirmed the major changes in the protein structure of the fungal biomass after Zn accumulation. In vivo, pathogen infection caused the highest leaf spot disease incidence, and cumulative disease index, which resulted in a significant reduction in the plant's growth (length and biomass), and physiochemical traits (photosynthetic pigment, activity of catalase, peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase). The heat map and principal component analysis based on disease, growth and, physico-chemical variables generated useful information regarding the best treatment useful for disease management. Foliar Zn (0.036 mM) acted as a resistance inducer in chili pepper plants that improved activities of antioxidants (CAT and POX), and defense compounds (PPO and PAL), while managing 77% of disease. The study indicated foliar ZnSO4 as an effective and sustainable agriculture practice to manage Alternaria leaf spot disease in chili pepper plants.

Lupeol acetate as a potent antifungal compound against opportunistic human and phytopathogenic mold Macrophomina phaseolina.

Antifungal activity of Monotheca buxifolia methanolic extract and its various fractions were assessed against Macrophomina phaseolina, a soil-borne fungal pathogen of more than 500 vegetal species as well as rare and emerging opportunistic human pathogen. Different concentrations of methanolic extract (3.125 to 200 mg mL-1) inhibited fungal biomass by 39-45%. Isolated n-hexane, chloroform and ethyl acetate fractions suppressed fungal biomass by 32-52%, 29-50% and 29-35%, respectively. Triterpenes lupeol and lupeol acetate (1, 2) were isolated from n-hexane while betulin, ß-sitosterol, ß-amyrin, oleanolic acid (3-6) were isolated from chloroform fraction. Vanillic acid, protocatechuic acid, kaempferol and quercetin (7-10) were isolated from the ethyl acetate fraction and identified using various spectroscopic techniques namely mass spectroscopy and NMR. Antifungal activity of different concentrations (0.0312 to 2 mg mL-1) of the isolated compounds was evaluated and compared with the activity of a broad spectrum fungicide mancozeb. Different concentrations of mencozeb reduced fungal biomass by 83-85%. Among the isolated compounds lupeol acetate (2) was found the highest antifungal against M. phaseolina followed by betulin (3), vanillic acid (7), protocatechuic acid (8), ß-amyrin (5) and oleanolic acid (6) resulting in 79-81%, 77-79%, 74-79%, 67-72%, 68-71% and 68-71%, respectively. Rest of the compounds also showed considerable antifungal activity and reduced M. phaseolina biomass by 41-64%.

Screening and histopathological characterization of sunflower germplasm for resistance to Macrophomina phaseolina.

Twenty-two sunflower germplasms were screened for resistance to Macrophomina phaseolina to select parental genetic resources useful for the development of charcoal rot-resistant sunflower cultivars. Potting soil inoculated with pathogen (10 mL pot-1, 2 × 105 sclerotia mL-1) sown with sunflower seeds was examined for disease severity index (%), disease incidence (%), mortality (%), and growth inhibition index (%) 90 d after inoculation. None of the germplasm was disease-free; four were found to be resistant, five moderately resistant, six moderately susceptible, five susceptible, and two highly susceptible. All inoculated plants exhibited disease symptoms both externally and internally. Mild to severe symptoms included brown lesions on aboveground plant, pith disintegration in stem, and shredded appearance of tap root. Histopathological features exposed different colonization mechanism of the pathogen in the resistant and susceptible cultivars. Physical blockage, tissue disintegration, blackening and rupturing of cortical, pith and vascular regions by fungal mycelia, and sclerotia and pycnidia causing large spaces in the center of stem rendered it a hollow structure in all susceptible germplasm. However, stem and root tissues of the resistant germplasm indicated local infection restricted to few cells. This suggested expression of true resistance genes in resistant germplasm. Therefore, the sunflower lines resistant to the M. phaseolina infection are potential genetic resources for the development of quality sunflower cultivars resistant to charcoal rot disease.

Contending charcoal rot disease of mungbean by employing biocontrol Ochrobactrum ciceri and zinc.

Role of rhizobacteria and zinc (Zn) was investigated in the management of charcoal rot disease in mungbean [Vigna radiata (L.) Wilczek] caused by Macrophomina phaseolina (Tassi) Goid. In vitro, screening tests with eight rhizobacteria [Bacillus subtilis (FCBP-0324), B. subtilis (FCBP-0189), Rhizobacter daucus (FCBP-0450), Azospirillum brasilense (FCBP-0025), Azospirillum lipoferum (FCBP-0022), Pseudomonas malophilia (FCBP-0099), Pseudomonas florescense (FCBP-0083) and Ochrobactrum ciceri (FCBP-0727)] were conducted against M. phaseolina and FCBP-0727 were found as the most effective biocontrol agent. Molecular analyses of 16S rDNA combined with cultural and biochemical analyses confirmed FCBP-0727 identification (GeneBank Accession No. LC415039). Cell-free culture filtrate (CFCF) and cell culture of O. ciceri were separated and antifungal trials of both substrates indicated inhibition in mycelial growth and suppression in sclerotia formation, although the CFCF appeared to be more destructive against the pathogen. Ethyl-acetate and chloroform extracts of bacterial secondary metabolites completely halted the growth of M. phaseolina. The GC-MS analysis of CFCF of chloroform extract proved to be rich sources of bioactive fungicide like phthalates, adipic acid, propanoic acid, and linoleic acid. Likewise, CFCF of ethyl acetate also exhibited important organic compounds like phthalates, diisopropylglycol and octasiloxan. Pot experiment revealed that soil inoculation with O. ciceri in combination with Zn (2.5 mg/kg) protected mungbean plants against M. phaseolina through improving photosynthetic pigment, total protein content and activities of antioxidant enzymes (catalase, peroxidase and polyphenol oxidase). The present study will open new vistas for biological management of charcoal rot disease of mungbean using a combination of rhizobacteria and Zn.

The counter defence system of antioxidants in Coelomycetous emerging human and plant pathogenic fungus Macrophomina phaseolina against copper toxicity.

Macrophomina phaseolina (Tassi) Goid. is primarily a phytopathogen but also exhibits potential to cause infection in human being due to its aggressive and robust nature. Adaptation potential in M. phaseolina was assessed after exposing to heavy metal copper through analysing macro- and microscopic as well as physiological attributes. Considerable modifications were observed in morphology with an increase in concentrations (25, 75, and 100 ppm) of copper as compared with control. Total content of protein and activities of the antioxidant enzymes were affected differently at different copper concentrations. The fungal biomass, metal accumulation, metal uptake efficiency, and bioaccumulation factors were decreased due to the increase in copper concentrations. Fourier transformed infrared spectroscopic assessment showed hydroxyl, carboxyl, and amine groups as major metal accumulation sites. It is concluded that Cu-based fungicides can manage this pathogen but excessive application may accumulate in the plant that will transfer along the food chain, reaching ultimately the human body.

Crosstalk of Zn in Combination with Other Fertilizers Underpins Interactive Effects and Induces Resistance in Tomato Plant against Early Blight Disease.

The present study was undertaken to evaluate the integrated effect of zinc (Zn) with other nutrients in managing early blight (EB) disease in tomato. A pot experiment was carried out with basal application of the recommended level of macronutrients [nitrogen, phosphorus and potassium (NPK)] and micronutrients [magnesium (Mg) and boron (B)] in bilateral combination with Zn (2.5 and 5.0 mg/kg) in a completely randomized deigned in replicates. Results revealed that interactive effect of Zn with Mg or B was often futile and in some cases synergistic. Zn with NPK yield synergistic outcome, therefore EB disease was managed significantly (disease incidence: 25% and percent severity index: 13%), which resulted in an efficient signaling network that reciprocally controls nutrient acquisition and uses with improved growth and development in a tomato plant. Thus, crosstalk and convergence of mechanisms in metabolic pathways resulted in induction of resistance in tomato plant against a pathogen which significantly improved photosynthetic pigment, total phenolics, total protein content and defense-related enzymes [superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL)]. The tremendous increase in total phenolics and PAL activity suggesting their additive effect on salicylic acid which may help the plant to systemically induce resistance against pathogen attack. It was concluded that interactive effect of Zn (5.0 mg/kg) with NPK significantly managed EB disease and showed positive effect on growth, physiological and biochemical attributes therefor use of Zn + NPK is simple and credible efforts to combat Alternaria stress in tomato plants.

Necrotrophic fungus Macrophomina phaseolina tolerates chromium stress through regulating antioxidant enzymes and genes expression (MSN1 and MT).

Cr(VI) tolerance level of phytopathogenic fungus viz., Macrophomina phaseolina (Tassi) Goid was assessed through growth, morphological, physiological, and metal accumulation assays. Initially, the fungus growth assays indicated that the fungus can grow over concentration range of 20-3000 ppm and exhibited high tolerance index (0.88-1.00) and minimum inhibitory concentration at 3500 ppm of Cr. Observations under compound and scanning electron microscope un-revealed the structural features of hyphae under Cr stress as thick-walled, aggregated, branched, short and broken, along with attachment of irregular objects on them. Metal accumulation analysis revealed reduction in Cr(VI) accumulation by the fungus with increase in metal concentration in the growth medium (500-3000 ppm). Cr stress induced upregulation of antioxidant enzyme activities (catalase, peroxidase and polyphenol oxidase), expression of genes (MSN1 and metallothionein) and appearnace of new protein bands suggesting the possible role in protection and survival of M. phaseolina against Cr(VI)-induced oxidative stress. This study concludes that interference of Cr with growth and physiological process of M. phaseolina could affect its infection level on its host plant, therefore, synergistic action of two factors needs to be addressed, which may aid to guide future research efforts in understanding impact of plant-pathogen-heavy metal interaction.

Influence of salinity and Fusarium oxysporum as the stress factors on morpho-physiological and yield attributes in onion.

Occurrence of salt stress with the soil borne fungus Fusarium oxysporum f. sp. cepa (FOC) are potential threat to the crop yield. This investigation reports effect of the concurrent stresses (salinity and FOC) on morpho-physiological and yield attributes in onion. In vitro growth tests revealed proliferation of FOC biomass at different levels of salinity (2-8 dS m-1). A greenhouse pot experiment with the proposed levels of salinity (2.5, 3.5 and 4.5 dS m-1) in combination with FOC inoculation showed more drastic effect of combined stress on disease severity, plant growth and bulb as compared to the individual stress. In general, osmotic potential, total chlorophyll content, membrane stability index and total protein content of the leaf were decreased, while total phenolics were increased due to the given stress/s. Total sugar content decreased due to effect of the  individual stress of FOC, while it increased under the individual stress of salinity and in combination with FOC. FOC infection did not change activity of polyphenol oxidase (PPO), while it improved peroxidase (POX) and phenylalanine ammonia lyase (PAL) and decreased catalase (CAT) activity. Activities of POX and PPO increased, however PAL and CAT declined under individual as well as simultaneous stress of salinity and FOC. The research work concluded that FOC will be a more severe disease threat for onion cultivation in saline soils.

Chromium tolerance, oxidative stress response, morphological characteristics, and FTIR studies of phytopathogenic fungus Sclerotium rolfsii.

Sclerotium rolfsii is one of the most destructive fungal plant pathogens that can infect over 500 plants and can adapt to diverse environmental conditions. The present research work was carried out to evaluate the impact of both hexa- and trivalent chromium (Cr) on growth, morphology, enzymatic characteristics, and metal accumulation in S. rolfsii under laboratory conditions. Experiments were performed in both malt extract broth and agar growth medium amended with six different concentrations (10, 20, 40, 60, 80, and 100 ppm) of each Cr(III) and Cr(VI) ions inoculated with fungus and incubated for 6-7 days at 25 ± 3 °C. In broth medium, the total protein content was declined and activities of antioxidant enzymes were increased with an increase in metal concentrations. Lower concentrations (10 ppm) of the metal ions stimulated the growth of fungus and higher concentrations (60-100) inhibited it. The Fourier transform infrared spectroscopy (FTIR) assessment showed hydroxyl, carboxyl, and amine groups as major metal binding sites. In agar medium, tolerance index was decreased up to 0.56 at 10-80 ppm of Cr(III) and up to 0.62 at 10-60 ppm of Cr(VI). Considerable modifications were observed in hyphal and sclerotial morphology with an increase in concentration of metal ions. The current study concluded that interference of Cr with growth and physiological process of S. rolfsii could affect its infection level on its host plant. This study provides important information regarding cultivation of susceptible plant varieties in Cr-polluted soil as evidenced by pathogen growth up to 50 ppm of Cr(III) and Cr(VI) ions.

ANTIFUNGAL POTENTIAL OF LEAF EXTRACTS OF LEGUMINOUS TREES AGAINST SCLEROTIUM ROLFSII.

BACKGROUND: Sclerotium rolfsii Sacc. is a destructive soil-borne plant pathogen that infects over 500 plant species and causes significant yield losses in many economically important plant species. Synthetic fungicides used to combat the menace also pollute the environment and cause health hazards. In order to search environmental friendly alternatives from natural resources, methanolic extracts of three leguminous tree species namely Acacia nilotica (L.) Willd. ex Delile subsp. indica (Benth.) Brenan, Prosopis juliflora (Sw.) DC. and Albizia lebbeck (L.) Benth. were evaluated for their antifungal activity against S. rolfsii and A. nilotica subsp. indica exhibited the maximum fungicidal potential. MATERIALS AND METHODS: Two hundred grams dried leaf material of each of the three test plant species were extracted with methanol for two weeks. After filtration, methanol was evaporated on a rotary evaporator. Malt extract broth was used to make various concentrations of the crude methanolic extracts and their antifungal potential was determined by comparing the fungal biomass in various treatments with control. Chemical composition of methanolic leaf extract of A. nilotica subsp. indica was determined through GC-MS analysis. RESULTS: Methanolic leaf extract of A. nilotica subsp. indica showed the highest fungicidal activity. Fungal biomass was decreased by 17-55% due to various concentrations of this extract over control. Different concentrations of P. juliflora reduced fungal biomass by 3-52%. Fourteen compounds were identified in methanolic extract of A. nilotica subsp. indica. 9,12,15-octadecatrienoic acid, methyl ester, (Z,Z,Z,)- (16.59%) was the most abundant compound followed by 1-pentanol, 2 methyl-, acetate (14.80%); hexanedioic acid, dimethyl ester (13.10%) and cyclotriaconta- 1, 7, 16, 22-tetraone (10.28%). CONCLUSION: This study concludes that methanolic leaf extract of A. nilotica subsp. indica can be used for management of S. rolfsii.

Practical access to highly enantioenriched quaternary carbon Michael adducts using simple organocatalysts.

A three component catalyst system entailing an amino acid (O(t)Bu-L-threonine), a hydrogen bond donor (sulfamide), and an amine base (DMAP) allows α-branched aldehyde addition to nitroalkenes in good to high yield and excellent ee. Importantly, the lowest reported catalyst loading (5.0 mol%) and aldehyde stoichiometry (1.2-2.0 equiv) is demonstrated and in most instances the best current product profile is observed.