Assessment of antimicrobial, antialgal and cytotoxic activities of crude extracts from rhizospheric and freshwater cyanobacterial strains

Background: This study describes the evaluation of antimicrobial, antialgal and cytotoxic activities of crude extracts from cyanobacterial strains isolated from rhizospheric and freshwater environment.Methods: Four cyanobacterial strains were isolated from freshwater and rhizospheric samples collected from various sites of University of the Punjab, Lahore, Pakistan. Selected strains were identified by 16S rDNA ribotyping as species of genera, Cyanothece (CY1), Synechococcus (CY2), Leptolyngbya (CY3) and Synechococcus (CY4). The organic extracts i.e., methanolic, ethanolic and acetonic of selected cyanobacterial strains were checked for antibacterial and cytotoxic activity. Antibacterial and antialgal activities of cyanobacterial extracts were determined against, four Gram positive and three Gram negative bacteria using Muller-Hinton (MH) agar well diffusion assay and two algal species using 96-well microtiter plate respectively. Cytotoxic activity was determined against Vero cells and Huh-7 cells.Results: The results showed that all cyanobacterial extracts showed activities against Gram positive bacteria while some of the extracts showed activity against Gram negative bacteria. Acetonic extract of CY4 and CY2 showed moderate discoloration against Chlamydomonas sp. and Chroococcus sp. respectively. In cytotoxicity bioassay, methanolic extracts of strain CY1 and CY2 were most active with an IC50 of 0.625 mg/ml against Vero cells while acetonic extract of strain CY1 showed highest activity against Huh-7 cells (p<0.05).Conclusion: The data of current study conclusively suggest that selected cyanobacteria may be an excellent source for further fractionation to obtain novel antibacterial, antialgal and anticancer substances.Keywords: Cyanobacteria; MTT bioassay; Microtiter plates; Antimicrobial activity; Cytotoxicity

sGenotypes, Epidemiological Variables and Fungicides Application Associated With Wheat Leaf Rust Development and Grain Yield

The present study was carried out at the Plant Pathology Hafizabad Research Station, the University of Layyah, during the crop seasons 2021–2022 and 2022–2023 to evaluate the response of various wheat genotypes against leaf rust severity (%), environmental conditions favourable for disease development and grain yield. Except for minimum temperature and minimum relative humidity, which had a negative association with disease development, there was a significant correlation between leaf rust severity (%) and all environmental conditions such as maximum temperature, maximum relative humidity, rainfall, and wind speed. All epidemiological variables such as maximum temperature, minimum temperature, minimum relative humidity, rainfall and wind speed significantly affect the disease progression. The disease predictive model accounted for 48-69% variability in leaf rust severity. The model performance was evaluated using the coefficient of determination (R2 = 0.69) and RMSE, both demonstrated acceptable predictive results for leaf rust severity (%) management. Leaf rust severity (%) increased with an increase in maximum temperature (17.8 to 30 °C), maximum relative humidity (76.3 to 85%), rainfall (2.2 to 10.85 mm) and wind speed 1.1-2.7 km/h and decreased with the increase of minimum temperature (7.91 to 16.71 °C) minimum relative humidity (47.15 to 56.45%) during both rating seasons 2021–2022 and 2022–2023. The single and two applications of fungicides at the Zadok's scale 3, ZS 4.3, and ZS 5.4 stages led to a significant reduction in grain yield losses caused by leaf rust severity (%) in both the 2021-2022 and 2022-2023 crop seasons. Single and two sprays of prothioconazole, were found to be the first choice among all treatments to reduce the disease severity and increase grain production and maximum gross revenue (513.1-777.8$/ha), as compared to followed by single and two sprays of propiconazole (Progress), tebuconazole + trifloxystrobin, tebuconazole, bixafen + tebuconazole, and propiconazole (Tilt), respectively. These findings recommend the involvement of genotype resistance and weather predictors in wheat leaf rust development, along with fungicide application studies, to improve the predictability of host resistance to disease, future models, and the sustainability of disease control methods

sGenotypes, Epidemiological Variables and Fungicides Application Associated With Wheat Leaf Rust Development and Grain Yield

The present study was carried out at the Plant Pathology Hafizabad Research Station, the University of Layyah, during the crop seasons 2021–2022 and 2022–2023 to evaluate the response of various wheat genotypes against leaf rust severity (%), environmental conditions favourable for disease development and grain yield. Except for minimum temperature and minimum relative humidity, which had a negative association with disease development, there was a significant correlation between leaf rust severity (%) and all environmental conditions such as maximum temperature, maximum relative humidity, rainfall, and wind speed. All epidemiological variables such as maximum temperature, minimum temperature, minimum relative humidity, rainfall and wind speed significantly affect the disease progression. The disease predictive model accounted for 48-69% variability in leaf rust severity. The model performance was evaluated using the coefficient of determination (R2 = 0.69) and RMSE, both demonstrated acceptable predictive results for leaf rust severity (%) management. Leaf rust severity (%) increased with an increase in maximum temperature (17.8 to 30 °C), maximum relative humidity (76.3 to 85%), rainfall (2.2 to 10.85 mm) and wind speed 1.1-2.7 km/h and decreased with the increase of minimum temperature (7.91 to 16.71 °C) minimum relative humidity (47.15 to 56.45%) during both rating seasons 2021–2022 and 2022–2023. The single and two applications of fungicides at the Zadok's scale 3, ZS 4.3, and ZS 5.4 stages led to a significant reduction in grain yield losses caused by leaf rust severity (%) in both the 2021-2022 and 2022-2023 crop seasons. Single and two sprays of prothioconazole, were found to be the first choice among all treatments to reduce the disease severity and increase grain production and maximum gross revenue (513.1-777.8$/ha), as compared to followed by single and two sprays of propiconazole (Progress), tebuconazole + trifloxystrobin, tebuconazole, bixafen + tebuconazole, and propiconazole (Tilt), respectively. These findings recommend the involvement of genotype resistance and weather predictors in wheat leaf rust development, along with fungicide application studies, to improve the predictability of host resistance to disease, future models, and the sustainability of disease control methods