Bioimaging structural signatures of the oomycete pathogen Sclerospora graminicola in pearl millet using different microscopic techniques

Abstract

In this case study, the mycelium growth of Sclerospora graminicola in the infected tissues of pearl millet and the process of sporulation and liberation of sporangia and zoospores were observed using four different microscopic techniques. The cotton blue-stained samples observed under light microscope revealed the formation of zoospores with germ tubes, appressoria and initiation of haustorium into the host cells, while the environmental scanning electron microscopy showed the rapid emergence of sporangiophores with dispersed sporangia around the stomata. For fluorescence microscopy, the infected leaf samples were stained with Fluorescent Brightener 28 and Calcofluor White, which react with β-glucans present in the mycelial walls, sporangiophores and sporangia. Calcoflour White was found to be the most suitable for studying the structural morphology of the pathogen. Therefore, samples observed by confocal laser scanning microscopy (CLSM) were pre-treated with Calcofluor White, as well as with Syto-13 that can stain the cell nuclei. Among the four microscopic techniques, CLSM is ideal for observing live host-pathogen interaction and studying the developmental processes of the pathogen in the host tissues. The use of different microscopic bioimaging techniques to study pathogenesis will enhance our understanding of the morphological features and development of the infectious propagules in the host.

Green Synthesis and Characterization of Zinc Oxide Nanoparticles Using Eucalyptus globules and Their Fungicidal Ability Against Pathogenic Fungi of Apple Orchards

“…To evaluate the efficacy of ZnNPs for the growth of mycelia, fungal mass was collected by hand-picking using sterilized cork borer from the surface of petri plates containing D. seriata culture developed on PDA media treated with 50 ppm of synthesized E. globules ZnNPs. Concurrently, the fungal plates treated with tap water were preserved as control samples and observed for the fungal morphology under florescence microscope [40].…”

A whole cell fluorescence quenching-based approach for the investigation of polyethyleneimine functionalized silver nanoparticles interaction with Candida albicans

“…Calcofluor white (CFW) is a fluorescent blue-colored dye that is used for diagnosing fungal onychomycosis, which binds to the 1-3 and 1-4, β-linkage of chitin and cellulose in fungal, plant, and algal cell walls. The excitation wavelength for CFW is 380 nm; the emission maxima are between 440 and 475 nm (Shetty et al, 2019). The results showed that PEI-f-Ag-NPs quenched the fluorescence of CFW within 5 min; however, complete quenching was recorded at 120 min of incubation (Figure 5).…”

Ameliorating Forage Crop Resilience in Dry Steppe Zone Using Millet Growth Dynamics

“…Pearl millet (Pennisetum glaucum) is the sixth most important cereal crop after rice, wheat, maize, barley, and sorghum [8]. It is widely grown on 30 million ha in Asia and Africa's arid and semi-arid tropical regions.…”