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

Eucalyptus globules belonging to the Myrtaceae family was explored for the synthesis of zinc oxide nanoparticles and for biological applications. The aqueous extract of the synthesized zinc nanoparticles (ZnNPs) was characterized using UV-visible spectrophotometer, FTIR, SEM and TEM. The aqueous broth was observed to be an efficient reducing agent, leading to the rapid formation of ZnNPs of varied shapes with sizes ranging between 52-70 nm. In addition, antifungal activity of the biosynthesized ZnNPs was evaluated against major phytopathogens of apple orchards. At 100 ppm of ZnNPs, the fungal growth inhibition rate was found to be 76.7% for Alternaria mali, followed by 65.4 and 55.2% inhibition rate for Botryosphaeria dothidea and Diplodia seriata, respectively. The microscopic observations of the treated fungal plates revealed that ZnNPs damages the topography of the fungal hyphal layers leading to a reduced contraction of hyphae. This considerable fungicidal property of ZnNPs against phytopathogenic fungi can have a tremendous impact on exploitation of ZnNPs for fungal pest management and ensure protection in fruit crops.

Study of bio-fabrication of iron nanoparticles and their fungicidal property against phytopathogens of apple orchards.

Current research trends on iron nanoparticles (FeNPs) are extensively focused because of their unique magnetic and electrical properties mostly applicable in essential medical devices. However, their fungicidal property against plant pathogens is very less known until date. Present study demonstrates a green technique for blending of FeNPs by utilising aqueous extract of neem leaf (Azadirachta indica A. Juss.) as reducing agent. Various characterisation techniques such as ultraviolet (UV)-visible spectroscopy, Fourier transform infrared spectroscopy transmission electron microscopy, scanning electron microscopy and X-ray diffraction were performed for FeNPs. The authors' results demonstrate the more cluster formation of FeNPs with size distribution of 20-80 nm. The bio-fabricated FeNPs showed enhanced biocidal activity against economically important phytopathogens of apple such as Alternaria mali, Botryosphaeria dothidea and Diplodia seriata. From the obtained results, it can be suggested that further delve into green synthesis of FeNPs can address future biotechnology concerns to limit the synthesis of FeNPs by conventional methods. Furthermore, the field study on pathogenic fungi can be an effective step to verify their agricultural applications.

High throughput de novo RNA sequencing elucidates novel responses in Penicillium chrysogenum under microgravity.

In this study, the transcriptional alterations in Penicillium chrysogenum under simulated microgravity conditions were analyzed for the first time using an RNA-Seq method. The increasing plethora of eukaryotic microbial flora inside the spaceship demands the basic understanding of fungal biology in the absence of gravity vector. Penicillium species are second most dominant fungal contaminant in International Space Station. Penicillium chrysogenum an industrially important organism also has the potential to emerge as an opportunistic pathogen for the astronauts during the long-term space missions. But till date, the cellular mechanisms underlying the survival and adaptation of Penicillium chrysogenum to microgravity conditions are not clearly elucidated. A reference genome for Penicillium chrysogenum is not yet available in the NCBI database. Hence, we performed comparative de novo transcriptome analysis of Penicillium chrysogenum grown under microgravity versus normal gravity. In addition, the changes due to microgravity are documented at the molecular level. Increased response to the environmental stimulus, changes in the cell wall component ABC transporter/MFS transporters are noteworthy. Interestingly, sustained increase in the expression of Acyl-coenzyme A: isopenicillin N acyltransferase (Acyltransferase) under microgravity revealed the significance of gravity in the penicillin production which could be exploited industrially.

Effect of low shear modeled microgravity on phenotypic and central chitin metabolism in the filamentous fungi Aspergillus niger and Penicillium chrysogenum.

Phenotypic and genotypic changes in Aspergillus niger and Penicillium chrysogenum, spore forming filamentous fungi, with respect to central chitin metabolism were studied under low shear modeled microgravity, normal gravity and static conditions. Low shear modeled microgravity (LSMMG) response showed a similar spore germination rate with normal gravity and static conditions. Interestingly, high ratio of multiple germ tube formation of A. niger in LSMMG condition was observed. Confocal laser scanning microscopy images of calcofluor flurophore stained A. niger and P. chrysogenum showed no significant variations between different conditions tested. Transmission electron microscopy images revealed number of mitochondria increased in P. chrysogenum in low shear modeled microgravity condition but no stress related-woronin bodies in fungal hyphae were observed. To gain additional insight into the cell wall integrity under different conditions, transcription level of a key gene involved in cell wall integrity gfaA, encoding the glutamine: fructose-6-phosphate amidotransferase enzyme, was evaluated using qRT-PCR. The transcription level showed no variation among different conditions. Overall, the results collectively indicate that the LSMMG has shown no significant stress on spore germination, mycelial growth, cell wall integrity of potentially pathogenic fungi, A. niger and P. chrysogenum.