Molecular diversity and allergenic profiles of Alternaria spp. from desert environments in Arizona

Synergistic Microbial Inhibition and Quality Preservation for Grapes through High-Voltage Electric Field Cold Plasma and Nano-ZnO Antimicrobial Film Treatment

To ensure their quality and safety, harvested grapes should be protected from microbial contamination before reaching consumers. For the first time, this study combined high-voltage electric field cold plasma (HVEF-CP) and nano-ZnO antimicrobial film to inhibit microbial growth on grapes. Using the response surface method, the optimal processing parameters of HVEF-CP (a voltage of 78 kV, a frequency of 110 Hz, and a time of 116 s) were identified to achieve 96.29% sterilization. The effects of co-processing with HVEF-CP and nano-ZnO antimicrobial film on the quality and safety of grapes during storage were explored. When stored at 4 °C and 20 °C, the co-processing extended the shelf life of grapes to 14 and 10 days, respectively. The co-processing increased the sterilization rate to 99.34%, demonstrating a synergistic effect between the two methods to ensure not only the safety of grapes but also their nutrient retention during storage. This novel approach is promising for the efficient, safe, and scalable preservation of grapes as well as other foods.

Molecular phylogenetic species in Alternaria pathogens infecting pistachio and wild relatives

Many important pathogens of crops worldwide are members of section Alternaria within the genus Alternaria. Representative species in this section such as Alternaria alternata, Alternaria tenuissima, and Alternaria arborescens show high variability, intermediate characters and plasticity in morphological features, which makes species identification difficult. The aim of this study was to characterize Alternaria species associated with pistachio and wild relatives in Turkey using molecular phylogenetics. One hundred isolates of Alternaria spp. from pistachio and wild relatives from Turkey were investigated. In addition, standard morphological reference isolates and Alternaria blight pathogens of pistachio from USA were included. Sequence data from major allergen a1, ATPase, endopolygalacturanase, and anonymous regions OPA1.3 and SCAR2 were obtained. Gene trees were estimated based on maximum parsimony, maximum-likelihood, and bayesian inference methods. Species tree estimation was performed based on Yule speciation and strict molecular clock assumption. Among the collection of Alternaria spp. from Turkey, only one A. arborescens isolate and three isolates which were morphologically A. alternata/A. arborescens intermediate types, but, phylogenetically close to A. arborescens were discovered. While A. alternata and A. tenuissima formed one phylogenetic species, A. alternata/tenuissima were phylogenetically distinct from A. arborescens. Furthermore, a TaqI restriction site in the endopolygalacturanase gene was explored as a novel diagnosis for identification of A. alternata/tenuissima and A. arborescens. All these molecular phylogenetic approaches allow to distinguish morphologically similar Alternaria pathogens and molecular phylogenies of Alternaria pathogens from pistachio and wild relatives in Turkey are described for the first time.