The growing media is one of the significant elements affecting microgreens’ yield and quality. This experiment investigated the possibility of waste utilization instead of employing peat moss to produce sunflower and water-spinach microgreens. The treatments consisted of peat moss (Control), coconut coir dust (CD), leaf compost (LC), food waste compost (FC), CD:LC = 1:1 v/v, CD:FC = 1:1 v/v, LC:FC = 1:1 v/v, and CD:LC:FC = 1:1:1 v/v. The results proved that the highest yield of sunflower microgreens was observed when cultivated in 1:1 v/v of CD:LC media (10,114.81 g m−2), whereas the highest yield of water spinach microgreens was recorded under the treatments of CD, Control, 1:1 v/v of CD:LC, and 1:1:1 v/v of CD:LC:FC media (10,966.67–9800.00 g m−2). The biochemical composition of the microgreens varied within the types. Our findings demonstrated that a tendency of an increase in chlorophyll and carotenoid contents depended on the growth of both microgreens under different growing media. All growing media did not cause excess nitrate residue or pathogenic contamination in both microgreens, namely Clostridium perfringens, Salmonella spp., and Staphylococcus aureus. In contrast, almost all the growing media resulted in a higher population of Bacillus cereus contamination in both microgreens than the standard set limit, except for sunflower microgreens grown in the control and CD growing media. These findings could suggest that the 1:1 v/v of CD:LC and CD media were the most effective growing media for sunflower and water spinach microgreens, respectively, but further cleaning before consumption is recommended to avoid or reduce the foodborne incidences caused by B. cereus in microgreens.
Flower blight caused by Neopestalotiopsis clavispora is an emerging disease of flamingo flower (Anthurium andraeanum Lind.) that negatively impacts flower production. The use of rhizosphere fungi as biocontrol agents is an alternative way to control this disease instead of using synthetic fungicides. This research aimed to screen the potential of rhizosphere fungi, Trichoderma spp., with diverse antifungal abilities to control N. clavispora and to reduce flower blight in flamingo flowers. A total of ten isolates were tested against N. clavispora by dual culture assay, and T1-02 was found to be the most effective isolate against N. clavispora, with inhibition of 78.21%. Morphology and molecular phylogeny of multiple DNA sequences of the genes, the internal transcribed spacer (ITS), translation elongation factor 1-α (tef1-α), and RNA polymerase 2 (rpb2) identified isolate T1-02 as Trichoderma virens. Sealed plate method revealed T. virens T1-02 produced volatile antifungal compounds (VOCs) against N. clavispora, with inhibition of 51.28%. Solid-phase microextraction (SPME) was applied to trap volatiles, and GC/MS profiling showed VOCs emitted from T. virens T1-02 contained a sesquiterpene antifungal compound—germacrene D. The pre-colonized plate method showed that T. virens T1-02 aggressively colonized in tested plates with inhibition of 100% against N. clavispora, and microscopy revealed direct parasitism onto fungal hyphae. Furthermore, the application of T. virens T1-02 spore suspension reduced the disease severity index (DSI) of flower blight in flamingo flowers. Based on the results from this study, T. virens T1-02 displays multiple antagonistic mechanisms and has the potential ability to control flower blight of flamingo flowers caused by N. clavispora.
Natural amendments from agricultural waste to improve soil physicochemical properties continuously attract research interest in promoting eco-friendly plant production. The present study evaluated the proper use of sawdust, biochar, and compost made from farm waste for kale production from seedling propagation to field conditions. From the seedling propagation process, the results demonstrate that the most suitable growing medium for kale seedings was 0.5:1:1 v/v of sawdust + biochar + compost, which gave the fastest mean germination times (2.71 days) and the highest seed germination percentage (78.33%). In addition to investigating the selected growing media as the soil amendments at five different rates (0, 6.25, 12.50, 18.75, 25.00, and 31.25 t ha−1), the result reveals that the fresh weight of marketable leaves was significantly highest under the 31.25 t ha−1 treatment. The application rate that yielded the highest gross profit margins was eight times higher than the control. Moreover, in some harvesting periods, the kale leaf yields under the treatment of 31.25 t ha−1 showed higher total chlorophyll and carotenoid contents.
The Gram-negative xylem-limited bacterium, Xylella fastidiosa, is an important plant pathogen that infects a number of high value crops. The Temecula 1 strain infects grapevines and induces Pierce′s disease, which causes symptoms such as scorching on leaves, cluster collapse, and eventual plant death. In order to understand the pathogenesis of X. fastidiosa, researchers routinely perform gene deletion studies and select mutants via antibiotic markers. Site-directed pilJ mutant of X. fastidiosa were generated and selected on antibiotic media. Mutant cultures were assessed by PCR to determine if they were composed of purely transformant cells or included mixtures of non-transformants cells. Then pure pilJ mutant and wildtype cells were mixed in PD2 medium and following incubation and exposure to kanamycin were assessed by PCR for presence of mutant and wildtype populations. We have discovered that when creating clones of targeted mutants of X. fastidiosa Temecula 1 with selection on antibiotic plates, X. fastidiosa lacking the gene deletion often persist in association with targeted mutant cells. We believe this phenomenon is due to spontaneous antibiotic resistance and/or X. fastidiosa characteristically forming aggregates that can be comprised of transformed and non-transformed cells. A combined population was confirmed by PCR, which showed that targeted mutant clones were mixed with non-transformed cells. After repeated transfer and storage the non-transformed cells became the dominant clone present. We have discovered that special precautions are warranted when developing a targeted gene mutation in X. fastidiosa because colonies that arise following transformation and selection are often comprised of transformed and non-transformed cells. Following transfer and storage the cells can consist primarily of the non-transformed strain. As a result, careful monitoring of targeted mutant strains must be performed to avoid mixed populations and confounding results.