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Melatonin plays an important role in stress tolerance in plants. In this study, exogenous melatonin significantly alleviated the dwarf phenotype and inhibited the decrease of plant fresh weight induced by excess copper (Cu2+). Our results indicated that melatonin alleviated Cu2+ toxicity by improving Cu2+ sequestration, carbon metabolism and ROS (reactive oxygen species) scavenging, rather than by influencing the Cu2+ uptake under excess Cu2+ conditions. Transcriptome analysis showed that melatonin broadly altered gene expression under Cu2+ stress. Melatonin increased the levels of glutathione and phytochelatin to chelate excess Cu2+ and promoted cell wall trapping, thus keeping more Cu2+ in the cell wall and vacuole. Melatonin inhibited ROS production and enhanced antioxidant systems at the transcriptional level and enzyme activities, thus building a line of defense in response to excess Cu2+. The distribution of nutrient elements was recovered by melatonin which was disturbed by Cu2+. In addition, melatonin activated carbon metabolism, especially glycolysis and the pentose phosphate pathway, to generate more ATP, an intermediate for biosynthesis. Taken together, melatonin alleviated Cu2+ toxicity in cucumber via multiple mechanisms. These results will help to resolve the toxic effects of Cu2+ stress on plant growth and development. These results can be used for new strategies to solve problems associated with Cu2+ stress. [ABSTRACT FROM AUTHOR]

Although previous studies have found that melatonin can promote seed germination, the mechanisms involved in perceiving and signaling melatonin remain poorly understood. In this study, it was found that melatonin was synthesized during cucumber seed germination with a peak in melatonin levels occurring 14 hr into germination. This is indicative of a correlation between melatonin synthesis and seed germination. Meanwhile, seeds pretreated with exogenous melatonin (1 μM) showed enhanced germination rates under 150 mM NaCl stress compared to water-pretreated seeds under salinity stress. There are two apparent mechanisms by which melatonin alleviated salinity-induced inhibition of seed germination. Exogenous melatonin decreased oxidative damage induced by NaCl stress by enhancing gene expression of antioxidants. Under NaCl stress, compared to untreated control, the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly increased by approximately 1.3-5.0-fold, with a concomitant 1.4-2.0-fold increase of CsCu-ZnSOD, CsFe-ZnSOD, CsCAT, and CsPOD in melatoninpretreated seeds. Melatonin also alleviated salinity stress by affecting abscisic acid (ABA) and gibberellin acid (GA) biosynthesis and catabolism during seed germination. Compared to NaCl treatment, melatonin significantly upregulated ABA catabolism genes (e.g., CsCYP707A1 and CsCYP707A2, 3.5 and 105-fold higher than NaCl treatment at 16 hr, respectively) and downregulated ABA biosynthesis genes (e.g., CsNECD2, 0.29-fold of CK2 at 16 hr), resulting in a rapid decrease of ABA content during the early stage of germination. At the same time, melatonin positively up-regulated GA biosynthesis genes (e.g., GA20ox and GA3ox, 2.3 and 3.9-fold higher than NaCl treatment at 0 and 12 hr, respectively), contributing to a significant increase of GA (especially GA4) content. In this study, we provide new evidence suggesting that melatonin alleviates the inhibitory effects of NaCl stress on germination mainly by regulating the biosynthesis and catabolism of ABA and GA4. [ABSTRACT FROM AUTHOR]

A comprehensive investigation was carried out to determine the changes that occurred in water-stressed cucumber (Cucumis sativus L.) in response to melatonin treatment. We examined the potential roles of melatonin during seed germination and root generation and measured its effect on reactive oxygen species (ROS) levels, antioxidant enzyme activities, and photosynthesis. Melatonin alleviated polyethylene glycol induced inhibition of seed germination, with 100 μm melatonin-treated seeds showing the greatest germination rate. Melatonin stimulated root generation and vitality and increased the root:shoot ratio; therefore, melatonin may have an effect on strengthening cucumber roots. Melatonin treatment significantly reduced chlorophyll degradation. Seedlings treated with 100 μm melatonin clearly showed a higher photosynthetic rate, thus reversing the effect of water stress. Furthermore, the ultrastructure of chloroplasts in water-stressed cucumber leaves was maintained after melatonin treatment. The antioxidant levels and activities of the ROS scavenging enzymes, i.e., superoxide dismutase, peroxidase, and catalase, were also increased by melatonin. These results suggest that the adverse effects of water stress can be minimized by the application of melatonin. [ABSTRACT FROM AUTHOR]

Presents a study of the genetic effect of cytoplasm on resistance to Gibberella zeae organism in alloplasmic wheat. Resistance of explant calli; Identification of inoculating single fixed position; Identification of field resistance.

Purpose: This prospective case series aimed to investigate the effect of vertical alveoloplasty on the changes in keratinized mucosa width (KMW) following full-arch immediate implant placement and rehabilitation., Materials and Methods: A total of 17 potential edentulous patients were enrolled and received implant placement and full-arch implant-supported immediate rehabilitations. The main outcome was to analyze the effect of vertical alveoloplasty on the changes in KMW. The amount of vertical alveoloplasty during implant surgery as well as the changes in KMW at buccal aspects from the day of surgery to 6 months post-surgery were recorded on the implant-level using a periodontal probe. The secondary outcome was to analyze the other possible factors that affected the changes in KMW. The included factors were the initial KMW, the distribution of implants in the maxilla and mandible, the distribution of implants in the anterior and posterior regions, the distribution of implants in extraction sockets and healed ridges, and gender. Mann-Whitney non-parametric tests and multiple linear regression adjusted by generalized estimating equations (GEE) were used to statistically analyze the data., Results: A total of 121 implant positions were analyzed. The KMW was 4.1± 2.0 mm on the day of the surgery and 4.1± 1.7 mm 6 months post-surgery. The mean changes in KMW following 6 months were -0.1± 1.6 mm (p = 0.824). From the results of GEE, the vertical amount of alveoloplasty had no significant effect on changes in KMW. Both initial KMW and the distribution of implants in the anterior and posterior regions had significant impacts on the changes in KMW (p < 0.0001)., Conclusion: The amount of vertical alveoloplasty during implant surgery has no significant impact on the KMW. The KMW remained stable from baseline to 6 months after alveoloplasty, implant placement, and immediate rehabilitations in potential edentulous arches. The initial KMW and the distribution of implants in the anterior and posterior regions were the possible factors affecting changes in KMW., (© 2024 by the American College of Prosthodontists.)

Ginger (Zingiber officinale Roscoe) is one of the most widely consumed medicinal herb in the world, and the U.S. imports of ginger have risen in recent years because of its health benefits. Seed rhizome and soilborne diseases are serious concerns of ginger worldwide (Stirling 2004; Moreira et al. 2013), including the recent observations of Fusarium yellows and rhizome rot in the Commonwealth of Virginia. In October 2018 and 2019, ginger plants with yellowing of leaf margins and stunted growth were uprooted from a 9.1 m × 14.6 m high tunnel (HT) and from an outdoor raised bed at Virginia State University's Randolph farm. Disease incidence in the HT and the raised bed was estimated between 5-70%. Small pieces (2-5 mm) of symptomatic rhizomes were disinfected with 0.6% sodium hypochlorite solution and placed on potato dextrose agar (PDA) Petri plates to recover fungal isolates. Hyphal tips from these isolates were transferred to fresh PDA to obtain pure cultures. The fungal colonies were pinkish-white initially, and turned purplish-pink after 5-7 days of incubation at 25 °C. The microconidia were aseptate, oval or elliptical, hyaline, and measured 5 to 12 × 4 to 6 µm in size. Macroconidia were with 3 to 5 septations, curved like a sickle towards the ventral side, hyaline, smooth and thin-walled, and 15 to 40 × 3 to 6 µm in size. Fungal genomic DNA of one isolate (Gf-VA-3) was extracted from a 7-days old culture using PrepMan®Ultra (Thermo Fischer Scientific, Cheshire UK). Four conserved regions of the isolated pathogen, internal transcribed spacer (ITS), translation elongation factor (EF), β-tubulin (Bt), and calmodulin (cal) gene regions were amplified using ITS1 and ITS4 (White et al. 1990), ef1α and ef2α (O'Donnell et al. 1998), Bt2a and Bt2b (Glass and Donaldson 1995), and calA1 and calQ1 (Carbone and Kohn 1999), respectively. PCR products were sequenced, and amplicons deposited in GenBank with accession numbers MT337417 for ITS, MT436712 for Bt, MT802441 for cal and MW816632 for EF. A 99-100% identity with Fusarium oxysporum was matched with accession nos. MW776326 for ITS, MN646766 for the β-tubulin, MT010904 for the calmodulin and MN258350 for the translation elongation factor genes. For pathogenicity test, six 6-week-old healthy ginger plants grown on sterilized potting mix in the greenhouse were inoculated by injecting 3-ml of a 1 × 108 micro- and macro-conidia suspension per ml at the crown area transcending to the rhizome. Another set of six plants were injected with distilled and autoclaved water in the same way. After four weeks, leaves withered, plants exhibited yellowing and wilt followed by stunted growth and eventually complete collapse of the six inoculated plants, however control plants showed none of the symptoms. The same pathogen was re-isolated from the inoculated plants. The pathogenicity test was repeated, and the same results were observed. Fusarium yellows and rhizome rot has been reported from Hawaii in the U.S. (Trujillo 1963), Brazil (Moreira et al. 2013), Australia (Stirling 2004), China (Li et al. 2014), and India (Shanmugam et al. 2013). To our knowledge, this is the first report of Fusarium yellows and rhizome rot on ginger in the Continental U.S. The disease is seed rhizome and soilborne leading to poor establishment and hence economic loss in ginger production.

Switchgrass (Panicum virgatum L.) is a bioenergy crop; thus, it is important to improve biomass to effectively produce bioethanol, particularly under adverse stress conditions. NAC transcription factors are involved in the abiotic stress response. PvNAC1 was isolated in the nucleus of switchgrass, with its C-terminal region containing a transcriptional activation domain. PvNAC1 expression was induced by dehydration, salt, H 2 O 2 , and abscisic acid treatments. Overexpressing (OE) PvNAC1 improved growth performance, leading to significantly taller and heavier (dry weight) plants. Moreover, cellulose content was significantly higher in OE plants, indicating that PvNAC1 plays an important role regulating growth and bioethanol production. PvNAC1 RNA interference (RNAi) switchgrass plants exhibited reduced dry weight and cellulose content. OE PvNAC1 enhanced tolerance to salt stress, through higher reactive oxygen species scavenging ability and less Na + and more K + accumulation in roots and shoots. RNAi plants were more sensitive to salt stress. The quantitative polymerase chain reaction results revealed that some stress responsive genes, three antioxidant enzymatic genes, and an ion homeostasis-related gene were upregulated in OE plants and downregulated in RNAi plants. These results show that PvNAC1 functions as a transcriptional activator in response to salt stress and growth., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A high-efficient, eco-friendly and applicable oxidant of percarbonate (SPC, Na 2 CO 3 ·1.5H 2 O 2 ) is applied as oxidant in ozonation (O 3 ) process. In this work, coumarin (COU) decomposition by O 3 and O 3 /SPC was proposed in terms of diverse parameters, including ozone concentration, SPC dosage and pH, with regard to the pseudo-first-order kinetic model. About 96.5% of 25 mg L -1 COU was removed by 209.3 mg L -1 SPC and 2.08 mg L -1 O 3 within 30 min, whereas 49.8% of COU was exhausted in O 3 system alone. High ozone concentration and pH could enhance COU removal, and overdose SPC has an inhibition effect as CO 3 2- could react with ·OH. Furtherly, the generation of hydroxyl radicals (OH) via a chain reaction in O 3 was ascertained based on indirect alcohols quenching tests and direct electron spin resonance (ESR) spin-trapping tests, though high initial SPC concentration led to no trapping of OH by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) in O 3 /SPC. According to the concentration of dissolved ozone and prior study, a fast reaction kinetic model was estimated firstly for O 3 /SPC system and well fitted with different condition. The hydroxylated intermediates of 7-hydroxylcoumarin and 6,7-hydroxylcoumarin were recognized and the degradation pathways were proposed. The findings of the study can broaden the research direction of SPC and provide a new application information for SPC in environmental pollution control., (Copyright © 2018 Elsevier Ltd. All rights reserved.)