Chitosan is a natural elicitor, used for stimulating plant growth and inducing plant defense. However, due to difficulty in monitoring root growth and activity, the effects of chitosan treatment on plant root systems have been less studied as compared to plant shoot parts that include leaves, seeds, and fruits. This results in an indefinite outcome of the benefits of chitosan on plant roots. Therefore, this review aims to evaluate the effects of chitosan treatment on root growth and defense responses based on current evidence. Interestingly, many studies have demonstrated that chitosan can induce plant root defense systems, yet conversely inhibiting root growth. The effects were most clearly observed from studies using liquid or solid media as substrates, while the results from the studies using soil were inconclusive and require additional investigation to observe the effects of environmental factors. In addition, root chitosan treatment showed variable effects on shoot growth, where low chitosan concentrations tend to promote shoot growth, but high chitosan concentrations may affect shoot development. Additionally, this review discusses the potential methods of chitosan application onto plant roots. Water insolubility of chitosan is likely a major issue for root treatment. Chitosan can be dissolved in acids, but this could induce acidity stress in plant roots. Modified versions of chitosan, such as chitosan nanoparticles, carboxylated chitosan, and graft chitosan copolymers have been developed to improve solubility and functionality. Chitosan nanoparticles can also be used to encapsulate other biocontrol agents to augment biological effects on plant defense. In conclusion, root chitosan treatment could help to promote plant defense and prevent root infections, abating the uses of chemical fungicides in agriculture. However, further research is required to monitor the impact of root chitosan treatment on long-term plant growth in order to gain multifaceted information to maximize the effectiveness of root chitosan application.

Drought stress requires plants to adjust their water balance to maintain tissue water levels. Isohydric plants (‘water-savers’) typically achieve this through stomatal closure, while anisohydric plants (‘water-wasters’) use osmotic adjustment and maintain stomatal conductance. Isohydry or anisohydry allows plant species to adapt to different environments. In this paper we show that both mechanisms occur in bread wheat (Triticum aestivum L.). Wheat lines with reproductive drought-tolerance delay stomatal closure and are temporarily anisohydric, before closing stomata and become isohydric at higher threshold levels of drought stress. Drought-sensitive wheat is isohydric from the start of the drought treatment. The capacity of the drought-tolerant line to maintain stomatal conductance correlates with repression of ABA synthesis in spikes and flag leaves. Gene expression profiling revealed major differences in the drought response in spikes and flag leaves of both wheat lines. While the isohydric drought-sensitive line enters a passive growth mode (arrest of photosynthesis, protein translation), the tolerant line mounts a stronger stress defence response (ROS protection, LEA proteins, cuticle synthesis). The drought response of the tolerant line is characterised by a strong response in the spike, displaying enrichment of genes involved in auxin, cytokinin and ethylene metabolism/signalling. While isohydry may offer advantages for longer term drought stress, anisohydry may be more beneficial when drought stress occurs during the critical stages of wheat spike development, ultimately improving grain yield.

Fungal pathogens pose a major threat to Cannabis sativa production, requiring safe and effective management procedures to control disease. Chitin and chitosan are natural molecules that elicit plant defense responses. Investigation of their effects on C. sativa will advance understanding of plant responses towards elicitors and provide a potential pathway to enhance plant resistance against diseases. Plants were grown in the in vitro Root‐TRAPR system and treated with colloidal chitin and chitosan. Plant morphology was monitored, then plant tissues and exudates were collected for enzymatic activity assays, phytohormone quantification, qPCR analysis and proteomics profiling. Chitosan treatments showed increased total chitinase activity and expression of pathogenesis‐related (PR) genes by 3–5 times in the root tissues. In the exudates, total peroxidase and chitinase activities and levels of defense proteins such as PR protein 1 and endochitinase 2 were increased. Shoot development was unaffected, but root development was inhibited after chitosan exposure. In contrast, chitin treatments had no significant impact on any defense parameters, including enzymatic activities, hormone quantities, gene expression levels and root secreted proteins. These results indicate that colloidal chitosan, significantly enhancing defense responses in C. sativa root system, could be used as a potential elicitor, particularly in hydroponic scenarios to manage crop diseases.

This study aimed to investigate the resin compounds from CAD-CAM 3D-printed denture resins, focusing on the identification and classification of free monomers and other components. The primary objective was to determine the chemical profile of these 3D-prinding resin materials. Four 3D-printed denture resins, two base materials (1: DentaBASE, Asiga Ltd., Alexandria, NSW, Australia; 2: DENTURETEC, SAREMCO Dental AG), and two tooth-colored materials (1: DentaTOOTH, Asiga Ltd.; 2: CROWNTEC (SAREMCO Dental AG), were analyzed using high-performance liquid chromatography and mass spectrometry (HPLC-MS). Data analysis was processed including peak alignment and normalization to an ethanol blank, resulting in detailed identification of compounds in the resin. Out of 5,208 detected compounds in the resin, 63 were retained after applying filtering criteria for further analysis, categorized into methyl methacrylate (MMA) and derivatives (31), photo initiators (8), UV stabilizers (1), and other additives (23). Sample 2B exhibited the highest number of resin compounds (62), including the most MMA derivatives and additives. MMA accounted for over 69% in abundance across samples, with unique additives such as ethyl-4-dimethylaminobenzoate and bis(acryloyloxymethyl) tricyclo[5.2.1.02,6] decane (TCD-DI-HEA) identified. Variations in the resin composition distribution and abundance highlighted differences in resin formulations. Within the limits of this in vitro, exploratory study, unpolymerized 3D-printed denture resins were analyzed, and various resin compounds in 3D-printed denture resins, including MMA, photo initiators, UV stabilizers, and additives, were identified along with significant variability between samples. While 3D-printing enhances efficiency and customization, further investigation is needed to better understand and assess the long-term intraoral effects and their effectiveness in complete dentures. This study provides insights into the chemical composition of 3D-printed denture resins, highlighting variability in resin compound profiles. Understanding these materials is essential for ensuring biocompatibility and performance. The findings support the need for further research and standardized testing to guide clinicians in the safe and effective use of 3D-printed dentures.

Southern blight disease, caused by the fungal pathogen Athelia rolfsii, suppresses plant growth and reduces product yield in Cannabis sativa agriculture. Mechanisms of pathology of this soil‐borne disease remain poorly understood, with disease management strategies reliant upon broad‐spectrum antifungal use. Exposure to chitosan, a natural elicitor, has been proposed as an alternative method to control diverse fungal diseases in an eco‐friendly manner. In this study, C. sativa plants were grown in the Root‐TRAPR system, a transparent hydroponic growth device, where plant roots were primed with .2% colloidal chitosan prior to A. rolfsii inoculation. Both chitosan‐primed and unprimed inoculated plants displayed classical symptoms of wilting and yellowish leaves, indicating successful infection. Non‐primed infected plants showed increased shoot defense responses with doubling of peroxidase and chitinase activities. The levels of growth and defense hormones including auxin, cytokinin, and jasmonic acid were increased 2–5‐fold. In chitosan‐primed infected plants, shoot peroxidase activity and phytohormone levels were decreased 1.5–4‐fold relative to the unprimed infected plants. When compared with shoots, roots were less impacted by A. rolfsii infection, but the pathogen secreted cell wall‐degrading enzymes into the root‐growth solution. Chitosan priming inhibited root growth, with root lengths of chitosan‐primed plants approximately 65% shorter than the control, but activated root defense responses, with root peroxidase activity increased 2.7‐fold along with increased secretion of defense proteins. The results suggest that chitosan could be an alternative platform to manage southern blight disease in C. sativa cultivation; however, further optimization is required to maximize effectiveness of chitosan.

Metabolome profiling is becoming more commonly used in the study of complex microbial communities and microbiomes; however, to date, little information is available concerning appropriate extraction procedures. We studied the influence of different extraction solvent mixtures on untargeted metabolomics analysis of two continuous culture enrichment communities performing enhanced biological phosphate removal (EBPR), with each enrichment targeting distinct populations of polyphosphate-accumulating organisms (PAOs). We employed one non-polar solvent and up to four polar solvents for extracting metabolites from biomass. In one of the reactor microbial communities, we surveyed both intracellular and extracellular metabolites using the same set of solvents. All samples were analysed using ultra-performance liquid chromatography mass spectrometry (UPLC-MS). UPLC-MS data obtained from polar and non-polar solvents were analysed separately and evaluated using extent of repeatability, overall extraction capacity and the extent of differential abundance between physiological states. Despite both reactors demonstrating the same bioprocess phenotype, the most appropriate extraction method was biomass specific, with methanol: water (50:50 v/v) and methanol: chloroform: water (40:40:20 v/v/v) being chosen as the most appropriate for each of the two different bioreactors, respectively. Our approach provides new data on the influence of solvent choice on the untargeted surveys of the metabolome of PAO enriched EBPR communities and suggests that metabolome extraction methods need to be carefully tailored to the specific complex microbial community under study.