Unveiling the impact of microplastics and nanoplastics on vascular plants: A cellular metabolomic and transcriptomic review.

With increasing plastic manufacture and consumption, microplastics/nanoplastics (MP/NP) pollution has become one of the world's pressing global environmental issues, which poses significant threats to ecosystems and human health. In recent years, sharp increasing researches have confirmed that MP/NP had direct or indirect effects on vegetative growth and sexual process of vascular plant. But the potential mechanisms remain ambiguous. MP/NP particles can be adsorbed and/or absorbed by plant roots or leaves and thus cause diverse effects on plant. This holistic review aims to discuss the direct effects of MP/NP on vascular plant, with special emphasis on the changes of metabolic and molecular levels. MP/NP can alter substance and energy metabolism, as well as shifts in gene expression patterns. Key aspects affected by MP/NP stress include carbon and nitrogen metabolism, amino acids biosynthesis and plant hormone signal transduction, expression of stress related genes, carbon and nitrogen metabolism related genes, as well as those involved in pathogen defense. Additionally, the review provides updated insights into the growth and physiological responses of plants exposed to MP/NP, encompassing phenomena such as seed/spore germination, photosynthesis, oxidative stress, cytotoxicity, and genotoxicity. By examining the direct impact of MP/NP from both physiological and molecular perspectives, this review sets the stage for future investigations into the complex interactions between plants and plastic pollutants.

Use of folic acid supplementation to halt and even reverse the progression of gastric precancerous conditions: a meta-analysis.

BACKGROUND: Current data indicate that supplements such as folic acid and vitamin B may be beneficial in halting and even reversing atrophic gastritis, intestinal metaplasia and intraepithelial neoplasia, generally referred to as gastric precancerous conditions(GPC). However, there is no Meta-analysis article to evaluate the prevention and treatment of folic acid in the gastric precancerous conditions. We therefore conducted a meta-analysis to confirm the efficacy of folic acid in treating GPC. METHODS: Using a systematic review method, consider randomized controlled trials (RCT), including clinical trial reports, unpublished clinical trial data, and conference papers. The search time was been set from the database's establishment to June 2, 2021. The language was not limited, using PubMed, SinoMed, Lancet, Web of Science, CNKI, Cochrane, Ovid, Science Direct, Embase, and EBSCO databases. Data were extracted using a pre-designed extraction tool and analysis was undertaken using RevMan5.2.Besides,we use Origin software to construct the Time-dose interval analysis. RESULTS: Of the 225 records identified, 13 studies involving 1252 patients (including 11 clinical controlled trials, 1 conference paper report and 1 unpublished research report) met the inclusion conditions. Folic acid dose maintained at 20-30 mg / d for 3-6 months may be beneficial to pathological changes of GPC. Moreover, in the 3 month treatment of 5 trials, the effect was more obvious when the folic acid dose was maintained at 30 mg / d. In the 7 trials, the symptom ineffective rate of GPC treated with folic acid was 32% (RR:0.32, 95% confidence interval CI:0.21-0.48), which was combined using a fixed analysis model; The effect of folic acid on gastric mucosal atrophy in 5 trials (RR: 1.61, 95%CI 1.07-2.41). The changes of folic acid on intestinal metaplasia in the 2 experiments (RR: 1.77, 95% CI: 1.32-2.37).The 2 results are combined using a fixed analytical model. However, the subgroup analysis of 9 trials revealed no significant effectiveness of symptom. CONCLUSIONS: Our research showed that folic acid supplementation brings benefits in preventing and even reversing the progression of GPC in the stomach, and provided evidence for its potential clinical use in management of GPC. REGISTRATION: The logn number of our Meta-anlysis on PROSPERO is CRD420223062.

Modification of plant Rac/Rop GTPase signalling using bacterial toxin transgenes.

Bacterial protein toxins which modify Rho GTPase are useful for the analysis of Rho signalling in animal cells, but these toxins cannot be taken up by plant cells. We demonstrate in vitro deamidation of Arabidopsis Rop4 by Escherichia coli Cytotoxic Necrotizing Factor 1 (CNF1) and glucosylation by Clostridium difficile toxin B. Expression of the catalytic domain of CNF1 caused modification and activation of co-expressed Arabidopsis Rop4 GTPase in tobacco leaves, resulting in hypersensitive-like cell death. By contrast, the catalytic domain of toxin B modified and inactivated co-expressed constitutively active Rop4, blocking the hypersensitive response caused by over-expression of active Rops. In transgenic Arabidopsis, both CNF1 and toxin B inhibited Rop-dependent polar morphogenesis of leaf epidermal cells. Toxin B expression also inhibited Rop-dependent morphogenesis of root hairs and trichome branching, and resulted in root meristem enlargement and dwarf growth. Our results show that CNF1 and toxin B transgenes are effective tools in Rop GTPase signalling studies.

Data-Driven Modeling of Intracellular Auxin Fluxes Indicates a Dominant Role of the ER in Controlling Nuclear Auxin Uptake.

In plants, the phytohormone auxin acts as a master regulator of developmental processes and environmental responses. The best characterized process in the auxin regulatory network occurs at the subcellular scale, wherein auxin mediates signal transduction into transcriptional programs by triggering the degradation of Aux/IAA transcriptional repressor proteins in the nucleus. However, whether and how auxin movement between the nucleus and the surrounding compartments is regulated remain elusive. Using a fluorescent auxin analog, we show that its diffusion into the nucleus is restricted. By combining mathematical modeling with time course assays on auxin-mediated nuclear signaling and quantitative phenotyping in single plant cell systems, we show that ER-to-nucleus auxin flux represents a major subcellular pathway to directly control nuclear auxin levels. Our findings propose that the homeostatically regulated auxin pool in the ER and ER-to-nucleus auxin fluxes underpin auxin-mediated downstream responses in plant cells.

A quantitative ratiometric sensor for time-resolved analysis of auxin dynamics.

Time-resolved quantitative analysis of auxin-mediated processes in plant cells is as of yet limited. By applying a synergistic mammalian and plant synthetic biology approach, we have developed a novel ratiometric luminescent biosensor with wide applicability in the study of auxin metabolism, transport, and signalling. The sensitivity and kinetic properties of our genetically encoded biosensor open new perspectives for the analysis of highly complex auxin dynamics in plant growth and development.

Mutation of the rice Narrow leaf1 gene, which encodes a novel protein, affects vein patterning and polar auxin transport.

The size and shape of the plant leaf is an important agronomic trait. To understand the molecular mechanism governing plant leaf shape, we characterized a classic rice (Oryza sativa) dwarf mutant named narrow leaf1 (nal1), which exhibits a characteristic phenotype of narrow leaves. In accordance with reduced leaf blade width, leaves of nal1 contain a decreased number of longitudinal veins. Anatomical investigations revealed that the culms of nal1 also show a defective vascular system, in which the number and distribution pattern of vascular bundles are altered. Map-based cloning and genetic complementation analyses demonstrated that Nal1 encodes a plant-specific protein with unknown biochemical function. We provide evidence showing that Nal1 is richly expressed in vascular tissues and that mutation of this gene leads to significantly reduced polar auxin transport capacity. These results indicate that Nal1 affects polar auxin transport as well as the vascular patterns of rice plants and plays an important role in the control of lateral leaf growth.

A comparative study of genetic relationships among the AA-genome Oryza species using RAPD and SSR markers.

In order to estimate genetic relationships of the AA-genome Oryza species, RAPD and SSR analyses were performed with 45 accessions, including 13 cultivated varieties (eight Oryza sativa and five Oryza glaberrima) and 32 wild accessions (nine Oryza rufipogon, seven Oryza nivara, three Oryza glumaepatula, four Oryza longistaminata, six Oryza barthii, and three Oryza meridionalis). A total of 181 clear and repeatable bands were amplified from 27 selected RAPD primers, and 101 alleles were detected from 29 SSR primer pairs. The dendrogram constructed using UPGMA from a genetic-similarity matrix based on the RAPD data supported the clustering of distinct five groups with a few exceptions: O. rufipogon/ O. nivara/ O. meridionalis, O. barthii/ O. glaberrima, O. glumaepatula, O. sativa and O. longistaminata. The dendrogram based on the SSR analysis showed a more-complicated genetic variation pattern, but the O. longistaminata and O. barthii/ O. glaberrima accessions were consistently separated from all other accessions, indicating significant differentiation of the African AA-genome Oryza species. For accessions in the O. rufipogon/ O. nivara/ O. sativa complex, it is apparent that geographical isolation has played an important role in differentiation of the Asian AA-genome Oryza taxa. It is also demonstrated from this study that both RAPD and SSR analyses are powerful methods for detecting polymorphisms among the different AA-genome Oryza accessions. However, the RAPD analysis provides a more-informative result in terms of the overall genetic relationships at the species level compared to the SSR analysis. The SSR analysis effectively reveals diminutive variation among accessions or individuals within the same species, given approximately the same number of primers or primer-pairs used in the studies.