ABSTRACT
BACKGROUND: Plant chemical defense can be elicited by signaling chemicals. As yet, the elicitation is mainly known from volatile aboveground signals. Root-secreted belowground signals and their underlying mechanisms are largely unknown. This study examined a root-secreted signaling (-)-loliolide to trigger chemical defense in rice and wheat against pests by means of cocultivation and incubation experiments. RESULTS: Wild-type Arabidopsis (WT) and its root exudates with (-)-loliolide induced the production of defensive metabolites of rice and wheat and reduced the performance of weeds, pathogens and herbivores, while a carotenoid-deficient mutant (szl1-1) and its root exudates without (-)-loliolide had no similar effects. However, the induction and reduction occurred in the szl1-1 root exudates by (-)-loliolide supplementation with the level equal to that of WT. RNA-sequencing analysis revealed a significant change in the transcript level of defense-related genes in rice exposure to (-)-loliolide. Furthermore, (-)-loliolide enhanced rice resistance against Rhizoctonia solani through changing reactive oxygen species (ROS) system, and mediating jasmonic acid, salicylic acid and abscisic acid biosynthesis. CONCLUSION: Root-secreted signaling (-)-loliolide can trigger chemical defense in rice and wheat against their pests. Such perception-dependent chemical defenses provide an intriguing possibility for ecological pest management to increase crop productivity and sustainability. © 2024 Society of Chemical Industry.
ABSTRACT
The improvement of performance and yield in both cultivar and species mixtures has been well established. Despite the clear benefits of crop mixtures to agriculture, identifying the critical mechanisms behind performance increases are largely lacking. We experimentally demonstrated that the benefits of rice cultivar mixtures were linked to relatedness-mediated intraspecific neighbour recognition and discrimination under both field and controlled conditions. We then tested biochemical mechanisms of responses in incubation experiments involving the addition of root exudates and a root-secreted signal, (-)-loliolide, followed by transcriptome analysis. We found that closely related cultivar mixtures increased grain yields by modifying root behaviour and accelerating flowering over distantly related mixtures. Importantly, these responses were accompanied by altered concentration of signalling (-)-loliolide that affected rice transcriptome profiling, directly regulating root growth and flowering gene expression. These findings suggest that beneficial crop combinations may be generated a-priori by manipulating neighbour genetic relatedness in rice cultivar mixtures and that root-secreted (-)-loliolide functions as a key mediator of genetic relatedness interactions. The ability of relatedness discrimination to regulate rice flowering and yield raises an intriguing possibility to increase crop production.
ABSTRACT
Plant-plant interactions are a central driver for plant coexistence and community assembly. Chemically mediated plant-plant interactions are represented by allelopathy and allelobiosis. Both allelopathy and allelobiosis are achieved through specialized metabolites (allelochemicals or signaling chemicals) produced and released from neighboring plants. Allelopathy exerts mostly negative effects on the establishment and growth of neighboring plants by allelochemicals, while allelobiosis provides plant neighbor detection and identity recognition mediated by signaling chemicals. Therefore, plants can chemically affect the performance of neighboring plants through the allelopathy and allelobiosis that frequently occur in plant-plant intra-specific and inter-specific interactions. Allelopathy and allelobiosis are two probably inseparable processes that occur together in plant-plant chemical interactions. Here, we comprehensively review allelopathy and allelobiosis in plant-plant interactions, including allelopathy and allelochemicals and their application for sustainable agriculture and forestry, allelobiosis and plant identity recognition, chemically mediated root-soil interactions and plant-soil feedback, and biosynthesis and the molecular mechanisms of allelochemicals and signaling chemicals. Altogether, these efforts provide the recent advancements in the wide field of allelopathy and allelobiosis, and new insights into the chemically mediated plant-plant interactions.
ABSTRACT
Two new rare trachylobane euphoratones A-B (1-2), together with five known diterpenoids (compounds 3-7), were isolated from the aerial parts of Euphorbia atoto. Their structures were unambiguously elucidated through HRESIMS, 1D and 2D NMR spectral analysis. Compounds 1, 3, 4 and 7 showed weak anti-inflammatory activities (IC50 77.49 ± 6.34, 41.61 ± 14.49, 16.00 ± 1.71 and 33.41 ± 4.52 µM, respectively), compared to the positive control quercetin (IC50 15.23 ± 0.65 µM).
Subject(s)
Diterpenes , Euphorbia , Molecular Structure , Euphorbia/chemistry , Magnetic Resonance Spectroscopy , Diterpenes/pharmacology , Diterpenes/chemistry , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/chemistryABSTRACT
Introduction: The visual cortex is a key region in the mouse brain, responsible for processing visual information. Comprised of six distinct layers, each with unique neuronal types and connections, the visual cortex exhibits diverse decoding properties across its layers. This study aimed to investigate the relationship between visual stimulus decoding properties and the cortical layers of the visual cortex while considering how this relationship varies across different decoders and brain regions. Methods: This study reached the above conclusions by analyzing two publicly available datasets obtained through two-photon microscopy of visual cortex neuronal responses. Various types of decoders were tested for visual cortex decoding. Results: Our findings indicate that the decoding accuracy of neuronal populations with consistent sizes varies among visual cortical layers for visual stimuli such as drift gratings and natural images. In particular, layer 4 neurons in VISp exhibited significantly higher decoding accuracy for visual stimulus identity compared to other layers. However, in VISm, the decoding accuracy of neuronal populations with the same size in layer 2/3 was higher than that in layer 4, despite the overall accuracy being lower than that in VISp and VISl. Furthermore, SVM surpassed other decoders in terms of accuracy, with the variation in decoding performance across layers being consistent among decoders. Additionally, we found that the difference in decoding accuracy across different imaging depths was not associated with the mean orientation selectivity index (OSI) and the mean direction selectivity index (DSI) neurons, but showed a significant positive correlation with the mean reliability and mean signal-to-noise ratio (SNR) of each layer's neuron population. Discussion: These findings lend new insights into the decoding properties of the visual cortex, highlighting the role of different cortical layers and decoders in determining decoding accuracy. The correlations identified between decoding accuracy and factors such as reliability and SNR pave the way for more nuanced understandings of visual cortex functioning.
ABSTRACT
Despite increasing knowledge of the fitness costs of viability and fecundity involved in the herbicide-resistant weeds, relatively little is known about the linkage between herbicide resistance costs and phytochemical cues in weed species and biotypes. This study demonstrated relative fitness and phytochemical responses in six herbicide-resistant weeds and their susceptible counterparts. There were significant differences in the parameters of viability (growth and photosynthesis), fecundity fitness (flowering and seed biomass) and a ubiquitous phytochemical (-)-loliolide levels between herbicide-resistant weeds and their susceptible counterparts. Fitness costs occurred in herbicide-resistant Digitaria sanguinalis and Leptochloa chinensis but they were not observed in herbicide-resistant Alopecurus japonicas, Eleusine indica, Ammannia arenaria, and Echinochloa crus-galli. Correlation analysis indicated that the morphological characteristics of resistant and susceptible weeds were negatively correlated with (-)-loliolide concentration, but positively correlated with lipid peroxidation malondialdehyde and total phenol contents. Principal component analysis showed that the lower the (-)-loliolide concentration, the stronger the adaptability in E. crus-galli and E. indica. Therefore, not all herbicide-resistant weeds have fitness costs, but the findings showed several examples of resistance leading to improved fitness even in the absence of herbicides. In particular, (-)-loliolide may act as a phytochemical cue to explain the fitness cost of herbicide-resistant weeds by regulating vitality and fecundity.
ABSTRACT
Tri-(2,4,6-trichlorophenyl)methyl (TTM) based radicals can be promising in providing relatively high fluorescence quantum efficiency. In this study, we have evaluated the photoluminescence properties of a series of TTM-based radicals by means of DFT and TD-DFT methods. The optimized structures of the ground states (D0) and the first excited states (D1) of all the radicals are calculated and the computed emission bands are comparable with previous experimental results. knr is determined from transition dipole moments (µ12) and the energy gaps between D0 and D1 (ΔE), both of which can be regulated by the conjugated structures from the substituent groups. knr was derived from the mode-averaging method and is consistent with the experimental results. Factors influencing kr and knr, including the potential energy differences (ΔG0), the vibrational reorganization energies (λ) and the electron coupling term (Hab), are discussed. By comparing kr and knr in solvents with different polarities (cyclohexane, toluene, and chloroform), TTM based radicals in cyclohexane exhibit the most promising fluorescence efficiencies. Besides, two substituted radicals, namely 2Br-TTM-3PCz and 2F-TTM-3PCz, have been fabricated. The results show that fluorine atoms are able to increase ΔG0 and a considerably small knr has been predicted. We expect that our calculation can benefit the design of light-emitting molecules in further experiments.
ABSTRACT
The optical microscope is customarily an instrument of substantial size and expense but limited performance. Here we report an integrated microscope that achieves optical performance beyond a commercial microscope with a 5×, NA 0.1 objective but only at 0.15 cm3 and 0.5 g, whose size is five orders of magnitude smaller than that of a conventional microscope. To achieve this, a progressive optimization pipeline is proposed which systematically optimizes both aspherical lenses and diffractive optical elements with over 30 times memory reduction compared to the end-to-end optimization. By designing a simulation-supervision deep neural network for spatially varying deconvolution during optical design, we accomplish over 10 times improvement in the depth-of-field compared to traditional microscopes with great generalization in a wide variety of samples. To show the unique advantages, the integrated microscope is equipped in a cell phone without any accessories for the application of portable diagnostics. We believe our method provides a new framework for the design of miniaturized high-performance imaging systems by integrating aspherical optics, computational optics, and deep learning.
ABSTRACT
In this study, a novel aerobic mesophilic bacterial strain with capable of degrading chitin, designated YIM B06366T, was isolated and classified. The rod-shaped, Gram-stain-negative, on-spore-forming bacterium originated from rhizosphere soil sample collected in Kunming City, Yunnan Province, southwest PR China. Strain YIM B06366T exhibited growth at temperatures between 20 and 35 °C (optimum, 30 °C) and at pH 6.0-8.0 (optimum, pH 6.0). The analysis of 16S rRNA gene sequence similarity revealed that strain YIM B06366T was most closely related to type strain Chitinolyticbacter meiyuanensis SYBC-H1T (98.9%). Phylogenetic analysis based on genome data indicated that strain YIM B06366T should be assigned to the genus Chitinolyticbacter. The Average Nucleotide Identity (ANI) and digital DNA-DNA Hybridization (dDDH) values between strain YIM B06366T and the reference strain Chitinolyticbacter meiyuanensis SYBC-H1T were 84.4% and 27.7%, respectively. The major fatty acids included Summed Feature 3 (C16:1 ω6c/C16:1 ω7c), Summed Feature 8 (C18:1 ω6c/C18:1 ω7c), and C16:0. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, aminophospholipids, and two unidentified phospholipids. The predominant menaquinone was Q-8, and the genomic DNA G + C content was 64.1%. Considering the polyphasic taxonomic evidence, strain YIM B06366T is proposed as a novel species within the genus Chitinolyticbacter, named Chitinolyticbacter albus sp. nov. (type strain YIM B06366T = KCTC 92434T = CCTCC AB 2022163T).
Subject(s)
Chitin , Rhizosphere , China , Phylogeny , RNA, Ribosomal, 16S/genetics , Wood/chemistry , Phospholipids/chemistry , Fatty Acids/chemistry , DNA , Sequence Analysis, DNA , DNA, Bacterial/genetics , Bacterial Typing TechniquesABSTRACT
Despite increasing evidence of kin recognition in natural and crop plants, there is a lack of knowledge of kin recognition in herbicide-resistant weeds that are escalating in cropping systems. Here, we identified a penoxsulam-resistant barnyardgrass biotype with the ability for kin recognition from two biotypes of penoxsulam-susceptible barnyardgrass and normal barnyardgrass at different levels of relatedness. When grown with closely related penoxsulam-susceptible barnyardgrass, penoxsulam-resistant barnyardgrass reduced root growth and distribution, lowering belowground competition, and advanced flowering and increased seed production, enhancing reproductive effectiveness. However, such kin recognition responses were not occurred in the presence of distantly related normal barnyardgrass. Root segregation, soil activated carbon amendment, and root exudates incubation indicated chemically-mediated kin recognition among barnyardgrass biotypes. Interestingly, penoxsulam-resistant barnyardgrass significantly reduced a putative signaling (-)-loliolide production in the presence of closely related biotype but increased production when growing with distantly related biotype and more distantly related interspecific allelopathic rice cultivar. Importantly, genetically identical penoxsulam-resistant and -susceptible barnyardgrass biotypes synergistically interact to influence the action of allelopathic rice cultivar. Therefore, kin recognition in plants could also occur at the herbicide-resistant barnyardgrass biotype level, and intraspecific kin recognition may facilitate cooperation between genetically related biotypes to compete with interspecific rice, offering many potential implications and applications in paddy systems.
ABSTRACT
A new Gram-negative, rod-shaped, flagellated bacterium was isolated from soil in the Guishan, Xinping County, Yuxi City, Yunnan Province, China, and named YIM B01952T. Growth occurred at 10-40 °C (optimum, 30 °C), pH 6.0-9.0 (optimum, pH 7.5) and with up to ≤ 5.0% (w/v) NaCl on Tryptic Soy Broth Agar (TSA) plates. Phylogenetic analysis based on the 16S rRNA gene and draft-genome sequence showed that strain YIM B01952T belonged to the genus Pseudomonas, and was closely related to the type strain of Pseudomonas alcaligenes (sequence similarity was 98.8%). The digital DNA-DNA hybridization (dDDH) value between strain YIM B01952T and the parallel strain P. alcaligenes ATCC 14909T was 49.0% based on the draft genome sequence. The predominant menaquinone was Q-9. The major fatty acids were summed feature 8 (C18:1 ω6c and/or C18:1 ω7c), summed feature 3 (C16:1 ω6c and/or C16:1 ω7c) and C16:0. The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol. The genome size of strain YIM B01952T was 4.341 Mb, comprising 4156 predicted genes with a DNA G + C content of 66.4 mol%. In addition, we detected that strain YIM B01952T had some traditional functional genes (plant growth promotion and multidrug resistance), unique genes through genome comparison and analysis with similar strains. Based on genetic analyses and biochemical characterization, the strain YIM B01952T was identified as a novel species in the genus Pseudomonas, for which the name Pseudomonas subflava sp. nov. is proposed. The type strain is YIM B01952T (=CCTCC AB 2021498T = KCTC 92073T).
Subject(s)
Fatty Acids , Pseudomonas , China , Phylogeny , RNA, Ribosomal, 16S/genetics , Pseudomonas/genetics , DNA, Bacterial/genetics , DNA, Bacterial/chemistry , Fatty Acids/analysis , Sequence Analysis, DNA , Bacterial Typing Techniques , Phospholipids/analysisABSTRACT
BACKGROUND: The incidence of herbicide-resistant barnyardgrass is escalating in paddy fields, yet the interactions between resistant weeds and rice are largely unknown. The microbiota of herbicide-resistant barnyardgrass rhizosphere soil is critical for both barnyardgrass and rice fitness. RESULTS: Rice has different biomass allocation and root traits in the presence of penoxsulam-resistant versus penoxsulam-susceptible barnyardgrass or in their conditioned soil. Compared to susceptible barnyardgrass, resistant barnyardgrass led to an allelopathic increase in rice root, shoot, and whole-plant biomasses. Resistant barnyardgrass recruited distinct core and unique microbes in rhizosphere soil compared to susceptible barnyardgrass. In particular, resistant barnyardgrass assembled more Proteobacteria and Ascomycota to enhance plant stress tolerance. Furthermore, the root exudates from resistant and susceptible barnyardgrass were responsible for the assembly and establishment of the root microbial structure. Importantly, (-)-loliolide and jasmonic acid in root exudates were correlated with the core microbes in the rhizosphere soil. CONCLUSION: The interference of barnyardgrass with rice can be mediated by rhizosphere microbial communities. Biotype-specific variation in the ability to generate soil microbial communities appears to ameliorate the negative consequences for rice growth, providing an intriguing possibility for modulation of the rhizosphere microbiota to increase crop productivity and sustainability. © 2023 Society of Chemical Industry.
Subject(s)
Echinochloa , Herbicides , Microbiota , Oryza , Rhizosphere , Plant Roots/microbiology , Soil/chemistry , Soil Microbiology , Herbicides/pharmacologyABSTRACT
The production of defensive metabolites in plants can be induced by signaling chemicals released by neighboring plants. Induction is mainly known from volatile aboveground signals, with belowground signals and their underlying mechanisms largely unknown. We demonstrate that (-)-loliolide triggers defensive metabolite responses to competitors, herbivores, and pathogens in seven plant species. We further explore the transcriptional responses of defensive pathways to verify the signaling role of (-)-loliolide in wheat and rice models with well-known defensive metabolites and gene systems. In response to biotic and abiotic stressors, (-)-loliolide is produced and secreted by roots. This, in turn, induces the production of defensive compounds including phenolic acids, flavonoids, terpenoids, alkaloids, benzoxazinoids, and cyanogenic glycosides, regardless of plant species. (-)-Loliolide also triggers the expression of defense-related genes, accompanied by an increase in the concentration of jasmonic acid and hydrogen peroxide (H2 O2 ). Transcriptome profiling and inhibitor incubation indicate that (-)-loliolide-induced defense responses are regulated through pathways mediated by jasmonic acid, H2 O2 , and Ca 2+ . These findings argue that (-)-loliolide functions as a common belowground signal mediating chemical defense in plants. Such perception-dependent plant chemical defenses will yield critical insights into belowground signaling interactions.
Subject(s)
Cyclopentanes , Plants , Plants/metabolism , Cyclopentanes/metabolism , Oxylipins/metabolismABSTRACT
Plant defense, growth, and reproduction can be modulated by chemicals emitted from neighboring plants, mainly via volatile aboveground signals. However, belowground signals and their underlying control mechanisms are largely unknown. Here, we experimentally demonstrate that the root-secreted carotenoid (-)-loliolide mediates both defensive and reproductive responses in wild-type Arabidopsis, a carotenoid-deficient Arabidopsis mutant (szl1-1), and tobacco (Nicotiana benthamiana). Wild-type Arabidopsis plants flower later than szl1-1, and they secrete (-)-loliolide into the soil, whereas szl1-1 roots do not. When Arabidopsis and tobacco occur together, wild-type Arabidopsis induces nicotine production and defense-related gene expression in tobacco, whereas szl1-1 impairs this induction but accelerates tobacco flowering. Furthermore, nicotine production and the expression of the key genes involved in nicotine biosynthesis (QPT, PMT1), plant defense (CAT1, SOD1, PR-2a, PI-II, TPI), and flowering (AP1, LFY, SOC1, FT3, FLC) are differently regulated by incubation with wild-type Arabidopsis and szl1-1 root exudates or (-)-loliolide. In particular, (-)-loliolide up-regulated flowering suppressors (FT3 and FLC) and transiently down-regulated flowering stimulators (AP1 and SOC1), delaying tobacco flowering. Therefore, root-secreted (-)-loliolide modulates plant belowground defense and aboveground flowering, yielding critical insights into plant-plant signaling interactions.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Nicotiana/metabolism , Nicotine , Plants/metabolism , Carotenoids/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Flowers , Gene Expression Regulation, Plant , MADS Domain Proteins/geneticsABSTRACT
Plants actively respond to their neighbors by altering root placement patterns. Neighbor-modulated root responses involve root detection and interactions mediated by root-secreted functional metabolites. However, chemically mediated root placement patterns and their underlying mechanisms remain elusive. We used an allelopathic wheat model system challenged with 60 target species to identify root placement responses in window rhizobox experiments. We then tested root responses and their biochemical mechanisms in incubation experiments involving the addition of activated carbon and functional metabolites with amyloplast staining and auxin localization in roots. Wheat and each target species demonstrated intrusive, avoidant or unresponsive root placement, resulting in a total of nine combined patterns. Root placement patterns were mediated by wheat allelochemicals and (-)-loliolide signaling of neighbor species. In particular, (-)-loliolide triggered wheat allelochemical production that altered root growth and placement, degraded starch grains in the root cap and induced uneven distribution of auxin in target species roots. Root placement patterns in wheat-neighbor interactions were perception dependent and species dependent. Signaling (-)-loliolide induced the production and release of wheat allelochemicals that modulated root placement patterns. Therefore, root placement patterns are generated by both signaling chemicals and allelochemicals in allelopathic plant-plant interactions.
Subject(s)
Plants , Triticum , Plants/metabolism , Triticum/metabolism , Indoleacetic Acids/metabolism , Allelopathy , Pheromones/metabolism , Plant Roots/metabolismABSTRACT
Species interactions and mechanisms affect plant coexistence and community assembly. Despite increasing knowledge of kin recognition and allelopathy in regulating inter-specific and intra-specific interactions among plants, little is known about whether kin recognition mediates allelopathic interference. We used allelopathic rice cultivars with the ability for kin recognition grown in kin versus non-kin mixtures to determine their impacts on paddy weeds in field trials and a series of controlled experiments. We experimentally tested potential mechanisms of the interaction via altered root behaviour, allelochemical production and resource partitioning in the dominant weed competitor, as well as soil microbial communities. We consistently found that the establishment and growth of paddy weeds were more inhibited by kin mixtures compared to non-kin mixtures. The effect was driven by kin recognition that induced changes in root placement, altered weed carbon and nitrogen partitioning, but was associated with similar soil microbial communities. Importantly, genetic relatedness enhanced the production of intrusive roots towards weeds and reduced the production of rice allelochemicals. These findings suggest that relatedness allows allelopathic plants to discriminate their neighbouring collaborators (kin) or competitors and adjust their growth, competitiveness and chemical defense accordingly.
Subject(s)
Allelopathy , Oryza/physiology , Pheromones/metabolism , Plant Weeds/physiologyABSTRACT
Plant-to-plant signalling is a key mediator of interactions among plant species. Plants can perceive and respond to chemical cues emitted from their neighbours, altering survival and performance, impacting plant coexistence and community assembly. An increasing number of studies indicate root exudates as key players in plant-to-plant signalling. Root exudates mediate root detection and behaviour, kin recognition, flowering and production, driving inter- and intra-specific facilitation in cropping systems and mixed-species plantations. Altered interactions may be attributed to the signalling components within root exudates. Root ethylene, strigolactones, jasmonic acid, (-)-loliolide and allantoin are signalling chemicals that convey information on local conditions in plant-plant interactions. These root-secreted signalling chemicals appear ubiquitous in plants and trigger a series of belowground responses inter- and intra-specifically, involving molecular events in biosynthesis, secretion and action. The secretion of root signals, mainly mediated by ATP-binding cassette transporters, is critical. Root-secreted signalling chemicals and their molecular mechanisms are rapidly revealing a multitude of fascinating plant-plant interactions. However, many root signals, particularly species-specific signals and their underlying mechanisms, remain to be uncovered due to methodological limitations and root-soil interactions. A thorough understanding of root-secreted chemical signals and their mechanisms will offer many ecological implications and potential applications for sustainable agriculture.
Subject(s)
Plant Roots/physiology , Plants/metabolism , Communication , Ecology , Plant Physiological Phenomena , Plant Roots/metabolismABSTRACT
The controversy of adjuvant radiotherapy of meningiomas is at least partially due to the insufficient understanding on meningioma cells' response to irradiation and the shortage of radiosensitivity-promotion methods. MicroRNA-221 and microRNA-222 were identified as critical regulators of radiosensitivity in several other tumors. However, their effect in meningiomas has yet to be confirmed. Therefore, the malignant meningioma IOMM-Lee cells were adopted, transfected with microRNA-221/222 mimics or inhibitors, and irradiated with different dosages. The effects of radiation and microRNA-221/222 were then assessed in vitro and in vivo. Radiation dose increases and microRNA-221/222 downregulation synergistically inhibited cell proliferation and colony formation, prevented xenograft tumor progression, and promoted apoptosis, but antagonistically regulated cell invasiveness. Pairwise comparisons revealed that only high-dose radiations (6 and 8 Gy) can significantly promote cell invasiveness in comparison with unirradiated counterparts. Further comparisons exhibited that downregulating the microRNA-221/222 expression can reverse this radiation-induced cell invasiveness to a level of untransfected and unirradiated cells only if cells were irradiated with no more than 6 Gy. In addition, this approach can promote IOMM-Lee's radiosensitivity. Meanwhile, we also detected that the dose rate of irradiation affects cell cycle distribution and cell apoptosis of IOMM-Lee. A high dose rate irradiation induces G0/G1 cell cycle arrest and apoptosis-promoting effect. Therefore, for malignant meningiomas, high-dose irradiation can facilitate cell invasiveness significantly. Downregulating the microRNA-221/222 level can reverse the radiation-induced cell invasiveness while enhancing the apoptosis-promoting and proliferation-inhibiting effects of radiation and promoting cell radiosensitivity.
ABSTRACT
Plant-plant interactions is a fundamental issue in ecology. Plants are able to detect and perceive inter-specific and intra-specific neighbors and then adjust their growth, reproduction and defense strategies. Such inter-specific and intra-specific recognition and perception are mostly media-ted by secondary metabolites. Those chemical communications can initiate and activate the corresponding mechanism in allelopathy. In recent years, several novel plant-plant chemical interactions have been observed, such as kin recognition, and flowering and reproduction mediated by root communication. Till now, the inter-specific and intra-specific chemical interactions among plants mediated by volatiles have been substantially clarified. However, the mechanisms and soil-borne signaling chemicals involved in plant-plant chemical interactions mediated by root exudates remain poorly understood. Belowground chemical interactions not only determine the behavior of root invasion (approaching) and avoidance (repelling), but also regulate the flowering time and florescence. Accordingly, the chemical interactions involve the coordination between belowground and aboveground parts. On the basis of allelopathy and chemical recognition as well as corresponding allelochemicals and signaling chemicals, this review outlined recent research advances regarding plant-plant chemical interactions from kin recognition, root communication and behavior patterns, belowground chemical interactions to regulate flowering and reproduction. The efforts represented a mechanistically exhaustive view of plant-plant interactions.
Subject(s)
Plant Roots , Plants , Allelopathy , Ecology , PheromonesABSTRACT
A structurally stable stacked multilayer carbonitride is predicted with the aid of ab initio calculations. This carbonitride consists of C3N tetrahedra, and is similar to T-carbon and thus named T-C3N. Its 2-dimensional (2D) monolayer is also carefully investigated in this work. The studies on electronic properties reveal that bulk and 2D T-C3N are insulators with a 5.542 eV indirect band gap and a 5.741 eV direct band gap, respectively. However, the monolayer T-C3N exhibits an excellent uniform porosity. Its 5.50 Å pore size is perfect for water nanofiltration. The adsorption and permeation of water molecules on the monolayer T-C3N are investigated. Its promising potential application in highly efficient nanofiltration membranes for seawater desalination is discussed.