Uncovering the effective substances and mechanism of Ipomoea pes-caprae against rheumatoid arthritis using liquid chromatography-mass spectrometry and targeted network pharmacology.

Ipomoea pes-caprae (L.) R. Br (Convolvulaceae) is a commonly used marine traditional Chinese medicine in the southern coastal areas of China. It has been widely used to treat rheumatoid arthritis, but its effective substances and anti-rheumatoid arthritis mechanism remain ambiguous. Hence, in this study, the chemical profile and absorbed ingredients of Ipomoea pes-caprae were elucidated by ultra-performance liquid chromatography-mass spectrometry. Moreover, targeted network pharmacology was used to clarify the mechanism of action of Ipomoea pes-caprae in treating rheumatoid arthritis. Finally, 23 compounds were identified in the aqueous extracts of Ipomoea pes-caprae and 12 absorbed ingredients were detected in rats' plasma. These 12 absorbed ingredients might be the essential effective substances of Ipomoea pes-caprae. The tissue distributions of 3 absorbed ingredients in rats were successfully analyzed. The targeted network pharmacological analysis results indicated that the regulation of inflammatory reaction, immune response, cell proliferation, and apoptosis were the critical mechanism of Ipomoea pes-caprae against rheumatoid arthritis. This study successfully clarified the effective substances and potential mechanisms of Ipomoea pes-caprae in treating rheumatoid arthritis. The results of this research could provide a valuable reference for further scientific research and clinical application.

Thermal adaptation of photosynthetic physiology of the invasive vine Ipomoea cairica (L.) enhances its advantage over native Paederia scandens (Lour.) Merr. in South China.

Ipomoea cairica (L.) Sweet is an invasive vine in South China with strong ecological adaptability in tropical and subtropical ecosystems. However, its invasion mechanism under global warming still remains unknown. In the present study, the thermal adaptability of I. cairica was investigated from the perspective of photosynthetic physiology to explain its successful invasiveness in South China, compared to a niche-overlapping native vine Paederia scandens (Lour.) Merr. Results of field photosynthesis measurements indicated a higher photosynthesis of I. cairica than P. scandens, which was also more temperature-sensitive. Under heat treatment (40 °C), the thermal-avoidance strategy of P. scandens and the thermal-adaptation strategy of the I. cairica enhanced the photosynthetic growth advantage of I. cairica over P. scandens. In I. cairica, the increase of soluble sugar and antioxidant enzyme activity along with the decrease of Malondialdehyde and oxide accumulation demonstrated that I. cairica has superior thermal-adaptation, contrary to P. scandens. Expression of IcOr and IcSRO1 in I. cairica was induced at 40 °C, maintaining the stability of photosynthetic system II and enhancing antioxidant ability. Out study suggested that a higher frequency of heat disturbance under global warming will enhance the invasion capability I. cairica but inhibit the native vine P. scandens. HIGHLIGHT: This paper reveals that contrary thermal-adaptation strategies expanded the photosynthetic, growing, and physiological advantages of invasive I. cairica over native P. scandens under high temperature.

Doubly guaranteed mechanism for pollination and fertilization in Ipomoea purpurea.

Flowers, the reproductive organs of angiosperms, show a high degree of diversity in morphological structure and flowering habit to ensure pollination and fertilization of the plants. Effect of flower movement on pollination and fertilization was investigated in Ipomoea purpurea (Convolvulaceae) in this study. Fluorescence microscopy was used to observe the germination of pollen grains at different temperatures. From 04:00 to 06:00 h, the stigma was taller than the filaments, so that self-pollination could not occur, and cross-pollination was carried out by insects. Pollen grains germinated rapidly after falling on the stigma; the pollen tube reached the ovule to complete fertilization after 2-3 h. From 07:00 to 09:00 h, filaments of two stamens grew rapidly and reached the same height as the stigma, thus allowing self-crossing. But at this time, the ambient temperature was already high and was not conducive to the germination of pollen grains. The corolla closed, forming an inverted bell shape, where the inner microenvironment ensured completion of pollen germination and fertilization. Preferential cross-pollination and delayed self-crossing of I. purpurea provided a doubly guaranteed mechanism for pollination and fertilization, facilitating its adaptation to a high temperature climate.

Interactive effects of arsenic and antimony on Ipomoea aquatica growth and bioaccumulation in co-contaminated soil.

Antimony (Sb) is an emerging contaminant and until recently it was assumed to behave in a similar way to arsenic (As). Arsenic and Sb often co-occur in contaminated sites, yet most investigations consider their toxicity to plants singly. More research is needed to understand the interactions between As and Sb in soils and plants. This study investigated the interactive effect of As and Sb in terms of soil bioavailability, plant toxicity and bioaccumulation on the commercially important agricultural plant, water spinach (Ipomoea aquatica) using a pot experiment. Plants were exposed to As and Sb individually (As (individual), Sb (individual)) and as a mixture (As + Sb (combined)) at different concentrations. Plant growth was measured using shoot and root dry mass, length and chlorophyll a content of leaves. At the end of the bioassay, bioavailable metalloids were extracted from the soil as per a sequential extraction procedure (SEP) and plant tissue was analysed for metalloid content. For As, there were no differences observed between the bioavailability of As in the As + Sb (combined) and As (individual) treatments. For Sb, no increase in bioavailability was observed with co-contamination compared to single-Sb exposures for most concentrations except at 1250 mg/kg. Single-Sb was not toxic to I. aquatica shoot dry mass and length, but there was greater shoot Sb accumulation in the As + Sb (combined) than the Sb (individual) treatment. In contrast, single-As was toxic to I. aquatica growth. When As and Sb were present together in the soil, there was a synergistic toxicity to shoot dry mass (EC50 Toxic Unit (TU) was less than 1) and additive toxicity (EC50 equal to 1 TU) to shoot length. This work shows that the co-occurrence of As and Sb in soil increases Sb bioavailability and can cause synergistic toxicity to an important agricultural crop.

Geography is essential for reproductive isolation between florally diversified morning glory species from Amazon canga savannahs.

The variety, relative importance and eco-evolutionary stability of reproductive barriers are critical to understanding the processes of speciation and species persistence. Here we evaluated the strength of the biotic prezygotic and postzygotic isolation barriers between closely related morning glory species from Amazon canga savannahs. The flower geometry and flower visitor assemblage analyses supported pollination by the bees in lavender-flowered Ipomoea marabaensis and recruitment of hummingbirds as pollinators in red-flowered Ipomoea cavalcantei. Nevertheless, native bee species and alien honeybees foraged on flowers of both species. Real-time interspecific hybridization underscored functionality of the overlap in flower visitor assemblages, questioning the strength of prezygotic isolation underpinned by diversification in flower colour and geometry. Interspecific hybrids were fertile and produced offspring in nature. No significant asymmetry in interspecific hybridization and hybrid incompatibilities among offspring were found, indicating weak postmating and postzygotic isolation. The results suggested that despite floral diversification, the insular-type geographic isolation remains a major barrier to gene flow. Findings set a framework for the future analysis of contemporary evolution of plant-pollinator networks at the population, community, and ecosystem levels in tropical ecosystems that are known to be distinct from the more familiar temperate climate models.

Root-zone-specific sensitivity of K+-and Ca2+-permeable channels to H2O2 determines ion homeostasis in salinized diploid and hexaploid Ipomoea trifida.

Polyploids generally possess superior K+/Na+ homeostasis under saline conditions compared with their diploid progenitors. In this study, we identified the physiological mechanisms involved in the ploidy-related mediation of K+/Na+ homeostasis in the roots of diploid (2x) and hexaploid (6x; autohexaploid) Ipomoea trifida, which is the closest relative of cultivated sweet potato. Results showed that 6x I. trifida retained more K+ and accumulated less Na+ in the root and leaf tissues under salt stress than 2x I. trifida. Compared with its 2x ancestor, 6x I. trifida efficiently prevents K+ efflux from the meristem root zone under salt stress through its plasma membrane (PM) K+-permeable channels, which have low sensitivity to H2O2. Moreover, 6x I. trifida efficiently excludes Na+ from the elongation and mature root zones under salt stress because of the high sensitivity of PM Ca2+-permeable channels to H2O2. Our results suggest the root-zone-specific sensitivity to H2O2 of PM K+- and Ca2+-permeable channels in the co-ordinated control of K+/Na+ homeostasis in salinized 2x and 6x I. trifida. This work provides new insights into the improved maintenance of K+/Na+ homeostasis of polyploids under salt stress.

Coconut shell derived biochar to enhance water spinach (Ipomoea aquatica Forsk) growth and decrease nitrogen loss under tropical conditions.

Farms usually apply excessive nitrogen (N) fertilizers, especially in a vegetable production system, resulting in severe N leaching loss. Although there have been some reports on the impact of biochar on the N leaching in farmlands, most of them focused on field crops in temperate or subtropical religions. Limited information about N leaching in the tropical vegetable system is available regarding the quantitative data and effective countermeasures. A field experiment was conducted to quantify N leaching in a tropical leafy production system (Ipomoea aquatica Forsk) and to evaluate the effects of coconut shell biochar on N loss and crop growth. The results showed that compared to conventional fertilization with the 240 kg N ha-1 application rate (NPK), biomass yield of water spinach increased by 40.1% under the high biochar application rate of 48 t ha-1 (HBC), which was significantly higher than that of NPK treatment. Moreover, The HBC treatment decreased N leaching by 34.0%, which can be attributed to enhanced crop uptake which increased by 40.3% as compared to NPK treatment. The NH4+/NO3- ratio in leachates was between 0.01 and 0.05. It was concluded that coconut shell derived biochar improved the biomass yields of water spinach and reduced the leaching N loss, which provides a promising amendment in tropical regions.

Functional Identification of Salt-Stress-Related Genes Using the FOX Hunting System from Ipomoea pes-caprae.

Ipomoea pes-caprae is a seashore halophytic plant and is therefore a good model for studying the molecular mechanisms underlying salt and stress tolerance in plant research. Here, we performed Full-length cDNA Over-eXpressor (FOX) gene hunting with a functional screening of a cDNA library using a salt-sensitive yeast mutant strain to isolate the salt-stress-related genes of I. pes-caprae (IpSR genes). The library was screened for genes that complemented the salt defect of yeast mutant AXT3 and could grow in the presence of 75 mM NaCl. We obtained 38 candidate salt-stress-related full-length cDNA clones from the I. pes-caprae cDNA library. The genes are predicted to encode proteins involved in water deficit, reactive oxygen species (ROS) scavenging, cellular vesicle trafficking, metabolic enzymes, and signal transduction factors. When combined with the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses, several potential functional salt-tolerance-related genes were emphasized. This approach provides a rapid assay system for the large-scale screening of I. pes-caprae genes involved in the salt stress response and supports the identification of genes responsible for the molecular mechanisms of salt tolerance.

Facilitation of amphibious habit by physiological integration in the clonal, perennial, climbing herb Ipomoea aquatica.

Physiological integration of connected ramets of clonal plants can increase clonal performance when ramets grow in contrasting microenvironments within a habitat. In amphibious clonal species, integration of ramets in different habitats, terrestrial and aquatic, is possible. This may increase performance of amphibious clones, especially under eutrophic conditions. To test this, clonal fragments consisting of two ramets of the amphibious, perennial, climbing herb Ipomoea aquatica connected by a stem were placed such that the proximal ramet was rooted in a simulated riparian community of four other species, while the distal ramet extended into a simulated aquatic habitat with open water and sediment. The connection between ramets was either left intact or severed, and 0, 5, or 25mg N L-1 was added to the aquatic habitat to simulate different degrees of eutrophication. Without added N, fragments in which the original ramets were left connected accumulated two times more total mass than fragments in which the ramets were disconnected from one another. The positive effect of connection increased two-fold with increasing N. These results were consistent with the hypotheses that physiological integration between connected terrestrial and aquatic ramets can increase clonal performance in plants and that this effect can be greater when the aquatic ramet is richer in nutrients. Connection reduced root to shoot ratio in terrestrial ramets, but increased it in aquatic ones, suggesting that physiological integration induced a division of labor in which terrestrial ramets specialized for light acquisition and aquatic ramets specialized for acquisition of nutrients. This provides the first report of increase in clonal performance and induction of division of labor due to physiological integration between ramets in different habitats.

Natural and Anthropogenic Influences on the Mating System of the Common Morning Glory.

Evolutionary biologists remain puzzled by the often dramatic variation of mating strategies within single species. Of particular interest is the extent to which environmental conditions shape patterns of variation of mating system components within mixed mating species, and how widespread anthropogenic manipulations may influence these associations. Here, we address this question in the common morning glory (Ipomoea purpurea) by combining a dataset of floral traits, estimates of the mating system, and relevant environmental factors compiled for 22 populations of this species distributed along a wide range of environments from the Southeastern and Midwestern United States. We identify a disparate set of environmental factors to influence population-level variation in selfing, inbreeding, and flower morphology. Although floral traits are primarily associated with climatic variation, the outcrossing rate and inbreeding coefficient are primarily influenced by the level of herbicide resistance. Furthermore, we find that populations with higher levels of herbicide resistance exhibit a stronger correlation between mating system-floral traits and mating system estimates (outcrossing rate and inbreeding coefficient). Altogether, these results demonstrate the dominant role that herbicide application plays in the determination of I. purpurea's mating system, and more generally uncover the complex and unforeseen evolutionary consequences of anthropogenic manipulations in natural systems.

Salt tolerance response revealed by RNA-Seq in a diploid halophytic wild relative of sweet potato.

Crop wild relatives harbor exotic and novel genetic resources, which hold great potential for crop improvement. Ipomoea imperati is a wild diploid relative of sweet potato with the capability of high salinity tolerance. We compared the transcriptomes of I. imperati under salt stress vs. control to identify candidate genes and pathways involved in salt response. De novo assembly produced 67,911 transcripts with a high depth of coverage. A total of 39,902 putative genes were assigned annotations, and 936 and 220 genes involved in salt response in roots and leaves, respectively. Functional analysis indicated a whole system response during salt stress in I. imperati, which included four metabolic processes: sensory initiation, transcriptional reprogramming, cellular protein component change, and cellular homeostasis regulation. We identified a number of candidate genes involved in the ABA signaling pathway, as well as transcription factors, transporters, antioxidant enzymes, and enzymes associated with metabolism of synthesis and catalysis. Furthermore, two membrane transporter genes, including vacuole cation/proton exchanger and inositol transporter, were considered to play important roles in salt tolerance. This study provided valuable information not only for understanding the genetic basis of ecological adaptation but also for future application in sweet potato and other crop improvements.

Selection on intra-individual variation in stigma-anther distance in the tropical tree Ipomoea wolcottiana (Convolvulaceae).

It is well known that animals can exert strong selective pressures on plant traits. However, studies on the evolutionary consequences of plant-animal interactions have mainly focused on understanding how these interactions shape trait means, while overlooking its potential direct effect on the variability among structures within a plant (e.g. flowers and fruits). The degree of within-plant variability can have strong fitness effects but few studies have evaluated its role as a potential target of selection. Here we reanalysed data on Ipomoea wolcottiana stigma-anther distance to test alternate mechanisms driving selection on the mean as well as on intra-individual variance in 2 years. We found strong negative selection acting on intra-individual variation but not on mean stigma-anther distance, suggesting independent direct selection on the latter. Our result suggests that intra-individual variance has the potential to be an important target of selection in nature, and that ignoring it could lead to the wrong characterisation of the selection regime. We highlight the need for future studies to consider patterns of selection on the mean as well as on intra-individual variance if we want to understand the full extent of plant-animal interactions as an evolutionary force in nature.

Shifts in outcrossing rates and changes to floral traits are associated with the evolution of herbicide resistance in the common morning glory.

Human-mediated selection can strongly influence the evolutionary response of natural organisms within ecological timescales. But what traits allow for, or even facilitate, adaptation to the strong selection humans impose on natural systems? Using a combination of laboratory and greenhouse studies of 32 natural populations of the common agricultural weed, Ipomoea purpurea, we show that herbicide-resistant populations self-fertilise more than susceptible populations. We likewise show that anther-stigma distance, a floral trait associated with self-fertilisation in this species, exhibits a nonlinear relationship with resistance such that the most and least resistant populations exhibit lower anther-stigma separation compared to populations with moderate levels of resistance. Overall, our results extend the general finding that plant mating can be impacted by human-mediated agents of selection to that of the extreme selection of the agricultural system. This work highlights the influence of human-mediated selection on rapid responses of natural populations that can lead to unexpected long-term evolutionary consequences.

Variation in floral morphology and plant reproductive success in four Ipomoea species (Convolvulaceae) with contrasting breeding systems.

This study tested the hypothesis that self-compatibility would be associated with floral traits that facilitate autonomous self-pollination to ensure reproduction under low pollinator visitation. In a comparison of two pairs of Ipomoea species with contrasting breeding systems, we predicted that self-compatible (SC) species would have smaller, less variable flowers, reduced herkogamy, lower pollinator visitation and higher reproductive success than their self-incompatible (SI) congeners. We studied sympatric species pairs, I. hederacea (SC)- I. mitchellae (SI) and I. purpurea (SC)-I. indica (SI), in Mexico, over two years. We quantified variation in floral traits and nectar production, documented pollinator visitation, and determined natural fruit and seed set. Hand-pollination and bagging experiments were conducted to determine potential for autonomous self-pollination and apomixis. Self-compatible Ipomoea species had smaller flowers and lower nectar production than SI species; however, floral variation and integration did not vary according to breeding system. Bees were primary pollinators of all species, but visitation rates were seven times lower in SC than SI species. SC species had a high capacity for autonomous self-pollination due to reduced herkogamy at the highest anther levels. Self-compatible species had two to six times higher fruit set than SI species. Results generally support the hypothesis that self-compatibility and autonomous self-pollination ensure reproduction under low pollinator visitation. However, high variation in morphological traits of SC Ipomoea species suggests they maintain variation through outcrossing. Furthermore, reduced herkogamy was associated with high potential for autonomous self-pollination, providing a reproductive advantage that possibly underlies transitions to self-compatibility in Ipomoea.

Temporal rhythm of petal programmed cell death in Ipomoea purpurea.

Flowers are the main sexual reproductive organs in plants. The shapes, colours and scents of corolla of plant flowers are involved in attracting insect pollinators and increasing reproductive success. The process of corolla senescence was investigated in Ipomoea purpurea (Convolvulaceae) in this study. In the research methods of plant anatomy, cytology, cell chemistry and molecular biology were used. The results showed that at the flowering stage cells already began to show distortion, chromatin condensation, mitochondrial membrane degradation and tonoplast dissolution and rupture. At this stage genomic DNA underwent massive but gradual random degradation. However, judging from the shape and structure, aging characteristics did not appear until the early flower senescence stage. The senescence process was slow, and it was completed at the late stage of flower senescence with a withering corolla. We may safely arrive at the conclusion that corolla senescence of I. purpurea was mediated by programmed cell death (PCD) that occurred at the flowering stage. The corolla senescence exhibited an obvious temporal rhythm, which demonstrated a high degree of coordination with pollination and fertilization.

Pollen competition in style: Effects of pollen size on siring success in the hermaphroditic common morning glory, Ipomoea purpurea.

PREMISE OF THE STUDY: Pollen size varies greatly among flowering plant species and has been shown to influence the delivery of sperm cells to the eggs. Relatively little is known, however, about the functional significance of within-species genetic variation in pollen size. This study tests whether pollen size influences the relative siring success of a pollen donor during in vivo pollen competition experiments. METHODS: We used two groups of Ipomoea purpurea plants genetically divergent in their pollen sizes and applied equal number of pollen grains from one large-pollen and one small-pollen donor onto the same stigma. Using microsatellite genetic markers, we identified the pollen parent of each of the resulting progeny to determine the relative siring success of the competing donors. Competitions between donors of equal-sized pollen served as a control. KEY RESULTS: Differences in pollen size significantly affected the relative siring success of a pollen donor; larger-grained individuals outcompeted smaller-grained competitors but not equal-sized competitors. Relative siring success, however, sometimes varied across different pollen recipients. CONCLUSIONS: Pollen size can influence the relative siring success of different individuals competing on the same stigma during postpollination processes. However, other factors, such as pollen-pistil interaction and environmental conditions, are likely to influence these competitions as well.

The Invasion of Coastal Areas in South China by Ipomoea cairica May Be Accelerated by the Ecotype Being More Locally Adapted to Salt Stress.

Local adaptation and phenotypic plasticity are two alternative mechanisms used by invasive plants for range expansion. We conducted a series of experiments to investigate the role of these mechanisms in the recent expansion of the invasive Ipomoea cairica from non-saline to salt-stressed coastal habitats. A comparison of the plant's photosynthetic traits and construction costs across habitats was conducted through a field survey. Meanwhile, a full factorial greenhouse experiment was conducted with two ecotypes (non-saline and coastal) of I. cairica and two salinity gradients (water and 4 g L-1 NaCl solution) to evaluate the roles of the two strategies by comparing their main traits. The results revealed that the construction cost and Amax of I. cairica did not change with the habitat type. The ecotype and saline treatments, however, significantly influenced the plant growth. The non-saline ecotype (NE) generally showed higher or equal plasticity of biomass-allocation and functional traits compared to the coastal ecotype (CE). However, the fitness and biomass of the NE significantly decreased with salinity, whereas those aspects of the CE did not change. Our results indicate that the recent expansion of I. cairica into coastal areas may be accelerated by the local adaptation of the CE to salt stress. Additionally, in South China, the CE will most likely evolve adaptations to both saline and non-saline environments, which will further broaden the invasion range of I. cairica in the future.

Inherent optical properties of pollen particles: a case study for the morning glory pollen.

Biological aerosols, such as bacteria, fungal spores, and pollens, play an important role on various atmospheric processes, whereas their inherent optical property is one of the most uncertainties that limit our ability to assess their effects on weather and climate. A numerical model with core-shell structure, hexagonal grids and barbs is developed to represent one kind of realistic pollen particles, and their inherent optical properties are simulated using a pseudo-spectral time domain method. Both the hexagonal grids and barbs substantially affect the modeled pollen optical properties. Results based on the realistic particle model are compared with two equivalent spherical approximations, and the significant differences indicate the importance of considering pollen geometries for their optical properties.

Is Allelopathic Activity of Ipomoea murucoides Induced by Xylophage Damage?

Herbivory activates the synthesis of allelochemicals that can mediate plant-plant interactions. There is an inverse relationship between the activity of xylophages and the abundance of epiphytes on Ipomoea murucoides. Xylophagy may modify the branch chemical constitution, which also affects the liberation of allelochemicals with defense and allelopathic properties. We evaluated the bark chemical content and the effect of extracts from branches subjected to treatments of exclusion, mechanical damage and the presence/absence of epiphytes, on the seed germination of the epiphyte Tillandsia recurvata. Principal component analysis showed that branches without any treatment separate from branches subjected to treatments; damaged and excluded branches had similar chemical content but we found no evidence to relate intentional damage with allelopathy; however 1-hexadecanol, a defense volatile compound correlated positively with principal component (PC) 1. The chemical constitution of branches subject to exclusion plus damage or plus epiphytes was similar among them. PC2 indicated that palmitic acid (allelopathic compound) and squalene, a triterpene that attracts herbivore enemies, correlated positively with the inhibition of seed germination of T. recurvata. Inhibition of seed germination of T. recurvata was mainly correlated with the increment of palmitic acid and this compound reached higher concentrations in excluded branches treatments. Then, it is likely that the allelopathic response of I. murucoides would increase to the damage (shade, load) that may be caused by a high load of epiphytes than to damage caused by the xylophages.

A novel role of ethephon in controlling the noxious weed Ipomoea cairica (Linn.) Sweet.

Several auxin herbicides, such as 2, 4-D and dicamba, have been used to eradicate an exotic invasive weed Ipomoea cairica in subtropical China, but restraining the re-explosion of this weed is still a challenge. Since ethylene is one of the major intermediate functioning products during the eradication process, we explored the possibility, mechanism and efficiency of using ethephon which can release ethylene to control Ipomoea cairica. The results of the pot experiment showed that 7.2 g /L ethephon could totally kill Ipomoea cairica including the stems and roots. The water culture experiment indicated that ethephon released an abundance of ethylene directly in leaves and caused increases in electrolyte leakage, 1-aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA) and H2O2 and decreases in chlorophyll content and photosynthetic activity, finally leading to the death of Ipomoea cairica. The field experiment showed that the theoretical effective concentration of ethephon for controlling Ipomoea cairica (weed control efficacy, WCE = 98%) was 4.06 g/L and the half inhibitory concentration (I50) was 0.56 g/L. More than 50% of the accompanying species were insensitive to the phytotoxicity of ethephon. Therefore, ethephon is an excellent alternative herbicide for controlling Ipomoea cairica.