Sicyos Angulatus Research Articles

Enhancing image recognition robustness in early weed detection through optimal training data curation

Abstract Using convolutional neural networks (CNNs) for image recognition is effective for early weed detection. However, the impact of training data curation, specifically concerning morphological changes during the early growth phases of weeds, on recognition robustness remains unclear. We focused on four weed species (giant ragweed [Ambrosia trifida L.], red morningglory [Ipomoea coccinea L.], pitted morningglory [Ipomoea lacunosa L.], and burcucumber [Sicyos angulatus L.]) with varying cotyledon and true leaf shapes. Creating 16 models in total, we employed four dataset patterns with different growth stage combinations, two image recognition algorithms (object detection: You Look Only Once [YOLO] v5 and image classification: Visual Geometry Group [VGG] 19), and two conditions regarding the number of species treated (four and two species). We evaluated the effects of growth stage training on weed recognition success using two datasets. One evaluation revealed superior results with a single class/species training dataset, achieving >90% average precision for detection and classification accuracy under most conditions. The other dataset revealed that merging different growth stages with different shapes as a class effectively prevented misrecognition among different species when using YOLOv5. Both results suggest that integrating different shapes in a plant species as a single class is effective for maintaining robust recognition success amid temporal morphological changes during the early growth stage. This finding not only enhances early detection of weed seedlings but also bolsters the robustness of general plant species identification.

The Gastroprotective Effect of Sicyos angulatus Against Hydrochloric Acid/Ethanol-Induced Acute Gastritis and Gastric Ulcer in Mice.

Gastritis and gastric ulcers are common gastric diseases that are caused by infection, drugs, alcohol consumption, or stress. These conditions lead to increased inflammatory cytokines and recruitment of leukocytes, which damage the stomach mucosa and exacerbate disease severity. Sicyos angulatus (SA), an annual vine in the Cucurbitaceae family, is known to have an anti-inflammatory effect, but its efficacy for preventing gastritis and gastric ulcers has not yet been evaluated. In the present study, we investigated the gastroprotective effect of SA using a hydrochloric acid/ethanol-induced gastric mucosal injury mouse model and lipopolysaccharide (LPS)-stimulated KATO III cells. Macroscopic analysis revealed a reduction in gastric ulcer area. Similarly, histopathological analysis showed a dose-dependent decrease in gastric mucosal injury, with significant improvement at 750 mg/kg of SA treatment. Gene expressions of inflammatory cytokines, chemokines, and adhesion molecule were reduced in the SA-administered group. Immunohistochemical staining indicated that SA significantly decreased neutrophil infiltration in the lamina propria and epithelium of the stomach. Kaempferol, a major bioactive flavonoid of SA, also improved gastric injury by reducing macroscopic and microscopic lesions, inflammatory mediator gene expression, and neutrophil infiltration. Furthermore, both SA and kaempferol downregulated LPS-mediated increases in inflammatory cytokines and chemokines following inhibition of p38 and c-Jun N-terminal kinase (JNK) phosphorylation in KATO III cells. These results suggest that SA can ameliorate gastric mucosal injury by inhibiting the recruitment of inflammatory cells, particularly neutrophils, and by suppressing p38 and JNK phosphorylation.

Invasion of Sicyos angulatus in Riparian Habitats in the Jiu and Danube Area (Romania)

Sicyos angulatus (Cucurbitaceae) is an invasive species because of its rapid growth rate, intensive dispersal and ability to adapt to a wide range of environments. It has become an invasive species in the Ostroveni area, an area at the confluence of the Jiu River and the Danube River in the Oltenia region of Romania. This species spreads, climbs and takes over everything in its path. It can also outcompete native plants very quickly as it is a prolific breeder. The aim of this study was to demonstrate the invasive potential of S. angulatus in the forests of the Jiu and Danube confluence area by calculating several indicator values. The results showed that the number of plants varies depending on factors such as location, water availability and shade. They also showed that S. angulatus is a plant that occupies its niche in the ecosystem and has a negative impact on the local flora. Population control should therefore start with early detection, so that control and eradication are less costly.

Flexible Resource Allocation-Efficient Water Use Strategies Facilitate Invasion of Invasive Vine Sicyos angulatus L.

The invasive vine Sicyos angulatus L. destroys the natural ecosystem of invaded areas. Understanding the differences in growth and development between S. angulatus and other plants is necessary to explore the invasion mechanisms of S. angulatus and implement appropriate prevention and control measures. Thus, this study compared the growth, photosynthesis, and root characteristics of invasive liana S. angulatus and other three vine plants, Ipomoea nil (L.) Roth, Ipomoea purpurea (L.), and Thladiantha dubia Bunge, at different growth stages: seedling, flowering, and fruiting. The results showed that the total biomass of S. angulatus in the fruiting stage was 3-6 times that of the other three plants, and the root biomass ratio and root-shoot ratio decreased throughout the growth stage. Throughout the growth stage, the total leaf area of S. angulatus was significantly higher than that of the other three plant types, and the specific leaf area of S. angulatus at the seedling and flowering stages was 2.5-3 and 1.4-3 times that of the other three plants, respectively. The photosynthetic rate, stomatal conductance, and transpiration rate of S. angulatus at the fruiting stage were significantly higher than those of the other three plants, and its water use efficiency was higher than that of the other three plants at the three growth stages, indicating its strong photosynthetic capacity. The root activity and root pressure of S. angulatus were also significantly higher than those of the other three plants at the seedling and flowering stages. These results show that S. angulatus flexibly allocates resources to its aboveground parts during the growth stage to ensure that the plant obtains the space necessary for its growth and development and that with the help of higher root pressure and root activity, S. angulatus can maintain higher photosynthesis and water use efficiency with fewer resources. Therefore, the prevention and control of S. angulatus requires a combination of aboveground and underground measures. Spraying conventional weedicide/herbicide and manually removing aboveground plants may lead to its resurgence.

Evaluation of the Indoor Efficacy of Various Foliar-Applied Herbicides on Sicyos angulatus Seedlings

Sicyos angulatus is an increasingly pervasive alien species, has been identified as a significant contributor to the deterioration of biodiversity within the northern quadrant of the china. The objective of this investigation was to assess the efficacy of seven herbicides in suppressing the growth of S. angulatus seedlings, specifically targeting the early developmental phase. The application of the herbicides took place during the trileaf stage, a critical growth period. The herbicides under scrutiny included Prometryn, Thifensulfuron methyl, Nicosulfuron, Mesotrione, Bentazone, Imazethapyr, and a composite of Dicamba-Glyphosate-Triclopyr, with water serving as the control. To ensure consistent application and growth conditions, calibrated sprayers and standardized soil conditions were utilized. Data collection encompassed observations of toxicity, measurements of fresh weight, assessment of fresh weight effect, and the implementation of ANOVA to discern treatment variances, facilitating graphical comparison. The results indicated that all evaluated agents exhibited inhibitory effects on the seedlings. The Bentazone treatment exhibited an excellent control effect, with a fresh weight inhibition rate exceeding 95% on S. angulatus seedlings. Similarly, the Mesotrione and Dicamba-Glyphosate-Triclopy treatments demonstrated a good control effect, resulting in a fresh weight inhibition rate of over 85%. When treated with Prometryn, the S. angulatus seedlings displayed a moderate control effect, as indicated by a fresh weightinhibition rate exceeding 55%. However, Thifensulfuron methyl, Nicosulfuron, andImazethapyr showed poor control effects with a fresh weight inhibition rate below 55%. In light of these findings, it is posited that Mesotrione, Bentazone, and the Dicamba-Glyphosate-Triclopyr blend manifest as viable candidates for the prophylaxis and remediation of the early-stage growth of S. angulatus. Paramount to the study's conclusions is the lack of statistically significant disparity in the suppression outcomes across the concentration spectrum of the aforementioned efficacious agents. Hence, when juxtaposing ecotoxicological ramifications and economic considerations, the adoption of a concentration commensurate with the standard unitary dosage is proposed.

The Study of Distribution for the Flora of Alien Species and Ecosystem Disturbing Species on Coastal Sand Dune in Chungcheong to Jeolla Region, South Korea

This study was conducted to provide the coastal sand dunes flora of vascular plants in Chungcheong to Jeolla region based national coastal dune natural environment survey from 2018 to 2019. In the study area, a total 631 taxa, consisting of 119 family, 372 genera, 566 species, 8 subspecies, 50 varieties, and 7 forma, were found. Among them, there were 95 taxa with 23 family, 66 genera, 99 species and 5 varieties as alien species. The number of alien species ranged from 7 to 45 on each coastal sand dune. The largest number was recorded in Sinjimyeongsa dune, while the lowest was in Namujeon dune. Moreover, ecosystem disturbing species had mainly existed on Sinhap dune. Japanese hop (Humulus japonicus) were distributed most widely on 17 coastal sand dune, and bur cucumber (Sicyos angulatus) was only found on Sinhap dune. The spatial status of flora of coastal sand dune in our data can be basic ecological information for the conservation and management of the coastal dune plant species diversity.

Distribution and invasiveness of four non-native species of plants in ecosystems in the Chorokhi delta (SW Georgia)

Chorokhi Delta is known for its high diversity and many habitats, which however are being threatened by invasive plants. Here, the effects of four invasive species of plants, namely Ambrosia artemisiifolia, Sicyos angulatus, Solidago canadensis and Verbena brasiliensis were studied. These species were recorded in the coastal area of the Black Sea and in particular in Georgia for the first time in the first half of the last century and S. angulatus is a very recent arrival. Currently, these species constitute a significant threat to biodiversity at local, national and global levels. These invasive species were monitored from 2021 to 2022. During this period, sites with high densities of the invasive species were identified. For each species, 5 transects were randomly set, and along each of them, 10 plots (1 × 1 m) were surveyed. The density, frequency, coverage and average height of the invasive plants were measured in each plot. These measurements were recorded twice per year for two years (2021–2022). All this information will be used to develop management plans aimed at preventing their further spread or control their abundance. The results indicate that Ambrosia artemisiifolia is the most invasive and widely distributed. Verbena brasiliensis and Sicyos angulatus are also highly competitive species that can seriously affect semi-natural habitats in the Chorokhi Delta and in agricultural land located close to the Delta. Unlike these species, Solidago canadensis is not widely distributed in the area studied. However, its ability to survive in a wide range of habitats and clonal growth indicate that it is potentially a highly dangerous invasive species, which in the future is expected to expand its range and severely affect the semi-natural ecosystems and agricultural land in the Chorokhi Delta. The results of the present study demonstrate the high adaptability of the species studied and their potential for spreading further in the near future.

First Report of Cercospora citrullina Causing Spot Disease on Watermelon in China.

Watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai], Cucurbitaceae family, is an important vegetable crop. It is believed to be native to Africa and is cultivated in the temperate regions of Africa, central Asia, Americas and the Mediterranean (Chomicki & Renner 2015). China is the largest producer and consumer of watermelon, with an annual production of about 60.25 million tons in 2020 (https://www.fao.org/faostat/en/#home). In May 2022, a new fungal disease was observed on the leaves, vines and fruits of watermelon (cv. Heimeiren, 8424, Qilin) with an incidence of up to 75% in greenhouses, in Gudi Industrial Park, Hanting district, Weifang City, Shandong Province, China. The symptomatic leaves, vines and fruits showed small circular black spots. The disease caused the leaves and vines to desiccate rapidly, and severely affected the fruit quality. Symptomatic leaves, vines and fruits were randomly collected, and isolations were performed from infected tissues. The edges of necrotic lesions were cut into small pieces (about 5 mm), surface sterilized with 2% NaClO for 2 min, followed by 75% ethanol for 30 s, rinsed three times in sterile distilled water and placed in Petri dishes on potato dextrose agar (PDA). The same fungus was isolated from all tissue pieces and formed colonies white fluffy on the surface, and dark gray on the reverse side after 7 days incubation at 25oC. Colonies were subcultured on PDA and Corn Meal Agar (CMA), respectively, and grew slowly (the diameter was approximately 2 cm in 10 days) on PDA showing a white edge, but they grew more rapidly on CMA (approximately 3.5 cm in diameter after 10 days incubation) showing an orange halo. Hyphae were branched, brown and smooth. Conidiophores were fasciculate, brown, straight, unbranched and measured 20.03 to 304.08 × 3.41 to 6.41 μm. Conidia were needle-shaped to clavate, colorless, erect or curved and measured 22.53 to 243.97 × 3.16 to 7.02 μm. According to these morphological characteristics, the fungus was tentatively identified as Cercospora spp. (Chupp 1954). To determine the species of the fungus, three representative isolates, UNL090101, UNL090102 and UNL090103 obtained from symptomatic leaves, vines and fruits, respectively, were characterized. The genomic DNA was extracted to amplify the nuclear ribosomal internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF-1), histone H3 (HIS), and actin (ACT) genes, using the following primer pairs ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone & Kohn 1999), CYLH3F/CYLH3R (Crous et al. 2004), ACT-512F/ACT-783R (Carbone & Kohn 1999), respectively. The ITS, EF-1, HIS, and ACT gene sequences were blasted and deposited in GenBank (accession numbers ON849061/OQ102622/OQ102623, ON890306/OQ108278/OQ108281, ON890307/OQ108279/OQ108282 and ON890308/OQ108280/OQ108283, respectively). A phylogenetic tree based on concatenated sequences of ITS-CAT-TEF-H3 from the genus Cerospora was constructed using the maximum likelihood method. Isolates from watermelon and C. citrullina formed a monophyletic group with 100% bootstrap support, which was in accordance with BLAST results. Therefore, the fungus associated to watermelon spot disease was identified as C. citrullina. To fulfill the Koch's postulates, each of the three isolates was artificially inoculated onto watermelon (cv. Qilin) detached expanded leaves, vines and fruits. Three wounds were made with sterilized entomological needles on each leaf, vine and fruit, and each wound was inoculated with 6 mm CMA medium with the fungus, and without fungus as control. All the experiments were conducted for three times. All the inoculated and control leaves were placed in an incubator and incubated at 28oC and 85% relative humidity, with a 12 h photoperiod. Three days after inoculation, the inoculated leaves showed similar symptoms to those observed on naturally infected plants, while the control leaves remained asymptomatic. C. citrullina was re-isolated from symptomatic artificially inoculated leaves and identified by microscopy and re-sequencing, thus fulfilling Koch's postulates. C. citrullina has been reported on several Cucurbitaceae plants worldwide, eg. on watermelon in South Carolina (Rennberger et al. 2019) and on Burcucumber (Sicyos angulatus L.) in Korea (Hong et al. 2014), but, to our knowledge, this is the first report of C. citrullina causing spot disease on watermelon in China.

Comparative Analysis of the Chloroplast Genome of Sicyos angulatus with Other Seven Species of Cucurbitaceae Family.

Sicyos angulatus (SA) is an annual plant from the Cucurbitaceae family that is native to the eastern part of North America. This study aims to assemble and annotate the chloroplast genome of S. angulatus, and then compare it with plastomes of the other species representing the Cucurbitaceae family. The chloroplast genome size of S. angulatus is 154,986 bp, including a pair of inverted repeats (IR) of 26,276 bp, and small single-copy region (SSC) of 18,079 bp and large single-copy region (LSC) of 84,355 bp. Compared to other Cucurbitaceae species, the chloroplast genome of S. angulatus is almost 4222 bp smaller than the plastome Gynostemma pentaphyllum. All other seven species have an identical set of tRNA (37), except Citrullus laevigata, which contains 36 tRNA. The IRa/LSC junction in all eight species is located upstream of rpl2 and downstream of trnH gene. Moreover, variation in the size of the gene and the presence of pseudogene ycf1 has been seen because of the IR contraction and expansion. The highest number of tandem repeats was seen in G. pentaphyllum, and then Corynocarpus leavigata. The sequence divergence analysis and topology of the phylogenetic tree indicate that S. angulatus is more similar to genus Citrullus as compared to genus Gynostemma. These findings contribute to developing the genomic marker for the purpose of future genetic studies.

Hydrogen Peroxide Measurement Can Be Used to Monitor Plant Oxidative Stress Rapidly Using Modified Ferrous Oxidation Xylenol Orange and Titanium Sulfate Assay Correlation

Various methodologies, sensitivities, and types of interference affect the quantification of plant hydrogen peroxide (H2O2) concentration. Modified ferrous oxidation xylenol orange (eFOX) assay and titanium sulfate (Ti(SO4)2 assay are relatively accessible methods. However, their correlation is unknown, for example whether we can get the same results for different species in different environments. Leaf samples of Ambrosia trifida, Solidago altissima, Artemisia princeps, and Sicyos angulatus were collected from a riparian vegetation zone on sunny days. The H2O2 concentration in the plant leaves was evaluated in two groups. Nonfrozen leaf samples were prepared for analysis soon after arriving at the laboratory, and frozen leaf samples were stored at −80 °C for 25 days and prepared afterwards. The eFOX assay can measure even lower fluctuations in H2O2 concentration than the Ti(SO4)2 assay. A substantial correlation was observed between nonfrozen and frozen samples in the eFOX (r = 0.879, p < 0.001) and Ti(SO4)2 assays (r = 0.837, p < 0.001). Sample weight did not affect H2O2 quantification. Each species showed a substantial correlation between the eFOX and Ti(SO4)2 assays in nonfrozen conditions (Ambrosia trifida (r = 0.767, p < 0.001), Solidago altissima (r = 0.583, p < 0.001), Artemisia princeps (r = 0.672, p < 0.001), and Sicyos angulatus (r = 0.828, p < 0.001)). Therefore, both methods can be utilized easily and rapidly to quantify oxidative stress using H2O2.

Pollination biology of Sicyos angulatus: An invasive plant primarily pollinated by the native insects and introduced honeybee Apis mellifera

AbstractBurcucumber (Sicyos angulatus), first introduced in 1952 from North America to Japan, has recently become a seriously invasive alien species that has spread nationwide. The pollination mode is likely to play a crucial role in seed production and invasion. Burcucumbers have been characterized as self‐compatible flowers with distinct anthers and stigmas, indicating pollen vector‐mediated pollination. In this study, we aimed to describe the floral biology of burcucumbers and clarify their relationships with pollinators. We found that: (1) primarily native insects (at least 70 species) repeatedly visited burcucumbers, both during the day and night; (2) in terms of visitation frequency and pollen‐carrying load, honeybees, vespid wasps, and hoverflies were the most important diurnal pollinators, followed by sphingid and noctuid moths as nocturnal ones; and (3) the production of highly concentrated nectar as floral reward coupled with floral scents, predominantly aliphatic compounds such as heptanal and hexanol, may mediate the visitation of floral visitors. Our observations confirmed that burcucumber visitation is dominated by native pollinators, indicating the integration of burcucumbers into native pollinator webs. Our findings highlight the significance of a generalized pollination system in alien plants to overcome reproductive failure within a new region.

New distribution records of the alien plant – Sicyos angulatus L. (Cucurbitaceae) from Georgia

The invasion of alien plants into the territory of Georgia started in ancient times and continues today. Sicyos angulatus L., a species of North American origin, is an example of such an invasion. The first established populations of S. angulatus occurrence in Georgia were observed in 2012. Since then, new localities have been recorded, both in agricultural and disturbed natural communities. The species, which has easily adapted to local soil and climatic conditions, is expanding every year and is already widely spread in west Georgia. The plant is characterized by fast and intense growth and a climbing habit using other plants as a support. In this contribution, the peculiarities of its distribution in Georgia and the morphological features and life-history characteristics of Georgian populations are provided.

NEW DATA ON THE DISTRIBUTION AND INVASION STATUS OF SOME ALIEN PLANTS IN ROMANIA

In this paper we report new chorological data for 20 alien plant taxa from the vascular flora of Romania. A total of 9 species (Campsis radicans, Euphorbia glyptosperma, Grindelia squarrosa, Impatiens balfourii, Oenothera suaveolens, Robinia x ambigua, Rudbeckia triloba, Sedum sarmentosum, Setaria faberi) are reported as new to the regional floras within the country. Oenothera pycnocarpa and Dittrichia graveolens are reported in their second and the third sites in Romania, respectively. For the remaining 9 species (Cytisus scoparius, Dysphania pumilio, Eleusine indica, Erigeron sumatrensis, Eriochloa villosa, Oenothera depressa, Paspalum distichum, Rosa rugosa and Sicyos angulatus), we provided new field data, to improve knowledge on their current distribution and invasion status. All taxa are neophytes, introduced either accidentally (11 taxa) or deliberately (9 taxa), more than half of which are currently invasive or potentially invasive in the country.

Do non-native and dominant native species carry a similar risk of invasiveness? A case study for plants in Turkey

Most risk analysis studies in invasion biology have focused on the invasiveness of non-native species, even though some native species also can pose a high risk to the environment and human well-being. This is especially true under current global change, which may cause dominant native species to expand their range of distribution and have substantial effects on the ecosystem. In this study, the risk of invasiveness of five non-native and five native plant species in Turkey was evaluated using a standard risk screening protocol. All ten species selected for screening are known to be invasive in several parts of the world, i.e. non-native Ailanthus altissima, Cuscuta campestris, Phytolacca americana, Robinia pseudoacacia and Sicyos angulatus, and native Cirsium arvense, Hedera helix, Onopordum acanthium, Phragmites australis and Sorghum halepense. The Australian Weed Risk Assessment decision-support tool adapted to Turkey’s geographical and climatic conditions was used for screening the study species based on their biological traits, ecology and management approaches. All species were classified as high-risk, with R. pseudoacacia among non-natives and P. australis among natives achieving the highest scores followed by S. halepense, C. campestris, C. arvense, O. acanthium, P. americana, S. angulatus, A. altissima and H. helix. Based on their risk scores, all non-native species were classified as invasive and all native species as ‘expanding’ for Turkey. An ordination based on the risk scores showed similarities between invasive and expanding species. The outcomes of this study indicate that species can have several risk-related traits resulting in high risk scores irrespective of their origin. Such species can modify their environment and interact with other species with severe consequences for biodiversity. It is argued that dominant species with highly negative environmental and socioeconomic impacts in their habitats should be included in priority lists for management measures irrespective of their origin (i.e. native or non-native). More studies are needed to evaluate the magnitude and prevalence of the present findings for other regions worldwide.

Synergistic effects of soil nutrient level and native species identity and diversity on biotic resistance to Sicyos angulatus, an invasive species.

Sicyos angulatus is a serious threat to riverine ecosystem functions and services worldwide. Here, we studied the effect of species identity and diversity on biotic resistance to S. angulatus under two different soil nutrient levels (unfertilized vs. fertilized). Soil nutrient levels showed no significant effect on invasion by S. angulatus in the control treatment, where intervention by native plants was absent. Species identity of native plants and its interaction with soil nutrient levels had a significant effect on biotic resistance to S. angulatus. For instance, Pennisetum alopecuroides and Lespedeza cuneata best resisted invasion in fertilized soil, whereas Lespedeza bicolor and Lactuca indica best resisted invasion in unfertilized soil. In addition, a mixture of four plant species resisted invasion equally as well as the monoculture of a species in unfertilized soil, whereas the mixed treatment resisted invasion much better in fertilized soil compared with unfertilized soil. Structural equation modeling revealed that species identity and diversity as well as fertilizer application significantly influenced biotic resistance to S. angulatus invasion, while soil nutrients did not influence invasion success directly. Based on these results, we strongly suggest sowing seed mixtures of various species after eradicating S. angulatus plants to prevent re-invasion. Overall, these results demonstrate how native plants rely on resource availability to resist colonization by an invasive plant, such as S. angulatus. This information can be used for the development of improved guidelines for plant restoration and invasive species control.

The complete chloroplast genome sequences of the Sicyos angulatus (Cucurbitaceae)

Sicyos angulatus (burcucumber) is an annual plant native to the north-eastern America. We investigated the genomic characteristics of the complete chloroplast (CP) genome in S. angulatus with a de novo strategy. The CP genome was 154,986 bp in length including 84 protein coding genes, 37 tRNA genes, and eight rRNA genes. It has large single-copy (LSC) (84,355 bp), small single-copy (SSC) (18,079 bp), and a pair of inverted repeats (IRs) (26,276 bp), which consists of typical quadripartite structure. A phylogenetic analysis of 64 CP genomes from Cucurbitaceae revealed that the Sicyos angulatus was separated from other species and clustered together with Sicyos edulis, which is congruent with previous studies. Infrafamilial classification system inferred from our data was also congruent with previous study based on CP DNA data.

English

Sicyos angulatus has become an important invasive plant exhibiting good ecological adaptability and strong competitive ability. However, studies on this plant at the molecular level are limited by a lack of sequencing data. The present study obtained transcriptome sequences and gene expression profiles using RNA-Seq during S. angulatus seed germination. In total, RNA-Seq generated 491,967,468 reads, which were de novo assembled and 127,874 unigenes with N50 length of 807 bp. About 34.9% of the unigenes (44,660) were annotated against the protein databases, and 35,176 coding sequences were determined. During S. angulatus seed germination, over 127,860 unigenes were expressed and 66,664 unigenes differentially expressed genes (DEGs), among which 8919 DEGs were similar in pairwise comparison. Gene Ontology (GO) analysis of DEGs revealed that genes related to post-embryonic development, meristem development, and photosynthesis were enriched. In addition, the GO term “plant hormone signal transduction pathway” was also enriched in the DEGs. Important changes in genes expression related to auxin and gibberellin signal transduction might possibly be associated with S. angulatus seed germination. The findings of this study provide a foundation for research on S. angulatus that may contribute to prevent further invasion of this plant, consequently protecting the environment. © 2021 Friends Science Publishers

Improved Glucose Recovery from Sicyos angulatus by NaOH Pretreatment and Application to Bioethanol Production

As greenhouse gases and environmental pollution become serious, the demand for alternative energy such as bioethanol has rapidly increased, and a large supply of biomass is required for bioenergy production. Lignocellulosic biomass is the most abundant on the planet and a large part of it, the second-generation biomass, has the advantage of not being a food resource. In this study, Sicyos angulatus, known as an invasive plant (harmful) species, was used as a raw material for bioethanol production. In order to improve enzymatic hydrolysis, S. angulatus was pretreated with different NaOH concentration at 121 °C for 10 min. The optimal NaOH concentration for the pretreatment was determined to be 2% (w/w), and the glucan content (GC) and enzymatic digestibility (ED) were 46.7% and 55.3%, respectively. Through NaOH pretreatment, the GC and ED of S. angulatus were improved by 2.4-fold and 2.5-fold, respectively, compared to the control (untreated S. angulatus). The hydrolysates from S. angulatus were applied to a medium for bioethanol fermentation of Saccharomyces cerevisiae K35. Finally, the maximum ethanol production was found to be 41.3 g based on 1000 g S. angulatus, which was 2.4-fold improved than the control group.

Survival of Xanthomonas cucurbitae in Different Crop Rotations, Plant Debris, and Weeds in Pumpkin Fields

This study was conducted to evaluate the effectiveness of crop rotation in managing Xanthomonas cucurbitae, the causal agent of Xanthomonas leaf spot, in pumpkin fields. The study was conducted using ‘Howden’ pumpkin, a susceptible pumpkin cultivar, at four sites with no history of cucurbit production. All sites were planted with pumpkins in the first year of crop rotations. The disease developed at all four sites. In a 3-year rotation with nonhost crops, the severity of Xanthomonas leaf spot in pumpkin plots was significantly (P < 0.05) lower than those of plots in the 2-year rotation with nonhost crops and continuous pumpkin production. Furthermore, X. cucurbitae was recovered from pumpkin plant debris 15 months after harvesting pumpkins in commercial fields, and the pathogen was viable. X. cucurbitae was also isolated from asymptomatic weeds in pumpkin fields. In a greenhouse inoculation of weeds with X. cucurbitae, however, Xanthomonas leaf spot developed only on leaves of burcucumber (Sicyos angulatus) and velvetleaf (Abutilon theophrasti) weeds. In the infested soil with X. cucurbitae, the bacterium was not recovered after 15, 42, and 56 days at 22, 12, and 4°C, respectively. The results showed that crop rotation alone does not provide adequate protection of pumpkin plants against X. cucurbitae.

Seed density is as important as limiting similarity, diversity effect, and propagule pressure in plant restoration to control invasion

Restoring invasion-resistant plant communities is critical for the successful control of invasive plant species. It is based on ecological principles, such as limiting similarity, and the diversity–invasibility hypothesis, which can be used to select optimal combinations of species and determine appropriate plant density for the effective suppression of invasion due to propagule pressure. However, no attempt has been made to combine these factors in a single research framework. Here, we show for the first time the relative importance of all significant factors, including seed density, limiting similarity, diversity effect, and propagule pressure, in the invasion mechanism of Sicyos angulatus, an invasive plant species. Our results suggest that seed density, rarely explored in previous studies, is as important a determinant of invasion success as limiting similarity, diversity effect, and propagule pressure. Thus, the density-mediated mechanism must be given careful consideration for the restoration of strong invasion-resistant native plant communities.