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Sorghum bicolor is among the most important cereals globally and a staple crop for smallholder farmers in sub-Saharan Africa. Approximately 20% of sorghum yield is lost annually in Africa due to infestation with the root parasitic weed Striga hermonthica. Existing Striga management strategies are not singularly effective and integrated approaches are needed. Here, we demonstrate the functional potential of the soil microbiome to suppress Striga infection in sorghum. We associate this suppression with microbiome-mediated induction of root endodermal suberization and aerenchyma formation and with depletion of haustorium-inducing factors, compounds required for the initial stages of Striga infection. We further identify specific bacterial taxa that trigger the observed Striga-suppressive traits. Collectively, our study describes the importance of the soil microbiome in the early stages of root infection by Striga and pinpoints mechanisms of Striga suppression. These findings open avenues to broaden the effectiveness of integrated Striga management practices.

ABSTRACT Aim Location Taxon Methods Results Main Conclusions Forest pathogens, insect pests and parasitic plants are among the most important disturbance agents in forested ecosystems. Understanding where pests occur and where they might occur in the future will be important for understanding their impacts on host trees, and planning for future pest outbreaks.North America.Insect pests, pathogens and parasitic plants of forest trees.Here, we develop and implement a framework to predict the contemporary distributions of 26 pest species that accounts for climate, host abundance and, for non‐native species, their spread on the landscape.We show that pest distributions can be predicted primarily by climatic variables. The abundance of individual host trees had only minor explanatory power, but the summed total of host abundance frequently had greater importance—suggesting forest composition and the relative frequency of hosts and non‐hosts place strong limits on pest distributions. Non‐native pests were strongly impacted by the distance from their original discovery location in North America, which tended to interact with climate variables—suggesting most non‐native pests are not yet at equilibrium with their potential climatic ranges in North America.This work helps to clarify the generalised controls on pest distributions and provide a framework for predicting pest distributions in future climates. [ABSTRACT FROM AUTHOR]

AbstractPhytoparasitic nematodes pose a widespread threat to agricultural crops worldwide. The escalating nematode damage has placed a substantial burden on growers, compelling heavy reliance on chemical nematicides. However, the use of these chemicals not only inflates production costs but also poses considerable risks to human health and the environment. In response to these challenges, researchers are actively exploring alternative nematode control techniques in agronomic crops, with a focus on environmentally friendly and economically viable solutions. The imperative to reduce dependence on chemical nematicides has spurred interest in developing strategies that are both agronomically effective and environmentally safe. Current nematode management methods often integrate biological and cultural approaches, taking into account ecological and financial considerations. Among these strategies, the utilization of antagonistic plants has emerged as particularly effective. Despite extensive research on the allelopathic properties of plants such as Tagetes, Crotalaria, Brassica, and Azadirachta indica against phytonematodes, the practical implementation of cover cropping with these antagonistic plants in commercial operations still requires attention. This review explores the impact of various antagonistic plants in combating phytonematodes, highlighting their significance in nematode management. [ABSTRACT FROM AUTHOR]

Background: Dendrobium officinale Kimura et Migo (D. officinale) is parasitic on rocks or plants with very few mineral elements that can be absorbed directly, so its growth and development are affected by nutritional deficiencies. Previous studies found that phosphorus deficiency promotes polysaccharides accumulation in D. officinale, the expression of DoCSLA6 (glucomannan synthase gene) was positively correlated with polysaccharide synthesis. However, the molecular mechanism by which the low phosphorus environment affects polysaccharide accumulation remains unclear. Results: We found that DoSPX1 can reduce phosphate accumulation in plants and promote the expression of PSIs genes, thereby enhancing plant tolerance to low phosphorus environments.Y1H and EMSA experimental show that DoMYB37 can bind the promoter of DoCSLA6. DoSPX1 interact with DoMYB37 transiently overexpressed DoSPX1 and DoMYB37 in D. officinale protocorm-like bodies, decreased the Pi content, while increased the expression of DoCSLA6. Conclusions: The signaling pathway of DoSPX1-DoMYB37-DoCSLA6 was revealed. This provides a theoretical basis for the accumulation of polysaccharide content in D. officinale under phosphorus starvation. [ABSTRACT FROM AUTHOR]

Social Impact Statement Summary The parasitic weed Striga affects crops such as sorghum, maize, millet, and rice in over 40 countries on the African continent and negatively impacts the livelihood of over 300 million small‐holder farmers. Striga seeds can remain dormant in the soil for many years until they are triggered to germinate by germination stimulants, called strigolactones, exuded from the roots of their host. Here, the current knowledge on the biosynthesis of the strigolactones, their structural diversity, and biological relevance are reviewed. This knowledge could improve Striga control and thus improve the livelihood of small‐holder farmers.The parasitic plant genus Striga causes major yield losses to several crops such as sorghum, millet, and rice in arid and semi‐arid regions of the tropics. For Striga to successfully parasitize its host plant, two conditions should be fulfilled: suitable germination conditions and the presence of a host plant that exudes so‐called germination stimulants, strigolactones, that are also as a signal to attract beneficial micro‐organisms such as arbuscular mycorrhizal (AM) fungi. Different plant species exude qualitatively and quantitatively different blends of strigolactones, and this plays a key role in determining Striga host specificity. Sorghum lgs1 genotypes with a mutation in a sulfotransferase (SbSOT4A), for example, exude orobanchol and are resistant to Striga, while 5‐deoxystrigol is the major strigolactone exuded by susceptible cultivars with wild type SbSOT4A. In this review, we discuss the current knowledge on the biosynthesis of the large diversity of strigolactones, how SbSOT4A may be involved in this, and how strigolactone diversity may contribute to microbiome recruitment. Finally, we discuss how knowledge on the importance of strigolactone diversity can contribute to Striga control. [ABSTRACT FROM AUTHOR]

Cuscuta chinensis have a significant regulatory effect on plant growth, but the response mechanism of functional traits to the parasitism of C. chinensis and the trade-off relationship between traits and hyperspectral characteristics are not clear. We investigated the functional trait response and hyperspectral characteristics of Euonymus japonicus, the most common urban hedge plant in China, to the parasitism of C. chinensis. The results showed that the parasitism of C. chinensis led to the difference of leaf functional traits: the leaf thickness, stomatal density, and leaf dry matter content were significantly increased, whereas the leaf area, leaf weight, specific leaf area, chlorophyll content index, and leaf tissue density were significantly decreased. Notably, the parasitism of C. chinensis changed the spatial distribution pattern of stomata and promoted the stomata to be evenly distributed. Furthermore, the spectral reflectance of leaves treated with the parasitism of C. chinensis tended to increase. The parasitism of C. chinensis led to the "blue shift" of hyperspectral reflectance of leaves. There was a significant correlation between spectral parameters and leaf functional traits, and leaf biomass accounted for 83% of the variation in reflectance of the water stress band. In general, the parasitism of C. chinensis determines the strategic way of plant utilization of resources and affects the change of plant strategy by affecting the difference of traits. Urban plants were more inclined to invest resources in nutrient storage capacity at the expense of resources investment in photosynthetic capacity and defense mechanism. The plant ecological strategy changed from resource acquisition to resource conservation. This finding comes up with a new strategy that urban tree species can modify the plasticity of functional traits for survival and growth under the interference of parasitic plants. [ABSTRACT FROM AUTHOR]

Introduction: Cistanche salsa (C.A.Mey.) G. Beck is a perennial holoparasitic herb recognized for its medicinal properties, particularly in kidney-tonifying and laxative treatments. Despite its therapeutic potential, little is known about the endophyte communities inhabiting C. salsa and its host plants, and how these microorganisms may impact the production and accumulation of metabolites in C. salsa. Methods: We conducted a dual analysis focusing on metabolomics of wild C. salsa and microbiome characterization of both C. salsa and its host plant, Kalidium foliatum (Pall.) Moq. The metabolomics analysis revealed variations in metabolite composition across different parts of C. salsa. Additionally, the microbiome analysis involved studying endophytic bacteria and fungi, comparing their community structures between parasitic C. salsa and its host plant. Results: Significant variations in metabolite composition were observed through metabolomic profiling, which identified 93 secondary metabolites and 398 primary metabolites across various parts of C. salsa. Emphasis was placed on differences in metabolite composition within the flowers. Microbiome analysis revealed differential community compositions of endophytic bacteria between the parasitic and host plants, whereas differences in endophytic fungi were less pronounced. Certain endophytes, such as Bacteroidota, Proteobacteria, Ascomycota, and Basidiomycota, were associated with the production of specific secondary metabolites in C. salsa, including the plant-specific compound salsaside. Discussion: Our findings highlight the intricate relationship between C. salsa and its endophytic microbiota, suggesting a potential role of these microorganisms in modulating the biosynthesis of bioactive compounds. The differential preferences of endophytic bacteria and fungi across various microenvironments within the parasitic plant system underscore the complexity of these interactions. Further elucidation of these dynamics could enhance our understanding of C. salsa's medicinal properties and its ecological adaptations as a holoparasitic herb. [ABSTRACT FROM AUTHOR]

Background and aims: Olive trees are one of the most important crops in the Mediterranean, especially in Morocco, and they are vulnerable to various soil-borne pathogens that can cause significant yield losses and economic damage. This study aimed to investigate the diversity, abundance, and community composition of phytopathogenic nematodes in Moroccan olive agroecosystems, and to evaluate the impact of agroecological patterns on their abundance. Methods: Soil and root samples were collected from 13 olive-growing localities across 7 Moroccan regions (43 nurseries/22 orchards), and nematodes were ecologically assessed through the calculation of several diversity indices (e.g., Shannon Index, Evenness, and Plant Parasitic Index). In addition, the main nematode genera were evaluated in terms of soil types, irrigation regimes, and landscape complexity. Results: The obtained results revealed the presence of a diverse and complex community of phytopathogenic nematodes represented by 25 genera, including Meloidogyne, Pratylenchus, and Helicotylenchus among others. The abundance and diversity of nematodes varied significantly between the different regions and agroecological patterns, with higher densities observed in simple landscapes and higher irrigation regimes. Moreover, the community of dominant nematodes was influenced by soil types. Root-knot nematodes were the most prevalent in sandy soils, while root-lesion nematodes were significantly present in the clayish setting. The occurrence and severity of nematode damage were also correlated with the overall taxonomic richness shaped in different olive landscape modes. Conclusion: This study provides updated information and prospects into nematode sustainable monitoring and management in North African olive agroecosystems. [ABSTRACT FROM AUTHOR]

The efficient protoplast transient transformation system in plants is an important tool to study gene expression, metabolic pathways, and various mutagenic parameters, but it has not been established in Phelipanche aegyptiaca. As a root parasitic weed that endangers the growth of 29 species of plants in 12 families around the world, there is still no good control method for P. aegyptiaca. Even the parasitic mechanisms of P. aegyptiaca and the related genes regulating parasitism are not yet understood. In this study, by comparing the factors related to protoplast isolation and transfection, we developed the optimal protocol for protoplast isolation and transfection in Phelipanche aegyptiaca haustorium. The optimal protoplast yield and activity were 6.2 × 106 protoplasts/g fresh weight [FW] and 87.85%, respectively, by using 0.5 mol/L mannitol, enzyme concentrations of 2.5% cellulase R-10 and 0.8% Macerozyme R-10 at 24 °C for 4 h. At the same time, transfection efficiency of protoplasts was up to 78.49% when using 30 μg plasmid, 40% polyethylene glycol (PEG) concentration, 24 °C incubation temperature, and 20 min transfection time. This is the first efficient protoplasts' isolation and transient transformation system of Phelipanche aegyptiaca haustorium, laying a foundation for future studies on the gene function and mechanisms of haustorium formation in parasitic plants. [ABSTRACT FROM AUTHOR]

Hemiparasitic Cassytha filiformis commonly infects native host (Dillenia suffruticosa and Melastoma malabathricum) and introduced host (Acacia auriculiformis and Acacia mangium) species in threatened heath forests in Brunei. This study aims to investigate the impact of parasitism on the ecophysiology of these host species. This study addresses the research gap in understanding the ecophysiology of C. filiformis–host associations, particularly when native and introduced hosts were infected. We generated CO2 and light response curves to examine the effects of increasing CO2 and light levels of infected and uninfected hosts and examined gaseous exchange, mineral nutrients, and secondary bioactive compounds of host–parasite associations. Infected hosts were negatively impacted by C. filiformis as exhibited in the CO2 and light response curves, with C. filiformis–native host association performing better than introduced species. There were no significant differences in photosynthetic parameters between infected and uninfected hosts, except in D. suffruticosa. Certain nutrient contents showed significant differences, but total N, Ca, and K in uninfected hosts were similar to infected hosts. Total phenols and tannins were significantly higher in introduced hosts than native hosts. Our findings asserted that this hemiparasitic vine relies on both its photosynthetic efficiency and nutrient acquisition from its hosts. The parasitism did not significantly hinder the ecophysiological performance of infected hosts, suggesting a plausible co‐existence between the hosts and C. filiformis. This study provides essential ecophysiological information for future research on how C. filiformis can establish itself without negatively impacting the co‐habitating native hosts. [ABSTRACT FROM AUTHOR]

Nematodes serve as key indicators of soil health in ecological studies. Therefore, the current study examined the community structure and metabolic footprint of soil nematodes in alfalfa fields across varying levels of N supply in the semi-arid Loess Plateau. The findings offer theoretical guidance for the sustainable management of artificial alfalfa grasslands in this region. The research was based on alfalfa fields with different N application rates (0, 50, 100, 150 kg/ha2) as the research object, The shallow plate method was used to separate and extract soil nematodes, identify soil nematode groups, calculate ecological function index and metabolic footprint, and identify indicator species. A total of 6346 nematodes were isolated in this study, belonging to 27 genera and 19 families. Notably, the plant parasitic nematode Helicotylenchus was predominant. As N addition increased, the plant parasitic index (PPI) increased significantly. A N50 application significantly enhanced the soil nematode diversity index (H ) and the free-living index (MI). The findings showcased a noticeable decrease in disturbance within the N50 soil nematode community. This resulted in a mature and stable community structure primarily attributed to the heightened abundance of omnivorous/predatory nematodes. Across various N levels, soil nematode communities underwent significant alterations in the soil food web structure through shifts in their metabolic footprint. Future strategies should focus on refining N management practices and integrating sustainable approaches like crop rotation and pest management. These efforts will contribute to guidelines ensuring artificial alfalfa grasslands lasting health and productivity. [ABSTRACT FROM AUTHOR]

Dodder (Cuscuta spp.) is a dangerous parasitic plant that causes serious damage to crop production and is challenging to eliminate. Herbicide application is a common strategy to control dodder in the field, but it is costly, ineffective, and further results in hazardous outcomes. Therefore, our study aims to identify the potential pathogens in naturally occurring dodder infections which may provide efficient biocontrol options. In this regard, the pathogens were isolated from the infected plants, their pathogenicity was validated through inoculation, and the optimal culture conditions for their growth were identified by determining the pathogenicity difference. The pathogenicity range was determined in vitro using the leaves of common horticultural plants and crops. Furthermore, a small range of horticultural plants parasitized by Cuscuta reflexa in the field were inoculated with the pathogen to determine their biosafety and biocontrol potential, and the pathogens were identified by morphological and molecular characterization. We found 7 strains that were isolated after pathogen enrichment culture. Among them, Cbp6 and Cbp7 showed the highest pathogenicity against C. reflexa. After testing the inoculation of more than 50 species of plants, only 9 species showed varying degrees of lesions on leaves, which proved the high biosafety for common plants. Field spraying of these pathogens showed a good control effect on C. reflexa after 21 days; the disease severityreached 66.0%, while its host plant did not display obvious symptoms. In conclusion, the pathogens Cbp6 and Cbp7 were identified as Alternaria alternata, and the results of this study provide a theoretical basis for the biological control of dodder. [ABSTRACT FROM AUTHOR]

Broomrape (Phelipanche ramosa) is an obligate root parasitic plant that is known to infest many important crops. It is emerging as a serious biotic threat for Brassica juncea cultivation in India. There is very limited information available about broomrape species and its infestation in B. juncea. Hence, the present study encompassed a comprehensive five-year field survey spanning from 2018 to 2023 of 47 different B. juncea fields in the states of Rajasthan and Haryana in India. The level of broomrape infestation varied from season to season and field to field. In the B. juncea fields, broomrape with blue/violet color corolla, along with occasionally white color type were also noticed. The hairy anther, corolla shape and use of mitochondrial DNA-specific molecular markers revealed that both these broomrape types belong to Phelipanche ramosa. Scanning electron microscopy (SEM) analysis showed that P. ramosa seeds have varying shapes and seed coat have fibrillar periclinal cell wall. In addition to all the known host species for P. ramosa till date, we also identified a new host, a wild Brassicaceae weed species; Lepidium didymum in Haryana. The presence of an alternative weed host may help P. ramosa survive even in the absence of major crop host species. Overall, the present study revealed some insights into the P. ramosa-B. juncea host-parasite complex and its effect on B. juncea which could be further investigated in more detail. [ABSTRACT FROM AUTHOR]

Parasitic plants have a heterotrophic lifestyle, in which they withdraw all or part of their nutrients from their host through the haustorium. Despite the release of many draft genomes of parasitic plants, the genome evolution related to the parasitism feature of facultative parasites remains largely unknown. In this study, we present a high‐quality chromosomal‐level genome assembly for the facultative parasite Pedicularis kansuensis (Orobanchaceae), which invades both legume and grass host species in degraded grasslands on the Qinghai‐Tibet Plateau. This species has the largest genome size compared with other parasitic species, and expansions of long terminal repeat retrotransposons accounting for 62.37% of the assembly greatly contributed to the genome size expansion of this species. A total of 42,782 genes were annotated, and the patterns of gene loss in P. kansuensis differed from other parasitic species. We also found many mobile mRNAs between P. kansuensis and one of its host species, but these mobile mRNAs could not compensate for the functional losses of missing genes in P. kansuensis. In addition, we identified nine horizontal gene transfer (HGT) events from rosids and monocots, as well as one single‐gene duplication events from HGT genes, which differ distinctly from that of other parasitic species. Furthermore, we found evidence for HGT through transferring genomic fragments from phylogenetically remote host species. Taken together, these findings provide genomic insights into the evolution of facultative parasites and broaden our understanding of the diversified genome evolution in parasitic plants and the molecular mechanisms of plant parasitism. [ABSTRACT FROM AUTHOR]

Background and Aims Infection by the hemi-parasitic plant Striga hermonthica causes severe host plant damage and seed production losses. Increased availability of essential plant nutrients reduces infection. Whether, how and to what extent it also reduces striga-induced host plant damage has not been well studied. Methods The effects of improved macro- and micronutrient supply on host plant performance under striga-free and infected conditions were investigated in glasshouse pot assays. One striga-sensitive and two striga-tolerant genotypes were compared. Plants growing in impoverished soils were supplied with (1) 25 % of optimal macro- and micronutrient quantities, (2) 25 % macro- and 100 % micronutrients, (3) 100 % macro- and 25 % micronutrients, or (4) 100 % macro- and micronutrients. Key Results Photosynthesis rates of striga-infected plants of the sensitive genotype increased with improved nutrition (from 12.2 to 22.1 μmol m−2 s−1) but remained below striga-free levels (34.9–38.8 μmol m−2 s−1). For the tolerant genotypes, increased macronutrient supply offset striga-induced photosynthesis losses. Striga-induced relative grain losses of 100 % for the sensitive genotype were reduced to 74 % by increased macronutrients. Grain losses of 80 % in the tolerant Ochuti genotype, incurred at low nutrient supply, were reduced to 5 % by improved nutrient supply. Conclusions Increasing macronutrient supply reduces the impact of striga on host plants but can only restore losses when applied to genotypes with a tolerant background. [ABSTRACT FROM AUTHOR]

Orobanche coerulescens is a parasitic plant that cannot complete its life cycle without a host and is incapable of photosynthesis. The habitats of O. coerulescens span the coasts of Korea and its volcanic islands, Ulleungdo and Dokdo. Those on the volcanic islands exhibit morphological differences and have distinct hosts compared to those on the peninsula. The family of Orobanchaceae, encompassing both autotrophic and parasitic species, serves as a model for evolutionary studies of parasitic states. However, there are limited genome assemblies for the Orobanche genus. In our study, we produced approximately 100x ONT long reads to construct a chromosome-level genome of O. coerulescens. The resulting assembly has a total size of 3,648 Mb with an N50 value of 195 Mb, and 82.0% of BUSCO genes were identified as complete. Results of the repeat annotation revealed that 86.3% of the genome consisted of repeat elements, and 29,395 protein-coding genes were annotated. This chromosome-level genome will be an important biological resource for conserving biodiversity and further understanding parasitic plants. [ABSTRACT FROM AUTHOR]

This article comments on: Mutinda S, Mobegi FM, Hale B, Dayou O, Ateka E, Wijeratne A, Wicke S, Bellis ES, Runo S. 2023. Resolving intergenotypic Striga resistance in sorghum. Journal of Experimental Botany 74, 5294–5306.

Two independent pot experiments were conducted to evaluate the potential of two different application methods for culture filtrates of 10 Trichoderma spp. strains to reduce infection of Phelipanche aegyptiaca in tomatoes. In the first method (foliar spray), seedlings were foliar sprayed three times with culture filtrate of each Trichoderma spp. strains pre- and posttransplanting. In the second method (soil drench), these culture filtrates were incorporated into the top 5 cm of the soil surface during transplantation. Foliar sprays of T33, T60, and T36 significantly reduced the progression of P. aegyptiaca infection throughout the growing period (85 days). The number of P. aegyptiacaʹs aboveground stalks and underground juveniles was also significantly reduced (83 and 66%) in T33-treated plants at the end of the experiment, while the fresh and dry weights of tomato fruits was significantly increased (86% and 90%). In the second approach, T66, T33, T35, T36, and T67 strains caused a significant reduction in the progression of P. aegyptiaca infection on tomatoes during the same period. The fresh and dry weights of stalks and attached juveniles of P. aegyptiaca in T66-treated plants were significantly reduced by 77, 52, 75, and 49%, respectively, compared to the control. The conclusion showed that T. virens T33 culture filtrate as foliar spray through some kind of induced systemic resistance (ISR) and T. brevicompactum T66 culture filtrate as soil drench can be used as natural bioherbicides to control P. aegyptiaca in tomatoes.

Abstract Background Many parasitic plants of the genera Striga and Cuscuta inflict huge agricultural damage worldwide. To form and maintain a connection with a host plant, parasitic plants deploy virulence factors (VFs) that interact with host biology. They possess a secretome that represents the complement of proteins secreted from cells and like other plant parasites such as fungi, bacteria or nematodes, some secreted proteins represent VFs crucial to successful host colonisation. Understanding the genome-wide complement of putative secreted proteins from parasitic plants, and their expression during host invasion, will advance understanding of virulence mechanisms used by parasitic plants to suppress/evade host immune responses and to establish and maintain a parasite-host interaction. Results We conducted a comparative analysis of the secretomes of root (Striga spp.) and shoot (Cuscuta spp.) parasitic plants, to enable prediction of candidate VFs. Using orthogroup clustering and protein domain analyses we identified gene families/functional annotations common to both Striga and Cuscuta species that were not present in their closest non-parasitic relatives (e.g. strictosidine synthase like enzymes), or specific to either the Striga or Cuscuta secretomes. For example, Striga secretomes were strongly associated with ‘PAR1’ protein domains. These were rare in the Cuscuta secretomes but an abundance of ‘GMC oxidoreductase’ domains were found, that were not present in the Striga secretomes. We then conducted transcriptional profiling of genes encoding putatively secreted proteins for the most agriculturally damaging root parasitic weed of cereals, S. hermonthica. A significant portion of the Striga-specific secretome set was differentially expressed during parasitism, which we probed further to identify genes following a ‘wave-like’ expression pattern peaking in the early penetration stage of infection. We identified 39 genes encoding putative VFs with functions such as cell wall modification, immune suppression, protease, kinase, or peroxidase activities, that are excellent candidates for future functional studies. Conclusions Our study represents a comprehensive secretome analysis among parasitic plants and revealed both similarities and differences in candidate VFs between Striga and Cuscuta species. This knowledge is crucial for the development of new management strategies and delaying the evolution of virulence in parasitic weeds.

The plant parasitic nematode species Pratylenchus penetrans has been known to form a synergistic relationship with the fungal plant pathogen Verticillium dahliae in potato cropping systems across North America. The results of this interaction can be devastating; with plants suffering from choloris, wilting, and premature death or complete yield loss in infected fields. Many studies have been conducted in order to understand how this symbiotic connection is occurring; whether that be from competition within the soil microbial community, through the development of amendment-induced suppressive soils, or from other interactions caused by nematode activity. While the mechanisms behind the hostile interaction between V. dahliae and P. penetrans are undetermined, the purpose of this review is to compile recent developments relating to this symbiotic relationship, the effects the soil microbial community has on said relationship, as well as identify potential gaps in research. [ABSTRACT FROM AUTHOR]

The phytohormones strigolactones (SLs) control root and shoot branching and are exuded from roots into the rhizosphere to stimulate interaction with mycorrhizal fungi. The exuded SLs serve as signaling molecules for the germination of parasitic plants. The broomrape Phelipanche aegyptiaca is a widespread noxious weed in various crop plants, including tomato (Solanum lycopersicum). We have isolated three mutants that impair SL functioning in the tomato variety M82: SHOOT BRANCHING 1 (sb1) and SHOOT BRANCHING 2 (sb2), which abolish SL biosynthesis, and SHOOT BRANCHING 3 (sb3), which impairs SL perception. The over-branching phenotype of the sb mutants resulted in a severe yield loss. The isogenic property of the mutations in a determinate growth variety enabled the quantitative evaluation of the contribution of SL to yield under field conditions. As expected, the mutants sb1 and sb2 were completely resistant to infection by P. aegyptiaca due to the lack of SL in the roots. In contrast, sb3 was more susceptible to P. aegyptiaca than the wild-type M82. The SL concentration in roots of the sb3 was two-fold higher than in the wild type due to the upregulation of the transcription of SL biosynthesis genes. This phenomenon suggests that the steady-state level of root SLs is regulated by a feedback mechanism that involves the SL signaling pathway. Surprisingly, grafting wild-type varieties on sb1 and sb2 rootstocks eliminated the branching phenotype and yield loss, indicating that SL synthesized in the shoots is sufficient to control shoot branching. Moreover, commercial tomato varieties grafted on sb1 were protected from P. aegyptiaca infection without significant yield loss, offering a practical solution to the broomrape crisis. [ABSTRACT FROM AUTHOR]

Parasitic plants represent a peculiar group of semi- or fully heterotrophic plants, possessing the ability to extract water, minerals, and organic compounds from other plants. All parasitic plants, either root or stem, hemi- or holoparasitic, establish a vascular connection with their host plants through a highly specialized organ called haustoria. Apart from being the organ responsible for nutrient extraction, the haustorial connection is also a highway for various macromolecules, including DNA, proteins, and, apparently, phytopathogens. At least some parasitic plants are considered significant agricultural pests, contributing to enormous yield losses worldwide. Their negative effect is mainly direct, by the exhaustion of host plant fitness and decreasing growth and seed/fruit formation. However, they may pose an additional threat to agriculture by promoting the trans-species dispersion of various pathogens. The current review aims to summarize the available information and to raise awareness of this less-explored problem. We further explore the suitability of certain phytopathogens to serve as specific and efficient methods of control of parasitic plants, as well as methods for control of the phytopathogens. [ABSTRACT FROM AUTHOR]

Background: The lifestyle transition from autotrophy to heterotrophy often leads to extensive degradation of plastomes in parasitic plants, while the evolutionary trajectories of plastome degradation associated with parasitism in hemiparasitic plants remain poorly understood. In this study, phylogeny-oriented comparative analyses were conducted to investigate whether obligate Loranthaceae stem-parasites experienced higher degrees of plastome degradation than closely related facultative root-parasites and to explore the potential evolutionary events that triggered the 'domino effect' in plastome degradation of hemiparasitic plants. Results: Through phylogeny-oriented comparative analyses, the results indicate that Loranthaceae hemiparasites have undergone varying degrees of plastome degradation as they evolved towards a heterotrophic lifestyle. Compared to closely related facultative root-parasites, all obligate stem-parasites exhibited an elevated degree plastome degradation, characterized by increased downsizing, gene loss, and pseudogenization, thereby providing empirical evidence supporting the theoretical expectation that evolution from facultative parasitism to obligate parasitism may result in a higher degree of plastome degradation in hemiparasites. Along with infra-familial divergence in Loranthaceae, several lineage-specific gene loss/pseudogenization events occurred at deep nodes, whereas further independent gene loss/pseudogenization events were observed in shallow branches. Conclusions: The findings suggest that in addition to the increasing levels of nutritional reliance on host plants, cladogenesis can be considered as another pivotal evolutionary event triggering the 'domino effect' in plastome degradation of hemiparasitic plants. These findings provide new insights into the evolutionary trajectory of plastome degradation in hemiparasitic plants. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Parasitic plants that deprive crops of water and nutrients are an increasingly concerning food security issue, affecting the livelihood of millions of subsistence, small‐ and mid‐scale farmers. An in‐depth understanding of parasite–host interactions is required to develop species‐specific and ecologically sustainable parasite management methods. The non‐invasive visualization of herbaceous contact zones, applicable to diverse parasite–host pathosystems presented in this study, brings methodological advance to the research of biotic interactions between crops and plant parasites belonging to the most devastating parasitic plant family (Orobanchaceae). This work also provides first insights into how the parasites' feeding organ displaces host tissue beyond the direct parasite–host interface.High‐resolution X‐ray computed tomography (HRXCT) enables sectioning‐free two‐dimensional imaging of biological structures and reconstruction of three‐dimensional objects. Although its application is common in many areas of biomedicine and despite its flexibility regarding resolution levels, the technology remains underutilized in the plant sciences. Here, we explored HRXCT for the study of parasitic plant–plant interactions by developing protocols to access soft‐tissue host–parasite contact zones at cell‐level resolution. We tested various sample preparation methods and contrast stains for their efficiency to improve the imaging of haustorium samples. In doing so, we achieved cellular resolution with the visible cellular organization of haustorial structures, especially of the vascular system. Fresh stained and dehydrated sample preparation of soft haustoria enables the highest spatial resolution with fine‐cellular discrimination of haustorium versus host cells. Application of cell‐level resolved HRXCT to five pathosystems: Alectra‐cowpea, Phelipanche‐tomato, Phtheirospermum‐tomato, Rhamphicarpa‐tomato, and Striga‐sorghum highlighted a life history‐specific organization and uncovered an as yet undescribed internal displacement of host tissue at parasite–host interfaces. Following image‐based training, our HRXCT approach could invoke AI‐based cell recognition for automated parasite cell–host cell differentiation. Superseding extensive microsectioning for 3D imaging, the newly established HRXCT protocol for 2D‐ and 3D‐visualization of herbaceous plant–plant contact zones and the first insights gained from it, is useful for mid‐throughput, comparative studies of parasitic plant–host interactions. [ABSTRACT FROM AUTHOR]

Plants are exposed to infection and predation by organisms from most kingdoms of life, including their own. Layers of molecular defence mechanisms have evolved to limit damage and disease from microbial and insect pathogens, and plants can also defend themselves against attack by members of their own kingdom. These so‐called parasitic plants attach to and take up nutrients from a host plant. It is not yet known whether parasites belonging to the plant kingdom can elicit a systemic defence response in their hosts, to which they have much more in common molecularly than viruses and fungi. To gain insight as to whether previous infection reduces the susceptibility of a host, we used two successive rounds of infection of the same host plants with the holoparasitic plant Phelipanche ramosa (‘broomrape,’ Orobanchaceae). We tested seven cultivars of tomato, and found that the ‘Moneymaker’ cultivar was re‐infested at a lower rate than its naïve counterpart and, if pre‐infested, supported fewer parasites than other cultivars. We collected tissue for RNA sequencing at the host–parasite interface of two cultivars, ‘Moneymaker’ and ‘Zuckertraube’, the latter of which showed no difference in susceptibility upon reinfection. These data revealed tomato cultivar‐specific transcriptional profiles in the parasite, including the upregulation of several peroxidase genes in parasites infecting ‘Moneymaker’, compared to ‘Zuckertraube’. Furthermore, we detected the upregulation of lignin biosynthesis genes in ‘Moneymaker’ tomato plants when they were pre‐infected with the holoparasitic plant. Together, our data suggest that some tomato cultivars may be naturally able to build up defences against parasitic plant infection. This could be relevant for agriculture, in that cuttings or other forms of vegetative propagation of pre‐infected tomato plants can prime crops to withstand field infestations more effectively. [ABSTRACT FROM AUTHOR]

Phelipanche aegyptiaca (Pers.) Pomel, commonly known as Egyptian broomrape, is an obligate root parasite, infesting solanaceous crops mainly in Mediterranean countries. Certain antagonistic fungi could be effectively used as a biocontrol agent for this parasitic plant. In this study, three fungal isolates (F1, F2 and F3) were obtained from P. aegyptiaca seeds covered with mycelium. The isolates were characterized based on morphological features and ITS and TEF sequence analysis. They were classified as belonging to Fusarium fujikuroi with a sequence similarity of 99.80% and 100%, respectively. The pathogenicity of the isolates on P. aegyptiaca and tomato were determined. In a P. aegyptiaca seed assay, all isolates allowed seed germination with delayed radicle development. Disease severity among the isolates ranged from 40%–70% on the basis of radicle necrotic area. The F1 isolate caused more than 40% disease on the spiders and tubercles in a polyethylene bag assay. The average of the total of spider and tubercle mortality caused by the F1 isolate was 63.5% at 9 days after inoculation. Moreover, the F1 isolate was considered non‐pathogen on tomato with 6.66% disease severity after root inoculation. To the best of our knowledge, this is the first report of F. fujikuroi on P. aegyptiaca seed. Pending further development, the F1 isolate could have potential for the biocontrol of P. aegyptiaca in the future. [ABSTRACT FROM AUTHOR]

This study investigates the host diversity and characteristics of the rare parasitic plant Silverberry-like taxillus (Taxillus yadoriki). Seogwipo, Jeju Island, where T. yadoriki grows naturally, was examined to clarify the diversity of host species, their location, and the part of the tree where T. yadoriki is attached. A total of 687 host trees were found. Taxillus yadoriki was intensively distributed in the lowlands below 200 m a.s.l. The host trees belonged to 40 species, four varieties, three cultivars, and two hybrids from 32 genera and 21 families, of which 23 taxa were identified as host plants for the first time in this study. Incredibly, this plant was found to be able to parasitize a variety of plants from 12 orders. Taxillus yadoriki was found to be parasitic in three orders of Gymnosperms, Ginkgoales, Cupressales, and Pinales, as well as nine orders of Angiosperms, including Magnoliales, Rosales, and Ericales. Rosaceae was the most diverse at 18.0%, and most species were broad-leaved and arboreal. Among them, Cryptomeria japonica and Litsea japonica had the highest frequency of parasitization and T. yadoriki was mainly attached to the upper part of the main tree and the main branch; as a result, T. yadoriki was distributed and showed specificity in the position of disturbance on the host. T. yadoriki's specific distribution model was built as a Maxent program. The area under the curve of the receiver operation characteristic was 0.948 ± 0.026 (mean ± standard deviation), and the performance of the constructed model was excellent. Of the total eight environmental factors, density of artistic forest and meant temperature of coldest quarter accounted for 75.3% of the total importance, which was the main distribution determinant of species. In the average distribution probability map of T. yadoriki, the critical probability for determining distribution was calculated to be 0.2898 ± 0.1018. Accordingly, the distribution of species is predicted to expand from Jeju Island to the entire southern and southeastern coasts. [ABSTRACT FROM AUTHOR]

Orobanche foetida Poiret is the main constraint facing faba bean crop in Tunisia. Indeed, in heavily infested fields with this parasitic plant, yield losses may reach 90%, and the recent estimation of the infested area is around 80,000 ha. Identifying genes involved in the Vicia faba/O. foetida interaction is crucial for the development of effective faba bean breeding programs. However, there is currently no available information on the transcriptome of faba bean responding to O. foetida parasitism. In this study, we employed RNA sequencing to explore the global gene expression changes associated with compatible and incompatible V. faba/O. foetida interactions. In this perspective, two faba bean varieties (susceptible and resistant) were examined at the root level across three stages of O. foetida development (Before Germination (BG), After Germination (AG) and Tubercule Stage (TS)). Our analyses presented an exploration of the transcriptomic profile, including comprehensive assessments of differential gene expression and Gene Ontology (GO) enrichment analyses. Specifically, we investigated key pathways revealing the complexity of molecular responses to O. foetida attack. In this study, we detected differential gene expression of pathways associated with secondary metabolites: flavonoids, auxin, thiamine, and jasmonic acid. To enhance our understanding of the global changes in V. faba response to O. foetida, we specifically examined WRKY genes known to play a role in plant host-parasitic plant interactions. Furthermore, considering the pivotal role of parasitic plant seed germination in this interaction, we investigated genes involved in the orobanchol biosynthesis pathway. Interestingly, we detected the gene expression of VuCYP722C homolog, coding for a key enzyme involved in orobanchol biosynthesis, exclusively in the susceptible host. Clearly, this study enriches our understanding of the V. faba/O. foetida interaction, shedding light on the main differences between susceptible and resistant faba bean varieties during O. foetida infestation at the gene expression level. [ABSTRACT FROM AUTHOR]

Background: Many parasitic plants of the genera Striga and Cuscuta inflict huge agricultural damage worldwide. To form and maintain a connection with a host plant, parasitic plants deploy virulence factors (VFs) that interact with host biology. They possess a secretome that represents the complement of proteins secreted from cells and like other plant parasites such as fungi, bacteria or nematodes, some secreted proteins represent VFs crucial to successful host colonisation. Understanding the genome-wide complement of putative secreted proteins from parasitic plants, and their expression during host invasion, will advance understanding of virulence mechanisms used by parasitic plants to suppress/evade host immune responses and to establish and maintain a parasite-host interaction. Results: We conducted a comparative analysis of the secretomes of root (Striga spp.) and shoot (Cuscuta spp.) parasitic plants, to enable prediction of candidate VFs. Using orthogroup clustering and protein domain analyses we identified gene families/functional annotations common to both Striga and Cuscuta species that were not present in their closest non-parasitic relatives (e.g. strictosidine synthase like enzymes), or specific to either the Striga or Cuscuta secretomes. For example, Striga secretomes were strongly associated with 'PAR1' protein domains. These were rare in the Cuscuta secretomes but an abundance of 'GMC oxidoreductase' domains were found, that were not present in the Striga secretomes. We then conducted transcriptional profiling of genes encoding putatively secreted proteins for the most agriculturally damaging root parasitic weed of cereals, S. hermonthica. A significant portion of the Striga-specific secretome set was differentially expressed during parasitism, which we probed further to identify genes following a 'wave-like' expression pattern peaking in the early penetration stage of infection. We identified 39 genes encoding putative VFs with functions such as cell wall modification, immune suppression, protease, kinase, or peroxidase activities, that are excellent candidates for future functional studies. Conclusions: Our study represents a comprehensive secretome analysis among parasitic plants and revealed both similarities and differences in candidate VFs between Striga and Cuscuta species. This knowledge is crucial for the development of new management strategies and delaying the evolution of virulence in parasitic weeds. [ABSTRACT FROM AUTHOR]

Parasitic foodborne illnesses continue to pose a worldwide health problem, particularly in areas where people have limited access to medical services. The drawbacks of traditional pharmaceutical treatments, such as the development of drug resistance and negative health effects, require the investigation into alternative remedies. Medicinal plants, which have a long tradition in healing methods, are being seen as potentially valuable for addressing this problem. These plants contain a wide range of biologically active substances such as alkaloids, flavonoids and terpenoids, which possess strong anti-parasitic properties. Though, there are obstacles to be faced in the process of incorporating medicinal plants into modern medicine. To guarantee the safety and effectiveness of these natural remedies, it is crucial to have standardization, quality control and regulatory measures in place. We highlight the value of medicinal plants in addressing foodborne diseases caused by parasites and emphasize the importance of ongoing research and partnership between traditional and modern medicine. This article explores the potential use of medicinal plants to treat parasitic foodborne diseases. It examines their historical usage, how they work and their proven effectiveness. It ensures that diverse populations can access effective treatments, thus promoting global health equity. In order to address the obstacles associated with medicinal plant-based therapies, it is imperative to expand research efforts and integrate traditional knowledge into modern healthcare practices to facilitate advancements in the field. Through this process, we can effectively harness the capabilities of medicinal plants, promoting overall health and well-being on a global scale in the continuous battle against parasitic infections. [ABSTRACT FROM AUTHOR]

Despite being sessile, plants nonetheless forage for resources by modulating their growth. Adaptative foraging in response to changes in resource availability and presence of neighbours has strong implications for performance and fitness. It is an even more pressing issue for parasitic plants, which draw resources directly from other plants. Indeed, parasitic plants were demonstrated over the years to direct their growth towards preferred hosts and invest resources in parasitism relative to host quality. In contrast to root parasites that rely mostly on chemical cues, some shoot parasites seem to profit from the ability to integrate different types of abiotic and biotic cues. While significant progress in this field has been made recently, there are still many open questions regarding the molecular perception and the integration of diverse signalling pathways under different ecological contexts. Addressing how different cues are integrated in parasitic plants will be important when unravelling variations in plant interaction pathways, and essential to predict the spread of parasites in natural and agricultural environments. In this review, we discuss this with a focus on Cuscuta species as an emerging parasitic model, and provide research perspectives based on the recent advances in the topic and plant–plant interactions in general. Summary statement: In this review, selective foraging is discussed with a focus on Cuscuta species as an emerging parasitic model. [ABSTRACT FROM AUTHOR]

Cladocolea (Loranthaceae) is a neotropical genus currently containing 24 species. Its taxonomic history has included changes in its circumscription and the transfers of some of its species to other genera in the family. Several phylogenetic studies of Loranthaceae have recognized a close relationship between Cladocolea and Struthanthus. However, both genera were poorly represented in these studies, so here we generate a phylogeny of Mexican species of Cladocolea, Struthanthus, and related genera of Psittacanthinae, using nuclear DNA sequences of the ITS region, as well as the chloroplast regions matK and trnL-F. The sample includes 112 new sequences and an additional 12 sequences obtained from GenBank. These represent 23 taxa of Cladocolea, 14 of Struthanthus, and 10 from nine other genera of Loranthaceae. In order to understand character evolution and estimate ancestral states, 13 morphological characters were mapped, both vegetative and reproductive. Bayesian inference and Maximum likelihood analyses were performed using independent matrices and a concatenated matrix of 2842 characters. Our results show that Cladocolea and Struthanthus are both polyphyletic genera. However, the Mexican species of Cladocolea and Struthanthus with convolute or sigmoid styles form a monophyletic group. Finally, the analysis of ancestral character states indicates a trend towards a reduction of inflorescences in the Cladocolea-Struthanthus complex. New combinations and synonymies are proposed. [ABSTRACT FROM AUTHOR]

Various pomegranate and grapes orchards were surveyed during the year 2022 at various localities District Swabi, the study aimed the incidence as well as identification of different genera of plant parasitic nematode (PPN). The nematodes are simple, colorless roundworms, and their bodies are un-segmented and tapering towards the head and tail, but some plant parasitic species have different body shapes, like pear, kidney, or lemon. Nematodes are small, and throughout the world, including Pakistan, important pests of crops and plants are plant parasitic nematodes. The living plant cells and tissues are fed by PPN. For investigation of PPN soil samples were collected from various localities. PPN was extracted through Baermann funnel technique from the rhizoshpere, and counted via genera. After fixation of nematodes on slides species were identified through morphological identification keys. There were many species recorded which belong to seven different genera. Helicotylenchus, Tylenchorhynchus, Meloidogyne, Longidorus, Trichodorus, Xiphinema, and Pratylenchus were found in pomegranate. Among these genera, Meloidogyne species were recorded in large population followed by Helicotylenchus in all collected samples of pomegranate. While Helicotylenchus, Filenchus, Tylenchorhynchus, Xiphinema, Tylenchus, and Pratylenchus were found in all collect samples from grapes orchards. Among all genera species of Filenchus were recorded in large numbers and the second highest species of Tylenchus genera were recorded. The rate of incidence and inhabitants are highly diverse among all surveyed localities which simply reveals the fact that studied sites are extremely infected by diverse species of PPN which eventually damage the cultivation of grapes and pomegranates. [ABSTRACT FROM AUTHOR]

Two independent pot experiments were conducted to evaluate the potential of two different application methods for culture filtrates of 10 Trichoderma spp. strains to reduce infection of Phelipanche aegyptiaca in tomatoes. In the first method (foliar spray), seedlings were foliar sprayed three times with culture filtrate of each Trichoderma spp. strains pre- and posttransplanting. In the second method (soil drench), these culture filtrates were incorporated into the top 5 cm of the soil surface during transplantation. Foliar sprays of T33, T60, and T36 significantly reduced the progression of P. aegyptiaca infection throughout the growing period (85 days). The number of P. aegyptiaca's aboveground stalks and underground juveniles was also significantly reduced (83 and 66%) in T33-treated plants at the end of the experiment, while the fresh and dry weights of tomato fruits was significantly increased (86% and 90%). In the second approach, T66, T33, T35, T36, and T67 strains caused a significant reduction in the progression of P. aegyptiaca infection on tomatoes during the same period. The fresh and dry weights of stalks and attached juveniles of P. aegyptiaca in T66-treated plants were significantly reduced by 77, 52, 75, and 49%, respectively, compared to the control. The conclusion showed that T. virens T33 culture filtrate as foliar spray through some kind of induced systemic resistance (ISR) and T. brevicompactum T66 culture filtrate as soil drench can be used as natural bioherbicides to control P. aegyptiaca in tomatoes. [ABSTRACT FROM AUTHOR]

This study investigated the potential of endophytic fungi as biocontrol agents against Orobanche infestations in fruit crops such as chickpea, soybean, lentil, and pea plants from different sites in Ika agricultural habitats in Delta State, Nigeria, using appropriate standard methods. Fusarium sp. showed significant inhibition of Orobanche crenata (75%) by mycotoxin production and Penicillium sp. (65%) by biocombustion. Field trials showed a significant reduction in Orobanche-infested areas, with Fusarium sp. (40% to 10%) and Penicillium sp. (30% to 10%) treatments showing significant yield improvement (20% and 22%, respectively). The study concluded that selected fungi, especially Fusarium sp. and Penicillium sp., are effective control agents for Orobanche in legume crops. This information contributes to sustainable agriculture by providing environmentally friendly alternatives to pesticides, crop yields, and economic losses from plants, and it reduces the incidence of pests.

Abstract Hemiparasitic Cassytha filiformis commonly infects native host (Dillenia suffruticosa and Melastoma malabathricum) and introduced host (Acacia auriculiformis and Acacia mangium) species in threatened heath forests in Brunei. This study aims to investigate the impact of parasitism on the ecophysiology of these host species. This study addresses the research gap in understanding the ecophysiology of C. filiformis–host associations, particularly when native and introduced hosts were infected. We generated CO2 and light response curves to examine the effects of increasing CO2 and light levels of infected and uninfected hosts and examined gaseous exchange, mineral nutrients, and secondary bioactive compounds of host–parasite associations. Infected hosts were negatively impacted by C. filiformis as exhibited in the CO2 and light response curves, with C. filiformis–native host association performing better than introduced species. There were no significant differences in photosynthetic parameters between infected and uninfected hosts, except in D. suffruticosa. Certain nutrient contents showed significant differences, but total N, Ca, and K in uninfected hosts were similar to infected hosts. Total phenols and tannins were significantly higher in introduced hosts than native hosts. Our findings asserted that this hemiparasitic vine relies on both its photosynthetic efficiency and nutrient acquisition from its hosts. The parasitism did not significantly hinder the ecophysiological performance of infected hosts, suggesting a plausible co‐existence between the hosts and C. filiformis. This study provides essential ecophysiological information for future research on how C. filiformis can establish itself without negatively impacting the co‐habitating native hosts.

The article discusses the importance of stereochemistry in the biosynthesis and functions of strigolactones (SLs), which are plant hormones and signaling molecules. SLs have been found to induce seed germination in root parasitic plants and establish symbiosis with soil-borne arbuscular mycorrhizal fungi. The study focuses on the stereochemistry of orobanchol, a type of SL, and identifies an enzyme called DIR as the factor that controls the correct stereo-configuration of orobanchol. The research provides insights into SL biosynthesis and its potential applications in agriculture. [Extracted from the article]

This article examines the relationship between sunflower plants and the parasitic plant broomrape. The study reveals that broomrape infiltrates sunflower roots by entering the host cells, creating a new compartment. The researchers also observed cell divisions in the sunflower roots near the attachment sites, potentially leading to root enlargement. The study suggests that the parasitic plant damages the host cell walls with enzymes, but the host plants only exhibit minimal defense responses. These findings contribute to our understanding of parasitic plant interactions and may aid in the development of resistance strategies. [Extracted from the article]

Root parasitic weeds of the genera Striga, Orobanche, and Phelipanche cause enormous economic losses for farmers the world over. Germination of the seeds of these species requires a chemotropic signal in the form of strigolactones in the soil. Once a root parasitic weed germinates and becomes established, it draws nutrition from the host plants, leading to plant death and hence yield reduction. Despite the obvious importance of strigolactones, there is currently almost no information about the fate of strigolactones in the soil, although microbial involvement has been suggested. To begin to address this knowledge lacuna, we developed a bioassay—using the strigolactone synthetic analogue GR24—as a high‐throughput, inexpensive, and compact tool for monitoring the dissipation of strigolactones (GR24 in this case) in the soil by microorganisms and/or environmental conditions, including GR24 concentration, soil type, and temperature. As part of the bioassay, it was found that autoclaving the soil delayed the dissipation of GR24 versus sterilisation by gamma radiation and or no sterilisation. Analytical LC–MS/MS with a detection limit of 0.1 ppb confirmed this finding, with no GR24 being detected in non‐sterilised soil after 24 h. Application of the bioassay to monitor GR24 dissipation in soil showed that the higher the GR24 concentration the slower the degradation, and the higher the temperature, the faster the degradation. It also showed that the organic matter content of the soil affected the GR24 dissipation rate. These findings were also confirmed by analytical LC–MS/MS, indicating the applicability of the methodology for studies of root exudes. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) is increasingly prevalent globally. However, the frequent and prolonged use of corticosteroids, which are commonly employed for AD treatment, carries potential side effects. Korean mistletoe (Viscum album L. var. coloratum), a perennial parasitic plant, has demonstrated various biological effects. In this study, we conducted in vivo investigations to determine whether Korean mistletoe possesses anti-inflammatory effects that play pivotal roles in regulating the pathological mechanisms of AD. BALB/c mice with AD-like skin lesions induced by 2,4-dinitrochlorobenzene (DNCB) were utilized to explore the therapeutic effects of 1% and 2% Korean mistletoe extract (KME) ointments. The KME ointment was topically applied to the dorsal surface of the BALB/c mice, and they were categorized into four distinct groups: normal, DNCB-induced, DNCB-induced with 1% KME ointment, and DNCB-induced with 2% KME ointment. Each assessment parameter employed to evaluate the curative impact of the KME ointment displayed improvement with the application of the 1% KME ointment. While the effects observed were less pronounced than those of the 1% KME ointment, the overall therapeutic outcomes were also evident with the utilization of the 2% KME ointment. The results suggest the potential of Korean mistletoe as a viable therapeutic agent for AD. Further investigations are warranted to elucidate the underlying mechanisms of action. [ABSTRACT FROM AUTHOR]

Tobacco (Nicotiana tabacum L.) is one of the most important crops in southern Brazil, but little is known about the distribution and diversity of plant parasitic nematodes (PPNs). We surveyed the occurrence and diversity of PPNs in 36 tobacco‐growing areas in southern Brazil as well as evaluated their relationship with 19 bioclimatic variables. For these purposes, extracted nematodes (from soil and roots) were identified based on morphological and biochemical traits and estimates of incidence and abundance were obtained, which were used to compute diversity indices. Furthermore, the relationship between taxa and diversity and the influence of bioclimatic variables were studied using principal component analysis (PCA) and generalized linear models (GLMs), respectively. We observed diversity across the sampled sites, with values varying from 0.03 to 1.22 and from 0.05 to 0.76 according to the Shannon‐Wiener and Pielou's evenness indices, respectively. Seven genera of PPNs (Meloidogyne, Helicotylenchus, Tylenchus, Xiphinema, Pratylenchus, Paratylenchus and Mesocriconema) were identified, highlighting taxa with high incidence and abundance, such as Meloidogyne (100%; 1800 to 41,850 specimens/250 cm3), Helicotylenchus (100%; 50 to 9850 specimens/250 cm3), and Pratylenchus (86.1%; 50 to 1950 specimens/250 cm3). The PCA disclosed the major roles of Meloidogyne, Tylenchus, and Helicotylenchus in the structure of the PPN communities and their interplays. Among root‐knot nematodes, Meloidogyne javanica, M. arenaria and M. incognita were the predominant species. Using GLMs, we found that average annual temperature and annual precipitation strongly influenced the abundance of PPNs as well as the diversity indices (p <.01), with negative and/or positive interactions. Collectively, our findings fill gaps in knowledge about the current impact of PPNs and provide insights into future scenarios, including for other host crops. [ABSTRACT FROM AUTHOR]

Intraspecific autoparasitism, the phenomenon in which a parasite serves as the host for another individual of the same species, is a well-described interaction among hemiparasitic flowering plants. Here, I describe a rare case of autoparasitism in Epifagus virginiana (L.) W.P.C. Barton (Orobanchaceae), a holoparasitic plant normally found exclusively on the roots of Fagus grandifolia Ehrh. (Fagaceae). Confirmation of the autoparasitic relationship was obtained through microtomography and anatomical analyses. Results show the presence of vessel connections between the two E. virginiana plants and the unobstructed passage of solutes from one plant to another, thus suggesting the autoparasitic connection to be fully functional. While several segments of nearby host roots were entangled with the adventitious roots of the parasite, no parasite–host vascular connection was detected. Additionally, an analysis of digitized herbarium specimens showed that albeit rare, the observed autoparasitic relationship in E. virginiana is not a one-of case. A total of 3097 digitized herbarium specimens were also analyzed, among which 1.69% were observed to potentially include an autoparasitic connection. Altogether, these results provide new clues for the investigation of host-specificity and haustorium development processes in parasitic flowering plants. [ABSTRACT FROM AUTHOR]

Mistletoes have a fraught public relations history. Vilified as toxic tree-killing weeds, they have long been targeted for removal by arborists and forest managers concerned with tree health. Research on mistletoe ecology has revealed their positive influence on diversity and community structure via complex networks of interactions. In areas where mistletoe has traditionally been removed, managers are now asking whether these parasitic plants can return on their own or whether they should be reintroduced. To evaluate the practicalities of mistletoe restoration, we inoculated 28 London plane trees Platanus × acerfolia (Aiton) Willd. in inner Melbourne with creeping mistletoe Muellerina eucalyptoides (DC.) Barlow, a locally rare species. Branch dimensions and aspect had no discernible effect on germination or seedling emergence, but trees where access to possums (Trichosurus vulpecula (Kerr, 1792) and Pseudocheirus peregrinus (Boddaert, 1785)) was restricted were 30% more likely to host seedlings. Five years after inoculation, seven mistletoes successfully established on five trees, with two mistletoes bearing fruit. Communications with residents and city users elicited positive feedback, catalysing four additional inoculation trials in urban and forest settings elsewhere. In addition to representing a cost-effective means of enhancing habitat values, mistletoe restoration is useful for addressing open questions about mistletoe ecology and educating the community about the functional roles these parasitic plants play. [ABSTRACT FROM AUTHOR]

Flowers of most Piperales do not reward pollinators. However, a few mutualistic pollination relationships have been proposed among the perianth-bearing species. To test the hypothesis of a mutualistic relationship between Prosopanche and beetle pollinators, we studied the pollination biology of three species (P. americana , P. bonacinae , P. panguanensis). For all three species, we recorded flower visitors and flower volatile organic compounds (VOCSs). In addition, for P. americana we investigated flower phases, thermogenesis, visitors' behaviour, and viability of transported pollen. Using a behavioural experiment, we identified the role of flower heat and fragrance in pollinator attraction. We recorded Neopocadius nitiduloides and Lasiodactylus sp. sap beetles (Nitidulidae) as main pollinators and Hydnorobius hydnorae and H. helleri weevils (Belidae) as occasional pollinators. Thermogenic female flowers heat up to 8°C above the ambient temperature. Flowers only trap the small-sized sap beetles. Methyl-3-methyl-2-butenoate dominated the VOC profile. This was a powerful attractant for sap beetles in controlled bioassays. We conclude that pollination in Prosopanche is mutualistic. This was observed through a pollinator-size-based access limit to the stigmatic chamber and a strong olfactory attractant. Mutualism in Prosopanche therefore contrasts with that of most perianth-bearing Piperales, suggesting it is a novel pollination relationship in early-diverging angiosperms. [ABSTRACT FROM AUTHOR]

SUMMARY: Seeds of the root parasitic plant Striga hermonthica undergo a conditioning process under humid and warm environments before germinating in response to host‐released stimulants, particularly strigolactones (SLs). The plant hormone abscisic acid (ABA) regulates different growth and developmental processes, and stress response; however, its role during Striga seed germination and early interactions with host plants is under‐investigated. Here, we show that ABA inhibited Striga seed germination and that hindering its biosynthesis induced conditioning and germination in unconditioned seeds, which was significantly enhanced by treatment with the SL analog rac‐GR24. However, the inhibitory effect of ABA remarkably decreased during conditioning, confirming the loss of sensitivity towards ABA in later developmental stages. ABA measurement showed a substantial reduction of its content during the early conditioning stage and a significant increase upon rac‐GR24‐triggered germination. We observed this increase also in released seed exudates, which was further confirmed by using the Arabidopsis ABA‐reporter GUS marker line. Seed exudates of germinated seeds, containing elevated levels of ABA, impaired the germination of surrounding Striga seeds in vitro and promoted root growth of a rice host towards germinated Striga seeds. Application of ABA as a positive control caused similar effects, indicating its function in Striga/Striga and Striga/host communications. In summary, we show that ABA is an essential player during seed dormancy and germination processes in Striga and acts as a rhizospheric signal likely to support host infestation. Significance Statement: The root parasitic plant Striga hermonthica is a severe threat to cereal's yield, endangering global food security. Herein, we uncover a new role of known plant hormone abscisic acid as a rhizospheric signal released by germinated Striga seeds, allowing them to better compete with surrounding un‐conditioned seeds and facilitating host infestation. Our findings can help in developing strategies to control this parasite and mitigate its negative impact on food supply and income of smallholder farmers. [ABSTRACT FROM AUTHOR]

Strigolactone (SL) biosynthesis inhibitors have shown impressive activity in increasing shoot branching and inhibiting seed germination of the root parasitic plants Striga spp. and Orobanche spp. Herein, novel 1H-1,2,4-triazole derivatives were designed as SL biosynthesis inhibitors based on the backbone modification strategy, 33 target compounds were chemical synthesized and screened on Arabidopsis thaliana and Oryza sativa. The structure–activity relationship analysis enabled the discovery of a potential SL biosynthesis inhibitor B4 with the promising activity in increasing shoot branching, elongating taproot by inhibiting the biosynthesis of 4-deoxyorobanchol (4DO). We further found that B4-treated A. thaliana showed increased branching phenotype with the upregulated gene expression of AtMAX3 and AtMAX4. These results indicated that B4 might be a potent SL biosynthesis inhibitor and provide a unique scaffold for the development of new SL biosynthesis inhibitors. [ABSTRACT FROM AUTHOR]