Wild Grasses Research Articles

Assessment of environmental radiological impact in former metallic mines in Extremadura (Spain): A case study

Metal mining in the Extremadura region was very important in the 19th and 20th centuries. However, due to different reasons the great majority of mines ceased operations, leading to plenty of abandoned mining sites, most of them with on-site waste dumps. Although metal extraction is not radioactive per se, it is considered a NORM activity. In this study, three former mining sites, in which Pb-V-Zn-Ag, Pb-Ag, and Pb-Zn were extracted, were selected to assess the radiological impact on the population and the environment. The external γ exposure was estimated by determining the effective dose and elaborating isodose maps of the sites. The presence of the mining sites increased up to 0.41 mSv/y the effective dose over the surrounding background, which is below the reference value of 1 mSv/y. In only one mining site, the uranium and radium activity concentration of waste dumps were higher than the surrounding soil. The soil to plant (wild grass) transfer factors were similar to other reported values without the influence of NORM activities. So, no enhanced transfer of radionuclides was observed. The radiological impact on the environment was assessed by the risk to non-human biota using the tiered approach developed in ERICA Tool. The sum of the risk quotients of all considered radionuclides in the most conservative Tier 1 was below 1. Total dose rates for several terrestrial Reference Animal and Plants (RAPs) were estimated using Tier 3, obtaining values below 40 µGy/h. Therefore, the impact on non-human biota can be considered as negligible.

Metabolomic characterization of alkali stress responses in rice

Soil alkalinity due to the accumulation of alkaline salts greatly impairs crop production. Despite advancements in crop stress response studies through metabolomic analyses, limited progress has been made in understanding cultivar differences in alkali tolerance due to the scarcity of suitable genetic material. This study aimed to characterize the metabolic responses to alkali stress in two rice cultivars, Kasalath (alkali-sensitive) and Gharib (alkali-tolerant), which were screened in an alkali soil field. A metabolomic analysis of the responses of hydroponically grown seedlings of both cultivars to alkaline and neutral salt stress was performed. Under alkali stress, the tolerant cultivar Gharib showed a significant accumulation of metabolites from the TCA organic acid and arginine synthesis pathways. This accumulation is consistent with observations in alkaliphilic wild grasses and may account for the superior alkali tolerance of Gharib. Although amino acids and nitrogen-containing metabolites, such as asparagine and allantoin, also accumulated under alkali stress, their accumulation was not specific to alkali stress, as previously reported. They accumulated similarly in both Kasalath and Gharib, suggesting that while these metabolites may alleviate alkali stress, they are unlikely to be responsible for cultivar differences in rice alkali tolerance.

Transposition of HOPPLA in siRNA-deficient plants suggests a limited effect of the environment on retrotransposon mobility in Brachypodium distachyon.

Long terminal repeat retrotransposons (LTR-RTs) are powerful mutagens regarded as a major source of genetic novelty and important drivers of evolution. Yet, the uncontrolled and potentially selfish proliferation of LTR-RTs can lead to deleterious mutations and genome instability, with large fitness costs for their host. While population genomics data suggest that an ongoing LTR-RT mobility is common in many species, the understanding of their dual role in evolution is limited. Here, we harness the genetic diversity of 320 sequenced natural accessions of the Mediterranean grass Brachypodium distachyon to characterize how genetic and environmental factors influence plant LTR-RT dynamics in the wild. When combining a coverage-based approach to estimate global LTR-RT copy number variations with mobilome-sequencing of nine accessions exposed to eight different stresses, we find little evidence for a major role of environmental factors in LTR-RT accumulations in B. distachyon natural accessions. Instead, we show that loss of RNA polymerase IV (Pol IV), which mediates RNA-directed DNA methylation in plants, results in high transcriptional and transpositional activities of RLC_BdisC024 (HOPPLA) LTR-RT family elements, and that these effects are not stress-specific. This work supports findings indicating an ongoing mobility in B. distachyon and reveals that host RNA-directed DNA methylation rather than environmental factors controls their mobility in this wild grass model.

Development of a prototype of weeding robot

Weeds, or wild grasses, are naturally occurring grasses that grow in the wild without human cultivation. Weeds have detrimental effects on soil and crops, including competing with crops for space, nutrients, light, and moisture in the soil, which ultimately reduces crop productivity. Typically, herbicides are used to eliminate weeds, but all of these chemicals carry a potential threat to human well-being. This article presents a detailed plan for building a DELTA robot that is specifically engineered to eliminate weeds in agricultural environments. This article presents a systematic approach encompassing research, kinematics calculation, robot control, and the fabrication of a weed-killing robot prototype. The article proposes a prototype of a weed-killing robot with simple operation suitable for Vietnam’s economic conditions. The experiments show that the robot can effectively remove different types of weeds from lettuce fields. The results show that the proposed prototype is completely capable of replacing humans, helping to improve productivity as well as protect health and help farmers avoid unwanted effects from herbicide chemicals.

Symbiotic fungi from a wild grass (Celtica gigantea) increase the growth, grain yield and quality of tritordeum under field conditions.

Plants function in symbiosis with numerous microorganisms, which might contribute to their adaptation and performance. In this study, we tested whether fungal strains in symbiotic interaction with roots of Celtica gigantea, a wild grass adapted to nutrient-poor soils in semiarid habitats, could improve the field performance of the agricultural cereal tritordeum (Triticum durum × Hordeum chilense). Seedlings of tritordeum were inoculated with 12 different fungal strains isolated from roots of Celtica gigantea that were first proved to promote the growth of tritordeum plants under greenhouse conditions. The inoculated seedlings were transplanted to field plots at two locations belonging to different climatic zones in terms of mean temperatures and precipitation in the Iberian Peninsula. Only one strain, Diaporthe iberica T6, had a significant effect on plant height, number of tillers and grain yield in one location. This result showed a substantial divergence between the results of greenhouse and field tests. In terms of grain nutritional quality, several parameters were differentially affected at both locations: Diaporthe T6, Pleosporales T7, Zygomycota T29 and Zygomycota T80 increased the content of total carotenoids, mainly lutein, in the colder location; whereas gluten proteins increased with several treatments in the warmer location. In conclusion, early inoculation of tritordeum plants with fungal symbionts had substantial beneficial effects on subsequent plant growth and development in the field. Regarding grain nutritional quality, the effect of inoculation was affected by the agroclimatic differences between both field locations.

Enrichment and Diversification of the Wheat Genome via Alien Introgression

Wheat, including durum and common wheat, respectively, is an allopolyploid with two or three homoeologous subgenomes originating from diploid wild ancestral species. The wheat genome’s polyploid origin consisting of just three diploid ancestors has constrained its genetic variation, which has bottlenecked improvement. However, wheat has a large number of relatives, including cultivated crop species (e.g., barley and rye), wild grass species, and ancestral species. Moreover, each ancestor and relative has many other related subspecies that have evolved to inhabit specific geographic areas. Cumulatively, they represent an invaluable source of genetic diversity and variation available to enrich and diversify the wheat genome. The ancestral species share one or more homologous genomes with wheat, which can be utilized in breeding efforts through typical meiotic homologous recombination. Additionally, genome introgressions of distant relatives can be moved into wheat using chromosome engineering-based approaches that feature induced meiotic homoeologous recombination. Recent advances in genomics have dramatically improved the efficacy and throughput of chromosome engineering for alien introgressions, which has served to boost the genetic potential of the wheat genome in breeding efforts. Here, we report research strategies and progress made using alien introgressions toward the enrichment and diversification of the wheat genome in the genomics era.

Testing the presence of cereal-type pollen grains in coastal pre-Elm Decline peat deposits: Fine-resolution palynology at Roudsea Wood, Cumbria, UK

By the time of the Mid-Holocene Ulmus pollen decline (UD) ca. 5100 14C bp (ca. 5900 cal. BP), the Neolithic was becoming well established in Britain and Ireland. The importance of cereal cultivation as part of the initial neolithization process in the British Isles is uncertain, as archaeological sites of the first Neolithic remain elusive. Palaeoecologists have recorded cereal-type pollen grains in peat deposits that pre-date the UD significantly, but as some wild grasses can produce pollen that closely resembles cereal pollen grains, these early pollen records are not trusted as evidence of cereal cultivation. Some of these wild grass taxa grow in coastal wetland environments, making cereal-type pollen from such locations particularly open to question. This study uses fine-resolution palynology through a sequence of coastal hydroseral deposits that contain no evidence of human activity, to look for the presence of wild grass pollen of cereal size and morphology. Our results show that while such grains are not recorded at 1 cm resolution, at contiguous 2 mm resolution sampling sporadic occurrences of large grass pollen of possible cereal-type, resembling Hordeum, were detected. Morphology suggests that these cereal-type grains are of wild grass origin, almost certainly Glyceria, but their presence suggests that high-resolution analyses of coastal zone sediments will often discover cereal-type grains. Great care must be taken in identifying cereal-type pollen in coastal palaeo-wetland sediments, and rigorous identification protocols should be applied. Where grains could still be of cultivated cereal-type, the presence of other disturbance indicators is an important factor in inferring their origin.

First evidence for human occupation of a lava tube in Arabia: The archaeology of Umm Jirsan Cave and its surroundings, northern Saudi Arabia.

Recent advances in interdisciplinary archaeological research in Arabia have focused on the evolution and historical development of regional human populations as well as the diverse patterns of cultural change, migration, and adaptations to environmental fluctuations. Obtaining a comprehensive understanding of cultural developments such as the emergence and lifeways of Neolithic groups has been hindered by the limited preservation of stratified archaeological assemblages and organic remains, a common challenge in arid environments. Underground settings like caves and lava tubes, which are prevalent in Arabia but which have seen limited scientific exploration, offer promising opportunities for addressing these issues. Here, we report on an archaeological excavation and a related survey at and around Umm Jirsan lava tube in the Harrat Khaybar, north-western Saudi Arabia. Our results reveal repeated phases of human occupation of the site ranging from at least the Neolithic through to the Chalcolithic/Bronze Age. Pastoralist use of the lava tube and surrounding landscape is attested in rock art and faunal records, suggesting that Umm Jirsan was situated along a pastoral route linking key oases. Isotopic data indicates that herbivores primarily grazed on wild grasses and shrubs rather than being provided with fodder, while humans had a diet consistently high in protein but with increasing consumption of C3 plants through-time, perhaps related to the emergence of oasis agriculture. While underground and naturally sheltered localities are globally prominent in archaeology and Quaternary science, our work represents the first such combined records for Saudi Arabia and highlight the potential for interdisciplinary studies in caves and lava tubes.

Development of yellow rust in grain crops and wild cereal grasses and damage to winter wheat varieties

Factors that determine the degree of development of wheat brown rust are the influence of temperature (the growth limits of uredospores are from 2 to 32 °C with an optimum of 15-20 °C) and the effect of a drop of liquid for at least 4-6 hours. Under favorable conditions, the causative agent of brown rust can reduce the yield of wheat by up to 45%, and in the case of epiphytotic development at the germination stage by 80-100%, and damage to the grain can reach 50%. In the North Kazakhstan, Kostanay and Akmola regions, epiphytotic brown rust of wheat was found in cereals, including triticale. For successful breeding, it is important to find new resistance genes in the host plant.Yellow rust of wheat is a disease that affects more than 20 species of cultivated and wild cereals, including wheat, rye, barley, wheatgrass, Aegilops and others. As a result, the development of stripe rust disease was detected in four wild and cultivated grain crops. It has been established that the sources of infection are wild species of grain crops.

Nutrient and Microbiome-Mediated Plant-Soil Feedback in Domesticated and Wild Andropogoneae: Implications for Agroecosystems.

Plants influence the abiotic and biotic environment of the rhizosphere, affecting plant performance through plant-soil feedback (PSF). We compared the strength of nutrient and microbe-mediated PSF and its implications for plant performance in domesticated and wild grasses with a fully crossed greenhouse PSF experiment using four inbred maize genotypes (Zea mays ssp. mays b58, B73-wt, B73-rth3, and HP301), teosinte (Z. mays ssp. parviglumis), and two wild prairie grasses (Andropogon gerardii and Tripsacum dactyloides) to condition soils for three feedback species (maize B73-wt, teosinte, Andropogon gerardii). We found evidence of negative PSF based on growth, phenotypic traits, and foliar nutrient concentrations for maize B73-wt, which grew slower in maize-conditioned soil than prairie grass-conditioned soil. In contrast, teosinte and A. gerardii showed few consistent feedback responses. Both rhizobiome and nutrient-mediated mechanisms were implicated in PSF. Based on 16S rRNA gene amplicon sequencing, the rhizosphere bacterial community composition differed significantly after conditioning by prairie grass and maize plants, and the final soil nutrients were significantly influenced by conditioning, more so than by the feedback plants. These results suggest PSF-mediated soil domestication in agricultural settings can develop quickly and reduce crop productivity mediated by PSF involving changes to both the soil rhizobiomes and nutrient availability.

Determination of the main flavonoids in ojo de gallo (Sanvitalia procumbens Lamarck) yerba extracts from three different sites as potential biomolecules

This work focuses on determining the main flavonoids with medicinal effects present in the wild ojo de gallo plant endemic to the State of Guanajuato in Mexico. For this purpose, the concentration of kaempferol, catechin, and rutin was determined in the wild ojo de gallo grass collected from three different sites in the state of Guanajuato (Comedero Grande, Ex – Hacienda de Márquez, and Tejamanil). The dehydration process of the plant was carried out later to determine the concentration of the metabolites of interest using the high-performance liquid chromatography (HPLC) technique. A statistical analysis was carried out to determine the relationship between the concentration of each metabolite and the various collection sites, also considering the results of the fertility analysis. The results show that the highest concentration for kaempferol was obtained in Ex – Hacienda de Márquez with a value of 24.15 ppm, while for catechin and rutin, it was in Tejamanil reporting values of 26.52 ppm and 46.98 ppm, respectively. The statistical analysis shows no significant difference between Ex -Hacienda de Márquez and Tejamanil for the three metabolites. These results indicate that the site called Comedero Grande favors the presence of kaempferol and rutin while the site called Tejamanil favors the presence of catechin; this opens the possibility of future studies that allow finding the appropriate conditions to maximize the flavonoids of interest in this plant.

Taxonomic Analysis of Early Spring Plants of Shabran District Flora

Studies the early spring flora of the Shabran district, provides a taxonomic analysis of wild grasses, populations of species belonging to the Ophrys and Orchis genera of the Orchidaceae family, the genus Tulipa of the Liliaceae family, the genera Muscariand Bellevalia of the Asparagaceae family, as well as the new range of the species Spiranthes spiralisfor the study area. The data is mapped based on GPS coordinates. As a result of our research in the Shabran district, 26 species belonging to 13 families and 23 genera were identified. Among the herbarium materials there are rare species listed in the Red Book of the Azerbaijan Republic (Crocus adami, Galanthus caucasica, Pyrus salicifolia, Rosa sosnovskyi, Tulipa biebersteiniana, Orchis oestrifera, Ophrys caucasica, etc.).

Sequencing report of the rRNA amplicons of Echinochloa crus-galli in Iraq

This study was conducted to identify the genetic polymorphisms of one wild grass sample species and assess the phylogenetic distribution these isolates occupy based on their internal transcribed (ITS) ribosomal sequences. This study amplified one genetic locus covering a portion of the ITS rRNA sequences. A direct sequencing strategy was performed for the observed PCR amplicons in the amplified genetic locus. Subsequently, a comprehensive phylogenetic tree was constructed in the observed variants for these sequences to reveal the accurate phylogenetic distances alongside other relative sequences. Our results indicated the identity of the investigated wild grass samples (assigned S1 and S2). Sequencing reactions indicated that our investigated samples belonged to Echinochloa crusgalli var. crus-galli (panicum grass), a common wild grass dominated in tropical Asia. Two ribosomal variations were identified in the investigated wild grass samples, 61C>T, observed in the S2 sample and 408C>A, observed in both the S1 and S2 samples. According to the identified results, the investigated samples were positioned within one distinct phylogenetic clade of these identified wild grass sequences in the currently generated comprehensive tree. These positionings were observed within the main clade of Echinochloa crus-galli. Based on the identified ribosomal sequences, it was found that the currently investigated samples may exhibit variable extents of diversities originating from several Asian and South American ancestors. Also, the currently constructed tree revealed that the investigated wild grass sequences belonged to one distinct clade of Echinochloa crus-galli, having many sequences of close phylogenetic connections. This clade occupied far away phylogenetic positions from the other comparable grasses within the same tree. Keywords: rRNA amplicons, Echinochloa crus-galli, Rice

Silicon-based anti-herbivore defense in tropical tree seedlings.

Silicon-based defenses deter insect herbivores in many cultivated and wild grass species. Furthermore, in some of these species, silicon (Si) uptake and defense can be induced by herbivory. Tropical trees also take up Si and leaf Si concentrations vary greatly across and within species. As herbivory is a major driver of seedling mortality and niche differentiation of tropical tree species, understanding anti-herbivore defenses is pivotal. Yet, whether silicon is a constitutive and inducible herbivory defense in tropical forest tree species remains unknown. We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil Si concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiple-choice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar (Spodoptera frugiperda). Leaf damage was assessed. Three species showed a significant decrease in leaf damage under high compared to low Si conditions (by up to 72%), consistent with our expectation of Si-based defenses acting in tropical tree species. In one species, leaf damage was increased by increasing soil Si and in four species, no effect of soil Si on leaf damage was observed. Opposite to our expectation of Si uptake and defense being inducible by herbivory damage, simulated herbivory increased leaf damage in two species. Furthermore, simulated herbivory reduced Si concentrations in one species. Our results showed that tropical tree seedlings can be better defended when growing in Si-rich compared to Si-poor soils, and that the effects of Si on plant defense vary strongly across species. Furthermore, Si-based defenses may not be inducible in tropical tree species. Overall, constitutive Si-based defense should be considered part of the vast array of anti-herbivore defenses of tropical tree species. Our finding that Si-based defenses are highly species-specific combined with the fact that herbivory is a major driver of mortality in tropical tree seedling, suggests that variation in soil Si concentrations may have pervasive consequences for regeneration and performance across tropical tree species.

A Burning Grass and Removing Root Immunoregulatory Strategy Toward Chronic Wounds Therapy by MnO2 Nanoparticle Incorporated Hyaluronic Acid Hydrogel

AbstractComplex immune microenvironment of diabetic wound possesses polarization misalignment of macrophages and excessive inflammatory response, which prolong the healing process. Consequently, developing hydrogel dressings with immunoregulatory ability shows huge potential in clinical management of diabetic wound. Nevertheless, recent immunoregulatory strategies are mainly focusing on switching the proinflammatory M1‐type to anti‐inflammatory M2‐type macrophages by using high‐cost dressings composed of cytokines and cells. Considering the hyperpolarized M1 macrophages of diabetic wounds as wild grass of wasteland, a burning grass and removing root immunoregulatory strategy toward wound healing is developed based on dopamine‐manganese dioxide nanoparticle incorporated high molecular weight hyaluronic acid (HHA) hydrogel. The self‐healing and injectable hydrogel is formed by boronate ester bonds between the HHA grafted with phenylboronic acid and polyvinyl alcohol. Notably, in vitro and vivo results confirm that the HHA components can burn the grass by switching M1 to M2 in the inflammatory microenvironment while the dopamine‐manganese dioxide nanoparticles can remove the root by relieving M1 polarization through eliminating reactive oxygen species. The comprehensive immunoregulation ability enables the hydrogel as effective therapeutic that improves wound healing, and shows reliable potential in clinical dressings for the management of diabetic wounds.

Exploring agronomic traits and breeding prospects of primary tritipyrum and triticale lines to increase grain yield potential

A study was conducted to evaluate 13 non-Iranian primary tritipyrum (AABBEbEb, 2n=6x=42) as new amphiploid cereal derived from the hybridization of wild sand couch grass species, Thinopyrum bessarabicum (2n=4x=14, EbEb) and durum (Triticum durum, 2n=4x=28, AABB) wheat and five promising triticales for 31 different phenological and agronomic traits in a randomized complete block design (RCBD) with three replications under field conditions. The analysis of variance (ANOVA) showed significant differences between genotypes for most of the studied traits. The factor analysis results revealed five factors that almost explained 89% of the total variance. The stepwise regression and path coefficient analyses revealed that the number of grains per spike and harvest index were the most important traits contributing to the high-yield of the genotypes. Cluster analysis grouped 18 lines into three diverse genotypic clusters. Cluster III included 4115, 4116, and M45 triticale lines indicating the highest value for harvest index as well as grain yield and its components. The non-Iranian primary combined tritipyrum line, (Ka/b)(Cr/b)-5 and promising triticale line No. 4116, showed the highest values for grain-related traits, and therefore these lines may be used in further breeding programs to develop new commercial cereal hybrid/cultivars. Overall, the results indicated grain number per spike and harvest index could be utilized as the key selection criteria in breeding for improvement of grain yield in primary tritipyrum and triticale genotypes.

Assessment of dose rates to non-human biota from radioactive discharges from Sellafield Ltd. using PC-CREAM

PC-CREAM is a tool for assessing the radiological impact of routine discharges of radionuclides to the environment. It can be used for prospective assessments, to calculate doses to members of the public for authorisation of proposed discharges, or for retrospective assessments of previous discharges where doses are compared with dose limits. These types of assessment are a fundamental requirement of regulations governing the control of radioactive discharges. However, the latest publications of the basic safety standards for radiation protection, EU (Council of the European Union, 2014) and the IAEA (IAEA, 2014), now include the requirement to demonstrate protection of the environment as well as members of the public. To this end, a module has been added to PC-CREAM for calculating dose rates to non-human biota (Anderson et al., 2022). The methodology used for this calculation is based on the recommendations contained in ICRP Publication 108 (ICRP, 2008), which provides a general framework for protection of the environment. The additional module means that PC-CREAM can be used to assess doses to humans and dose rates to biota in an integrated way, for the same set of discharges and using the same dispersion models. This paper describes an assessment of dose rates to biota living in the vicinity of the Sellafield nuclear site, carried out using the new biota module of PC-CREAM. Historical discharges from Sellafield to the sea and atmosphere were considered for the period 1951 to 2017, excluding those from the Windscale fire in 1957. Dose rates calculated for marine biota (flatfish, crabs and brown seaweed) are less than 1 mGy d−1 and are below the lower derived consideration reference level (DCRL) for the ICRP marine reference animals and plants (RAPs). Dose rates for terrestrial biota (bees, deer, earthworms, frogs, wild grass, pine trees and rats) are less than the relevant lower DCRL for terrestrial RAPs, ie 0.1 mGy d−1. Dose rates were also calculated for a user defined organism ‘seabird’ to represent birds which inhabit both marine and terrestrial environments near Sellafield. For seabird, the lower DCRL of 0.1 mGy d−1 is exceeded throughout the 1950s, 1960s and 1970s, when the discharges were at their highest, due to exposures from the marine environment. Since the mid-1980s, no dose rates were calculated that exceeded the lower DCRLs.

Bio- accumulation of Cd, Cr, Cu, Ni and Pb in a wild grass, Parthenium hysterophorus L. Asteraceae, growing naturally on barren land and evaluation of phyto-extraction potential of the plant for studied metals

Because of the inbuilt bio-accumulation mechanism several plants have shown a remarkable capability of accumulation of metals from contaminated soil into roots, tubers and upper parts of the plants. This study was undertaken to evaluate the bio-accumulation potential of a wild grass, Parthenium hysterophorus L., Asteraceae grown on the barren land along with the National highways for Cd, Cr, Cu, Ni and Pb by determining the bio-accumulated levels of these metals in the samples of soil, roots and shoot of the plant. The various bio-concentration factors (BCFs), translocation factors (TFs) and Biological accumulation coefficients (BACs) for studied metals were evaluated, to find out the suitability of Parthenium plant for phyto-extration of the studied metals. The order of observed levels of heavy metals in the samples of soil, root and shoots were: Pb (8.12±0.48) > Cr (7.18± 0.39) > Cu (5.64± 0.26) > Ni (3.91± 0.21) > Cd (1.31± 0.08) and Pb (6.67± 0.34) > Cu (6.11 ±0.27) >Cr (6.05± 0.23) >Ni (4.14± 0.18) > Cd (1.42± 0.11) and Pb (7.22±0.29) > Cr (5.97±0.23)>Cu (5.96 ±0.25)>Ni (5.13±0.21) > Cd (1.70±0.14 mg/Kg, dw), respectively. The soil to roots bio-concentration factors, BCFRoot for studied metals were: Cd (1.08) > Cu (1.08) >Ni (1.06) > Cr (0.84)>Pb (0.82). The order of root to shoot translocation factors, TFShoot for these metals in Parthenium hysterophorus L., was: Ni (1.24) > Cd (1.20) > Pb (1.08) > Cr (0.99~1.00)> Cu (0.98~1.00). The various soil to shoot biological accumulation coefficients, BACShoot for studied metals in Parthenium plant were, Ni (1.31) > Cd (1.30)> Cu (1.06) > Pb (0.89) >Cr (0.83), respectively. Comparatively higher BCF >1, TF >1 and higher BAC values for metals under study suggested that the plant Parthenium hysterophorus L has potential to translocate these metals to the above ground parts of the plants and thereby their phyto-extraction from contaminated soil.

Highly Aggressive Invasive Race Group PstS2 in Russian Populations of the Wheat Yellow Rust Pathogen

The expansion of the area of harmfulness of the wheat yellow rust pathogen (Puccinia striiformis) (Pst) has be observed all over the world in the 2000s. This is due to the emergence of new highly aggressive invasive groups of races PstS1 and PstS2, adopted to the high temperatures, and also as a result of virulence mutations of regional pathogen populations. SCAR-markers were developed for identification of invasive races, and pathogen collections from many countries were studied. In these studies in first in Russia, the analysis of regional populations of P. striiformis for the presence of invasive races PstS1 and PstS2 was carried out. Single pustule isolates were obtained from urediosamples collected from common and durum wheat, triticale and wild grasses in seven regions of the Russian Federation (North Caucasian, Northwestern, Central Black Earth, Lower Volga, Middle Volga, Volga–Vyatka, West Siberian) in 2019–2020. In total 82 isolates were studied. Using SCAR markers, three genotypes were identified in the studied collection of P. striiformis, and one of which belongs to the invasive group PstS2. The other two genotypes had a different origin (other). Isolates of PstS2 group were received from pathogen population samples collected in the Russian Northwest in 2020. Virulence analysis revealed two phenotypes among them: PstS2_R1 (3 isolates) and PstS2_R2 (1 isolate). According to information from the Global Rust Reference Center (http://www.wheatrust.org/), the main characteristic of isolates from invasive PstS2 group is virulence to wheat lines with resistance genes Yr2, Yr6, Yr7, Yr8, Yr9, and Yr25. The Russian R1 phenotype PstS2 was also characterized by virulence to these genes, as well as to Yr1, Yr32, and YrSp. The PstS2_R2 phenotype differed from PstS2_R1 for avirulence to Yr25 and virulence to Yr3 and Yr4. The main difference of Russian PstS2 isolates with detected in other countries is virulence to wheat lines with genes Yr4, Yr32, and YrSp. The first detection of invasive races in the Northwest of Russia indicates the relevance of annual monitoring of regional populations of P. striiformis.

Prevalence and Importance of the Necrotrophic Effector Gene ToxA in Bipolaris sorokiniana Populations Collected from Spring Wheat and Barley.

Bipolaris sorokiniana is a necrotrophic fungal pathogen that causes foliar and root diseases on wheat and barley. These diseases are common in all wheat- and barley-growing regions, with more severe outbreaks occurring under warm and humid conditions. B. sorokiniana can also infect a wide range of grass species in the family Poaceae and secrete ToxA, an important necrotrophic effector also identified other wheat leaf spotting pathogens. In this study, the prevalence and virulence role of ToxA were investigated in a collection of 278 B. sorokiniana isolates collected from spring wheat and barley in the Upper Midwest of the United States or other places, including 169 from wheat leaves, 75 from wheat roots, 30 from barley leaves, and 4 from wild quack grass leaves. ToxA was present in the isolates from wheat leaves, wheat roots, and wild grass leaves but was absent from isolates collected from barley leaves. Prevalence of ToxA in wheat leaf isolates (34.3%) was much higher than that in wheat root isolates (16%). Sequencing analysis revealed the presence of two haplotypes, with the majority being BsH2. All ToxA+ isolates produced the functional effector in liquid cultures. Pathogenicity assays revealed that ToxA+ isolates caused significantly more disease on spring wheat lines harboring Tsn1 than their tsn1 mutants, suggesting that the ToxA-Tsn1 interaction plays an important role in spot blotch development. This work confirms the importance of ToxA in B. sorokiniana populations infecting wheat and, thus, the need to eliminate Tsn1 from spring wheat cultivars to reduce susceptibility to spot blotch.