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1.
Chemosphere ; 286(Pt 2): 131764, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34364229

RESUMO

In this study, a novel and sustainable approach was used to synthesize nitrogen-doped carbon dots (NCDs) from the waste biomass of Poa Pratensis (Kentucky bluegrass (KB)) by a facile hydrothermal method. The prepared KBNCDs were subjected to various characterization techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Fourier-transform infrared spectroscopy to verify the formation of carbon dots and their surface functional groups. The KBNCDs exhibited good hydrophilic fluorescence (FLU) properties with an acceptable quantum yield (7%). The synthesized KBNCDs showed excitation wavelength-dependent FLU emission behavior with strong cyan-blue FLU upon irradiation with 365 nm UV-light. The hydrophilic optical properties of the as-synthesized KBNCDs were used to detect Fe3+ and Mn2+ ions in an aqueous medium with good selectivity and sensitivity. It was found that the FLU of the KBNCDs is quenched in the presence of Fe3+ and Mn2+ ions, and the quenching rate was linear with the concentration of Fe3+ and Mn2+ ions. The limit of detection (LOD) of KBNCDs with metal ions was calculated using the Stern-Volmer relationship. The LOD values for Fe3+ or Mn2+ ions were calculated as 1.4 and 1.2 µM, respectively with the detection range from 5.0 to 25 µM. Based on these results, this study provides an underpinning for the development of KBNCD as FLU sensors that can be used in aqueous media.


Assuntos
Poa , Pontos Quânticos , Biomassa , Carbono , Nitrogênio
2.
Molecules ; 26(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34576920

RESUMO

Heavy metal and metalloid-contaminated soil is a serious barrier to colonization for many plant species. The problem of the elimination of toxic waste accumulated in technogenous soils in many highly transformed regions is extremely important. Hence, another attempt was made to analyze the effect of the addition of sorbents (BCH-biochar, B-bentonite, ChM-chicken manure, OS-organo-zeolitic substrate) to contaminated copper soil on the germination and early growth of Eurasian common grass species (Agrostis capillaris, A. stolonifera, Festuca rubra and Poa pratensis), which could potentially be used in recultivation. This experiment was based on the laboratory sandwich method. Standard germination indexes, morphometry and biomass analysis were used. The percentage of germinating seeds was lower in each of the soil variants and sorbents used compared to the control. Dry mass was positively stimulated by all sorbents. The response to the addition of sorbents, expressed as the electrolyte leakage of seedlings, was different depending on the species and type of sorbent. Among all sorbents, the most positive effects on germination and growth were observed in the case of OS. Overall, the response to the addition of sorbents was different in the studied species, depending on their stage of development.


Assuntos
Cobre , Poluição Ambiental , Plântula , Sementes , Solo , Carvão Vegetal , Germinação , Poa
3.
Mycologia ; 113(5): 956-967, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34236950

RESUMO

Leptosphaerulina leaf blight occurs on most turfgrasses. Hitherto, Leptosphaerulina species associated with this disease include L. americana, L. argentinensis, L. australis, and L. trifolii. However, following Koch's postulates, L. australis was confirmed as saprobes but not pathogens, and the other three species have not been tested. The pathogenicity of Leptosphaerulina spp. is still questionable. In this study, we isolated 19 Leptosphaerulina strains from diseased golf turfgrasses in China, and they were identified as L. gaeumannii, L. saccharicola, and a new species, L. macrospora, through multilocus (ITS, 28S, rpb2, and tub2) phylogenetic analyses and morphological observations. Pathogenicity test revealed that the three Leptosphaerulina species identified in this study cannot infect live/healthy turfgrass tissues of Poa pratensis and Agrostis stolonifera and only produced pseudothecia on the dead leaves of stressed seedlings. Considering the results of pathogenicity tests in this and previous studies, we speculate that most Leptosphaerulina species isolated from diseased turfgrass are not pathogens but saprobes. Applying proper management practices to prevent severe turfgrass stress is a key measure to reduce or eliminate the effects of Leptosphaerulina on golf turfgrass.


Assuntos
Agrostis , Ascomicetos , Golfe , Poa , Filogenia
4.
Pest Manag Sci ; 77(11): 4993-5000, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34218510

RESUMO

BACKGROUND: Poa annua is a pervasive grassy, self-pollinating, weed that has evolved resistance to 10 different herbicide modes-of-action, third most of all weed species. We investigated constitutive overexpression of genes associated with non-target site resistance (NTSR) in POAAN-R3 and the response of those genes when treated with trifloxysulfuron despite the biotype having a known target site mutation in acetolactate synthase (ALS). RESULTS: Despite having an ALS target site mutation, POAAN-R3 still had a transcriptomic response to herbicide application that differed from a susceptible biotype. We observed differential expression of genes associated with transmembrane transport and oxidation-reduction activities, with differences being most pronounced prior to herbicide treatment. CONCLUSIONS: In the P. annua biotype we studied with confirmed target site resistance to ALS inhibitors, we also observed constitutive expression of genes regulating transmembrane transport, as well as differential expression of genes associated with oxidative stress after treatment with trifloxysulfuron. This accumulation of mechanisms, in addition to the manifestation of target site resistance, could potentially increase the chance of survival when plants are challenged by different modes of action.


Assuntos
Acetolactato Sintase , Herbicidas , Poa , Acetolactato Sintase/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Mutação , Proteínas de Plantas/genética
5.
Plant Physiol Biochem ; 159: 312-321, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33421907

RESUMO

Poa pratensis is a perennial turfgrass used worldwide. However, shortage of irrigation and drought induced by climate change adversely affect plant growth and turf quality. Cuticular wax covers plant aerial parts and plays important roles in decreasing plant water loss under drought-stressed conditions. Previous research proposed two candidate genes that were involved in wax very-long-chain alkane biosynthesis based on the transcriptome of Poa pratensis leaf. Here, one of the candidate genes, PpCER1-2 was further characterized. A subcellular localization study revealed that PpCER1-2 was localized on the endoplasmic reticulum. The expression of PpCER1-2 could be induced by drought and salt stresses. Overexpression of PpCER1-2 in Brachypodium distachyon increased the alkane amount, whereas decreased the amounts of primary alcohols and total wax. The relative abundance of C25 and C27 alkane and C26 aldehyde increased significantly, but the relative abundance of C29 and C31 alkane and C28 aldehyde decreased. Meanwhile, PpCER1-2 overexpression lines exhibited reduced cuticle permeability and enhanced drought tolerance. These results suggested that PpCER1-2 relatively promoted alkane biosynthesis by converting more very long chain fatty acids precursors into the decarbonylation pathway from the acyl-reduction pathway. Taken together, our data suggest that PpCER1-2 is involved in wax alkane biosynthesis in P. pratensis and plays important roles in improving plant drought tolerance.


Assuntos
Alcanos , Secas , Poa , Estresse Fisiológico , Ceras , Alcanos/metabolismo , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Poa/genética , Poa/metabolismo , Estresse Fisiológico/genética , Ceras/metabolismo
6.
Plant Cell Physiol ; 61(12): 2018-2030, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32931553

RESUMO

Choline, as a precursor of glycine betaine (GB) and phospholipids, is known to play roles in plant tolerance to salt stress, but the downstream metabolic pathways regulated by choline conferring salt tolerance are still unclear for non-GB-accumulating species. The objectives were to examine how choline affects salt tolerance in a non-GB-accumulating grass species and to determine major metabolic pathways of choline regulating salt tolerance involving GB or lipid metabolism. Kentucky bluegrass (Poa pratensis) plants were subjected to salt stress (100 mM NaCl) with or without foliar application of choline chloride (1 mM) in a growth chamber. Choline or GB alone and the combined application increased leaf photochemical efficiency, relative water content and osmotic adjustment and reduced leaf electrolyte leakage. Choline application had no effects on the endogenous GB content and GB synthesis genes did not show responses to choline under nonstress and salt stress conditions. GB was not detected in Kentucky bluegrass leaves. Lipidomic analysis revealed an increase in the content of monogalactosyl diacylglycerol, phosphatidylcholine and phosphatidylethanolamine and a decrease in the phosphatidic acid content by choline application in plants exposed to salt stress. Choline-mediated lipid reprogramming could function as a dominant salt tolerance mechanism in non-GB-accumulating grass species.


Assuntos
Colina/metabolismo , Metabolismo dos Lipídeos , Poa/metabolismo , Plantas Tolerantes a Sal/metabolismo , Betaína/metabolismo , Colina/farmacologia , Colina/fisiologia , Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/fisiologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/fisiologia , Folhas de Planta/metabolismo , Poa/efeitos dos fármacos , Poa/fisiologia , Estresse Salino , Tolerância ao Sal , Plantas Tolerantes a Sal/fisiologia
7.
Pest Manag Sci ; 77(4): 1903-1914, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33284481

RESUMO

BACKGROUND: Annual bluegrass is a troublesome weed in managed turf systems. A survey was conducted to evaluate the prevalence of herbicide resistance in golf course populations of annual bluegrass in eastern Texas. Screenings were conducted for two photosystem II (PS II)-inhibitor herbicides [simazine preemergence (PRE), amicarbazone postemergence (POST)], two acetolactate synthase (ALS) inhibitors (foramsulfuron POST, trifloxysulfuron POST) and one microtubule assembly inhibitor (pronamide PRE/POST). RESULTS: Ninety percent of the populations were found to be resistant to at least one of the tested herbicides. The TX15-14 population was >490-, 178-, 10-, 26-, 4.3- and 3.8-fold, and the TX15-27 population was >490-, 16-, 28-, 84-, 5.2- and 4.1-fold less sensitive to simazine, amicarbazone, foramsulfuron, trifloxysulfuron, pronamide POST and pronamide PRE, respectively, compared to the susceptible standard TX15-SUS. Populations resistant to pronamide POST were completely controlled by pronamide PRE at the label recommended rate. The ALS and psbA gene sequence analysis indicated the presence of target site mutations (Ser-264-Gly in the psbA gene of TX15-14 and Trp-574-Leu in the ALS gene of TX15-27). However, given the absence of any target-site mutation in the ALS gene of TX15-14, the psbA gene of TX15-27 and α-tubulin of both populations, nontarget site mechanisms of resistance are suspected. CONCLUSION: This is the first case of multiple herbicide resistance in annual bluegrass populations to three herbicide modes of action. Results show the widespread occurrence of multiple herbicide resistance in golf course annual bluegrass populations in eastern Texas and emphasize the need for the development and implementation of effective resistance management practices. © 2020 Society of Chemical Industry.


Assuntos
Acetolactato Sintase , Golfe , Herbicidas , Poa , Acetolactato Sintase/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Mutação , Proteínas de Plantas/genética , Poa/genética , Texas
8.
Bull Environ Contam Toxicol ; 105(4): 656-664, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32865632

RESUMO

Methiozolin is a novel herbicide for controlling annual bluegrass. After applying 14C labelled methiozolin in two sediment (clay loam and sand)-water systems under aerobic conditions, its distribution, half-life, and metabolites within 300 days were investigated. The mass balance ranged within 92.0%-104.4% of applied radioactivity (AR). Radioactivity in the water declined sharply from 94.4% to 0.5% AR, while in the sediment it increased to 83.9% AR at 14 days before declining to 9.1% AR. The volatiles were minimal (< 0.5% AR), and the evolved labelled CO2 accounted for up to ~ 33.4% AR. From Radio-HPLC analysis, labelled methiozolin in water decreased from 108.9% to 0% AR, while a maximum of 15.1% AR remained in the sediment at the end. Eight metabolites were detected, all at minor levels and accounting for < 5.5% AR. The half-life of labelled methiozolin in the total sediment-water systems were 50.7 and 38.7 days for clay loam and sand, respectively.


Assuntos
Herbicidas/análise , Isoxazóis/análise , Tiofenos/análise , Cromatografia Líquida de Alta Pressão , Argila , Meia-Vida , Herbicidas/metabolismo , Poa , Água
9.
DNA Cell Biol ; 39(9): 1606-1620, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32749870

RESUMO

The sugars will eventually be exported transporters (SWEET) gene family is a glycoprotein gene family that can regulate the transport of sugar in plants and plays an important role in plant growth and development, as well as in response to environmental stress. In this study, Kentucky bluegrass (cv. Baron) seedlings were grown in various treatments, including heavy metal cadmium, salt, drought, cold, and heat stress for 6 h, 24 h, 48 h, and 7 day. The relative expression of the identified PpSWEET genes in Kentucky bluegrass was measured. The results showed there were a total of 13 SWEET genes, which could be divided into four clades by phylogenetic analysis. Most PpSWEET genes are alkali proteins with seven transmembrane helices. Moreover, almost all PpSWEET proteins possess similar conserved motifs and active sites. In addition, an analysis of the relative expression of PpSWEET genes under various stress treatments indicated that PpSWEET12 and PpSWEET15 had very high expression under the five types of stress, meaning they can be used as important candidate genes for studying responses to environmental stresses of turfgrass. Furthermore, certain genes only showed changes in expression under one or two specific stress treatments. This study provides important insight into the SWEET gene family in Kentucky bluegrass and its functional roles in responses to various environmental stresses.


Assuntos
Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Plantas/genética , Poa/genética , Estresse Fisiológico , Sequência Conservada , Regulação da Expressão Gênica de Plantas , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Transporte de Monossacarídeos/metabolismo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Poa/classificação , Poa/metabolismo , Domínios Proteicos
10.
Genes (Basel) ; 11(8)2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32824095

RESUMO

The production of seeds without sex is considered the holy grail of plant biology. The transfer of apomixis to various crop species has the potential to transform plant breeding, since it will allow new varieties to retain valuable traits thorough asexual reproduction. Therefore, a greater molecular understanding of apomixis is fundamental. In a previous work we identified a gene, namely APOSTART, that seemed to be involved in this asexual mode of reproduction, which is very common in Poa pratensis L., and here we present a detailed work aimed at clarifying its role in apomixis. In situ hybridization showed that PpAPOSTART is expressed in reproductive tissues from pre-meiosis to embryo development. Interestingly, it is expressed early in few nucellar cells of apomictic individuals possibly switching from a somatic to a reproductive cell as in aposporic apomixis. Moreover, out of 13 APOSTART members, we identified one, APOSTART_6, as specifically expressed in flower tissue. APOSTART_6 also exhibited delayed expression in apomictic genotypes when compared with sexual types. Most importantly, the SCAR (Sequence Characterized Amplified Region) derived from the APOSTART_6 sequence completely co-segregated with apomixis.


Assuntos
Apomixia/genética , Fenômenos Fisiológicos Vegetais , Proteínas de Plantas/genética , Poa/fisiologia , Sexualidade , Alelos , Clonagem Molecular , Flores/genética , Regulação da Expressão Gênica de Plantas , Marcadores Genéticos , Hibridização In Situ , Modelos Moleculares , Filogenia , Melhoramento Vegetal , Fenômenos Fisiológicos Vegetais/genética , Proteínas de Plantas/química , Poa/classificação , Conformação Proteica , Reprodução Assexuada , Relação Estrutura-Atividade
11.
BMC Plant Biol ; 20(1): 362, 2020 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-32736517

RESUMO

BACKGROUND: Low temperature limits the growth and development and geographical distribution of plants. Poa pratensis is a cool-season turfgrass mainly grown in urban areas. However, low winter temperature or cold events in spring and autumn may cause P.pratensis mortality, affecting the appearance of lawns. P.pratensis var. anceps cv. Qinghai (PQ) is widely distributed in the Qinghai-Tibet Plateau above 3000 m. PQ has greater cold tolerance than the commercially cultivated P.pratensis varieties. However, existing studies on the response mechanism of PQ to low temperatures have mainly focused on physiological and biochemical perspectives, while changes in the PQ transcriptome during the response to cold stress have not been reported. RESULTS: To investigate the molecular mechanism of the PQ cold response and identify genes to improve the low-temperature tolerance of P.pratensis, we analyzed and compared the transcriptomes of PQ and the cold-sensitive P.pratensis cv. 'Baron' (PB) under cold stress using RNA sequencing. We identified 5996 and 3285 differentially expressed genes (DEGs) between the treatment vs control comparison of PQ and PB, respectively, with 5612 DEGs specific to PQ. Based on the DEGs, important Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, such as "starch and sucrose metabolism", "protein processing in endoplasmic reticulum", "phenylalanine metabolism" and "glycolysis/gluconeogenesis" were significantly enriched in PQ, and "starch and sucrose metabolism", "phenylpropanoid biosynthesis", "galactose metabolism" and "glutathione metabolism" were significantly enriched in PB. In addition, the "glycolysis" and "citrate cycle (TCA cycle)" pathways were identified as involved in cold tolerance of P.pratensis. CONCLUSIONS: As we know, this is the first study to explore the transcriptome of P.pratensis var. anceps cv. Qinghai. Our study not noly provides important insights into the molecular mechanisms of P.pratensis var. anceps cv. Qinghai responds to cold stress, but also systematically reveals the changes of key genes and products of glycolysis and TCA cycle in response to cold stress, which is conductive to the breeding of cold-tolerance P.pratensis genotype.


Assuntos
Resposta ao Choque Frio/genética , Poa/fisiologia , Ácido Cítrico/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Genoma de Planta , Glicólise , Anotação de Sequência Molecular , Fenótipo , Poa/genética , Poa/metabolismo , RNA-Seq
12.
Plant Physiol Biochem ; 151: 181-187, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32224389

RESUMO

Turfgrasses are monocotyledonous plants from the family Poaceae. They are widely used in green spaces and are considered one of the most economically important horticultural crops in the world. Turfgrass quality is affected by several environmental factors including light, which is involved in the quality decline of transplanted sod. Ultraviolet-B (UV-B) is an important regulator of plant growth and development. Plants growing and/or stored in protected systems, such as in sod production, may be more vulnerable to UV-B damage than those growing in the field due to acclimation. Few studies on the effects of UV-B on turfgrass physiology have been published. Therefore, the aim of this study was to evaluate the influence of UV-B irradiation on the photosynthetic performance of five cool-season turfgrasses, namely Agrostis stolonifera L., Festuca arundinacea Schreb., Poa supina Schrad., Poa pratensis L. and Lolium perenne L. Turfgrasses were exposed to 18.25 kJ m-2 d-1 biologically effective UV-B in growth chambers under controlled conditions. Measurements included photosynthetic pigments, chlorophyll fluorescence and gas exchanges monitored for 16 d-UV-B treatment and after recovery. Content of pigments decreased with UV-B exposure with significant differences among the species. UV-B also affected the photosystem II (PSII) efficiency depending on the exposure period and species. Similarly, gas exchange parameters showed different effects among species after UV-B exposure compromising the assimilation of CO2. Multivariate analysis highlighted three main clusters of species confirming their different UV-B tolerance and ability to restore PSII photochemistry after recovery, from which Festuca arundinacea resulted to be the most tolerant.


Assuntos
Agrostis/fisiologia , Festuca/fisiologia , Lolium/fisiologia , Fotossíntese , Poa/fisiologia , Raios Ultravioleta , Clorofila , Complexo de Proteína do Fotossistema II
13.
Sci Rep ; 10(1): 6415, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286483

RESUMO

Drought stress is the most pervasive threat to plant growth, which predominantly encumbers turf grass growth by causing alterations in plant functions. This study appraised the role of nitrogen isotopes in providing a theoretical basis for developing and improving Kentucky bluegrass cultivar performance under drought stress. Nitrogen isotopes labelled 15NH4Cl and K15NO3 were prepared to replace KNO3 in Hoagland's solution at concentrations of 15NH4+ and 15NO3 at 1.5, 15, and 30 mM; the solutions were imposed on stressed plants under glasshouse conditions. Nitrogenous nutrition reduced oxidative stress by elevating the enzymatic activities and proline contents of all three clonal ramet leaves, particularly under stress conditions. Apart from nitrogen content, nitrogen isotope abundance, relative water content and water potential within controls were enhanced in treated with 15NH4+ than in with 15NO3 in both the roots and leaves of Kentucky bluegrass. Nevertheless, an application of 15NH4Cl and K15NO3 at 30 mM had a positive influence to some extent on these attributes under drought stress. Overall, our results suggested that nitrogen isotopes contributed to drought tolerance in all three clonal ramets of Kentucky bluegrass by maintaining a better osmoprotectant and antioxidant defence system, which helped the plants eliminate reactive oxygen species.


Assuntos
Secas , Isótopos de Nitrogênio/metabolismo , Poa/enzimologia , Poa/fisiologia , Estresse Fisiológico , Água/metabolismo , Catalase/metabolismo , Peroxidase/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Prolina/metabolismo , Superóxido Dismutase/metabolismo
14.
Sci Rep ; 10(1): 4231, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144361

RESUMO

Haloxyfop is one of two acetyl-coenzyme A carboxylase (ACCase) inhibitors that is recommended for controlling Poa annua. We have characterised a population of P. annua that had developed resistance to haloxyfop. This resistant population was found to be almost 20 times less sensitive to haloxyfop than a susceptible population based on percentage survival of individuals in two dose-response experiments. However, the haloxyfop-resistant population was still susceptible to clethodim. Pre-treatment of resistant individuals with a cytochrome P450 inhibitor, malathion, did not change the sensitivity level of the resistant plants to haloxyfop, suggesting that a non-target site mechanism of resistance involving enhanced metabolism, was not responsible for this resistance in P. annua. Gene sequencing showed that a target site mutation at position 2041, which replaced isoleucine with threonine in the carboxyltransferase (CT) domain of the ACCase enzyme, was associated with resistance to haloxyfop in the resistant population. An evaluation of the 3-D structure of the CT domain suggested that, unlike Asn-2041, which is the most common mutation at this position reported to date, Thr-2041 does not change the conformational structure of the CT domain. This is the first study investigating the molecular mechanism involved with haloxyfop resistance in P. annua.


Assuntos
Acetil-CoA Carboxilase/metabolismo , Resistência a Medicamentos , Inibidores Enzimáticos/farmacologia , Poa/crescimento & desenvolvimento , Piridinas/farmacologia , Acetil-CoA Carboxilase/química , Poa/efeitos dos fármacos , Poa/enzimologia , Conformação Proteica
15.
J Econ Entomol ; 113(3): 1118-1128, 2020 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-32221577

RESUMO

We determined the potential of the entomopathogenic fungus Metarhizium brunneum Petch (Hypocreales: Clavicipitaceae) F52 strain, and of a microsclerotial formulation, for the control of the annual bluegrass weevil, Listronotus maculicollis Kirby, which is a major pest of golf course turf in eastern North America with widespread insecticide resistance. Under laboratory conditions in Petri dishes with moist sand, the microsclerotia (23-46 kg granules/ha) caused high rates of mortality (85-100%) and infection (67-80%) in annual bluegrass weevil adults, but these levels did not occur until after 9 d at constant 26°C and 12-15 d at 14 h at 23°C and 10 h at 17°C. Production of viable conidia was marginally higher at the higher temperature regime (7.3 vs. 5.2 × 109 per gram of granules). Application of microsclerotia did not provide significant control and infection of adults in pots with grass in the greenhouse. In field trials targeting spring generation larvae, microsclerotia application (50-100 kg granules/ha) was ineffective, and coapplication of hydrogel to stabilize soil moisture did not increase larval control. A liquid M. brunneum F52 conidial formulation (4.75-9.5 × 1013 colony forming units/ha) provided up to 51% control. Combinations of M. brunneum F52 with the neonicotinoid insecticide imidacloprid provided additive control with up to 70% control with the conidial formulation. Field efficacy was probably limited by suboptimal temperatures for the fungus, and future tests need to examine whether higher control rates can be achieved in applications targeting the summer generation larvae.


Assuntos
Besouros , Metarhizium , Poa , Gorgulhos , Animais , Hidrogéis , Larva , Neonicotinoides , Nitrocompostos , Controle Biológico de Vetores
16.
Ann Bot ; 125(6): 981-991, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32010946

RESUMO

BACKGROUND AND AIMS: The processes that maintain variation in the prevalence of symbioses within host populations are not well understood. While the fitness benefits of symbiosis have clearly been shown to drive changes in symbiont prevalence, the rate of transmission has been less well studied. Many grasses host symbiotic fungi (Epichloë spp.), which can be transmitted vertically to seeds or horizontally via spores. These symbionts may protect plants against herbivores by producing alkaloids or by increasing tolerance to damage. Therefore, herbivory may be a key ecological factor that alters symbiont prevalence within host populations by affecting either symbiont benefits to host fitness or the symbiont transmission rate. Here, we addressed the following questions: Does symbiont presence modulate plant tolerance to herbivory? Does folivory increase symbiont vertical transmission to seeds or hyphal density in seedlings? Do plants with symbiont horizontal transmission have lower rates of vertical transmission than plants lacking horizontal transmission? METHODS: We studied the grass Poa autumnalis and its symbiotic fungi in the genus Epichloë. We measured plant fitness (survival, growth, reproduction) and symbiont transmission to seeds following simulated folivory in a 3-year common garden experiment and surveyed natural populations that varied in mode of symbiont transmission. KEY RESULTS: Poa autumnalis hosted two Epichloë taxa, an undescribed vertically transmitted Epichloë sp. PauTG-1 and E. typhina subsp. poae with both vertical and horizontal transmission. Simulated folivory reduced plant survival, but endophyte presence increased tolerance to damage and boosted fitness. Folivory increased vertical transmission and hyphal density within seedlings, suggesting induced protection for progeny of damaged plants. Across natural populations, the prevalence of vertical transmission did not correlate with symbiont prevalence or differ with mode of transmission. CONCLUSIONS: Herbivory not only mediated the reproductive fitness benefits of symbiosis, but also promoted symbiosis prevalence by increasing vertical transmission of the fungus to the next generation. Our results reveal a new mechanism by which herbivores could influence the prevalence of microbial symbionts in host populations.


Assuntos
Epichloe , Poa , Endófitos , Herbivoria , Poaceae , Simbiose
17.
Chemosphere ; 250: 126158, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32092564

RESUMO

Kentucky bluegrass has good capability to absorb and accumulate cadmium (Cd) through developed root system, thus having potential phytoremediation function in Cd contaminated soils. Understanding the molecular mechanisms of Cd tolerance and accumulation in this species will be crucial to generating novel Cd-tolerance cultivars through genetic improvement, while it has not well documented yet. In the present study, comparative transcriptome analysis was performed for the seedlings of high Cd-tolerant genotype (M) and low Cd-tolerant genotype (R) under Cd stress. A total of 7022 up-regulated and 1033 down-regulated transcripts were identified in M genotype, whereas, only 850 up-regulated and 846 down-regulated transcripts were detected in R. Further transcriptional regulation analysis in M genotype showed that Dof, MADS25, BBR-BPC, B3, bZIP23 and MYB30 might be the hub transcription factors in response to Cd stress due to the orchestrated multiple functional genes associated with carbohydrate, lipid and secondary metabolism, as well as signal transduction. Differential expressed genes involved in auxin, ethylene, brassinosteroid and ABA signalling formed signal transduction cascades, which interacted with hub transcription factors, thereby finally orchestrated the expression of multiple genes associated with cell wall and membrane stability, cell elongation and Cd tolerance, including IAAs, ARFs, SnRK2, PP2C, PIFs, BES1/BZR1, CCR, CAD, FATB, fabF and HACD. Additionally, post-transcriptional modification of CIPKs, MAPKs, WAXs, UBCs, and E3 ubiquitin ligases were identified and also involved in plant signalling pathways and abiotic resistance. The study could contribute to our understanding the transcriptional regulation and complex internal network associated with Cd tolerance in Kentucky bluegrass.


Assuntos
Adaptação Fisiológica , Cádmio/fisiologia , Poa/fisiologia , Estresse Fisiológico/genética , Cádmio/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Poa/metabolismo , Plântula/metabolismo , Transcriptoma
18.
Pest Manag Sci ; 76(6): 2049-2057, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31943704

RESUMO

BACKGROUND: Indaziflam is an alkylazine herbicide used to control annual bluegrass (Poa annua L.). Several locations in the southeastern USA reported poor annual bluegrass control following treatment with indaziflam during autumn 2015. A series of controlled environment experiments were conducted to confirm putative resistance to indaziflam in annual bluegrass collected from these field locations. RESULTS: Indaziflam (25 g ha-1 ) effectively controlled all putative-resistant annual bluegrass collections when applied preemergence (PRE), but was ineffective when applied early-postemergence (< 2.5 cm plant height; BBCH scale = 1; EPOST). In agarose-based plate assays, EPOST I50 values for putative-resistant collections ranged from 2424 to 4305 pm compared with 633 pm for the herbicide-susceptible control; therefore, resistance indexes (R/S) ranged from 3.8 to 6.8. Resistant collections were not controlled by foramsulfuron, flumioxazin, glyphosate, glufosinate, metribuzin, pronamide, or simazine applied EPOST. Indaziflam content in herbicide-susceptible annual bluegrass was greater than a resistant collection from 0 to 10 days after treatment (DAT). Susceptibility was not restored when resistant collections were treated with indaziflam plus 1-aminobenzotriazole (10 mg L-1 ), tebuconazole (1510 g ha-1 ), or malathion (400 g ha-1 ). CONCLUSIONS: This is a first report of resistance to indaziflam in any plant. Additionally, we confirm that these annual bluegrass collections are resistant to several other herbicidal modes-of-action. It is unclear if this multi-herbicide resistance is due to a single resistance gene, multiple resistance genes, non-target site mechanisms, or a combination thereof. Additional research to better understand resistance mechanisms in these annual bluegrass collections is warranted. © 2020 Society of Chemical Industry.


Assuntos
Poa , Herbicidas , Indenos , Triazinas
19.
J Hazard Mater ; 388: 121784, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-31831284

RESUMO

As an immobilizing agent for metal ions, basic oxygen furnace slag may affect bacterial community succession, thus further promote metal ion immobilization in acidic contaminated soil. In this work, pot experiments were conducted to study the effects of adding 10 g/kg (S10) and 15 g/kg (S15) slag on soil properties, plant growth, bacterial community succession and various metal ion immobilization in acidic mine soils contaminated by Pb, Zn, Cu, Cr and Cd. The results showed that after 93 days of potting, the soil pH, electrical conductivity, total nitrogen and organic carbon content increased significantly (P < 0.05), and the dry weight of Poa pratensis L. increased significantly (P < 0.05) in S10 and S15 compared with in original soil group. With slag addition and plant growth, the diversity and richness indices of bacterial communities greatly improved, and at the genus level, the abundance of metal-tolerant bacteria and bacteria beneficial to plant growth increased, while the abundance of acidophiles decreased. After adding slag to the soil, the various metals were immobilized because slag could not only immobilize metal ions through ion exchange and coprecipitation, but also benefit plant growth and bacterial community succession which further promote the immobilization of metal ions.


Assuntos
Metais Pesados/química , Microbiota , Poa/crescimento & desenvolvimento , Poluentes do Solo/química , Bactérias , Biodiversidade , Concentração de Íons de Hidrogênio , Resíduos Industriais , Mineração , Oxigênio
20.
BMC Genet ; 20(1): 92, 2019 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-31801460

RESUMO

BACKGROUND: Grasslands in the Arctic tundra undergo irreversible degradation due to climatic changes and also over-exploitation and depletion of scarce resources. Comprehensive investigations of cytogenomic structures of valuable Arctic and sub-Arctic grassland species is essential for clarifying their genetic peculiarities and phylogenetic relationships, and also successful developing new forage grass cultivars with high levels of adaptation, stable productivity and longevity. We performed molecular cytogenetic characterization of insufficiently studied pasture grass species (Poaceae) from related genera representing two neighboring clades: 1) Deschampsia and Holcus; 2) Alopecurus, Arctagrostis and Beckmannia, which are the primary fodder resources in the Arctic tundra. RESULTS: We constructed the integrated schematic maps of distribution of these species in the northern, central and eastern parts of Eurasia based on the currently available data as only scattered data on their occurrence is currently available. The species karyotypes were examined with the use of DAPI-banding, multicolour FISH with 35S rDNA, 5S rDNA and the (GTT)9 microsatellite motif and also sequential rapid multocolour GISH with genomic DNAs of Deschampsia sukatschewii, Deschampsia flexuosa and Holcus lanatus belonging to one of the studied clades. Cytogenomic structures of the species were specified; peculiarities and common features of their genomes were revealed. Different chromosomal rearrangements were detected in Beckmannia syzigachne, Deschampsia cespitosa and D. flexuosa; B chromosomes with distinct DAPI-bands were observed in karyotypes of D. cespitosa and H. lanatus. CONCLUSIONS: The peculiarities of distribution patterns of the examined chromosomal markers and also presence of common homologous DNA repeats in karyotypes of the studies species allowed us to verify their relationships. The obtained unique data on distribution areas and cytogenomic structures of the valuable Arctic and sub-Arctic pasture species are important for further genetic and biotechnological studies and also plant breeding progress.


Assuntos
Avena/genética , Análise Citogenética/métodos , Poa/genética , Aberrações Cromossômicas , Cromossomos de Plantas/genética , Demografia , Cariótipo , Tundra
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