Asteraceae

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Reinhard Berndt - One of the best experts on this subject based on the ideXlab platform.

  • Additions to the southern African rust fungi: four new species and two new host genera from South Africa and Angola
    Mycological Progress, 2020
    Co-Authors: Reinhard Berndt
    Abstract:

    This paper describes four new species of rust fungi from southern Africa. Three of them, Puccinia dimorphothecae-cuneatae on Dimorphotheca cuneata (Asteraceae), P. feliciicola on Felicia filifolia (Asteraceae), and Uredo myricae on Myrica sp. (Myricaceae), were collected in the South African Cape region, while Uromyces hessii on Zantedeschia angustiloba (Araceae) is from Angola. Rust fungi are reported for the first time on the plant genera Thereianthus (Iridaceae) and Cullumia (Asteraceae), both from South Africa. The specimen on Thereianthus was provisionally determined as Uromyces ecklonii that has been known so far only on Freesia . The rust of Cullumia showed only uredinia that were similar to Puccinia clanwilliamensis , hitherto only known on Berkheya .

Hance Thierry - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of potential resistance of the phytophagous mite, Tetranychus urticae Koch (Acari: Tetranychidae) to four botanical pesticides
    Presses Agronomiques de Gembloux, 2015
    Co-Authors: Attia Sabrine, Kl Lebdi, Heuskin Stéphanie, Lognay Georges, Hance Thierry
    Abstract:

    peer reviewedaudience: researcher, professional, studentDescription of the subject. Synthetic acaricides have been widely used to manage Tetranychus urticae. Due to the excessive use of biocide and the associated problems of pesticide resistance and environmental pollution, there is an increasing demand for sustainable, environmentally-friendly control methods. Among the current alternative strategies aimed at decreasing the pest populations, the pesticides based on plant extracts are currently one of the most promising methods. Essential oils with acaricidal properties have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. Objectives. With an aim to reduce the use of synthetic pesticides, they represent a promising approach for eco-chemical control of mites. Method. The aim of the present work was to analyze the risk of resistance emergence of T. urticae to repeated treatments with four plant extracts: Deverra scoparia Coss. & Durieu (Araliales: Apiaceae), Hertia cheirifolia (L.) Kuntze (Asterales: Ateraceae), Santolina africana Jord. & Fourr. (Asterales: Asteraceae) essential oils and garlic distillate Allium sativum L. (Asparagales: Alliaceae) after 20 generations. Results. Repeated treatments with S. africana essential oil during 20 generations did not provoke an emergence of resistance while a low development of resistance was observed with H. cheirifolia, A. sativum and D. scoparia extracts. Conclusions. The efficacy of these extracts against the two spotted spider mite and their low development of resistance make them a promising use for pest management

  • An analysis of potential resistance of the phytophagous mite, Tetranychus urticae Koch (Acari: Tetranychidae) to four botanical pesticides
    2015
    Co-Authors: Attia Sabrine, Kl Lebdi, Heuskin Stéphanie, Lognay Georges, Hance Thierry
    Abstract:

    Description of the subject. Synthetic acaricides have been widely used to manage Tetranychus urticae. Due to the excessive use of biocide and the associated problems of pesticide resistance and environmental pollution, there is an increasing demand for sustainable, environmentally-friendly control methods. Among the current alternative strategies aimed at decreasing the pest populations, the pesticides based on plant extracts are currently one of the most promising methods. Essential oils with acaricidal properties have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. Objectives. With an aim to reduce the use of synthetic pesticides, they represent a promising approach for eco-chemical control of mites. Method. The aim of the present work was to analyze the risk of resistance emergence of T. urticae to repeated treatments with four plant extracts: Deverra scoparia Coss. & Durieu (Araliales: Apiaceae), Hertia cheirifolia (L.) Kuntze (Asterales: Ateraceae), Santolina africana Jord. & Fourr. (Asterales: Asteraceae) essential oils and garlic distillate Allium sativum L. (Asparagales: Alliaceae) after 20 generations. Results. Repeated treatments with S. africana essential oil during 20 generations did not provoke an emergence of resistance while a low development of resistance was observed with H. cheirifolia, A. sativum and D. scoparia extracts. Conclusions. The efficacy of these extracts against the two spotted spider mite and their low development of resistance make them a promising use for pest management.Peer reviewe

Roger G. Shivas - One of the best experts on this subject based on the ideXlab platform.

  • The rusts on Goodeniaceae and Stylidiaceae
    Mycological Progress, 2014
    Co-Authors: Alistair R. Mctaggart, Andrew D. W. Geering, Roger G. Shivas
    Abstract:

    Systematic relationships between the rusts on Goodeniaceae and Stylidiaceae were examined using phylogenetic analyses with two loci (internal transcribed spacer, large subunit region) from ribosomal DNA. Fresh specimens and herbarium material of four rust species ( Puccinia dampierae, P. gilgiana , P. saccardoi and Uromyces scaevolae ) from the Goodeniaceae and one ( P. stylidii ) from the Stylidiaceae were examined. A further species ( P. lagenophorae ) that is reported from hosts in Goodeniaceae and Asteraceae was included in our analysis. Our phylogenetic analysis recovered the rusts on Goodeniaceae and Stylidiaceae in clades sister to P. lagenophorae on Asteraceae. This supported a taxonomy in which P. lagenophorae is restricted to Asteraceae. Descriptions or taxonomic notes are provided for all of the known rusts on Goodeniaceae and Stylidiaceae.

Dae-kyun Ro - One of the best experts on this subject based on the ideXlab platform.

  • discovery of germacrene a synthases in barnadesia spinosa the first committed step in sesquiterpene lactone biosynthesis in the basal member of the Asteraceae
    Biochemical and Biophysical Research Communications, 2016
    Co-Authors: Trinhdon Nguyen, Maria Vardakou, Melissa Salmon, Paul E Omaille, Juan A Faraldos, Dae-kyun Ro
    Abstract:

    Abstract The Andes-endemic Barnadesioideae lineage is the oldest surviving and phylogenetically basal subfamily of the Asteraceae (Compositae), a prolific group of flowering plants with world-wide distribution (∼24,000 species) marked by a rich diversity of sesquiterpene lactones (STLs). Intriguingly, there is no evidence that members of the Barnadesioideae produce STLs, specialized metabolites thought to have contributed to the adaptive success of the Asteraceae family outside South America. The biosynthesis of STLs requires the intimate expression and functional integration of germacrene A synthase (GAS) and germacrene A oxidase (GAO) to sequentially cyclize and oxidize farnesyl diphosphate into the advanced intermediate germacrene A acid leading to diverse STLs. Our previous discovery of GAO activity conserved across all major subfamilies of Asteraceae, including the phylogenetically basal lineage of Barnadesioideae, prompted further investigation of the presence of the gateway GAS in Barnadesioideae. Herein we isolated two terpene synthases (BsGAS1/BsGAS2) from the basal Barnadesia spinosa (Barnadesioideae) that displayed robust GAS activity when reconstituted in yeast and characterized in vitro. Despite the apparent lack of STLs in the Barnadesioideae, this work unambiguously confirms the presence of GAS in the basal genera of the Asteraceae. Phylogenetic analysis reveals that the two BsGASs fall into two distinct clades of the Asteraceae's GASs, and BsGAS1 clade is only retained in the evolutionary closer Cichorioideae subfamily, implicating BsGAS2 is likely the ancestral base of most GASs found in the lineages outside the Barnadesioideae. Taken together, these results show the enzymatic capacities of GAS and GAO emerged prior to the subsequent radiation of STL-producing Asteraceae subfamilies.

  • biochemical conservation and evolution of germacrene a oxidase in Asteraceae
    Journal of Biological Chemistry, 2010
    Co-Authors: Don Trinh Nguyen, Jens Christian Gopfert, Gillian Macnevin, Otmar Spring, Nobuhiro Ikezawa, Jürgen Conrad, Meena Kathiresan, Dae-kyun Ro
    Abstract:

    Abstract Sesquiterpene lactones are characteristic natural products in Asteraceae, which constitutes ∼8% of all plant species. Despite their physiological and pharmaceutical importance, the biochemistry and evolution of sesquiterpene lactones remain unexplored. Here we show that germacrene A oxidase (GAO), evolutionarily conserved in all major subfamilies of Asteraceae, catalyzes three consecutive oxidations of germacrene A to yield germacrene A acid. Furthermore, it is also capable of oxidizing non-natural substrate amorphadiene. Co-expression of lettuce GAO with germacrene synthase in engineered yeast synthesized aberrant products, costic acids and ilicic acid, in an acidic condition. However, cultivation in a neutral condition allowed the de novo synthesis of a single novel compound that was identified as germacrene A acid by gas and liquid chromatography and NMR analyses. To trace the evolutionary lineage of GAO in Asteraceae, homologous genes were further isolated from the representative species of three major subfamilies of Asteraceae (sunflower, chicory, and costus from Asteroideae, Cichorioideae, and Carduoideae, respectively) and also from the phylogenetically basal species, Barnadesia spinosa, from Barnadesioideae. The recombinant GAOs from these genes clearly showed germacrene A oxidase activities, suggesting that GAO activity is widely conserved in Asteraceae including the basal lineage. All GAOs could catalyze the three-step oxidation of non-natural substrate amorphadiene to artemisinic acid, whereas amorphadiene oxidase diverged from GAO displayed negligible activity for germacrene A oxidation. The observed amorphadiene oxidase activity in GAOs suggests that the catalytic plasticity is embedded in ancestral GAO enzymes that may contribute to the chemical and catalytic diversity in nature.

Attia Sabrine - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of potential resistance of the phytophagous mite, Tetranychus urticae Koch (Acari: Tetranychidae) to four botanical pesticides
    Presses Agronomiques de Gembloux, 2015
    Co-Authors: Attia Sabrine, Kl Lebdi, Heuskin Stéphanie, Lognay Georges, Hance Thierry
    Abstract:

    peer reviewedaudience: researcher, professional, studentDescription of the subject. Synthetic acaricides have been widely used to manage Tetranychus urticae. Due to the excessive use of biocide and the associated problems of pesticide resistance and environmental pollution, there is an increasing demand for sustainable, environmentally-friendly control methods. Among the current alternative strategies aimed at decreasing the pest populations, the pesticides based on plant extracts are currently one of the most promising methods. Essential oils with acaricidal properties have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. Objectives. With an aim to reduce the use of synthetic pesticides, they represent a promising approach for eco-chemical control of mites. Method. The aim of the present work was to analyze the risk of resistance emergence of T. urticae to repeated treatments with four plant extracts: Deverra scoparia Coss. & Durieu (Araliales: Apiaceae), Hertia cheirifolia (L.) Kuntze (Asterales: Ateraceae), Santolina africana Jord. & Fourr. (Asterales: Asteraceae) essential oils and garlic distillate Allium sativum L. (Asparagales: Alliaceae) after 20 generations. Results. Repeated treatments with S. africana essential oil during 20 generations did not provoke an emergence of resistance while a low development of resistance was observed with H. cheirifolia, A. sativum and D. scoparia extracts. Conclusions. The efficacy of these extracts against the two spotted spider mite and their low development of resistance make them a promising use for pest management

  • An analysis of potential resistance of the phytophagous mite, Tetranychus urticae Koch (Acari: Tetranychidae) to four botanical pesticides
    2015
    Co-Authors: Attia Sabrine, Kl Lebdi, Heuskin Stéphanie, Lognay Georges, Hance Thierry
    Abstract:

    Description of the subject. Synthetic acaricides have been widely used to manage Tetranychus urticae. Due to the excessive use of biocide and the associated problems of pesticide resistance and environmental pollution, there is an increasing demand for sustainable, environmentally-friendly control methods. Among the current alternative strategies aimed at decreasing the pest populations, the pesticides based on plant extracts are currently one of the most promising methods. Essential oils with acaricidal properties have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. Objectives. With an aim to reduce the use of synthetic pesticides, they represent a promising approach for eco-chemical control of mites. Method. The aim of the present work was to analyze the risk of resistance emergence of T. urticae to repeated treatments with four plant extracts: Deverra scoparia Coss. & Durieu (Araliales: Apiaceae), Hertia cheirifolia (L.) Kuntze (Asterales: Ateraceae), Santolina africana Jord. & Fourr. (Asterales: Asteraceae) essential oils and garlic distillate Allium sativum L. (Asparagales: Alliaceae) after 20 generations. Results. Repeated treatments with S. africana essential oil during 20 generations did not provoke an emergence of resistance while a low development of resistance was observed with H. cheirifolia, A. sativum and D. scoparia extracts. Conclusions. The efficacy of these extracts against the two spotted spider mite and their low development of resistance make them a promising use for pest management.Peer reviewe