No description available.

Plant lipoxygenases (LOX) are non-heme iron containing dioxygenases that catalyze the hydroperoxidation of polyunsaturated fatty acids resulting in the synthesis of a large number of functionally diverse oxylipins. Although the physiological functions of jasmonate-producing 13-LOXs in dicots have been reported and highlighted in host defenses to pathogens and insects, the functions of 9-LOXs and 9-LOX derived oxylipins remain obscure for both monocots and dicots. The objective of this study was to elucidate the biochemical, molecular and physiological roles of a segmentaly duplicated pair of 9-LOXs, ZmLOX4 and ZmLOX5, in host defenses to diverse stresses. Despite of their extreme similarities at the sequence levels, the ZmLOX4 was preferentially expressed in underground organs, whereas ZmLOX5 was stress-induced in aboveground organs. Both genes were highly induced by exogenous jasmonic acid (JA) but transcripts of ZmLOX5 only were strongly induced in wounded leaves as well as in response to insect infestation, suggesting the role of ZmLOX5 in plant resistance response against insect herbivory. To test potential function of ZmLOX4 and ZmLOX5, near-isogenic wild-type and mutants were generated. In this study, I provided genetic evidence that ZmLOX5 is involved in host defense against insect herbivores via the regulation of wound-induced JA biosynthesis. Contrary to the role in insect defenses, ZmLOX5 mediated metabolism contributes to enhanced susceptibility to a leaf fungal pathogen, Colletotricum graminicola. ZmLOX4 appears to have evolved a defense function against C. graminicola. In addition, lox4 and lox5 mutants have opposite phenotypes in their ability to support production of conidia and to facilitate colonization of kernels in response to Aspergillus flavus. However, the two mutants were similar to each other in their enhanced susceptibility to kernel colonization and conidia production of Fusarium verticillioides. In conclusion, the data suggest that these two 9-LOXs, ZmLOX4 and ZmLOX5 and their metabolites have distinct roles in plant-insect and plant-pathogen interactions.

The interaction of herbivory and pollination is not well understood. Both topics on their own have been studied thoroughly, yet their interaction has not. Until the 1990s, few studies attempted to explore how herbivory might affect pollination, and vice versa.

A lagarta da borboleta Chlosyne lacinia utiliza como plantas hospedeiras quase exclusivamente espécies da família Asteraceae, tais como Vernonia sp e Tithonia diversifolia. V. polyanthes e T. diversifolia apresentam lactonas sesquiterpênicas (LST) em sua constituição química foliar, as quais, entre outras atividades biológicas, podem ser deterrentes e tóxicas para lepidópteras. Os objetivos deste trabalho foram investigar se os metabólitos secundários das Asteraceae V. polyanthes e T. diversifolia são metabolizados, excretados intactos e/ou sequestrados durante a fase larval de C. lacinia, e se são conservados pelo adulto, elucidando, assim, parte da interação ecoquímica da lagarta-do-girassol com Asteraceae. Os extratos das folhas de V. polyanthes e T. diversifolia permitiram a identificação de 22 substâncias entre ácidos clorogênicos, flavonoides e LST. As folhas de V. polyanthes apresentaram 12 destas substâncias, sendo estas, ácidos clorogênicos, flavonoides glicuronizados e LST do subtipo hirsutinolido. Já as folhas de T. diversifolia apresentaram 13 das 22 substâncias, tais como ácidos clorogênicos e LST dos subtipos furanoeliangolido e heliangolido. As lagartas de C. lacinia cultivadas em T. diversifolia se desenvolveram até o quarto estágio completando a metamorfose para a fase adulta, enquanto que as lagartas cultivadas em V. polyanthes se desenvolveram apenas até o segundo estágio. Além disso, o peso médio das lagartas no segundo estágio larval dos três cultivos feitos com T. diversifolia foi estatisticamente maior do que o peso médio das lagartas no mesmo estágio dos três cultivos feitos com V. polyanthes. Assim provavelmente, a diferença na composição química das duas plantas pode ter sido responsável pela diferença na performance de C. lacinia. Além disso, as lagartas no terceiro e no quarto estágios, alimentadas com T. diversifolia, acumularam metabólitos secundários ingeridos a partir das folhas, principalmente LST. Em relação à excreção, as lagartas tratadas com T. diversifolia foram capazes de excretar alguns metabólitos sob a forma inalterada em todos os estágios larvais, já as lagartas tratadas com V. polyanthes excretaram apenas flavonoides glicuronizados sob a forma inalterada e duas flavonas. Enquanto que as lagartas do segundo estágio cultivadas em V. polyanthes, apresentaram acúmulo apenas do flavonoide apigenina-7-O-glicuronil e do ácido 3-O-E-cafeoilquínico hidroxilado. Sugere-se que a presença de flavonoides glicuronizados e LST do subtipo hirsutinolido em V. polyanthes justifica, ao menos parcialmente, o desenvolvimento deficiente e a morte de C. lacinia quando cultivada com esta planta. Por outro lado, a presença de LST dos subtipos furanoeliangolido e heliangolido nas folhas de T. diversifolia podem ser favoráveis ao desenvolvimento completo deste herbívoro na presença desta planta. / The caterpillar of Chlosyne lacinia uses almost exclusively Asteraceae species as host plant, such as Vernonia sp and Tithonia diversifolia. V. polyanthes and T. diversifolia show sesquiterpene lactones (STL) in their chemistry composition. STL have biological activities and also can be feeding deterrents and toxics for Lepidoptera. The aims of this study were to investigate whether secondary metabolites of the Asteraceae V. polyanthes and T. diversifolia are metabolized, excreted intact and/or sequestered during larval stage of C. lacinia, and if they are retained by adult, thus explaining a part of the ecochemical interaction between sunflower caterpillar and Asteraceae. The extracts of leaves of V. polyanthes e T. diversifolia allowed the identification of 22 substances among chlorogenic acids, flavonoids and STL. The leaves of V. polyanthes presented 12 of these substances, which were chlorogenic acids, flavonoids glucuronides and STL of hirsutinolide subtype, whereas the leaves of T. diversifolia had 13 of these substances, such as chlorogenic acids and STL of furanoeliangolido and heliangolido subtypes. The caterpillars of C. lacinia cultivated with T. diversifolia developed up to the fourth stage, completing the metamorphosis into adult stage, while the caterpillars cultivated with V. polyanthes developed only until to the second stage. Moreover the average weight of caterpillars in the second stage of three replicates made with T. diversifolia was statistically higher than the average weight of caterpillars at the same stage of the three replicates made with V. polyanthes. The difference in chemical composition of the two plants may has been responsible for the difference in the performance of C. lacinia crops. Also, the caterpillars in the third and fourth stages cultivated with T. diversifolia accumulated secondary metabolites taken from these leaves, mainly STL. Regarding the excretion, caterpillars in all stages fed with T. diversifolia were able to excrete unchanged metabolites, while caterpillars fed with V. polyanthes excreted only unchanged flavonoids glucuronide and the respective aglicones. In the other hand, the caterpillars in the second stage cultivated in V. polyanthes showed that there was only accumulation of apigenin-7-O-glucuronyl and 3-hydroxy-O-E-caffeoylquinic acid. It is suggested that the presence of flavonoids glucuronides and STL of hirsutinolide subtype in V. polyanthes, justify, at least partially, defective development and deaths of C. lacinia cultivated with this plant. While the presence of STL of furanoheliangolide and heliangolide subtypes in T. diversifolia may be favorable to the full development of this herbivore in the presence of this plant.

Orientador: Anita Jocelyne Marsaioli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T01:12:50Z (GMT). No. of bitstreams: 1 Reis_MarizaGomes_D.pdf: 16254854 bytes, checksum: 5cb5b0e999b495a778232097e29554ff (MD5) Previous issue date: 2005 / Resumo: A composição química dos calos florais de 39 espécies, distribuidas em 10 gêneros, da subtribo Oncidiinae foi analisada por cromatografia gasosa acoplada a espectrometria de massas. Os resultados obtidos revelam que os componentes majoritários dos óleos florais de 13 espécies são diacilgliceróis substituídos assimetricamente, os demais calos apresentam como metabólitos secundários terpenóides, derivados de ácidos graxos, ésteres benzílicos e diacilgliceróis. Três novas estruturas de 1,2-diacilgliceróis, (2S, 3'R, 7'R)-1-acetil-2-(3',7'-diacetoxi-eicosanoil)-glicerol chamado de oncidinol, (3'R,7'R)-1-acetil-2-(3' -acetoxi,7'-hidroxi-octadecanoil)-glicerol e 1-acetil-2-(3'-acetoxi-octadecanoil)-glicerol, foram isoladas e identificadas por métodos espectroscópicos sendo suas configurações absolutas determinadas por aplicação da metodologia de Mosher. A similaridade química entre os calos florais foi avaliada através de métodos estatísticos. O dendrograma obtido desta análise estatística foi comparado a árvore filogenética obtida através de dados morfológicos, anatômicos e de DNA (introns ribossomal), sendo observado que algumas espécies do gênero Oncidium apresentam a composição do calo floral mais similar a outros gêneros (ex. Ornithophora e Baptistonia) do que a outras espécies do seu próprio gênero sendo o mesmo observado na análise filogenética. Os resultados do estudo dos calos florais de espécies da subtribo Oncidiinae levou a investigação do fenômeno de mimetismo floral entre Oncidiinae e a família Malpighiaceae, através do estudo da composição química do óleo floral da espécie Byrsonima intermedia, cujo principal constituinte é um novo derivado de ácido graxo, ácido (3R, 7R)-3,7-diacetoxi-docosanóico, que foi denominado de ácido birsónico. A similaridade entre a porção do ácido graxo do ácido birsónico e o oncidinol foi intrigante e sugere a presença de um mimetismo químico entre estes dois grupos de plantas que oferecem derivados de ácidos graxos como recompensa para abelhas polinizadoras. Outra evidência deste mimetismo foi investigada através da composição química da provisão larval do ninho da abelha Tetrapedia diversipes descrita como polinizadora de ambas famílias. Como resultado, foram detectadas as presenças dos ácidos 3,7-diidroxi-eicosanóico e 3,7-diidroxi-docosanóico denominados respectivamente de ácido tetrapédico A e B ambos estruturalmente relacionados aos compostos presentes em espécies de Oncidiinae e Byrsonima intermedia (Malpighiaceae). Isto demonstra que as abelhas coletam e usam os óleos florais para o provisionamento do ninho. Investigações adicionais revelaram que o óleo floral de uma terceira família de plantas representada por Calceolaria x herbeohybrida (Scrophulariaceae), também apresenta similares derivados de diacilgliceróis, 1-acetil-2-(3' -acetoxi-hexadecanoil)-glicerol. Esta observação indica que famílias filogeneticamente distantes estão ligadas por recompensas florais análogas para atrair abelhas coletoras de óleos florais. Neste trabalho, foi mapeada a rota química das recompensas florais de vários gêneros não relacionados e como sua presença é importante para a sobrevivência de abelhas coletoras de óleos florais. Também foram realizados estudos sintéticos visando a obtenção de diacilgliceróis naturais. / Abstract: The chemistry of the of 39 floral calluses of specimen belonging to the subtribe Oncidiinae is described revealing that diacyl-glycerols asymmetrically substituted are the major floral oil components in 13 species, in other calluses the terpenoids, fatty acid derivatives, flavonoids, benzyl esters and diacylglicerols are the secondary metabolites. Unknown constituents were isolated from cultivated species allowing the total structural determination of three new 1,2-diacylglycerols: (2S, 3'R, 7'R)-1-acetyl-2-(3',7'-diacetoxy-eicosanoyl)-glycerol named oncidinol, (3'R,7'R)-1-acetyl-2-(3'-acetoxy,7'-hydroxy-octadecanoyl)-glycerol and 1-acetyl-2-(3'-acetoxy octadecanoyl)-glycerol. The results were analyzed by statistical methods. The distribution patterns of the calluses chemical constituents in Oncidiinae were compared with the phylogenetic tree derived from the introns of the ribossomal DNA, morphological and anatomical data. This unusual glycerol and fatty acid derivatives prompted us to further investigate the Oncidiinae and Malpighiaceae floral mimicry by studying chemical composition of Byrsonima intermedia floral oil. This research revealed that the main constituent of this oil was a new fatty acid derivative, the (3R,7R)-3,7-diacetoxi-docosanoic acid named byrsonic acid. The similarity between byrsonic acid and oncidinol fatty acid moiety was intriguing suggesting chemical mimicry among species offering fatty acid derivatives as floral rewards to pollinating bees. Other evidence of this mimicry was investigated by analyzing Tetrapedia diversipes (oil collecting bee) nest provision. As result, it was detected the presence of 3,7-dihydroxy-ecosanoic and 3,7-dihydroxy-docosanoic acid named tetrapedic acid A and B, respectively, both structurally related to compounds present in Oncidinae species and Byrsonima intermedia (Malpighiaceae). This shows that oil collecting bees use the floral rewards. Further investigation shown that floral oil a third family of plants, represented by Calceolaria x herbeohybrida (Scrophulariaceae), also revealed the presence of a similar glycerol derivative, 1-acetyl-2-(3-acetoxy-hexadecanoyl)-glycerol which indicates that species from different families are linked by analogous floral reward in order to attract pollinating bees. Finally, we have mapped the chemical route of floral reward of several unrelated genera and how their offer is important to oil collecting bees survival. It was also done studies to synthesize natural diacylglycerols. / Doutorado / Quimica Organica / Doutor em Ciências

A lagarta da borboleta Chlosyne lacinia utiliza como plantas hospedeiras quase exclusivamente espécies da família Asteraceae, tais como Vernonia sp e Tithonia diversifolia. V. polyanthes e T. diversifolia apresentam lactonas sesquiterpênicas (LST) em sua constituição química foliar, as quais, entre outras atividades biológicas, podem ser deterrentes e tóxicas para lepidópteras. Os objetivos deste trabalho foram investigar se os metabólitos secundários das Asteraceae V. polyanthes e T. diversifolia são metabolizados, excretados intactos e/ou sequestrados durante a fase larval de C. lacinia, e se são conservados pelo adulto, elucidando, assim, parte da interação ecoquímica da lagarta-do-girassol com Asteraceae. Os extratos das folhas de V. polyanthes e T. diversifolia permitiram a identificação de 22 substâncias entre ácidos clorogênicos, flavonoides e LST. As folhas de V. polyanthes apresentaram 12 destas substâncias, sendo estas, ácidos clorogênicos, flavonoides glicuronizados e LST do subtipo hirsutinolido. Já as folhas de T. diversifolia apresentaram 13 das 22 substâncias, tais como ácidos clorogênicos e LST dos subtipos furanoeliangolido e heliangolido. As lagartas de C. lacinia cultivadas em T. diversifolia se desenvolveram até o quarto estágio completando a metamorfose para a fase adulta, enquanto que as lagartas cultivadas em V. polyanthes se desenvolveram apenas até o segundo estágio. Além disso, o peso médio das lagartas no segundo estágio larval dos três cultivos feitos com T. diversifolia foi estatisticamente maior do que o peso médio das lagartas no mesmo estágio dos três cultivos feitos com V. polyanthes. Assim provavelmente, a diferença na composição química das duas plantas pode ter sido responsável pela diferença na performance de C. lacinia. Além disso, as lagartas no terceiro e no quarto estágios, alimentadas com T. diversifolia, acumularam metabólitos secundários ingeridos a partir das folhas, principalmente LST. Em relação à excreção, as lagartas tratadas com T. diversifolia foram capazes de excretar alguns metabólitos sob a forma inalterada em todos os estágios larvais, já as lagartas tratadas com V. polyanthes excretaram apenas flavonoides glicuronizados sob a forma inalterada e duas flavonas. Enquanto que as lagartas do segundo estágio cultivadas em V. polyanthes, apresentaram acúmulo apenas do flavonoide apigenina-7-O-glicuronil e do ácido 3-O-E-cafeoilquínico hidroxilado. Sugere-se que a presença de flavonoides glicuronizados e LST do subtipo hirsutinolido em V. polyanthes justifica, ao menos parcialmente, o desenvolvimento deficiente e a morte de C. lacinia quando cultivada com esta planta. Por outro lado, a presença de LST dos subtipos furanoeliangolido e heliangolido nas folhas de T. diversifolia podem ser favoráveis ao desenvolvimento completo deste herbívoro na presença desta planta. / The caterpillar of Chlosyne lacinia uses almost exclusively Asteraceae species as host plant, such as Vernonia sp and Tithonia diversifolia. V. polyanthes and T. diversifolia show sesquiterpene lactones (STL) in their chemistry composition. STL have biological activities and also can be feeding deterrents and toxics for Lepidoptera. The aims of this study were to investigate whether secondary metabolites of the Asteraceae V. polyanthes and T. diversifolia are metabolized, excreted intact and/or sequestered during larval stage of C. lacinia, and if they are retained by adult, thus explaining a part of the ecochemical interaction between sunflower caterpillar and Asteraceae. The extracts of leaves of V. polyanthes e T. diversifolia allowed the identification of 22 substances among chlorogenic acids, flavonoids and STL. The leaves of V. polyanthes presented 12 of these substances, which were chlorogenic acids, flavonoids glucuronides and STL of hirsutinolide subtype, whereas the leaves of T. diversifolia had 13 of these substances, such as chlorogenic acids and STL of furanoeliangolido and heliangolido subtypes. The caterpillars of C. lacinia cultivated with T. diversifolia developed up to the fourth stage, completing the metamorphosis into adult stage, while the caterpillars cultivated with V. polyanthes developed only until to the second stage. Moreover the average weight of caterpillars in the second stage of three replicates made with T. diversifolia was statistically higher than the average weight of caterpillars at the same stage of the three replicates made with V. polyanthes. The difference in chemical composition of the two plants may has been responsible for the difference in the performance of C. lacinia crops. Also, the caterpillars in the third and fourth stages cultivated with T. diversifolia accumulated secondary metabolites taken from these leaves, mainly STL. Regarding the excretion, caterpillars in all stages fed with T. diversifolia were able to excrete unchanged metabolites, while caterpillars fed with V. polyanthes excreted only unchanged flavonoids glucuronide and the respective aglicones. In the other hand, the caterpillars in the second stage cultivated in V. polyanthes showed that there was only accumulation of apigenin-7-O-glucuronyl and 3-hydroxy-O-E-caffeoylquinic acid. It is suggested that the presence of flavonoids glucuronides and STL of hirsutinolide subtype in V. polyanthes, justify, at least partially, defective development and deaths of C. lacinia cultivated with this plant. While the presence of STL of furanoheliangolide and heliangolide subtypes in T. diversifolia may be favorable to the full development of this herbivore in the presence of this plant.

Species are experiencing shifts in their phenology (i.e., seasonal timing of recurring biological events) due to climate change, leading to disruptions in the relative timing of interacting species. These shifts can be detrimental to the fitness of the consumer (e.g., herbivore) in the interaction. In its larval form, the monarch butterfly (Danaus plexippus) is a specialist herbivore that feeds on milkweed plants (Asclepias spp.). Given that plants generally experience seasonal declines in quality, it is hypothesized that if climate change disrupts the timing of the larval stage relative to the availability of younger milkweed plants, monarch performance will be negatively affected. In this thesis, I explore the potential for negative consequences for the eastern monarch population due to potential shifts in the timing of their interaction with milkweed—due to phenological shifts in either species. I used field surveys around Ottawa, ON to determine monarch oviposition preference on common milkweed (Asclepias syriaca) plants and the seasonal availability of their preferred plants. To determine the potential consequences for monarch fitness where females oviposit on non-preferred plants, I conducted a field experiment to assess the effect of milkweed size on monarch larval performance. Based on field surveys, females preferentially oviposited on smaller milkweed plants in earlier developmental stages with low levels of discolouration. Plants in early developmental stages were consistently available in large proportion over the summer season. These results suggest that even if the relative timing of the monarch-milkweed interaction in the eastern population is shifted due to climate change, there will likely be suitable milkweed plants available for oviposition throughout the breeding season, which could act as a buffer to disruptions in the relative timing of the interaction. I found that bigger plants exuded more latex and had thicker leaves than smaller plants. However, larval performance was unaffected by these plant quality differences. While it is unclear how the relative timing of the monarch-milkweed interaction will change in the future, my results suggest that shifts in the relative timing of their interaction within the breeding season are unlikely to have negative consequences for larval performance in eastern Ontario. Future studies should determine how the relative timing of the interaction will change in the region and explore how climate change will affect the quality of milkweed plants.

Red alder (Alnus rubra) is the most commercially important hardwood tree species in the Pacific Northwest and has a long history of traditional medicinal use as a source of fungicide and insecticide. Chemical analysis has shown that the diarylheptanoid oregonin ((5S)-1,7-bis(3,4-dihydroxyphenyl)-5-(β-D-xylopyranosyloxy)-heptan-3-one) is the dominant phytochemical contributing to medicinal activity. It was recently discovered that high oregonin concentration in alder leaves is associated with enhanced resistance to western tent caterpillar (Malacosoma californicum), a leaf eating lepidopteran herbivore; however, oregonin has never been directly tested on insects, or red alder-associated fungal species. In this thesis, a novel purification method was developed for the preparative extraction of oregonin from red alder leaf and bark material to directly test its biological activity. A battery of insect feeding and toxicity bioassays were carried out with several tree-defoliating caterpillars, and fungal inhibition was tested against a range of plant-associated fungal species, including several alder-associated species. This research represents the first evaluation of oregonin biological activity on insects, plant-associated fungi of the phyla Basidiomycota, and fungal-like pathogens of the phyla Oomycota. Oregonin exhibited promising insect feeding deterrent activity against generalist lepidopteran pests, including cabbage loopers (Trichoplusia ni), white-marked tussock moths (Orgyia leucostigma), and fall webworm (Hyphantria cunea) at similar concentrations shown to reduce western tent caterpillar herbivory in alder leaf bioassays. The results suggest that oregonin concentration has potential for selection as a breeding trait in managed populations of red alder to improve host resistance to leaf-eating pests. / Graduate / 2021-08-10

No description available.

The hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Sternorrhyncha: Adelgidae) is a small invasive insect that frequently causes hemlock (Tsugae spp.) mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the insect's ability to obtain necessary nutrients and consequently affect their population and physiological health. A cluster analysis, based on quantitative and qualitative tree health measurements, grouped sample trees into categories of lightly and moderately impacted trees. The A. tsugae population health on each tree was determined by measuring insect density, survival from aestivation, and peak fecundity. A. tsugae physiological health was determined similarly by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen. A. tsugae from moderately impacted trees exhibited significantly greater fecundity; however, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. All A. tsugae physiological parameters increased significantly over time as the insects matured and reproduced regardless of tree health classification. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population fitness measurements of the insects. Further examination of A. tsugae egg health may elucidate this apparent contradiction. / Master of Science in Life Sciences