No description available.

Potato leafhopper causes considerable damage in red clover. The main objectives of this study were to clarify the inheritance of pubescence and to evaluate the relationship between pubescence and potato leafhopper (Empoasca fabae (Harris) resistance. Thirteen red clover clones of diverse origin, including both pubescent and non-pubescent types were used as parents. A series of crosses were made in all possible combinations among the 13 parental clones. Seedlings of F$ sb1$ progeny and stem cuttings from parents were planted in the field in the summer of 1993 in a randomized complete block design. Based on the results, the inheritance of pubescence type on red clover stems, petioles and abaxial leaf surfaces was best explained individually by two-locus models showing dominant and recessive interaction. A two locus model with recessive epistasis was proposed for pubescence on stipules and basal internodes, but there were a number of crosses that deviated from expected ratios. There was quantitative variation for trichome density on red clover and it appeared to be inherited as a quantitative trait. Based on mid-parent offspring regression, the heritability estimates of trichome density on petioles, stems, abaxial leaf surfaces, and adaxial leaf surfaces were 0.16, 0.77, 0.50 and 0.48, respectively. Pubescence was apparently associated with potato leafhopper resistance. Visual ratings of feeding injury, the numbers of leafhopper nymphs per plant and the numbers of nymphs per gram of dry plant material were higher on glabrous plants than on pubescent plants. (Abstract shortened by UMI.)

No description available.

No description available.

Afin de limiter l’impact négatif des ravageurs sur les plantes cultivées, des agents de lutte biologique sont souvent introduits sous abris. Or, des interactions peuvent apparaître entre eux, comme la prédation intraguilde, et modifier l’efficacité de la lutte biologique. De plus, les défenses directes des plantes hôtes peuvent perturber l’efficacité des ennemis naturels. La question se pose donc de savoir s’il est possible de limiter les interactions négatives entre ennemis naturels et l’impact de la plante hôte sur leur développement. Pour répondre à cet objectif, afin d’optimiser la lutte biologique contre l’acarien Tetranychus urticae, ravageur très problématique, nous avons considéré deux cultivars de tomates caractérisés par des densités en trichomes et des concentrations en composés secondaires contrastéesl’acarien prédateur Phytoseiulus macropilis et Macrolophus pygmaeus, punaise prédatrice souvent employée pour lutter contre les aleurodes. Au cours d’essais conduits en serre, P. macropilis a permis de réguler T. urticae sans différence entre les deux cultivars, alors qu’en microcosmes le taux d’oviposition de P. macropilis a été supérieur sur le cultivar ayant la densité en trichomes non glandulaires la plus élevée. La consommation d’œufs de P. macropilis par M. pygmaeus en microcosmes n’a pas été observée en serre. Les interactions entre arthropodes se sont également traduites par une agrégation supérieure des T. urticae en présence des deux prédateurs et de P. macropilis en présence de M. pygmaeus. Avant de proposer P. macropilis comme nouvel agent de lutte bio / To suppress pest populations to such levels that damage to thecrop is minimized, multiple biological control agents are oftenintroduced in greenhouses. However, negative interactionsamong them, such as intraguild predation, might appear thatcan decrease the effi ciency of the plant protection strategy.Furthermore, plant direct (physical or chemical) defenseshave a negative impact on the pests but might also have animpact on the natural enemies. Therefore, the question iswhether it is possible to limit the negative interactions amongbiological control agents and the infl uence of the crop on thebehavior and development of the natural enemies. To optimizebiological control of Tetranychus urticae, a very problematicpest in tomato greenhouses, the effi ciency of the predatorymite Phytoseiulus macropilis was tested on two cultivars withdifferent trichome densities and concentrations of secondarycompounds, in presence or absence of Macrolophus pygmaeus,a mirid often used to regulate whitefl y populations.During two years, under greenhouse conditions, P. macropiliswell-controlled the population of T. urticae. There was no evidenceof intraguild predation between the two predators, butin the presence of M. pygmaeus, P. macropilis tended to havea more clumped spatial distribution. However, in microcosms,M. pygmaeus fed on P. macropilis eggs. Moreover, P. macropilislaid signifi cantly more eggs on the tomato cultivar with thehighest density of non-glandular trichomes, but this resultwas only observed in microcosms. The different dynami

Os tricomas são estruturas de origem epidérmicas que podem ser classificados em dois tipos: glandulares e não glandulares (tectores) e estão relacionados, principalmente, com estratégias de defesas de plantas. Pouco se conhece sobre a via de desenvolvimento dos tricomas glandulares, já que a maior parte dos estudos é em Arabidopsis thaliana, modelo no qual os tricomas glandulares são ausentes. O gênero Solanum possui uma grande diversidade de tricomas, em especial glandulares (tipos I, IV, VI e VII). O estudo de tais estruturas vem ganhando cada vez mais destaque, já que são fontes de diversos metabólitos secundários de importância econômica e ecológica. Espécies selvagens são consideradas recursos genéticos para o tomateiro (S. lycopersicum), tais como S. galapagense, a qual possui variações genéticas naturais que lhe confere maior resistência ao ataque de herbívoros. Entre essas variações está a presença de tricomas glandulares do tipo IV, uma fonte do aleloquimico acilaçúcar. A ausência de tricomas glandulares do tipo IV é considerada uma das causas da suscetibilidade do tomateiro cultivado a insetos. No presente trabalho, foi demonstrado que o tomateiro cultivado na verdade forma tricomas do tipo IV, mas estas estruturas estão presentes somente até o primeiro par de folhas, além dos cotilédones. Desse modo, a presença de tricomas tipo IV em espécies selvagens seria considerada uma neotenia, ou seja, a manutenção de estruturas juvenis na fase adulta. Além de se determinar que mutantes de tomateiro afetando a juvenilidade (e.g. Mouse ears e fasciated) apresentam tricomas tipo IV na fase adulta, a formação dessas estruturas correlacionou se com a expressão de miR156, sendo também presentes em grandes quantidades em uma linhagem transgênica superexpressando esse micro RNA relacionado à juvenilidade. Quanto à base genética da presença de tricomas tipo IV nas espécies selvagens, no presente trabalho foi criada uma linhagem quase isogênica ao modelo genética Micro-Tom (MT) contendo a variação genética natural por nós denominada Galapagos enhanced trichomes (Get). Tal variação é derivada de S. galapagense e condiciona a presença de tricomas tipo IV em folhas adultas, quando introgredida em tomateiro cultivado (cv. Micro-Tom). O mapeamento preliminar de Get no cromossomo 2 de tomateiro também foi realizado através do mapa de \"single nucleotide polymorphism\" (SNPs) entre MT e a linhagem MT-Get. A eventual clonagem de GET irá contribuir não somente para se desvendar a base genética da formação de tricomas glandulares, como também contribuir para se criar variedades resistentes a insetos, reduzindo o uso de agrotóxicos. / Trichomes are epidermal structures that can be classified into two types: glandular or non-glandular, and they are mainly related to plant defense strategies. Little is known about the glandular trichome development pathway, since most of the studies are in Arabidopsis thaliana, a model in which this kind of trichome is absent. The Solanum genus has a wide variety of trichomes, especially glandular ones (Types I, IV, VI and VII). The study of these structures are gaining more prominence, since they are sources of several secondary metabolites of economic and ecological importance. Wild species are considered genetic resources for tomato (S. lycopersicum), such as S. galapagense which has natural genetic variations that gives resistance to herbivores attack. Among these variations is the presence of type IV glandular trichomes, a source of the acyl sugar allelochemical. The absence of type IV glandular trichomes is considered to be one of the causes of tomato susceptibility to insects. In this study, it was determined that tomato actually has type IV trichomes, but these structures are present only in the cotyledons and the first pair of leaves. Thus, the presence of type IV trichomes in wild species would be considered a neotenic feature, i.e. the maintenance of juvenile structures in adulthood. In addition, it was determined that tomato mutants affecting youthfulness (e.g. Mouse ears and fasciated) have type IV trichomes in adulthood. Moreover, the presence of these structures was correlated with the expression of miR156, besides the increased formation of type IV trichomes in a transgenic line overexpressing this micro RNA related to youthfulness. On the genetic basis of type IV trichomes presence in wild species, in this work it was created a near isogenic line (NIL) containing the natural genetic variation here named Galapagos enhanced trichomes (Get). This variation is derived from S. galapagense and harbors type IV trichomes in adult leaves, when introgressed in cultivated tomato (cv. Micro-Tom). The preliminary genetic map of Get in the tomato chromosome 2 was conducted through the analysis of \"single nucleotide polymorphism\" (SNPs) between MT and MT-Get. The eventual cloning of GET will contribute not only to unravel the genetic basis of glandular trichomes formation, but will also contribute to create varieties resistant to insects, reducing the pesticides use.

Duas espécies de Barbatimão, da família Leguminosae, foram utilizadas como modelo neste trabalho para elucidar as vias ontogenéticas de produção de taninos: Dimorphandra mollis Benth. (Caesalpinioideae) e Stryphnodendron adstringens (Mart.) Coville (Mimosoideae). Apesar de inseridas em grupos distantes de Leguminosae, as duas espécies são grandes produtoras de taninos, geralmente concentrados na casca, o que confere a elas uma grande procura para uso na medicina popular. Partes vegetativas de Indivíduos jovens e adultos foram processadas para observações em microscopia de luz e eletrônica (varredura e transmissão). Dois tipos de estruturas secretoras são responsáveis pela produção e acúmulo de taninos: idioblastos, encontrados já em indivíduos jovens de ambas espécies; e tricomas secretores, encontrados em gemas vegetativas de indivíduos adultos de S. adstringens. O processo de produção de taninos nas duas espécies é semelhante, com alguma diferença nas etapas de acúmulo. Plastídios e RER parecem ser as organelas associadas à produção de taninos nessas espécies. Destaca-se ainda o relato inédito da ocorrência de coléteres de origem protodérmica em D. mollis. Considerando a problemática referente à classificação de estruturas secretoras, pretende-se utilizar os resultados obtidos para reflexão sobre o tema / In this study, two species of Leguminosae, popularly known as Barbatimão, were used as a model to elucidate the ontogenetic process of tannin production: Dimorphandra mollis Benth. (Caesalpinioideae) and Stryphnodendron adstringens (Mart.) Coville (Mimosoideae). Although inserted in non-related groups of Leguminosae, the two species are largely known as tannin producers, a metabolite often concentrated in the bark, which makes them highly sought after for use in folk medicine. Vegetative parts of young and adult plants were processed for observation using light and electron microscopy (scanning and transmission). Two types of secretory structures are responsible for tannin production and accumulation: idioblasts, found even in young plants of both species, and secretory trichomes, observed in vegetative buds of mature plants of S.adstringens. Tannin production is similar in both species, although some differences in the stages of accumulation occur. Plastids and RER organelles appear to be associated with the production of tannins in these species. This study also provides the first report of colleters in D. mollis, which originate from protodermal cells. Considering the controversies regarding the classification and nomenclature of secretory structures, our results can be used to help clarify some issues regarding secretory structures, especially colleters

Artemisia annua L. is a common type of wormwood that grows throughout the world. Artemisinin, a terpene compound in A. annua, has recently been recognized as the most promising antimalaria drug. Artemisinin and other types of terpenoids are synthesized and accumulated in glandualr trichomes that appear on the surface of leaf, stem and flower bud. To identify new genes involved in artemisinin biosynthesis and trichome function in A. annua, a normalized glandular trichome cDNA collection was sequenced by Roche GS FLX pyrosequencing system. Two sequencing runs generated totally 85M nucleotides which were further assembled into 190,377 unigenes (42,678 contigs and 147,699 sigletons). Putative functions were assigned to the unigenes based on Blast search against GeneBank database. Many terpene biosynthesis pathway genes were identified from the pyrosequencing ESTs. Together with other identified A. annua terpene pathway genes, a global view of terpene biosynthesis in glandular trichomes of A. annua were re-established. Meanwhile, a WD repeat protein, AaWD40, which show high amino acid sequence similarity with its Arabidopsis ortholog, AtTTG1 (AT5G24520) was identified. To investigate the functional relevance of AaWD40 to its Arabidopsis counterpart, genetic complementation test using Arabidopsis mutants was conducted. When AaWD40 was transformed into Arabidopsis transparent testa glabrous1 (ttg1-1) mutant, the anthocyanins and proanthocyanidin (PAs) production in seeds were restored, and the trichomeless phenotype of ttg1-1 mutant was rescued. In addition, over-expression of AaWD40 and AtTTG1 modulated the expression of WUS and CLVs genes which are required to maintain the stem-cell niche of Arabidopsis shoot apex. Transcriptomic profiling of transgenic Arabidopsis over-expressing AaWD40, TTG1, or ttg1-1 mutant revealed lists of genes modulated by these two WD40 genes homologue and gene ontology (GO) analysis suggested that the top-ranked categories are defense, stress response and developmental programme. We hypothesize that WD40 repeat protein act as a crucial regulatory factor in a wide variety of cellular functions in A. thaliana. / Wang, Wei. / Advisers: Guo Dianjing; Jiang Liwen. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 82-105). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Os tricomas são estruturas de origem epidérmicas que podem ser classificados em dois tipos: glandulares e não glandulares (tectores) e estão relacionados, principalmente, com estratégias de defesas de plantas. Pouco se conhece sobre a via de desenvolvimento dos tricomas glandulares, já que a maior parte dos estudos é em Arabidopsis thaliana, modelo no qual os tricomas glandulares são ausentes. O gênero Solanum possui uma grande diversidade de tricomas, em especial glandulares (tipos I, IV, VI e VII). O estudo de tais estruturas vem ganhando cada vez mais destaque, já que são fontes de diversos metabólitos secundários de importância econômica e ecológica. Espécies selvagens são consideradas recursos genéticos para o tomateiro (S. lycopersicum), tais como S. galapagense, a qual possui variações genéticas naturais que lhe confere maior resistência ao ataque de herbívoros. Entre essas variações está a presença de tricomas glandulares do tipo IV, uma fonte do aleloquimico acilaçúcar. A ausência de tricomas glandulares do tipo IV é considerada uma das causas da suscetibilidade do tomateiro cultivado a insetos. No presente trabalho, foi demonstrado que o tomateiro cultivado na verdade forma tricomas do tipo IV, mas estas estruturas estão presentes somente até o primeiro par de folhas, além dos cotilédones. Desse modo, a presença de tricomas tipo IV em espécies selvagens seria considerada uma neotenia, ou seja, a manutenção de estruturas juvenis na fase adulta. Além de se determinar que mutantes de tomateiro afetando a juvenilidade (e.g. Mouse ears e fasciated) apresentam tricomas tipo IV na fase adulta, a formação dessas estruturas correlacionou se com a expressão de miR156, sendo também presentes em grandes quantidades em uma linhagem transgênica superexpressando esse micro RNA relacionado à juvenilidade. Quanto à base genética da presença de tricomas tipo IV nas espécies selvagens, no presente trabalho foi criada uma linhagem quase isogênica ao modelo genética Micro-Tom (MT) contendo a variação genética natural por nós denominada Galapagos enhanced trichomes (Get). Tal variação é derivada de S. galapagense e condiciona a presença de tricomas tipo IV em folhas adultas, quando introgredida em tomateiro cultivado (cv. Micro-Tom). O mapeamento preliminar de Get no cromossomo 2 de tomateiro também foi realizado através do mapa de \"single nucleotide polymorphism\" (SNPs) entre MT e a linhagem MT-Get. A eventual clonagem de GET irá contribuir não somente para se desvendar a base genética da formação de tricomas glandulares, como também contribuir para se criar variedades resistentes a insetos, reduzindo o uso de agrotóxicos. / Trichomes are epidermal structures that can be classified into two types: glandular or non-glandular, and they are mainly related to plant defense strategies. Little is known about the glandular trichome development pathway, since most of the studies are in Arabidopsis thaliana, a model in which this kind of trichome is absent. The Solanum genus has a wide variety of trichomes, especially glandular ones (Types I, IV, VI and VII). The study of these structures are gaining more prominence, since they are sources of several secondary metabolites of economic and ecological importance. Wild species are considered genetic resources for tomato (S. lycopersicum), such as S. galapagense which has natural genetic variations that gives resistance to herbivores attack. Among these variations is the presence of type IV glandular trichomes, a source of the acyl sugar allelochemical. The absence of type IV glandular trichomes is considered to be one of the causes of tomato susceptibility to insects. In this study, it was determined that tomato actually has type IV trichomes, but these structures are present only in the cotyledons and the first pair of leaves. Thus, the presence of type IV trichomes in wild species would be considered a neotenic feature, i.e. the maintenance of juvenile structures in adulthood. In addition, it was determined that tomato mutants affecting youthfulness (e.g. Mouse ears and fasciated) have type IV trichomes in adulthood. Moreover, the presence of these structures was correlated with the expression of miR156, besides the increased formation of type IV trichomes in a transgenic line overexpressing this micro RNA related to youthfulness. On the genetic basis of type IV trichomes presence in wild species, in this work it was created a near isogenic line (NIL) containing the natural genetic variation here named Galapagos enhanced trichomes (Get). This variation is derived from S. galapagense and harbors type IV trichomes in adult leaves, when introgressed in cultivated tomato (cv. Micro-Tom). The preliminary genetic map of Get in the tomato chromosome 2 was conducted through the analysis of \"single nucleotide polymorphism\" (SNPs) between MT and MT-Get. The eventual cloning of GET will contribute not only to unravel the genetic basis of glandular trichomes formation, but will also contribute to create varieties resistant to insects, reducing the pesticides use.

The distribution of epidermal hairs (trichomes) is an important taxonomic character in the genus Antirrhinum. Most species in subsection Antirrhinum produce trichomes from lower internodes and leaves, then have bald stems and leaf blades after the third node and resume trichomes production again in the inflorescence (the "bald" phenotype). All species in subsection Kickxiella produce trichomes throughout development (the "hairy" phenotype). Populations of some species are polymorphic for trichome distribution-both bald and hairy individuals were observed in A. australe, A. graniticum, A. latifolium and A. meonanthum. Antirrhinum species also varied in trichome morphology. Five types were recognized according to length and the presence or absence of a secretory gland. Some types were present in all species and had similar distributions-for example short glandular trichomes were found on the adaxial midribs of all leaves in all species, and the lower leaves and internodes of all species shared longer glandular and long eglandular trichomes. However, the trichomes on leaf blades and stems at higher vegetative nodes of hairy species and in the inflorescences differed in morphology between species, suggesting that they are regulated differently from trichomes at more basal positions. Other species in the tribe Antirrhineae showed similar variation in trichome morphology and distribution to Antirrhinum, suggesting that the control of trichome development might be conserved within the tribe. To understand the genetic basis for variation in trichome distribution, a near-isogenic line (NIL) was generated by introducing regions of the genome of A. charidemi (hairy, subsection Kickxiella) into the genetic background of A. majus subsp. majus (bald, subsection Antirrhinum). One NIL segregated bald and hairy progeny, with the same trichome distributions as the parent species, in a ratio that suggested a single locus is responsible for the differences and baldness is dominant. The locus was named as Hairy and assumed to act as a suppressor of trichome formation. Progeny of the NIL were used in genome resequencing of bulked phenotype pools (Pool-seq) to map Hairy. No recombination between Hairy and a candidate gene (GRX1) from the Glutaredoxin gene family, was detected in the mapping population. In addition, RNA-seq revealed that GRX1 was expressed in bald parts of bald progeny, but not in the same parts of hairy progeny, and in situ hybridisation showed GRX1 RNA was restricted to epidermal cells, which form trichomes in the absence of Hairy activity. A virus-induced gene silencing (VIGS) method was also developed to test GRX1 function further. Reducing GRX1 activity allowed ectopic trichome formation in the bald NIL. Together, this evidence strongly supported Hairy being GRX1. To investigate evolution of Hairy and its relationship to variation in trichome distribution, the NIL was crossed to other Antirrhinum species. These allelism tests suggested that Hairy underlies variation in trichome distribution throughout the genus, with the exception of A. siculum, which has a bald phenotype but might lack activity of hairy and a gene needed for trichome formation. Hairy sequences were obtained from representative of 24 Antirrhinum species and two related species in the tribe Antirrhineae. The conserved trichome-suppressing function of the sequence from one of these species (Misopates orontium, bald phenotype) was confirmed by VIGS. Gene phylogenies combined with RNA expression analysis suggested that the ancestral Antirrhinum had a bald phenotype, that a single mutation could have given rise to the hairy alleles in the majority of Kickxiella species, that these alleles were also present in polymorphic populations in the other subsections, consistent with transfer from Kickxiella by hybridisation, and that multiple, independent mutations had been involved in parallel evolution of the hairy phenotype in a minority of Kickxiella species. Phylogenetic analysis of GRX proteins suggested that Hairy gained its trichome-repressing function relatively late in the evolutionary history of eudicots, after the Antirrhineae-Phrymoideae split, but before divergence of the lineages leading to Antirrhinum and Misopates. A yeast two-hybrid screen identified members of the TGA and HD-Zip IV transcription factors as potential substrates of the Hairy GRX.