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Associational effects—in which the vulnerability of a plant to herbivores is influenced by its neighbors—have been widely implicated in mediating plant–herbivore interactions. Studies of associational effects typically focus on interspecific interactions or pest–crop dynamics. However, associational effects may also be important for species with intraspecific variation in defensive traits. In this study, we observed hundreds of Datura wrightii—which exhibits dimorphism in its trichome phenotype—from over 30 dimorphic populations across California. Our aim was to determine whether a relationship existed between the trichome phenotype of neighboring conspecifics and the likelihood of being damaged by four species of herbivorous insects. We visited plants at three timepoints to assess how these effects vary both within and between growing seasons. We hypothesized that the pattern of associational effects would provide rare morphs (i.e., focal plants that are a different morph than their neighbors) with an advantage in the form of reduced herbivory, thereby contributing to the negative frequency‐dependent selection previously documented in this system. We found the best predictor of herbivory/herbivore presence on focal plants was the phenotype of the focal plant. However, we also found some important neighborhood effects. The total number of plants near a focal individual predicted the likelihood and/or magnitude of herbivory by Tupiochoris notatus, Lema daturaphila, and Manduca sexta. We also found that velvety focal plants with primarily sticky neighbors are more susceptible to infestation by Tupiochoris notatus and Lema daturaphila. This does not align with the hypothesis that associational effects at the near‐neighbor scale contribute to a rare‐morph advantage in this system. Overall, the results of our study show that the number and trichome‐morph composition of neighboring conspecifics impact interactions between D. wrightii and insect herbivores., In this article, we demonstrate that intraspecific associational effects exist between neighboring plants within naturally dimorphic population of Datura wrightii. We use a generalized linear modeling approach to tease apart the relationship between the number and trichome phenotype of neighboring plants with the likelihood of herbivory present on focal plants. We find that focal plant trichome phenotype (glandular or nonglandular) was the main determinant of susceptibility differences, but also evidence for seasonal associational effects with respect to two insect herbivores: Tupiochoris notatus and Lema daturaphila.

Stinging trichomes are rare in plants, occurring only in angiosperms, where they are reported for a few genera belonging to six families. Although there is no report of stinging trichomes in Apocynaceae, previous fieldwork collections of Fischeria and Matelea caused us a mild allergic reaction on the skin when we contacted the dense indumentum of the plants. This fact associated with the well-known presence of glandular trichomes with acute apex in both genera raised suspicions that stinging trichomes could be present in the family. Hence, this study aimed to investigate the likely occurrence of stinging trichomes in Fischeria and Matelea. We analyzed vegetative shoots and leaves of Fischeria stellata and Matelea denticulata through the usual procedures of light and scanning electron microscopy. We also performed several histochemical tests to investigate the chemical composition of trichome secretion. We detected that glandular trichomes occur throughout the surface of the leaf and stem. They are multicellular, uniseriate with an apical secretory cell, which has a dilated base and a needle-shaped apex. The secretion is compressed into the acuminate portion of the apical cell by a large vacuole, and crystals are deposited in the cell wall in a subapical position, providing a preferential site of rupture. The secretion, composed of amino acids and/or proteins, is released under mechanical action, causing skin irritation. Based on our detailed morphological and anatomical analyses, and in the functional aspects observed, we concluded that the glandular trichomes in Fischeria and Matelea can indeed be classified as stinging. Thus, Apocynaceae is the seventh family for which this type of trichome has been reported. We also compiled information on stinging trichomes in all families of angiosperms. Their phylogenetic distribution indicates that they have evolved at least 12 times during angiosperm evolution and may represent an evolutionary convergence of plant defense against herbivory.

This work presents the morphology of 16 medicinal species of Lamiales used in Alta Floresta, Mato Grosso, Brazil, as well comments about phytogeography, popular use in the municipality, the status of the species in the National Policy on Medicinal Plants and Phytotherapeutics, and examples of preclinical trials. The work was performed between March and September 2020, through botanical sample of the Lamiales species presented in the book " Plantas medicinais de Alta Floresta: com contribuição a etnobotânica", obtained in rural communities and urban neighborhoods in the municipality of Alta Floresta, State of Mato Grosso. The morphological study was carried out at the Laboratory of Plant Morphology, located at the University Campus of Alta Floresta, Universidade do Estado de Mato Grosso. In general, the species are native (56%) with wide distributions in Brazil. Most species have glandular trichomes (72%) on the leaves and/or flowers and have been shown to be efficient and/or promising (85.5%) in studies. However, only 37.5% of these studies were conducted by the Ministry of Health. None of the species are offered as a phytotherapeutic by the Unified Health System (SUS), although six are on the last National Report of Medicinal Plants of Interest published by SUS. Based on the information provided, it is evident that these species could be used in studies about new phytotherapeutics for SUS users. Este trabajo presenta la morfología de 16 especies medicinales de Lamiales utilizadas en Alta Floresta, Mato Grosso, Brasil, así como comentarios sobre fitogeografía, uso popular en el municipio, estatus de la especie en la Política Nacional de Plantas Medicinales y Herbolarios, y ejemplos de ensayos preclínicos. El trabajo se realizó entre marzo y septiembre de 2020, a través de muestra botánica de especies de Lamiales presentada en el libro " Plantas medicinais de Alta Floresta: com contribuição a etnobotânica", obtenida en comunidades rurales y barrios urbanos del municipio de Alta Floresta, Estado de Mato Grosso. El estudio morfológico se realizó en el Laboratorio de Morfología Vegetal, ubicado en el Recinto Universitario de Alta Floresta, Universidade do Estado de Mato Grosso. En general, son especies nativas (56%), con amplia distribución en Brasil. La mayoría de las especies tienen tricomas glandulares (72%) en hojas y / o flores y han demostrado ser eficientes y / o prometedoras (85,5%) en estudios preclínico. Sin embargo, solo el 37,5% de estos estudios fueron realizados por el Ministerio de Salud, ninguna especie se ofrece como fitoterapia en el Sistema Único de Salud (SUS), aunque seis están incluidas en la última Lista Nacional de Plantas Medicinales de Interés Científico de la SUS. Con base en la información proporcionada, es evidente que estas especies se pueden utilizar en estudios de nuevos medicamentos a base de hierbas para usuarios del SUS. Este trabalho apresenta a morfologia de 16 espécies medicinais de Lamiales utilizadas em Alta Floresta, Mato Grosso, Brasil, além de comentários de fitogeografia, uso popular no município, status das espécies na Política Nacional de Plantas Medicinais e Fitoterápicos, e exemplos de ensaios pré-clínicos. O trabalho foi realizado entre março e setembro de 2020, através de amostra botânica das espécies de Lamiales apresentadas no livro "Plantas medicinais de Alta Floresta: com contribuição a etnobotânica", obtidas em comunidades rurais e bairros urbanos no município de Alta Floresta, Estado de Mato Grosso. O estudo morfológico foi realizado no Laboratório de Morfologia Vegetal, localizado no Campus Universitário de Alta Floresta, Universidade do Estado de Mato Grosso. No geral, são espécies nativas (56%), com ampla distribuição no Brasil. A maioria das espécies possui tricomas glandulares (72%) nas folhas e/ou flores e se mostrou eficiente e/ou promissora (85,5%) em estudos. No entanto, apenas 37,5% desses estudos foram realizados pelo Ministério da Saúde, nenhuma espécie é oferecida como fitoterápico no Sistema Único de Saúde (SUS), embora seis constem na última Relação Nacional de Plantas Medicinais de Interesse científico pelo SUS. Com base nas informações fornecidas, fica evidente que essas espécies podem ser utilizadas em estudos de novos fitoterápicos para usuários do SUS.

The isoprenoids play important ecological and physiological roles in plants. They also have a tremendous impact on human lives as food additives, medicines, and industrial raw materials, among others. Though some isoprenoids are highly abundant in nature, plants produce many at extremely low levels. Glandular trichomes (GT), which cover the aerial parts of more than 25% of vascular plants, have been considered as natural biofactories for the mass production of rare industrially important isoprenoids. In several plant genera (e.g., Lavandula and Mentha), GTs produce and store large quantities of the low molecular weight isoprenoids, in particular mono- and sesquiterpenes, as essential oil constituents. Within each trichome, a group of secretory cells is specialized to strongly and specifically express isoprenoid biosynthetic genes, and to synthesize and deposit copious amounts of terpenoids into the trichome’s storage reservoir. Despite the abundance of certain metabolites in essential oils and defensive resins, plants, particularly those lacking glandular trichomes, accumulate small quantities of many of the biologically active and industrially important isoprenoids. Therefore, there is a pressing need for technologies to enable the mass production of such metabolites, and to help meet the ever-increasing demand for plant-based bioproducts, including medicines and renewable materials. Considerable contemporary research has focused on engineering isoprenoid metabolism in GTs, with the goal of utilizing them as natural biofactories for the production of valuable phytochemicals. In this review, we summarize recent advances related to the engineering of isoprenoid biosynthetic pathways in glandular trichomes.

Background Perilla frutescens (L.) Britt is a medicinal and edible plant widely cultivated in Asia. Terpenoids, flavonoids and phenolic acids are the primary source of medicinal ingredients. Glandular trichomes with multicellular structures are known as biochemical cell factories which synthesized specialized metabolites. However, there is currently limited information regarding the site and mechanism of biosynthesis of these constituents in P. frutescens. Herein, we studied morphological features of glandular trichomes, metabolic profiling and transcriptomes through different tissues. Results Observation of light microscopy and scanning electron microscopy indicated the presence of three distinct glandular trichome types based on their morphological features: peltate, capitate, and digitiform glandular trichomes. The oil of peltate glandular trichomes, collected by custom-made micropipettes and analyzed by LC–MS and GC–MS, contained perillaketone, isoegomaketone, and egomaketone as the major constituents which are consistent with the components of leaves. Metabolomics and transcriptomics were applied to explore the bioactive constituent biosynthesis in the leaves, stem, and root of P. frutescens. Transcriptome sequencing profiles revealed differential regulation of genes related to terpenoids, flavonoids, and phenylpropanoid biosynthesis, respectively with most genes expressed highly in leaves. The genes affecting the development of trichomes were preliminarily predicted and discussed. Conclusions The current study established the morphological and chemical characteristics of glandular trichome types of P. frutescens implying the bioactive constituents were mainly synthesized in peltate glandular trichomes. The genes related to bioactive constituents biosynthesis were explored via transcriptomes, which provided the basis for unraveling the biosynthesis of bioactive constituents in this popular medicinal plant.

A study of the trichomes types and distribution and pollen morphology was carried out in nine Micromeria taxa (M. cristata ssp. cristata, M. cristata ssp. kosaninii, M. croatica, M. graeca ssp. graeca, M. graeca ssp. fruticulosa, M. juliana, M. kerneri, M. longipedunculata and M. microphylla) and five closely related Clinopodium species (C. dalmaticum, C. frivaldszkyanum, C. pulegium, C. serpyllifolium and C. thymifolium) from the Lamiaceae family of the Balkan Peninsula. By scanning electron microscope, non-glandular trichomes, peltate and capitate trichomes were observed on the calyx, leaves and stem of the studied species. Two subtypes of capitate trichomes were observed in Micromeria species: subtype 1 (consisting of a basal epidermal cell and an elliptically shaped head cell) and subtype 2 (consisting of a basal epidermal cell, two to three stalk cells and a round head cell). In Clinopodium species, three types of capitate trichomes were observed: subtype 1, subtype 3 (consisting of a basal epidermal cell, a short peduncle cell, and a single round head cell), and subtype 4 (consisting of a basal epidermal cell, a stalk cell, and an elongated head cell). These results support the recent transfer of Micromeria species from the section Pseudomelissa to the genus Clinopodium.

Main conclusion This review analyses the most recent scientific research conducted for the purpose of enhancing artemisinin production. It may help to devise better artemisinin enhancement strategies, so that its production becomes cost effective and becomes available to masses. Abstract Malaria is a major threat to world population, particularly in South-East Asia and Africa, due to dearth of effective anti-malarial compounds, emergence of quinine resistant malarial strains, and lack of advanced healthcare facilities. Artemisinin, a sesquiterpene lactone obtained from Artemisia annua L., is the most potent drug against malaria and used in the formulation of artemisinin combination therapies (ACTs). Artemisinin is also effective against various types of cancers, many other microbes including viruses, parasites and bacteria. However, this specialty metabolite and its derivatives generally occur in low amounts in the source plant leading to its production scarcity. Considering the importance of this drug, researchers have been working worldwide to develop novel strategies to augment its production both in vivo and in vitro. Due to complex chemical structure, its chemical synthesis is quite expensive, so researchers need to devise synthetic protocols that are economically viable and also work on increasing the in-planta production of artemisinin by using various strategies like use of phytohormones, stress signals, bioinoculants, breeding and transgenic approaches. The focus of this review is to discuss these artemisinin enhancement strategies, understand mechanisms modulating its biosynthesis, and evaluate if roots play any role in artemisinin production. Furthermore, we also have a critical analysis of various assays used for artemisinin measurement. This may help to develop better artemisinin enhancement strategies which lead to decreased price of ACTs and increased profit to farmers.

Red raspberry (Rubus idaeus L.) is a globally commercialized specialty crop with growing demand worldwide. The presence of prickles on the stems, petioles and undersides of the leaves complicates both the field management and harvesting of raspberries. An RNA sequencing analysis was used to identify differentially expressed genes in the epidermal tissue of prickled &ldquo, Caroline&rdquo, and prickle-free &ldquo, Joan J.&rdquo, and their segregating progeny. Expression patterns of differentially expressed genes (DEGs) in prickle-free plants revealed the downregulation of some vital development-related transcription factors (TFs), including a MIXTA-like R2R3-MYB family member, MADS-box, APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) and NAM, ATAF1/2 and CUC2 (NAC) in prickle-free epidermis tissue. The downregulation of these TFs was confirmed by qRT-PCR analysis, indicating a key regulatory role in prickle development. This study adds to the understanding of prickle development mechanisms in red raspberries needed for utilizing genetic engineering strategies for developing prickle-free raspberry cultivars and, possibly, other Rubus species, such as blackberry (Rubus sp.) and black raspberry (R. occidentalis L.).

Made available in DSpace on 2021-06-25T11:43:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-22 Silverleaf whitefly (Bemisia tabaci biotype B) has caused significant damage, year after year, and can be considered one of the major pests responsible for the increase in use of insecticides in cotton. This research aimed to evaluate the biology and preference for oviposition and feeding of Bemisia tabaci biotype B in wild cotton genotypes. The experiments were conducted at the Experimental Farm of the Mato Grosso do Sul State University, Cassilandia-MS, from March 24th to May 13th, 2017. The treatments were composed of the following genotypes:, APGO 01 and APGO 02 (Gossypium barbadense),TEX 1116 and TEX 1964 (G. hirsutum) and G. arboreum acquired in EMBRAPA germplasm, BRS 269 (standard cultivar/control) widely grown in Brazil. The infestations were carried out on plants 25 days after emergence in a no-choice test and at 42 days for the free-choice test, the cages they were infested with 100 whitefly adults per plant. The number of eggs per leaf, the density of trichomes, the viability of nymphs and the duration of the juvenile phases, in days, on the youngest leaf in the upper third of the plant were evaluated. The averages for cotton genotypes were grouped by the Scott Knott test at the 5% probability level. Low preference for oviposition of B. tabaci biotype B on genotypes APGO 01 and APGO 02 was observed in the no-choice test. The genotypes APGO 01, APGO 02, and BRS 269 were the least preferred for oviposition and had the lowest density of trichomes at 43 days after emergence in 24 hours after infestation. It was verified that in the genotypes APGO 01 and APGO 02, there was an increase in the density of trichomes, and consequently, there was an increase in the number of eggs per cm(2) in 48 hours after infestation. After 72 hours of infestation, a positive and significant correlation (r = 0687**) was observed between the number of eggs per cm(2) and the density of trichomes. A positive correlation was observed between the density of trichomes and the preference of oviposition. A negative effect of glandular trichomes and preference for oviposition was observed for APGO 02.. Resistance by antibiosis and / or non-preference for feeding in the genotypes APGO 01, APGO 02 and G. arboreum were observed for prolonging the development of the insect in the juvenile/nymph phase. Sao Paulo State Univ, Sao Paulo, Brazil Brazilian Agr Res Agcy, Brasilia, DF, Brazil Mato Grosso do Sul State Univ, Dourados, MS, Brazil USDA ARS US, ARS, Dept Agr, Grazinglands Res Lab, 7207 West Cheyenne St, El Reno, OK 73036 USA Sao Paulo State Univ, Sao Paulo, Brazil

A combination of biological control and host plant resistance would be desirable for optimally controlling the greenhouse whitefly, Trialeurodes vaporariorum in tomato crops. Whitefly settlement preference, oviposition, and survivorship were evaluated on ABL 10-4 and &lsquo, Moneymaker&rsquo, two nearly-isogenic tomato lines with, and without, whitefly-resistance traits based on type IV leaf glandular trichomes derived from the tomato wild species Solanum pimpinellifolium, respectively. Significantly reduced preference of T. vaporariorum adult whiteflies for ABL 10-4 leaves was observed. Moreover, T. vaporariorum altered its abaxial&ndash, adaxial settling performance on leaves of ABL 10-4 plants. A significantly lower tendency to settle on abaxial leaf surface was observed in ABL 10-4 compared to Moneymaker plants. Furthermore, T. vaporariorum deposited fewer eggs and exhibited a significantly reduced egg to adult survivorship in ABL 10-4 than in Moneymaker plants. Therefore, reduced fitness and distorted performance were observed for T. vaporariorum on ABL 10-4 tomato plants supporting that type IV leaf glandular trichomes might protect them from this pest and, indirectly, from the viruses it transmits.

Sample preparation including the dehydration and drying of the samples is the most intricate part in the field of scanning electron microscopy. Till to date, most of the sample preparation protocols use critical point drying with the help of liquid carbon dioxide. Very few cases have been reported where samples were dried using some chemical reagents. In this work, we have explored the possibility of using hexamethyldisilazane, a chemical drying reagent, for the preparation of plant samples. As glandular trichomes are one of the most fragile and sensitive surface structures found on plants, we chose to use Millingtonia hortensis leaf samples as our study materials that contain abundantly glandular trichome. The results obtained by this new method are identical with the results obtained from the critical point drying method, in every aspect.

1,8-Cineole is the main volatile produced by Thymus albicans Hoffmanns. & Link 1,8-cineole chemotype. To understand the contribution of distinct plant organs to the high 1,8-cineole production, trichome morphology and density, as well as emitted volatiles and transcriptional expression of the 1,8-cineole synthase (CIN) gene were determined separately for T. albicans leaves, bracts, calyx, corolla and inflorescences. Scanning electron microscopy (SEM) and stereoscope microscopy observations showed the highest peltate trichome density in leaves and bracts, significantly distinct from calyx and corolla. T. albicans volatiles were collected by solid phase micro extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC/MS) and by GC for component identification and quantification, respectively. Of the 23 components identified, 1,8-cineole was the dominant volatile (57-93 %) in all T. albicans plant organs. The relative amounts of emitted volatiles clearly separated vegetative from reproductive organs. Gene expression of CIN was assigned to all organs analyzed and was consistent with the relatively high emission of 1,8-cineole in leaves and bracts. Further studies will be required to analyze monoterpenoid biosynthesis by each type of glandular trichome. Ceratonia Project MONOTHYMUS, Universidade do Algarve, Portugal FCTPortuguese Foundation for Science and TechnologyEuropean Commission [SFRH/BPD/84033/2012] University of Algarve CESAM [UID/AMB/50017-POCI-01-0145-FEDER-007638] FEDER, within the PT2020 Partnership Agreement [FCT/UID/Multi/04326/2019/CCMAR] info:eu-repo/semantics/publishedVersion

Authors are grateful for funding provided by an NSF GRFP to J.K.G. (2015195769) and DEB‐1353970 to L.F.D. Negative frequency‐dependent selection (NFDS) has been shown to maintain polymorphism in a diverse array of traits. The action of NFDS has been confirmed through modeling, experimental approaches, and genetic analyses. In this study, we investigated NFDS in the wild using morph‐frequency changes spanning a 20‐year period from over 30 dimorphic populations of Datura wrightii. In these populations, plants either possess glandular (sticky) or non‐glandular (velvety) trichomes, and the ratio of these morphs varies substantially among populations. Our method provided evidence that NFDS, rather than drift or migration, is the primary force maintaining this dimorphism. Most populations that were initially dimorphic remained dimorphic, and the overall mean and variance in morph frequency did not change over time. Furthermore, morph‐frequency differences were not related to geographic distances. Together, these results indicate that neither directional selection, drift, or migration played a substantial role in determining morph frequencies. However, as predicted by negative frequency‐dependent selection, we found that the rare morph tended to increase in frequency, leading to a negative relationship between the change in the frequency of the sticky morph and its initial frequency. In addition, we found that morph‐frequency change over time was significantly correlated with the damage inflicted by two herbivores: Lema daturaphila and Tupiochoris notatus. The latter is a specialist on the sticky morph and damage by this herbivore was greatest when the sticky morph was common. The reverse was true for L. daturaphila, such that damage increased with the frequency of the velvety morph. These findings suggest that these herbivores contribute to balancing selection on the observed trichome dimorphism. Publisher PDF

Pelargonium graveolens is a wild predecessor to rose-scented geranium hybrids prized for their essential oils used as fragrances and flavorings. However, little is known about their biosynthesis. Here we present metabolic evidence that at least two distinct monoterpene biosynthetic pathways contribute to their volatile profiles, namely, cyclic p-menthanes such as (−)-isomenthone and acyclic monoterpene alcohols such as geraniol and (−)-citronellol and their derivatives (referred to here as citronelloid monoterpenes). We established their common origin via the 2C-methyl-d-erythritol-4-phosphate pathway but found no indication these pathways share common intermediates beyond geranyl diphosphate. Untargeted volatile profiling of 22 seed-grown P. graveolens lines demonstrated distinct chemotypes that preferentially accumulate (−)-isomenthone, geraniol, or (−)-citronellol along with approximately 85 minor volatile products. Whole plant 13CO2 isotopic labeling performed under physiological conditions permitted us to measure the in vivo rates of monoterpenoid accumulation in these lines and quantify differences in metabolic modes between chemotypes. We further determined that p-menthane monoterpenoids in Pelargonium are likely synthesized from (+)-limonene via (+)-piperitone rather than (+)-pulegone. Exploitation of this natural population enabled a detailed dissection of the relative rates of competing p-menthane and citronelloid pathways in this species, providing real time rates of monoterpene accumulation in glandular trichomes., This work was supported by a Discovery grant provided by the Natural Sciences and Engineering Research Council (RGPIN-2017-06400, to MP) and by a John Evans Leadership Fund grant from the Canadian Foundation for Innovation (36131, to M P).

The profile of volatile organic compounds (VOC), the composition of the essential oils (EOs) and the micromorphology of the leaf trichomes were investigated in two rosemary hybrids, Salvia×mendizabalii (Sagredo ex Rosua) Roma-Marzio & Galasso (S × m) and Salvia x lavandulacea (de Noe) Roma-Marzio & Galasso (S × l). The phytochemical analysis highlighted the dominance of monoterpene hydrocarbons in both aroma profiles (65.8 % in S × m and 77.9 % in S × l, respectively), although they displayed different main compounds except for α-pinene (28.2 % in S × m and 24.5 % in S × l). In S × m the EOs extracted from both fresh and dried leaves exhibited camphor (29.7 % and 25.9 %, respectively), α-pinene (21.0 % and 18.2 %, respectively) and 1,8-cineole (11.1 % and 13.6 %, respectively) as major compounds. Noteworthy is the occurrence of β-pinene (2.6 %) in the EO dried samples, whereas sabinene and limonene were exclusive of the fresh samples. In S × l the EOs from the fresh and dried leaves shared the same main compounds: camphor (24.0 % and 27.5 %, respectively), myrcene (14.9 % and 14.8 %, respectively) and α-pinene (13.1 % and 12.2 %, respectively). The micro-morphological observations on leaves proved the occurrence of non-glandular dendritic hairs with smooth cuticle in both hybrids. The glandular trichomes include three main morphotypes: peltate, short capitate and medium-long capitate. The peltate and the short capitates are common to both hybrids, however in the peltate the number of the head secreting cells is different, eight in S × m and sixteen in S × l. The medium-long capitate occurs exclusively on the leaf adaxial side of S × m.

The cultivation of aromatic species to obtain essential oils has great economic importance, presenting an increasing demand from different industrial sectors, especially to menthol mint (Mentha arvensis L.) essential oil, rich in menthol (70-80%). Consortium cultivation has been an important practice in agricultural systems whose land use is necessary, consequently promoting strong competition for light in reduced space. Thus, this study aimed verifying if different light intensities might promote chemical, metabolical and anatomical alterations in menthol mint. Plants were grown in greenhouse at different average of light intensities (137, 254, 406 and 543 µmol photons m2 s1). Samples were collected 43 days after germination and submitted to following analyses: Gravimetric test, photosynthetic pigments, soluble fractions, enzymatic activity, N-total, trichome density and histochemistry and chemometric test based on essential oil chemical profile. Fresh mass gain, trichome density, essential oil content and soluble sugars were positively influenced by light intensity increase. On the other hand, total-N, NO3−-N and pigments content have decreased influenced by light intensity increase. In the secretion from the trichomes, phenolic substances were reported, as well as lipophilic ones in the peltate ones. The increase of oxygenated monoterpenes was favored by light intensity decrease.

In the context of a wide research project, a micromorphological and phytochemical characterization was performed on the vegetative and reproductive organs of Scutellaria caucasica A. Ham. (Lamiaceae), cultivated at the Ghirardi Botanic Garden (Toscolano Maderno, BS, Lombardy, Italy). The morphological survey revealed the presence of both non-glandular and glandular trichomes. The latter belonged to three different morphotypes: peltate, short-stalked and long-stalked capitate. Histochemical assays demonstrated that the terpenes biosynthesis mainly took place in the peltates, while short-stalked capitates secreted only polysaccharides; the long-stalked ones mainly produced polysaccharides, coupled with terpene and polyphenolic fractions. An element of novelty was represented by the characterization of the VOC emission profile. Leaves and flowers showed differences in their emissions: the floral profile had a higher number of compounds than that of the leaves (37 vs 29), with a higher heterogeneity. The almost totality of the leaf profile was characterized by sesquiterpene hydrocarbons (98.8 %), while the flowers presented a more varied composition, with sesquiterpene hydrocarbons (87.2 %), monoterpenes (10.4 % oxygenated, 1.8 % hydrocarbons) and non-terpenes derivatives (0.6 %). The most abundant compounds were γ-muurolene (42.6 %) and β-caryophyllene (35.0 %) in the leaves and in the flowers, respectively. In the flower headspace, 16 exclusive compounds were identified, among which germacrene D (31.7 %) dominated; leaves had 8 exclusive compounds, with valencene (1.8 %) as the most represented one. 21 common compounds were revealed: β-caryophyllene (34.1 % leaves; 35.0 % flowers), α-humulene (3.0 % leaves; 3.1 % flowers), alloaromadendrene (2.4 % leaves; 1.0 % flowers), α-copaene (2.1 % leaves; 2.7 % flowers) and β-copaene (2.2 % leaves; 1.5 % flowers) were the most abundant ones. γ-Muurolene relative abundances (42.6 % leaves; 0.7 % flowers) were very different between the two profiles. Overall, this work represented the first multidisciplinary study on S. caucasica, combining a scientific research approach with the policies of the Open Science.

Glandular trichomes found on the surface of many higher plants contain specialized cells that produce and secrete copious amounts of particular secretory products. Leaf glandular trichomes of the non-model plant species Nicotiana tabacum represent a biologically active and stress-responsive tissue that contributes to plant defense response against biotic and abiotic stress and also influences leaf aroma and smoke flavor. Two morphologically different types of tobacco capitate trichomes, long- and short-stalked, with distinct functions, display ultrastructural features that are common to terpene-secreting glands, but only the secretory cells of the tall glandular trichomes are considered to be the site of biosynthesis of certain exudate compounds, including diterpenes and sucrose esters. Ultrastructural and histochemical characterization of tall glandular trichomes is described in an attempt to understand the contribution of these glands to the total secretion produced. Possible roles of distinct cellular compartments involved in the secretory process and secondary metabolite secretion under in vitro conditions are discussed. Gopal RK, Ekiert HM, Goyal S, editors. Plant Cell and Tissue Differentiation and Secondary Metabolites. Springer, Cham; 2020. p. 1–37. (Reference Series in Phytochemistry).

Within an Open Science project, research was carried out to describe to the public of the Ghirardi Botanic Garden (BS, Lombardy, Italy) the invisible features of plants. This work is dedicated to Scutellaria altissima L. (Lamiaceae). Micromorphological, histochemical and phytochemical investigations were conducted on the vegetative and reproductive organs to correlate the structures involved in the emission of substances and their unique productivity. This work reports volatile organic compound (VOC) profiles of leaves and flowers and the composition of essential oil (EO) obtained from aerial parts of plants cultivated in Italy that have never been described before. Three morphotypes of glandular trichomes were observed: peltate, short-stalked capitate and long-stalked capitate. Peltate trichomes were the main producers of terpenes, short-stalked capitates of polysaccharides and long-stalked capitates of terpenes and polyphenols. The leaf VOC profile showed heterogeneous composition, with non-terpene derivatives as the major chemical class (71.04%), while monoterpene hydrocarbons represented almost the totality of the flower (99.73%). The leaf presented a higher number of total (37 versus 11) and exclusive (33 versus 7) compounds. (Z)-3-Hexenol acetate was most abundant in the leaf and (E)-β-ocimene in the flower. Four common compounds were detected: β-pinene, β-caryophyllene, γ-muurolene and germacrene-D. The EO contaied 21 compounds, dominated by β-caryophyllene, linalool and hexahydrofarnesyl acetone. This research allowed us to correlate morphotypes of the secretory structures with the production of secondary metabolites, with the aim of providing the public of the Ghirardi Botanic Garden with a dedicated iconographic approach, which accounts for olfactory perception linked to S. altissima.

Supplemental ultraviolet radiation increases tomato resistance to thrips herbivory through activation of jasmonic acid signaling, and without changes in the plant metabolome or the density of type-VI trichomes and their associated volatiles., Ultraviolet (UV) radiation can modulate plant defenses against herbivorous arthropods. We investigated how different UV exposure times and irradiance intensities affected tomato (Solanum lycopersicum) resistance to thrips (Frankliniella occidentalis) by assessing UV effects on thrips-associated damage and host-selection, selected metabolite and phytohormone contents, expression of defense-related genes, and trichome density and chemistry, the latter having dual roles in defense and UV protection. Short UV daily exposure times increased thrips resistance in the cultivar ‘Moneymaker’ but this could not be explained by changes in the contents of selected leaf polyphenols or terpenes, nor by trichome-associated defenses. UV irradiance intensity also affected resistance to thrips. Further analyses using the tomato mutants def-1, impaired in jasmonic acid (JA) biosynthesis, od-2, defective in the production of functional type-VI trichomes, and their wild-type, ‘Castlemart’, showed that UV enhanced thrips resistance in Moneymaker and od-2, but not in def-1 and Castlemart. UV increased salicylic acid (SA) and JA-isoleucine concentrations, and increased expression of SA- and JA-associated genes in Moneymaker, while inducing expression of JA-defensive genes in od-2. Our results demonstrate that UV-mediated enhancement of tomato resistance to thrips is probably associated with the activation of JA-associated signaling, but not with plant secondary metabolism or trichome-related traits.

Dracocephalum moldavica is a valuable reward plant for flower visitors. The aim of the study was to ecologically characterise its flowers and leaves and assess the seasonal and daily dynamics of flowering in two white- and blue-flowered forms of this species in 2004 and 2005. Additionally, the duration and abundance of plant flowering as well as the nectar amount and sugar content were analysed. The signalling attractants of the plant include an intense scent emitted by trichomes located not only on its flowers but also on its stem and leaf surfaces. The average corolla length is 24 mm and the corolla tube, which can be completely filled with nectar, is 8.6 mm long. The floral lifespan was shown to reach 2-3 days and the mean blooming duration of both forms of dragonhead 45-48 days. The white-flowered plants produced a substantially greater number of flowers (5352) than the blue-flowered form (2965). The nectar amount obtained from ten blue flowers was 15.33 mg and that extracted from white flowers reached 17.56 mg, with 49.4% and 51.5% content of sugar, respectively. The total sugar mass produced by one white-flowered plant was 4656 mg, while one blue-flowered plant yielded 2164 mg of sugars. The sugar yield calculated in the study for the white-flowered form (586 kg · ha−1) was two-fold higher than that in the blue-flowered plants.

Leaf trichomes play well-established roles in defense against insect herbivores, both as a physical barrier that impedes herbivore movement and by mediating chemical defenses. However, little work has examined how different trichome types influence herbivory by herbivores at different stages of development. We examined whether caterpillar instar and trichome type (glandular or non-glandular) affected the ability of the specialist herbivore caterpillar Manduca sexta to initiate feeding on 11 Solanaceous species exhibiting variation in the density and type of leaf trichomes. Our results suggest that non-glandular trichomes are far more effective than glandular trichomes in deterring the initiation of feeding by first- and second-instar caterpillars. Meanwhile, neither glandular nor non-glandular trichomes significantly affected the ability of third-instar caterpillars to commence feeding. These findings suggest that while non-glandular trichomes deter feeding initiation by early instar caterpillars, the contribution of both trichomes on later instars may depend on effects after feeding initiation., Communicative & Integrative Biology, 11 (3), ISSN:1942-0889

Leaves of Rubus idaeus are a raw material, ingredients of herbal blend, and a source of antioxidants. There are no data concerning histochemistry of trichomes, and little is known about the leaf structure of this species. The aim of this study was to determine the histochemistry of active compounds and the structure of glandular trichomes, micromorphology, anatomy, and ultrastructure of leaves as well as content of elements. To determine the histochemistry of glandular trichomes, different chemical compounds were used. The leaf structure was analysed using light, scanning, and transmission electron microscopes. The content of elements was determined with atomic absorption spectrometry, and the microanalysis of the epidermis ultrastructure was carried out with a transmission electron microscope equipped with a digital X-ray analyser. In glandular trichomes, polyphenols, terpenes, lipids, proteins, and carbohydrates were identified. The main elements in the ultrastructure of the epidermis were Na, Mo, Se, Ca, and Mg. In dry matter of leaves, K, Mg, Ca, P, and Fe were dominant. Infusions from leaves are safe for health in terms of the Cd and Pb concentrations. Leaves can be a valuable raw material. Non-glandular trichomes prevent clumping of mixed raw materials in herbal mixtures.

Asteraceae is the largest family of angiosperms and occurs predominantly in grassland areas. This study aimed to identify and characterize the foliar trichomes of 34 Asteraceae species from Sand-fields of the Pampa biome, by means of epidermal analyzes (front and transverse view) under light and scanning electron microscopy. Eleven types of trichomes were identified and characterized: three glandular (recurved on the epidermis, erect-capitate and uniseriate to multiseriate vesicular-capitate) and eight non-glandular (simple conical, flagellate-filiform, aseptate-flagellate, whip-like, oblique-flagellate, branched with one arm, branched with two T-shaped arms, branched with three or more arms). The most representative glandular type was the uniseriate to multiseriate vesicular-capitate (58%) and the non-glandular type was the simple conical (35%). A large number of trichomes is an adaptive strategy to the adverse conditions of the Pampa biome and its morphological diversity can be useful in the family systematics. RESUMO Asteraceae é a maior família das angiospermas e ocorre predominante em áreas campestres. Este estudo buscou identificar e caracterizar os tricomas foliares de 34 espécies de Asteraceae dos Campos de Areais do bioma Pampa por meio de análises da epiderme (vista frontal e transversal) em microscopia de luz e eletrônica de varredura. Foram identificados e caracterizados 11 tipos de tricomas: três glandulares (recurvado, capitado ereto e capitado vesicular unisseriado a multisseriado) e oito tectores (cônico simples, filiforme-flagelado, asseptado-flagelado, forma de chicote, oblíquo-flagelado, ramificado com um braço, ramificado com dois braços em forma de T, ramificado com três ou mais braços). O tipo de tricoma glandular mais representativo foi o capitado vesicular unisseriado a multisseriado (58%) e o tipo não glandular (tector) foi o cônico simples (35%). A grande quantidade de tricomas é uma estratégia adaptativa às condições adversas do bioma Pampa e a sua diversidade morfológica pode ser útil na sistemática da família.

Made available in DSpace on 2021-06-25T10:56:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Muntingia calabura L. is a neotropical Muntingiaceae tree with medicinal properties and economic interest. Extracts from its leaves and stems are rich in carbohydrates, volatiles and phenolic compounds with proved anti-tumor, antinociceptive and thermogenic properties. However, little is known about the structural features of leaves and stem and where these compounds are produced. In addition to the glandular trichomes registered in the literature, we hypothesized that other morphotypes of secretory cells and tissues could be present in M. calabura. In this paper, we analysed the leaf and stem anatomical traits of M. calabura to assess the production sites of bioactive compounds. Leaf and stem samples were collected from plants living in an urban area in Botucatu city, southeastern Brazil, and submitted to standard methods for anatomical and histochemical assessments. The leafblade was hypoestomatic, heterobaric and exhibited dorsiventral mesophyll. The petiole had parenchyma cortex, central vascular system and parenchyma pith. The stem presented parenchyma cortex, peripheral vascular system and parenchyma pith. Druses of calcium occurred mainly in the inner cortex of stem, petiole and midrib. Abundant glandular and non-glandular trichomes characterized the epidermis of leaves and stem. Phenolic compounds and mucilage were detected in the glandular trichome head cells in all the analysed organs, in addition to the cortical cells of midrib, petiole and stem. Voluminous bi-compartmentalized cells containing phenolic compounds and mucilage characterized the epidermis in the adaxial surface of the leaf blade. These cells were a remarkable feature that deserve further investigation. Our results shed light to the poorly known secretory system of M. calabura and proved the occurrence of different morphotypes of secretory cells and tissues in its leaves and stem. The obtained data can guide more studies with ecological, structural and taxonomic approaches, and for researches on drug bioprospecting from this species. Graduate Program in Biological Sciences (Botany) UNESP - São Paulo State University IBB - Institute of Biosciences of Botucatu, PO Box 510 UNESP - São Paulo State University IBB - Institute of Biosciences of Botucatu, PO Box 510 Graduate Program in Biological Sciences (Botany) UNESP - São Paulo State University IBB - Institute of Biosciences of Botucatu, PO Box 510 UNESP - São Paulo State University IBB - Institute of Biosciences of Botucatu, PO Box 510

Artemisia annua is currently the only economically viable source of the antimalarial compound artemisinin. Synthesis of artemisinin takes place in glandular trichomes, primarily on the leaves from where artemisinin is extracted. It is not well understood why yields and concentrations of artemisinin vary across crops in relation to external conditions and agricultural practices. We therefore studied the diverse processes underlying artemisinin synthesis in A. annua crops, focussing on effects of |nitrogen fertilization on processes involved in formation of leaves and trichomes, and production of artemisinin in the individual leaves. In two field experiments, effects of nitrogen application levels (0, 75, 175, 400 kg N ha -1 ) on leaves from a selected position at the main stem and a primary branch were studied. Measurements during part of the life cycle of the leaves included: area and dry weight per leaf, trichome density on the abaxial (lower) leaf side, trichome size, and artemisinin concentration. Results showed that effects of N fertilization were generally small, but in line with the hypothesis that at low N levels individual leaves remain smaller but have higher trichome densities. These trends were especially clear in the branch leaves. The total |number of trichomes per leaf usually increased with increase in N application up to at least 175 kg N ha -1 . Within a leaf position, effects of N application on artemisinin concentration in the leaf dry mass were similar to effects on percentage of leaf area covered by trichomes. The total quantity of artemisinin produced per (abaxial) trichome varied, but seemed to decrease linearly with increase in N level. There were no systematic linear or quadratic responses to N application in the total quantity of artemisinin per leaf. The reduction in artemisinin concentration in the leaf mass at higher N levels was therefore caused by increased dry weights per leaf.

Made available in DSpace on 2018-12-11T17:02:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Lantana camara L. is a species of Verbenaceae known for its aromatic and medicinal properties. Compounds extracted from its leaves are used to treat infections of the respiratory tract and have demonstrated antimicrobial potential and repellent action to Aedes mosquitoes. Our aim was to identify and characterize the main production sites of the biologically active substances in the leaf blades of L. camara. Leaf samples were collected from plants living in the Brazilian Cerrado and processed according to standard techniques in plant anatomy and histochemistry as well as scanning and transmission electron microscopy. Six morphotypes of glandular trichomes (I-VI) were identified; they differ in shape and size, number of constituent cells, subcellular aspects, and form of accumulation, as well as release and composition of the secretion. Idioblasts producing hydrophilic and lipophilic substances were observed in the mesophyll and may be associated with protection of the plant against herbivores and pathogens and maintenance of the water potential of leaf tissues, complementing the action of glandular trichomes. Our results contribute to the understanding and knowledge of the sites responsible for the production of substances with ecological and medicinal value in Verbenaceae species, and may provide a foundation for future studies in different areas of science focusing on the manipulation of this production. Universidade Estadual Paulista UNESP Institute of Biosciences of Botucatu (IBB) Department of Botany Universidade Estadual Paulista UNESP Institute of Biosciences of Botucatu (IBB) Department of Botany FAPESP: 2013/07428-6

Chemical profile and antioxidant activity of the species Veronica saturejoides Vis. ssp. saturejoides (Plantaginaceae)&mdash, which is endemic to Croatia, Bosnia and Herzegovina and Montenegro &mdash, were investigated. Volatile compounds produced by glandular trichomes (composed of one stalk cell and two elliptically formed head cells according to scanning electron microscope investigation) were isolated from the plants collected in two locations. Additionally, as a part of specialized metabolites, total polyphenols, total tannins, total flavonoids and total phenolic acids were determined spectrophotometrically. In the lipophilic volatile fractions-essential oils, the most abundant compounds identified were hexahydrofarnesyl acetone, caryophyllene oxide and hexadecanoic acid. In total, the class of oxygenated sesquiterpenes and the group of fatty aldehydes, acids and alcoholic compounds dominated in the essential oils. In the hydrophilic volatile fractions-hydrosols, the most abundant compounds identified were trans-p-mentha-1(7),8-dien-2-ol, allo-aromadendrene and (E)-caryophyllene. A group of oxygenated monoterpenes and the sesquiterpene hydrocarbons dominated in the hydrosols. Antioxidant activity of essential oils and hydrosols was tested with two methods: 2,2&prime, diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC). Essential oils showed higher antioxidant activity than hydrosols and showed similar antioxidant activity to Rosmarinus officinalis essential oil. Obtained results demonstrate that this genus is a potential source of volatiles with antioxidant activity.

A plant can combine physical and chemical tools to interact with other organisms. Some are designed for pollinator attraction (i.e., colors and volatile organic compounds-VOCs), others can act to discourage herbivores (i.e., non-glandular trichomes). Few studies fully address available tools in a single species, notwithstanding, this information can be pivotal in understanding new interactions out of the home range. We characterized flower traits, emission profiles of constitutive compounds from flowers and leaves, micro-morphology of the glandular trichomes, and listed flower visitors of two Mexican bird-pollinated Salvia species (S. blepharophylla and S. greggii), growing in an Italian botanical garden. Flowers were highly variable in their morphometric characteristics. In both species, four trichome morphotypes with similar histochemistry and distribution were documented for leaves and flowers except the calyx abaxial side. The vegetative emission profiles were qualitatively more complex than the floral ones, however, common compounds occurring in high relative percentages were &beta, caryophyllene and germacrene D. Floral bouquets were dominated by limonene and &beta, pinene in S. greggii and by 1,8-cineole in S. blepharophylla. Two potential (non-bird) pollinators were especially abundant: small bees belonging to the genus Lasioglossum and large bees belonging to the species Xylocopa violacea. Our study highlights the plasticity of these plants, as well as tools that can be conveniently used to establish novel interactions.

The aim of the study was to assess the effects of Melittis melissophyllum shading on its development and accumulation of phenolics. Their content (verbascoside, apiin, luteolin-7-O-glucoside, coumarin, 3,4-dihydroxycoumarin, o-coumaric acid 2-O-glucoside as well as o-coumaric, p-coumaric, chlorogenic, caffeic, ferulic and cichoric acid) was determined in the herb using HPLC-DAD. The results showed that the content of abovementioned flavonoids and phenolic acids was highest in plants grown under full sunlight. On the other hand, a higher content of coumarin was observed in shaded plants, especially after the seed-setting stage. A similar tendency was noted for the amount of chlorophyll a and b. The content of hydrogen peroxide and malondialdehyde, the activity of polyphenol oxidase and catalase and the antioxidant capacity of plant extracts (measured using DPPH, ABTS and FRAP assays) were found to be the highest in the plants grown in full sunlight. However, the plants grown in moderate (30%) shade were found to thrive best.

A new species of Triumfetta from the Brazilian Atlantic Forest is described and illustrated by line drawings and scanning electron micrographs, along with notes on taxonomy, morphology, geographic distribution, and conservation status. Triumfetta multiglandulosa (Malvaceae, Grewioideae) grows in disturbed areas on sandy soils in the state of Goiás in midwestern Brazil. It resembles Triumfetta dioica and T. mexiae especially due to the paniculiform inflorescence and fruits without uncinate spines, but differs by having the indumentumwith glandular trichomes, ovate stipules with a caudate apex, inflorescences with three-flowered cymes, 10 stamens, and entire stigmas. An identification key for all species of Triumfetta from Brazil is also provided. Fil: Fernandes Júnior, Aluisio J.. Museu Paraense Emilio Goeldi; Brasil Fil: Ferrucci, María Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina Fil: Gil, André Dos S. B.. Museu Paraense Emilio Goeldi; Brasil

Tomato genotypes selected for their high foliar zingiberene (ZGB) contents in a segregating F2 population were assessed to determine their effect on behavior and biology of Tetranychus urticae Koch, the putative resistance mechanisms involved and the role of trichomes on that resistance. Genotypes with contrasting ZGB content (RVTZ-09 = low ZGB, RVTZ-79 = high ZGB, RVTZ-142 = high ZGB, and RVTZ-331 = high ZGB) were selected from an interspecific cross between wild S. habrochaites var. hirsutum accession PI-127826 (high ZGB content and resistant to mites) and S. lycopersicum cv. Redenção (low ZGB content and susceptible to mites). To determine the effect of these genotypes on mite behavior and biology, free- and no-choice tests, as well as biological studies were performed. Types and densities of trichomes on the foliar surface and their correlation with ZGB contents was determined. Genotypes rich in ZGB (RVTZ-79, RVTZ-142, and RVTZ-331) presented a high number of types IV and VI glandular trichomes, and both type IV and VI densities were positively correlated with ZGB content. In the free-choice test, T. urticae showed a high preference toward S. lycopersicum cv. Redenção and the genotype RVTZ-09 (low ZGB content), whereas, genotypes with high ZBG content were less preferred. Moreover, on high ZGB genotypes, increase in the egg incubation period and in total mortality of nymphs, and decrease of fecundity rate were observed, indicating deleterious effects in mite biology. Results indicated that high ZGB/high glandular trichome densities genotypes present both non-preference and antibiosis mechanisms of resistance to the mite.

Chemical derivatives of artemisinin, a sesquiterpene lactone produced by Artemisia annua, are the active ingredient in the most effective treatment for malaria. Comprehensive phytochemical analysis of two contrasting chemotypes of A. annua resulted in the characterization of over 80 natural products by NMR, more than 20 of which are novel and described here for the first time. Analysis of high- and low-artemisinin producing (HAP and LAP) chemotypes of A. annua confirmed the latter to have a low level of DBR2 (artemisinic aldehyde Δ11(13) reductase) gene expression. Here we show that the LAP chemotype accumulates high levels of artemisinic acid, arteannuin B, epi-deoxyarteannuin B and other amorpha-4,11-diene derived sesquiterpenes which are unsaturated at the 11,13-position. By contrast, the HAP chemotype is rich in sesquiterpenes saturated at the 11,13-position (dihydroartemisinic acid, artemisinin and dihydro-epi-deoxyarteannunin B), which is consistent with higher expression levels of DBR2, and also with the presence of a HAP-chemotype version of CYP71AV1 (amorpha-4,11-diene C-12 oxidase). Our results indicate that the conversion steps from artemisinic acid to arteannuin B, epi-deoxyarteannuin B and artemisitene in the LAP chemotype are non-enzymatic and parallel the non-enzymatic conversion of DHAA to artemisinin and dihyro-epi-deoxyarteannuin B in the HAP chemotype. Interestingly, artemisinic acid in the LAP chemotype preferentially converts to arteannuin B rather than the endoperoxide bridge containing artemisitene. In contrast, in the HAP chemotype, DHAA preferentially converts to artemisinin. Broader metabolomic and transcriptomic profiling revealed significantly different terpenoid profiles and related terpenoid gene expression in these two morphologically distinct chemotypes.

Nepetalactones are accumulated as the main secondary metabolites in the majority of Nepeta species; however, their biosynthetic pathway remains to a great extent unknown, as well as their relationship to the overall physiology of these plants. Nepetalactones most certainly arise through general iridoid biosynthetic pathway leading to nepetalactol, a common precursor of all plant-derived iridoids that is formed in a reaction catalysed by iridoid synthase (IS, EC 1.3.1.99). In this paper, we aimed to localize the sites of nepetalactone biosynthesis and accumulation by comparatively analysing the nepetalactones content and the expression of putative iridoid synthase (NrIS) in leaves of Nepeta rtanjensis Diklic & Milojevic, a trans,cis-nepetalactone and dehydronepetalactone rich species. Another aim was to give an insight into the developmental regulation of nepetalactone biosynthesis in leaves of cultivated N. rtanjensis plants. Knowledge on the spatial-, and developmental- regulation of nepetalactone metabolism could greatly benefit potential growers by enabling them to adequately plan and manage plant cultivation, harvesting, and handling and thus increase yield of bioactive compounds. The expression profile of putative NrIS1 is highly correlated with trans,cis-nepetalactone and dehydronepetalactone content/ratio in leaves of different developmental stages. The results strongly indicate that developmental regulation of nepetalactone biosynthesis in leaves resides largely at the level of gene expression, and suggest an important role of NrIS1. Young leaves exhibited the most intensive nepetalactone biosynthesis and accumulation, but also its conversion to dehydronepetalactone. Thus, the pattern of NL accumulation in leaves can be explained by both the rate of its biosynthesis and metabolic degradation. The gene expression patterns of NrIS1 and NrIS2 transcripts in trichomes and abraded leaves revealed trichomes as the main site of their activity. UHPLC/qqqMS profiling of nepetalactones in trichomes and abraded leaves, complemented with Raman spectroscopy and dichloromethane dipping experiment, supported glandular trichome-specific localization of nepetalactone biosynthesis and accumulation.

The glycosylation of nicotinate (NA), a key intermediate of the NAD salvage pathway, occurs widely in land plants. However, the physiological function of NA glycosylation is not well understood in planta, and no gene encoding NA glycosyltransferase has been reported to date. NA glycosylation in Arabidopsis thaliana occurs at either the N- or the O-position of the NA molecule, and O-glucosylation appears to be unique to the Brassicaceae. Using gene-enzyme correlations focused on Family 1 glycosyltransferases (GTs; EC 2.4), we identified and characterized three Arabidopsis GTs, which are likely involved in NA glycosylation. These include one NAOGT (UGT74F2; previously identified as a salicylic acid glycosyltransferases) and two NANGTs (UGT76C4 and UGT76C5). Arabidopsis mutants of UGT74F2 accumulate higher levels of free NA, but not salicylic acid, than that of the wild type, and this inversely correlated with seed germination rates under various abiotic stresses. The germination defect of the ugt74f2-1 mutant could be fully complemented by overexpression of UGT74F2. These observations, together with comprehensive chemical analysis, suggest that NA glycosylation may function to protect plant cells from the toxicity of NA overaccumulation during seed germination. Combined with phylogenetic analysis, our results suggest that NAOGTs arose recently in the Brassicaceae family and may provide a fitness benefit. The multifunctionality of UGT74F2 in Arabidopsis is also investigated and discussed.

In this study, we developed tissue culture protocol of Salvia dolomitica, a particularly fragrant sage and we evaluated the yield and the profile of essential oil (EO) produced from plants grown in vivo compared to in vitro plant material cultured in two light intensity growth conditions. Plant extracts secreted from glandular trichomes are, in Lamiacea, a valuable source of biologically active volatile compounds. Microscopical observations permitted to describe, for the first time, secretory structures from S. dolomitica leaves developed in vitro showing morphological identity to in vivo glands. The yield of EO obtained from light-stressed in vitro plants was higher than which obtained from the non-stressed in vitro plants and threefold higher that in vivo plants. Phytochemical analysis of EOs and volatile compounds showed quali-quantitative differences between S. dolomitica in vitro grown plantlets and those from open field. α-Pinene, β-phellandrene and borneol accumulated predominantly in micropropagated plants while β-caryophyllene, α-guaiene, δ-cadinene and valencene in in vivo material. Both EO and SPME analysis had the same trend: the percentage of total sesquiterpenes decreased strongly in vitro, on the contrary the total monoterpenes are abundant. The effect of the high light treatment on aromatic profile demonstrating that this stress can affect the EO composition and this can be exploited by researchers to address the accumulation of valuable amounts of EO.

Due to the presence of secondary metabolites exhibiting pharmacological activity, the flowers of Rosa rugosa Thunb. have found application in traditional and folk medicine. The essential oil obtained from them is also considered to be a phytoncide. The morphological and anatomical characters of glandular trichomes located on the sepals of R. rugosa were studied by light and scanning electron microscopy. Using histochemical tests, the type of secretion produced in the trichomes was determined and its contents were compared with the secretion produced by the papillae on the petals.It was found that multicellular glandular trichomes, having the features of colleters, and non-glandular trichomes were located on the abaxial epidermis, while only non-glandular trichomes were situated on the adaxial epidermis. The stalk cells of the glandular trichomes are arranged in multiple rows, whereas the epidermal cells of the head are arranged radially. The capitate trichomes were classified into two types: short and long trichomes. The largest density of glandular trichomes was recorded in the basal abaxial epidermis and in the middle part of the sepals. During the initial stages of bud development, the glandular hairs were green colored, whereas in the next development stages they changed the color to red. The histochemical tests used allowed us to find that the trichomes on the sepals and the papille on the petals produced lipid substances, polyphenols, tannins, and flavonoids. Sesquiterpenes were found only in the secretion of the glandular hairs on the sepals.

Background The objective of this work is to study the influence of arbuscal mycorrhizal fungi (Glomus intraradices) and water stress on the ultrastructural change of basil glandular hair and also on the essential oil synthesis, especially on the isomerization of the two main compounds methyl chavicol and trans-anethole. Results The results of this study show that mycorrhization increases the yield of essential oils, with a maximum recorded in mycorrhizal stressed plants (0.33%) and a minimum among non-mycorrhizal unstressed plants (0.22%). Oxygenated monoterpenes represent the main family of essential oils. Furthermore, the chemical composition of these essential oils changed under the condition in which the plant is. However, the main compound methyl chavicol was found to be at maximum concentration (93%) in mycorrhizal stressed plants and minimum in non-mycorrhizal stressed plants (84%). Contrariwise, its isomer trans-anethole reached the maximum (8%) among non-mycorrhizal non-stressed plants and minimum (2%) in non-mycorrhizal stressed plants. Conclusion Ocimum gratissimum L. leaves showed the presence of two types of peltate glands: the first one with 4 secreting cells and the second with 8 secreting cells. The diameter of these glands changed with the hydric state of plants; in the absence of mycorrhization, stress causes a decrease in the extracellular cavity diameter of glandular trichomes and their deflation which would cause a concentration of essential oil in the glands. Graphical abstract Effect of arbuscular mycorrhizal fungi and water stress on essential oil yield and compositions by the change in some endogenous plant growth regulators and glandular hairs morphology and density in Ocimum gratissimum

Made available in DSpace on 2018-12-11T17:30:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Studies that focus on understanding complex interactions among resistant plants, herbivores, and their natural enemies are fundamental to elucidating whether plant herbivore defenses impose beneficial, adverse, or neutral effects on natural enemies. The impacts of resistant plant genotypes on natural enemies can determine the feasibility of integrating host plant resistance with biological control in IPM programs. We investigated direct and indirect effects of tomato trichomes on the predatory stink bug Podisus nigrispinus by assessing the development, predatory capacity, and foraging behavior of bugs fed Tuta absoluta larvae reared on resistant and susceptible tomato genotypes in both the presence and absence of the plant. We also characterized and quantified glandular leaf trichomes on the tomato genotypes to assess correlations between these and observed effects on the predator. The resistant tomato genotype did not affect P. nigrispinus development in the absence of the plant, but survival, adult longevity, number of larval prey consumed, and foraging behavior were all negatively impacted in the presence of resistant plants. These negative effects on P. nigrispinus were associated with higher densities of type I and type IV glandular leaf trichomes on resistant plants compared to susceptible ones. We infer that resistant genotypes possessing high densities of glandular trichomes, especially those of type I and IV, could be antagonistic to biological control of T. absoluta by P. nigrispinus in tomato fields. Additional research is warranted to assess other effective and environmentally safe control methods for integration with P. nigrispinus biological control in tomato IPM. Federal Institute of Education Science and Technology of Goiás (IFG) Campus Iporá, Avenida Oeste, Saída para Piranhas, 76200-000 Iporá The University of Lavras (UFLA), Campus Universitário, 37200-000 Lavras São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences Campus Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane, 14884-900 Jaboticabal São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences Campus Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane, 14884-900 Jaboticabal CNPq: 553315/2010-2

Euphrasia stricta D. Wolff ex J. F. Lehm. (Orobanchaceae) is a representative of plants that are widely used in folk medicine, phytomedicine, and homeopathy. The medicinal raw material derived from the drug eyebright is applied primarily in treatment of ophthalmic diseases. The investigations of trichomes in drug eyebright (Euphrasia stricta D. Wolff ex J. F. Lehm) were conducted in 2010–2011. Using light microscopy and scanning electron microscopy, their location and morphological and anatomical features were identified. Three types of non-glandular trichomes were found: short unicellular, long 1–2 celled, and long 2-celled with wall ornamentation. Additionally, 7 types of glandular trichomes were found; these included: unicellular clavate, 2–3-celled clavate, capitate with a unicellular head and a 3-cel- led stalk, capitate with a unicellular head and a 2-celled stalk, capitate with a 2-celled head, conical papillae, and ribbon-like trichomes with wall thickening.

The anatomy and micromorphology of the vegetative organs and calyx of Stachys scardica (Griseb.) Hayek were investigated using light (LM) and scanning electron microscopy (SEM). The analysis of the anatomical structure of stem, leaf and leaf petiole showed the presence of an additional adaxial phloem in the vascular bundle of the petiole that was recorded exclusively in species belonging to the subgenus Betonica. On the surface of studied plant parts, three types of trichomes were found: simple nonglandular uniseriate multicellular, nonglandular branched elongated and glandular peltate trichomes. The present study shows that certain micromorphological and anatomical features of Stachys taxa are valuable taxonomic characters. [Projekat Ministarstva nauke Republike Srbije, br. 173029]

The secretory structures and the volatile fraction of Stachys officinalis (L.) Trevisan subsp. officinalis (Lamiaceae) from Italy were studied for the first time. Peltate and small capitate trichomes were observed on the whole plant (leaves and inflorescences). In the peltate trichomes, an unusual polyphenols content was evidenced by the histochemical methods. The volatile fraction was obtained by a solvent extract from the distillation water of leaves and inflorescences and analysed by GC-MS. Forty-four constituents for leaves, representing 94.1% of the total volatiles, and 57 compounds for flowers, accounting for 90.1% of the total volatiles, were identified. (E)-caryophyllene (20.1%), (E)-nerolidol (14.3%), caryophyllene oxide (6.1%) and γ-cadinene (5.7%) were recognised as the main constituents for the leaf volatile fraction, while caryophyllene oxide (16.5%), (E)-nerolidol (15.4%), humulene epoxide II (9.2%) and α-pinene (7.0%) were the main compounds for the flower volatile fraction.

Scutellaria agrestis A. St.-Hil. ex Benth., Lamiaceae (trevo-roxo) is cultivated for medicinal purposes by residents of the riverine communities in the State of Amazonas, Brazil. This study aimed to characterize the anatomy and to make histochemical analysis on vegetative organs of S. agrestis. Samples of the leaf, stem and root were collected from five plants cultivated by the communities located in the Solimões river, Amazon. These samples were fixed and prepared following standard techniques for scanning electron microscopy and for light microscopy. Histochemical tests were carried out on sections to detect the main classes of compounds present in the secretion. Numerous glandular trichomes are seen in both leaf and stem of S. agrestis. The leaves are amphihypostomatics and show dorsiventral mesophyll. Hydathodes are present at the tip of the marginal teeth. Anthocyanin pigments occur into the epidermal cells of the stem, petiole, and abaxial leaf surface. The petiole is concave-convex shaped and bears collateral vascular bundles. The stem showed square-shaped, evident endoderm, collateral vascular bundles and parenchymatous pith. The root displays a typical protostelic structure. Idioblasts containing mucilage and phenolic compounds occur in the cortex. These data are important, as they can be useful to identify this species, contributing to the quality control of the medicinal plant. Keywords: glandular trichomes, histochemistry, hydathodes, medicinal plant, mucilage idioblast, trevo-roxo

Solanum galapagense is closely related to the cultivated tomato and can show a very good resistance towards whitefly. A segregating population resulting from a cross between the cultivated tomato and a whitefly resistant S. galapagense was created and used for mapping whitefly resistance and related traits, which made it possible to study the genetic basis of the resistance. Quantitative trait loci (QTL) for adult survival co-localized with type IV trichome characteristics (presence, density, gland longevity and gland size). A major QTL (Wf-1) was found for adult survival and trichome characters on Chromosome 2. This QTL explained 54.1 % of the variation in adult survival and 81.5 % of the occurrence of type IV trichomes. A minor QTL (Wf-2) for adult survival and trichome characters was identified on Chromosome 9. The major QTL was confirmed in F3 populations. Comprehensive metabolomics, based on GCMS profiling, revealed that 16 metabolites segregating in the F2 mapping population were associated with Wf-1 and/or Wf-2. Analysis of the 10 most resistant and susceptible F2 genotypes by LCMS showed that several acyl sugars were present in significantly higher concentration in the whitefly resistant genotypes, suggesting a role for these components in the resistance as well. Our results show that whitefly resistance in S. galapagense seems to inherit relatively simple compared to whitefly resistance from other sources and this offers great prospects for resistance breeding as well as elucidating the underlying molecular mechanism(s) of the resistance.

Euphrasia stricta is a medicinal plant being one of the ingredients of "Herba Euphrasiae". Many studies have been devoted to the identification of biologically active substances in the herb of eyebright, but much less research has been done on the constitution of glandular structures of this taxon. This paper relates to glandular trichomes located on the stems and leaves of E. stricta. The trichome structure was examined using light and scanning electron microscopy. It was shown that the stems of E. stricta were mainly covered by non-glandular trichomes, whereas glandular trichomes were rarely found on them. However, clusters of short capitate trichomes were found to occur in specific epidermal regions on both surfaces of the leaf blades and bracts. On the adaxial leaf surface, glandular trichomes grew only in the grooves above the vascular bundles, while on the abaxial surface in the depressions located in the expanded part of the teeth. The glandular hairs consisted of 1-2 cells of the stalk and a two-celled head. Trichomes with 3- or 4-celled heads were found sporadically. The glandular trichomes functioned non-synchronously, since they differed in head size and the colour of cell protoplasts. The presence of a light secretion was found on the surface and around the trichomes in both fresh and dry plant material.

In its stems and leaves, Heracleum sosnovskii Manden. contains furanocoumarins, which exert a phototoxic effect on humans. The aim of the investigations was to describe the external secretory structures of the epidermis and internal secretory tissues in organs responsible for emission of secretion that is toxic to human skin. The study was conducted using light and fluorescence microscopy. On the stems and leaves, various types of secretory trichomes with dispersed or deposited secretion were found. The trichomes were most abundant on the abaxial leaf surface. Epidermal cells and the secretion present on the trichomes exhibited intense fluorescence, which may indicate the presence of furanocoumarins in the tissue and trichome secretions.

According to theory, variation in plant secondary metabolism against herbivores is driven by variation in biotic and abiotic conditions interacting with plants genotype to determine the expression of resistance traits. Particularly, it has been long postulated that plants growing along latitudinal gradients experience changes in biotic and abiotic interactions, specifically leading to a decrease of plant toxicity towards the poles. We tested this hypothesis using the asteraceous species Smallanthus macroscyphus. Smallanthus species are known to contain sesquiterpene lactones (STLs), bitter compounds with a broad spectrum of biological activities, including deterrence to herbivores. S. macroscyphus showed a decrease in chemical diversity of STLs when investigating populations growing from the tropical regions to less tropical ones. Populations from lower latitudes were found to be more chemically diverse with enhydrin, uvedalin and fluctuanin as main components, while populations southward were chemically fairly uniform, with polymatin A as the main and largely dominant STL. The STL chemistry of S. macroscyphus is in agreement with the hypothesis that plants of tropical forests have a greater diversity of secondary metabolites when compared to their temperate counterparts. Fil: Coll Araoz, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Miguel Lillo; Argentina Fil: Mercado, Maria Ines. Fundación Miguel Lillo; Argentina Fil: Grau, Alfredo. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Miguel Lillo; Argentina Fil: Catalan, Cesar Atilio Nazareno. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina

Sideritis montana subsp. montana is a small annual herb occurring in countries bordering the Mediterranean and Balkan regions. The secondary metabolism of this plant has not been fully explored so far. The aim of the present study was to understand the complex mixture of secondary metabolites and the type of secretory structures. The polar constituents were isolated by column chromatography from the ethanolic extract, and their structure was elucidated by NMR and MS. The essential oil was isolated by hydrodistillation and analysed by GC/MS. The plant indumentum was studied by light and scanning electron microscopy. To complete the work, the essential oil antioxidant activity and cytotoxicity on tumor cells were evaluated by DPPH, ABTS, FRAP, and MTT methods. Four different classes of secondary metabolites were isolated, namely flavonoids, caffeoylquinic derivatives, glycosidic hydroquinones and iridoids. The essential oil was mainly characterized by sesquiterpenene hydrocarbons. Peltate and long-capitate hairs were the main sites where terpenes and polar constituents are produced. The secondary metabolites found in S. montana subsp. montana are of chemotaxonomic interest, some of them being typical of the genus Sideritis. The trichomes types observed partially differ from those described in other members of the genus Sideritis. The essential oil showed noteworthy inhibition on tumor cells.

The concentration of the lifesaving antimalarial compound artemisinin (AN) in cultivated Artemisia annua (A. annua) plants is relatively low, and thus research in improving the content is important. In the present study, external stress was applied to adult plants of A. annua and the effect was examined on the concentrations of AN and its immediate precursors in leaves, and these concentrations were related to densities and sizes of the glandular trichomes (GT). Plants were stress treated weekly five times by sandblasting or spraying with salicylic acid, chitosan oligosaccharide, H 2O 2, and NaCl solutions. Contents of AN-related compounds (AN-c) were analysed in leaf samples from an upper and a lower position of the plants, and GT were quantified and measured. In lower leaves, several stress treatments had significant negative effects on concentrations of AN-c, whereas the ratios between compounds showed an increased conversion to AN. In the upper leaves, no changes were observed compared to controls. Linear relations were found between the concentrations of metabolites and the density of GT in both upper and lower leaves, and size of GT in lower leaves. Results suggested that older and younger leaves may respond differently to applied stress. A part of the plants were infected by powdery mildew, and this caused significantly different compositions of the AN-c, compared to uninfected plants. In conclusion, changes in concentrations of AN-c seemed largely to be related to changes in GT densities and sizes.

A systematic screen of volatile terpene production in the glandular trichomes of 79 accessions of Solanum habrochaites was conducted and revealed the presence of 21 mono- and sesquiterpenes that exhibit a range of qualitative and quantitative variation. Hierarchical clustering identified distinct terpene phenotypic modules with shared patterns of terpene accumulation across accessions. Several terpene modules could be assigned to previously identified terpene synthase (TPS) activities that included members of the TPS-e/f subfamily that utilize the unusual cis-prenyl diphosphate substrates neryl diphosphate and 2z,6z-farnesyl diphosphate. DNA sequencing and in vitro enzyme activity analysis of TPS-e/f members from S. habrochaites identified three previously unassigned enzyme activities that utilize these cisoid substrates. These produce either the monoterpenes α-pinene and limonene, or the sesquiterpene 7-epizingiberene, with the in vitro analyses that recapitulated the trichome chemistry found in planta. Comparison of the distribution of S. habrochaites accessions with terpene content revealed a strong preference for the presence of particular TPS20 alleles at distinct geographic locations. This study reveals that the unusually high intra-specific variation of volatile terpene synthesis in glandular trichomes of S. habrochaites is due at least in part to evolution at the TPS20 locus.