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1.
J Plant Physiol ; 263: 153465, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225176

RESUMO

Tea is one of the most consumed beverages worldwide, and trichome formation in tea plant leaves impairs their commercial value. In Arabidopsis thaliana leaves, trichome formation is negatively regulated by the CPC family genes, which encode R3-type MYB transcription factors. Here, we identified six CPC-like genes in a tea plant (Camellia sinensis var. sinensis) for the first time. Simulated three-dimensional structure of the MYB domains of all the six CPC-like proteins exhibited negative charge on the surface, as observed on that of the Arabidopsis CPC protein that does not bind to DNA, indicating their similarity with regard to molecular interaction. We further found that the six CPC-like genes were differentially expressed in different developmental stages of tea leaves, and four out of the six genes were upregulated in the youngest 1st leaves, which formed more trichomes than other older leaves. Although it does not establish a causal link, the correlation between differential expression of CPC-like genes and variable trichome formation suggests that the R3-type MYB transcription factors are potential precipitating factors in affecting the value of tea leaf.


Assuntos
Camellia sinensis/genética , Camellia sinensis/fisiologia , Genes de Plantas , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas Proto-Oncogênicas c-myb/genética , Tricomas/genética , Tricomas/fisiologia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Variação Genética , Japão , Proteínas Proto-Oncogênicas c-myb/fisiologia
2.
J Plant Physiol ; 260: 153413, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33848796

RESUMO

Trichomes are epidermal structures with a large variety of ecological functions and economic applications. Glandular trichomes produce a rich repertoire of secondary metabolites, whereas non-glandular trichomes create a physical barrier on the epidermis: both operate in tandem against biotic and abiotic stressors. A deeper understanding of trichome development and function would enable the breeding of more resilient crops. However, little is known about the impact of altered trichome density on leaf photosynthesis, gas exchange and energy balance. Previous work has compared multiple, closely related species differing in trichome density. Here, we analysed monogenic trichome mutants in the same tomato genetic background (Solanum lycopersicum cv. 'Micro-Tom'). We determined growth parameters, leaf spectral properties, gas exchange and leaf temperature in the hairs absent (h), Lanata (Ln) and Woolly (Wo) trichome mutants. Shoot dry weight, leaf area, leaf spectral properties and cuticular conductance were not affected by the mutations. However, the Ln mutant showed increased net carbon assimilation rate (An), associated with higher stomatal conductance (gs), with no differences in stomatal density or stomatal index between genotypes. Leaf temperature was furthermore reduced in Ln in the hottest, early hours of the afternoon. We show that a single monogenic mutation that modifies trichome density, a desirable trait for crop breeding, concomitantly improves leaf gas exchange and reduces leaf temperature.


Assuntos
Lycopersicon esculentum/fisiologia , Melhoramento Vegetal , Folhas de Planta/fisiologia , Estômatos de Plantas/fisiologia , Lycopersicon esculentum/genética , Mutação , Folhas de Planta/genética , Estômatos de Plantas/genética , Temperatura , Tricomas/genética , Tricomas/fisiologia
3.
Sci Rep ; 11(1): 6205, 2021 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-33737610

RESUMO

Siraitia grosvenorii, an herbaceous perennial plant, native to the southern parts of China, is commonly used as a low-calorie natural sweetener. It contains cucurbitane-type triterpene glycosides known as mogrosides. The extract from monk fruit is about 300 times sweeter than sucrose. In spite of its immense importance and International demand, Siraitia grosvenorii (Swingle) is not commercially cultivated outside China since scientific information for cultivation of this species is lacking. Planting material of monk fruit plant was not available in India. Thus, the seeds of monk fruit were introduced in India from China after following International norms. Then the experiments were conducted on different aspects such as seed germination, morphological and anatomical characterization, phenology, flowering and pollination behaviors, and dynamic of mogroside-V accumulation in fruit. The hydropriming at 40 °C for 24 h was found effective to reduce the germination time and to increase the germination rate (77.33%). The multicellular uniseriate trichomes were observed in both the leaf surfaces, however, higher trichomes density was observed in the ventral surface of males compared to females. The microscopic view revealed that the ovary was trilocular (ovary consists three chambers) having two ovules in each chamber or locule. Most of the fruits were globose or oblong type with 5-7 cm in length and 4-7 cm diameter. Mogroside-V content in fruit at 80 days after pollination was 0.69% on dry weight basis. The rate of increase of mogroside-V accumulation from 50 to 70 days was very slow, whereas a sharp increase was observed from 70 to 80 days. The higher receptivity of stigma was observed with fully open flowers. The floral diagram and formula have also been developed for both male and female flowers. Our results highlighted that monk fruit can be grown in Indian conditions.


Assuntos
Cucurbitaceae/fisiologia , Flores/fisiologia , Frutas/fisiologia , Folhas de Planta/fisiologia , Sementes/fisiologia , Edulcorantes/química , Triterpenos/química , Aclimatação/fisiologia , China , Cucurbitaceae/anatomia & histologia , Flores/anatomia & histologia , Frutas/anatomia & histologia , Frutas/química , Germinação/fisiologia , Glicosídeos/química , Glicosídeos/isolamento & purificação , Humanos , Índia , Folhas de Planta/anatomia & histologia , Polinização/fisiologia , Sementes/anatomia & histologia , Edulcorantes/isolamento & purificação , Paladar/fisiologia , Tricomas/anatomia & histologia , Tricomas/fisiologia , Triterpenos/isolamento & purificação
4.
BMC Plant Biol ; 20(1): 534, 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33228523

RESUMO

BACKGROUND: Salinity severely inhibit crop growth, yield, and quality worldwide. Allotetraploid rapeseed (Brassica napus L.), a major glycophyte oil crop, is susceptible to salinity. Understanding the physiological and molecular strategies of rapeseed salinity resistance is a promising and cost-effective strategy for developing highly resistant cultivars. RESULTS: First, early leaf senescence was identified and root system growth was inhibited in rapeseed plants under severe salinity conditions. Electron microscopic analysis revealed that 200 mM NaCl induced fewer leaf trichomes and stoma, cell plasmolysis, and chloroplast degradation. Primary and secondary metabolite assays showed that salinity led to an obviously increased anthocyanin, osmoregulatory substances, abscisic acid, jasmonic acid, pectin, cellulose, reactive oxygen species, and antioxidant activity, and resulted in markedly decreased photosynthetic pigments, indoleacetic acid, cytokinin, gibberellin, and lignin. ICP-MS assisted ionomics showed that salinity significantly constrained the absorption of essential elements, including the nitrogen, phosphorus, potassium, calcium, magnesium, iron, mangnese, copper, zinc, and boron nutrients, and induced the increase in the sodium/potassium ratio. Genome-wide transcriptomics revealed that the differentially expressed genes were involved mainly in photosynthesis, stimulus response, hormone signal biosynthesis/transduction, and nutrient transport under salinity. CONCLUSIONS: The high-resolution salt-responsive gene expression profiling helped the efficient characterization of central members regulating plant salinity resistance. These findings might enhance integrated comprehensive understanding of the morpho-physiologic and molecular responses to salinity and provide elite genetic resources for the genetic modification of salinity-resistant crop species.


Assuntos
Brassica napus/genética , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Transcriptoma/efeitos dos fármacos , Brassica napus/efeitos dos fármacos , Brassica napus/fisiologia , Perfilação da Expressão Gênica , Homeostase/efeitos dos fármacos , Íons/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/fisiologia , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/genética , Estômatos de Plantas/fisiologia , Salinidade , Cloreto de Sódio/farmacologia , Tricomas/efeitos dos fármacos , Tricomas/genética , Tricomas/fisiologia
5.
Plant Physiol ; 184(4): 1840-1852, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33051266

RESUMO

Nonstomatal water loss by transpiration through the hydrophobic cuticle is ubiquitous in land plants, but the pathways along which this occurs have not been identified. Tomato (Solanum lycopersicum) provides an excellent system in which to study this phenomenon, as its fruit are astomatous and a major target for desiccation resistance to enhance shelf life. We screened a tomato core collection of 398 accessions from around the world and selected seven cultivars that collectively exhibited the lowest and highest degrees of transpirational water loss for a more detailed study. The transpirational differences between these lines reflected the permeances of their isolated cuticles, but this did not correlate with various measures of cuticle abundance or composition. Rather, we found that fruit cuticle permeance has a strong dependence on the abundance of microscopic polar pores. We further observed that these transcuticular pores are associated with trichomes and are exposed when the trichomes are dislodged, revealing a previously unreported link between fruit trichome density and transpirational water loss. During postharvest storage, limited self-sealing of the pores was detected for certain cultivars, in contrast with the stem scar, which healed relatively rapidly. The abundance of trichome-associated pores, together with their self-sealing capacity, presents a promising target for breeding or engineering efforts to reduce fruit transpirational water loss.


Assuntos
Frutas/anatomia & histologia , Frutas/fisiologia , Lycopersicon esculentum/anatomia & histologia , Lycopersicon esculentum/genética , Lycopersicon esculentum/fisiologia , Transpiração Vegetal/genética , Transpiração Vegetal/fisiologia , Tricomas/anatomia & histologia , Tricomas/fisiologia , Produtos Agrícolas/anatomia & histologia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Frutas/genética , Variação Genética , Genótipo , Tricomas/genética
6.
Plant Physiol Biochem ; 155: 177-186, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32771929

RESUMO

Vesicular trichomes play a key role in excluding toxic ions from some halophyte species, preventing the essential processes and functions of plants from being altered. Thus, the present study aimed to evaluate the influence of these structures on Atriplex nummularia irrigated using waters with three levels of osmotic potential (-0.1, -1.4 and -2.7 MPa), formulated with NaCl in plants with vesicular trichomes and plants with partial removal of trichomes. The experiment was conducted in a protected environment and plants were evaluated for physiological parameters (water, osmotic and pressure potentials, relative water content, osmotic adjustment, pressure-volume curve, gas exchange), electrolyte leakage, lipid peroxidation and enzymatic activity (superoxide dismutase, ascorbate peroxidase, catalase). The results obtained made it possible to identify the strong contribution of vesicular trichomes to physiological and biochemical parameters, with indication of cell wall stiffening and maintenance of turgor. Furthermore, the evaluation of the osmotic potentials obtained in the study suggests that the contribution of vesicular trichomes to the salinity tolerance of the species is greater than that of osmotic adjustment. Furthermore, gas exchange results suggest that the presence of trichomes was able to regulate stomatal processes so that the plant maintains its photosynthetic performance. Evaluation of electrolyte leakage, together with the increase in malondialdehyde content, showed that the maintenance of trichomes reduces the probability of oxidative stress. The activity of antioxidant enzymes was efficient in eliminating reactive oxygen species, especially the activity of ascorbate peroxidase, which stood out in terms of hydrogen peroxide detoxification.


Assuntos
Atriplex/fisiologia , Parede Celular/fisiologia , Pressão Osmótica , Fotossíntese , Tricomas/fisiologia , Antioxidantes/fisiologia , Atriplex/enzimologia , Elasticidade , Peróxido de Hidrogênio , Folhas de Planta , Espécies Reativas de Oxigênio , Plantas Tolerantes a Sal/fisiologia
7.
BMC Plant Biol ; 20(1): 341, 2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32680457

RESUMO

BACKGROUND: Lonicera japonica Thunb. (L. japonica) has the functions of clearing away heat and detoxifying, broad-spectrum antibacterial and anti-virus, etc. More than 70% of anti-inflammatory and cold Chinese patent medicines contain L. japonica. Trichomes comprise specialized multicellular structures that have the capacity to synthesize and secrete secondary metabolites and protect plants from biotic and abiotic stresses. The extraction of trichome secretions has great commercial value. However, little is known about the trichome formation mechanism in L. japonica. Therefore, the study of trichome development between different varieties provides a basis for selecting suitable planting resources. RESULTS: Here, we present a genome-wide comparative transcriptome analysis between two L. japonica cultivars, toward the identification of biological processes and functional gene activities that occur during flowering stage trichome development. In this study, the density and average lengths of flower trichomes were at their highest during three-green periods (S2). Using the Illumina RNA-Seq method, we obtained 134,304 unigenes, 33,733 of which were differentially expressed. In an analysis of 40 differentially expressed unigenes (DEGs) involved in trichome development, 29 of these were transcription factors. The DEGs analysis of plant hormone signal transduction indicated that plant growth and development may be independent of gibberellin (GA) and cytokinine (CTK) signaling pathways, and plant stress may be independent of jasmonic acid (JA) and ethylene (ET) signaling pathways. We screened several genes involved in the floral biosynthesis of odors, tastes, colors, and plant hormones, and proposed biosynthetic pathways for sesquiterpenoid, triterpenoid, monoterpenoid, flavonoid, and plant hormones. Furthermore, 82 DEGs were assigned to cell cycles and 2616 were predicted as plant resistance genes (PRGs). CONCLUSIONS: This study provides a comprehensive characterization of the expression profiles of flower development during the seven developmental stages of L. japonica, thereby offering valuable insights into the molecular networks that underly flower development in L. japonica.


Assuntos
Lonicera/genética , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/genética , Transcriptoma , Flores/genética , Flores/crescimento & desenvolvimento , Flores/fisiologia , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Lonicera/crescimento & desenvolvimento , Lonicera/fisiologia , RNA-Seq , Fatores de Transcrição/genética , Tricomas/genética , Tricomas/crescimento & desenvolvimento , Tricomas/fisiologia
8.
Planta ; 252(1): 2, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32504343

RESUMO

MAIN CONCLUSION: Tissue-specific occurrence and formation of endogenous sesquiterpene lactones has been assessed and suggests physiological function as antagonists of auxin-induced plant growth in sunflower. Sunflower, Helianthus annuus, accumulate high concentrations of bioactive sesquiterpene lactones (STL) in glandular trichomes, but in addition, structurally different STL occur in only trace amounts in the inner tissues. The spatial and temporal production of these endogenous STL during early phases of plant development is widely unknown and their physiological function as putative natural growth regulators is yet speculative. By means of HPLC and MS analysis it was shown that costunolide, dehydrocostuslactone, 8-epixanthatin and tomentosin are already present in dry seeds and can be extracted in low amounts from cotyledons, hypocotyls and roots of seedlings during the first days after germination. Semi-quantitative and RT-qPCR experiments with genes of the key enzymes of two independent routes of the endogenous STL biosynthesis confirmed the early and individual expression in these organs and revealed a gradual down regulation during the first 72-96 h after germination. Light irradiation of the plants led to a fast, but transient increase of STL in parts of the hypocotyl which correlated with growth retardation of the stem. One-sided external application of costunolide on hypocotyls conferred reduced growth of the treated side, thus resulting in the curving of the stem towards the side of the application. This indicates the inhibiting effects of STL on plant growth. The putative function of endogenous STL in sunflower as antagonists of auxin in growth processes is discussed.


Assuntos
Helianthus/fisiologia , Lactonas/metabolismo , Sesquiterpenos/metabolismo , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Cotilédone/fisiologia , Germinação , Helianthus/genética , Helianthus/crescimento & desenvolvimento , Especificidade de Órgãos , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/fisiologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Tricomas/genética , Tricomas/crescimento & desenvolvimento , Tricomas/fisiologia
9.
Plant Cell Physiol ; 61(9): 1590-1599, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32579215

RESUMO

Many polypetalous plants have a constriction at the base of the petal that leaves a small gap that can provide entry into the young flower bud before the reproductive organs are fully developed. In cotton (Gossypium hirsutum L.), this gap is occluded by tufts of short unicellular trichomes superficially resembling the fibers found on cotton seeds. We are just beginning to understand the developmental regulation of the seed fibers and have previously characterized several MIXTA-like MYB transcription factors (TFs) that are critical for correct seed fiber development but know little about the molecular regulation of other types of cotton trichomes. Here, using RNAi or dominant suppression transgenic cotton lines and natural fiber mutants, we investigated the development and regulation of the petal base trichomes. Petal base trichomes and seed trichomes were also examined across several different species within and outside of the Malvoideae. We found that the petal base trichomes are regulated by the same MYB TFs as cotton seed fibers and, since they are more widely distributed across different taxa than the seed fibers, could have preceded them in the evolution of these important textile fibers produced by some cotton species.


Assuntos
Flores/metabolismo , Gossypium/metabolismo , Proteínas de Plantas/fisiologia , Sementes/metabolismo , Fatores de Transcrição/fisiologia , Tricomas/metabolismo , Fibra de Algodão , Flores/fisiologia , Gossypium/fisiologia , Proteínas de Plantas/metabolismo , Proteínas Proto-Oncogênicas c-myb/metabolismo , Proteínas Proto-Oncogênicas c-myb/fisiologia , Sementes/fisiologia , Fatores de Transcrição/metabolismo , Tricomas/fisiologia
10.
Plant Cell Environ ; 43(9): 2019-2032, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32323332

RESUMO

Interspecific New Rice for Africa (NERICA) varieties have been recently developed and used in Sub-Saharan Africa but herbivore resistance properties of these plants remain poorly understood. Here we report that, compared to a local Japanese cultivar Nipponbare, NERICA 1, 4 and 10 are significantly more damaged by insect herbivores in the paddy fields. In contrast to high levels of leaf damage from rice skippers and grasshoppers, constitutive and induced volatile organic compounds for indirect plant defense were higher or similar in NERICAs and Nipponbare. Accumulation of direct defense secondary metabolites, momilactones A and B, and p-coumaroylputrescine (CoP) was reduced in NERICAs, while feruloylputrescine accumulated at similar levels in all varieties. Finally, we found that Nipponbare leaves were covered with sharp nonglandular trichomes impregnated with silicon but comparable defense structures were virtually absent in herbivory-prone NERICA plants. As damage to the larval gut membranes by Nipponbare silicified trichomes that pass intact through the insect digestive system, occurs, and larval performance is enhanced by trichome removal from otherwise chemically defended Nipponbare plants, we propose that silicified trichomes work as an important defense mechanism of rice against chewing insect herbivores.


Assuntos
Herbivoria , Oryza/fisiologia , Tricomas/fisiologia , Animais , Digestão , Trato Gastrointestinal/ultraestrutura , Insetos , Japão , Larva/crescimento & desenvolvimento , Lepidópteros , Oryza/química , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/fisiologia , Metabolismo Secundário , Tricomas/química , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo
11.
Plant J ; 103(2): 769-780, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32279362

RESUMO

Foliar water uptake (FWU), the direct uptake of water into leaves, is a global phenomenon, having been observed in an increasing number of plant species. Despite the growing recognition of its functional relevance, our understanding of how FWU occurs and which foliar surface structures are implicated, is limited. In the present study, fluorescent and ionic tracers, as well as microcomputed tomography, were used to assess potential pathways for water entry in leaves of beech, a widely distributed tree species from European temperate regions. Although none of the tracers entered the leaf through the stomatal pores, small amounts of silver precipitation were observed in some epidermal cells, indicating moderate cuticular uptake. Trichomes, however, were shown to absorb and redistribute considerable amounts of ionic and fluorescent tracers. Moreover, microcomputed tomography indicated that 72% of empty trichomes refilled during leaf surface wetting and microscopic investigations revealed that trichomes do not have a cuticle but are covered with a pectin-rich cell wall layer. Taken together, our findings demonstrate that foliar trichomes, which exhibit strong hygroscopic properties as a result of their structural and chemical design, constitute a major FWU pathway in beech.


Assuntos
Fagus/metabolismo , Folhas de Planta/metabolismo , Tricomas/metabolismo , Microscopia Crioeletrônica , Fagus/fisiologia , Fagus/ultraestrutura , Folhas de Planta/ultraestrutura , Tricomas/fisiologia , Água/metabolismo
12.
Nat Commun ; 11(1): 396, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959754

RESUMO

The bromeliad Tillandsia landbeckii thrives in the Atacama desert of Chile using the fog captured by specialized leaf trichomes to satisfy its water needs. However, it is still unclear how the trichome of T. landbeckii and other Tillandsia species is able to absorb fine water droplets during intermittent fog events while also preventing evaporation when the plant is exposed to the desert's hyperarid conditions. Here, we explain how a 5800-fold asymmetry in water conductance arises from a clever juxtaposition of a thick hygroscopic wall and a semipermeable membrane. While absorption is achieved by osmosis of liquid water, evaporation under dry external conditions shifts the liquid-gas interface forcing water to diffuse through the thick trichome wall in the vapor phase. We confirm this mechanism by fabricating artificial composite membranes mimicking the trichome structure. The reliance on intrinsic material properties instead of moving parts makes the trichome a promising basis for the development of microfluidics valves.


Assuntos
Materiais Biomiméticos , Microfluídica/instrumentação , Tillandsia/fisiologia , Tricomas/ultraestrutura , Água/metabolismo , Chile , Clima Desértico , Membranas Artificiais , Microfluídica/métodos , Microscopia de Fluorescência , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Tillandsia/ultraestrutura , Tricomas/fisiologia
13.
Protoplasma ; 257(3): 863-870, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31897809

RESUMO

Salt stress is harmful to plants, especially for those that live under conditions of intense salt aport. For this reason, several species present alternatives to prevent or diminish the damages that high salt concentrations may cause to the cells. Salt glands are one of these alternatives once they are specialized structures that secrete salt. Here, we aimed to investigate if the glandular trichomes in the leaves of Jacquinia armillaris are salt glands. Anatomical and ultrastructural observations showed that the glandular trichomes in J. armillaris resemble the salt glands from other recretohalophytes Primulaceae, such as, their occurrence in sunken regions in the leaf epidermis, the presence of a large basal cell that acts as a collecting cell, the detachment of the cuticle from the outer periclinal walls forming a cuticular chamber, the thickness of the cuticle in the stalk portion of the trichome, and the presence of sodium and chloride ions in the secretion and in the xylem. Altogether, the gathered results support the hypothesis that the glandular trichomes in J. armillaris are adapted to salt secretion, thus characterizing as salt glands.


Assuntos
Primulaceae/fisiologia , Glândula de Sal/fisiologia , Animais , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Primulaceae/anatomia & histologia , Primulaceae/ultraestrutura , Glândula de Sal/ultraestrutura , Tricomas/fisiologia , Tricomas/ultraestrutura
14.
BMC Plant Biol ; 19(1): 444, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31651252

RESUMO

BACKGROUND: The plant-specific homeodomain-leucine zipper class IV (HD-ZIP IV) gene family has been involved in the regulation of epidermal development. RESULTS: Fifteen genes coding for HD-ZIP IV proteins were identified (NtHD-ZIP-IV-1 to NtHD-ZIP-IV-15) based on the genome of N. tabacum. Four major domains (HD, ZIP, SAD and START) were present in these proteins. Tissue expression pattern analysis indicated that NtHD-ZIP-IV-1, - 2, - 3, - 10, and - 12 may be associated with trichome development; NtHD-ZIP-IV-8 was expressed only in cotyledons; NtHD-ZIP-IV-9 only in the leaf and stem epidermis; NtHD-ZIP-IV-11 only in leaves; and NtHD-ZIP-IV-15 only in the root and stem epidermis. We found that jasmonates may induce the generation of glandular trichomes, and that NtHD-ZIP-IV-1, - 2, - 5, and - 7 were response to MeJA treatment. Dynamic expression under abiotic stress and after application of phytohormones indicated that most NtHD-ZIP IV genes were induced by heat, cold, salt and drought. Furthermore, most of these genes were induced by gibberellic acid, 6-benzylaminopurine, and salicylic acid, but were inhibited by abscisic acid. NtHD-ZIP IV genes were sensitive to heat, but insensitive to osmotic stress. CONCLUSION: NtHD-ZIP IV genes are implicated in a complex regulatory gene network controlling epidermal development and abiotic stress responses. The present study provides evidence to elucidate the gene functions of NtHD-ZIP IVs during epidermal development and stress response.


Assuntos
Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/metabolismo , Tabaco/genética , Redes Reguladoras de Genes , Zíper de Leucina , Proteínas de Plantas/genética , Estresse Fisiológico , Tabaco/fisiologia , Tricomas/genética , Tricomas/fisiologia
15.
Extremophiles ; 23(6): 635-647, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31512055

RESUMO

The true-branching cyanobacterium Fischerella thermalis (also known as Mastigocladus laminosus) is widely distributed in hot springs around the world. Morphologically, it has been described as early as 1837. However, its taxonomic placement remains controversial. F. thermalis belongs to the same genus as mesophilic Fischerella species but forms a monophyletic clade of thermophilic Fischerella strains and sequences from hot springs. Their recent divergence from freshwater or soil true-branching species and the ongoing process of specialization inside the thermal gradient make them an interesting evolutionary model to study. F. thermalis is one of the most complex prokaryotes. It forms a cellular network in which the main trichome and branches exchange metabolites and regulators via septal junctions. This species can adapt to a variety of environmental conditions, with its photosynthetic apparatus remaining active in a temperature range from 15 to 58 °C. Together with its nitrogen-fixing ability, this allows it to dominate in hot spring microbial mats and contribute significantly to the de novo carbon and nitrogen input. Here, we review the current knowledge on the taxonomy and distribution of F. thermalis, its morphological complexity, and its physiological adaptations to an extreme environment.


Assuntos
Aclimatação/fisiologia , Evolução Biológica , Cianobactérias/fisiologia , Fontes Termais/microbiologia , Temperatura Alta , Modelos Biológicos , Tricomas/fisiologia
16.
Plant Sci ; 285: 248-257, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203890

RESUMO

Halophytic Oryza coarctata is a good model system to examine mechanisms of salinity tolerance in rice. O. coarctata leaves show the presence of microhairs in adaxial leaf surface furrows that secrete salt under salinity. However, detailed molecular and physiological studies of O. coarctata microhairs are limited due to their relative inaccessibility. This work presents a detailed characterization of O. coarctata leaf features. O. coarctata has two types of microhairs on the adaxial leaf surface: longer microhairs (three morphotypes) lining epidermal furrow walls and shorter microhairs (reported first time) arising from bulliform cells. Microhair morphotypes include (i) finger-like, tubular structures, (ii) tubular hairs with bilobed and flattened heads and (iii) bi-or trifurcated hairs. The unicellular nature of microhairs was confirmed by propidium iodide (PI) staining. An efficient method for the isolation and enrichment of O. coarctata microhairs is presented (yield averaging ˜2 × 105/g leaf tissue). The robustness of the microhair isolation procedure was confirmed by subsequent viability staining (PI), total RNA isolation and RT-PCR amplification of O. coarctata trichome-specific WUSCHEL-related homeobox 3B (OcWox3B) and transporter gene-specific cDNA sequences. The present microhair isolation work from O. coarctata paves the way for examining genes involved in ion secretion in this halophytic wild rice model.


Assuntos
Oryza/anatomia & histologia , Folhas de Planta/anatomia & histologia , Plantas Tolerantes a Sal/anatomia & histologia , Microscopia Confocal , Oryza/fisiologia , Folhas de Planta/citologia , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Plantas Tolerantes a Sal/fisiologia , Tricomas/anatomia & histologia , Tricomas/fisiologia , Tricomas/ultraestrutura
17.
Plant Biol (Stuttg) ; 21(5): 975-985, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31062924

RESUMO

Reynoutria × bohemica is an invasive species causing significant damage to native ecosystems in North America and Europe. In this work, we performed an in-depth micromorphological characterisation of the extrafloral nectaries (EFN), during their secretory and post-secretory phases, in combination with field monitoring of nectary activity over time and the qualitative pool of insect visitors. EFN consist of secretory trichomes and vascularised parenchyma. Polysaccharides, lipids and proteins were histochemically detected in all trichome cells; phenolic substances were detected in parenchyma cells. Our data indicate that all nectary regions are involved in nectar production and release, constituting a functional unit. Moreover, the main compound classes of nectar and their transfer change over time: first, granulocrine secretion for sugars prevails, then eccrine secretion of the lipophilic fraction takes place. Active nectaries are mainly located in the apical portion of the stem during the growth phase (April-May), when we detected the highest number of individuals visited by ants; from mid-August onwards, during flowering, the number of active nectaries declined then ceased production (September), with a concomitant decrease in visits by the ants. The spectrum of nectar-foraging ants mainly included representatives of the genera Formica, Lasius and Camponotus. Reynoutria × bohemica produces an attractive secretion able to recruit local ants that may potentially act as 'bodyguards' for protecting young shoots, reducing secretions during the blooming stage. This defence mechanism against herbivores is the same as that displayed by the parental species in its native areas.


Assuntos
Néctar de Plantas/metabolismo , Polygonaceae/anatomia & histologia , Animais , Formigas , Herbivoria , Espécies Introduzidas , Microscopia Eletrônica de Varredura , Polygonaceae/fisiologia , Polygonaceae/ultraestrutura , Tricomas/anatomia & histologia , Tricomas/fisiologia , Tricomas/ultraestrutura
18.
Sci Total Environ ; 659: 1403-1414, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31096351

RESUMO

Many toxic and/or noxious cyanobacteria appear in nature with a filamentous, stacked cell arrangement called trichomes. Although water treatment can be optimized to keep cyanobacterial cells intact and avoid the release of toxic and/or noxious compounds, many physical and chemical stresses encountered during the treatment process may result in trichome truncation, decreasing treatment efficiency by allowing single cells or short trichomes to reach the product water. This makes it possible for harmful/noxious compounds as well as organic matter to enter the distribution system. Investigations in a pilot and three full-scale water treatment plants were carried out in order to elucidate the degree of trichome truncation across different unit processes. It was found that genera (Pseudanabaena, Planktolyngbya) with short trichomes (<10-12 cells per trichome), are hardly affected by the unit processes (loss of one to four cells respectively), while genera (Planktothrix, Geitlerinema, Dolichospermum) with longer trichomes (30+ cells per trichome) suffer from high degrees of truncation (up to 63, 30, and 56 cells per trichome respectively). The presence of a rigid sheath and/or mucilaginous layer appears to offer some protection from truncation. It was observed that certain unit processes alter the sensitivity or resilience of trichomes to disruption by physical stress. Some genera (Planktothrix, Geitlerinema) were sensitive to pre-oxidation making them more susceptible to shear stress, while Dolichospermum sp. appears more robust after pre-oxidation. While the potential of toxicogenic genera breaking through into the product water is a real danger, in the current study no toxicogenic cyanobacteria were observed. This work stresses the need for plant operators to study the incoming cyanobacterial composition in the raw water in order to adjust treatment parameters and thus limit the potential of toxic/noxious compound breakthrough.


Assuntos
Cianobactérias/fisiologia , Tricomas/fisiologia , Purificação da Água/métodos , Microcistinas
19.
Curr Biol ; 29(8): R273-R274, 2019 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-31014481

RESUMO

Trichomes serve diverse functions for plants, and are an intriguing developmental model.


Assuntos
Folhas de Planta , Plantas , Tricomas , Folhas de Planta/citologia , Folhas de Planta/fisiologia , Tricomas/citologia , Tricomas/fisiologia
20.
Protoplasma ; 256(4): 893-907, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30656458

RESUMO

Ocimum species commonly referred to as "Tulsi" are well-known for their distinct medicinal and aromatic properties. The characteristic aroma of Ocimum species and cultivars is attributed to their specific combination of volatile phytochemicals mainly belonging to terpenoid and/or phenylpropanoid classes in their essential oils. The essential oil constituents are synthesized and sequestered in specialized epidermal secretory structures called as glandular trichomes. In this comparative study, inter- and intra-species diversity in structural attributes and profiles of expression of selected genes related to terpenoid and phenylpropanoid biosynthetic pathways have been investigated. This is performed to seek relationship of variations in the yield and phytochemical composition of the essential oils. Microscopic analysis of trichomes of O. basilicum, O. gratissimum, O. kilimandscharicum, and O. tenuiflorum (green and purple cultivars) revealed substantial variations in density, size, and relative proportions of peltate and capitate trichomes among them. The essential oil yield has been observed to be controlled by the population, dominance, and size of peltate and capitate glandular trichomes. The essential oil sequestration in leaf is controlled by the dominance of peltate glandular trichome size over its number and is also affected by the capitate glandular trichome size/number with variations in leaf area albeit at lower proportions. Comprehension and comparison of results of GC-MS analysis of essential oils showed that most of the Ocimum (O. basilicum, O. tenuiflorum, and O. gratissimum) species produce phenylpropanoids (eugenol, methyl chavicol) as major volatiles except O. kilimandscharicum, which is discrete in being monoterpenoid-rich species. Among the phenylpropanoid-enriched Ocimum (O. basilicum, O. gratissimum, O. tenuiflorum purple, O. tenuiflorum green) as well, terpenoids were important constituents in imparting characteristic aroma. Further, comparative abundance of transcripts of key genes of phenylpropanoid (PAL, C4H, 4CL, CAD, COMT, and ES) and terpenoid (DXS and HMGR) biosynthetic pathways was evaluated vis-à-vis volatile oil constituents. Transcript abundance demonstrated that richness of their essential oils with specific constituent(s) of a chemical group/subgroup was manifested by the predominant upregulation of phenylpropanoid/terpenoid pathway genes. The study provides trichomes as well as biosynthetic pathway-based knowledge for genetic improvement in Ocimum species for essential oil yield and quality.


Assuntos
Ocimum/metabolismo , Óleos Voláteis/química , Óleos Voláteis/metabolismo , Tricomas/metabolismo , Vias Biossintéticas , Regulação da Expressão Gênica de Plantas , Monoterpenos/metabolismo , Ocimum/genética , Folhas de Planta/anatomia & histologia , Óleos Vegetais/química , Óleos Vegetais/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Tricomas/fisiologia , Tricomas/ultraestrutura
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