Grape breeding programs are mostly focused on developing new varieties with high production volume, sugar contents, and phenolic compound diversity combined with resistance and tolerance to the main ...pathogens under culture and adverse environmental conditions. The 'Niagara' variety (Vitis labrusca
Vitis vinifera) is one of the most widely produced and commercialized table grapes in Brazil. In this work, we selected three Niagara somatic variants with contrasting berry phenotypes and performed morphological and transcriptomic analyses of their berries. Histological sections of the berries were also performed to understand anatomical and chemical composition differences of the berry skin between the genotypes. An RNA-Seq pipeline was implemented, followed by global coexpression network modeling. 'Niagara Steck', an intensified russet mutant with the most extreme phenotype, showed the largest difference in expression and showed selection of coexpressed network modules involved in the development of its russet-like characteristics. Enrichment analysis of differently expressed genes and hub network modules revealed differences in transcription regulation, auxin signaling and cell wall and plasmatic membrane biogenesis. Cutin- and suberin-related genes were also differently expressed, supporting the anatomical differences observed with microscopy.
The characterization of a coffee gene encoding a protein similar to miraculin-like proteins, which are members of the plant Kunitz serine trypsin inhibitor (STI) family of proteinase inhibitors ...(PIs), is described. PIs are important proteins in plant defence against insects and in the regulation of proteolysis during plant development. This gene has high identity with the Richadella dulcifica taste-modifying protein miraculin and with the tomato protein LeMir; and was named as CoMir (Coffea miraculin). Structural protein modelling indicated that CoMir had structural similarities with the Kunitz STI proteins, but suggested specific folding structures. CoMir was up-regulated after coffee leaf miner (Leucoptera coffella) oviposition in resistant plants of a progeny derived from crosses between C. racemosa (resistant) and C. arabica (susceptible). Interestingly, this gene was down-regulated during coffee leaf miner herbivory in susceptible plants. CoMir expression was up-regulated after abscisic acid application and wounding stress and was prominent during the early stages of flower and fruit development. In situ hybridization revealed that CoMir transcripts accumulated in the anther tissues that display programmed cell death (tapetum, endothecium and stomium) and in the metaxylem vessels of the petals, stigma and leaves. In addition, the recombinant protein CoMir shows inhibitory activity against trypsin. According to the present results CoMir may act in proteolytic regulation during coffee development and in the defence against L. coffeella. The similarity of CoMir with other Kunitz STI proteins and the role of CoMir in plant development and plant stress are discussed.
Stigma structure and receptivity in Bromeliaceae Souza, Everton Hilo; Carmello-Guerreiro, Sandra Maria; Souza, Fernanda Vidigal Duarte ...
Scientia horticulturae,
05/2016, Letnik:
203
Journal Article
Recenzirano
•Two stigma types were observed in 18 species of bromeliad: conduplicate-spiral and convolute-blade.•Stigma receptivity is closely related to floral opening.•The use of the α-naphthyl acetate ...solution presented the best stigma receptivity results, also allowing the identification of the stigma receptive area.
Morphoanatomical characterization of the stigma of different species has provided important data for the taxonomy of Bromeliaceae. Stigma receptivity is fundamental for the effectiveness of reproduction in plants, and the production of hybrids by controlled pollination. This study aimed to characterize stigma morphoanatomy of 18 Bromeliaceae species, from five genera, by means of light and scanning electron microscopy, and to determine the stigma receptivity of these species. The species investigated were: Aechmea bicolor, Aechmea bromeliifolia, Aechmea distichantha, Aechmea fasciata, Aechmea nudicaulis, Ananas sp., Ananas ananassoides, Ananas bracteatus, Ananas lucidus, Ananas parguazensis, Alcantarea nahoumii, Pseudananas sagenarius, Vriesea carinata, Vriesea friburgensis, Vriesea michaelii, Vriesea paraibica, Vriesea simplex and Vriesea unilateralis. Three methods were used comparatively to determine stigma receptivity during floral opening: hydrogen peroxide, benzidine and α-naphthyl acetate. Two stigma types were observed: conduplicate-spiral in Aechmea, Ananas, Alcantarea and Pseudananas and convolute-blade in Vriesea. The stigma is trifid, formed by a unistratified epidermis, parenchyma with numerous idioblasts containing raphides, and three vascular bundles, one for each carpel. In the conduplicate-spiral stigmas type, the inner epidermal cells contain dense cytoplasm and a prominent nucleus, a characteristic not observed in the convolute-blade stigmas type. The stigmatic papillae vary according to species, as well as the presence of an ornamented cuticle. The longest pistil length was observed in A. nahoumii (91.75mm) and shortest in A. bromeliifolia (4.19mm). Higher stigma receptivity is observed at anthesis for the species studied, with the highest receptivity at 8 am and remaining receptive until noon, with the exception of V. unilateralis, for which the greatest receptivity was observed at midnight and extended until dawn. The use of α-naphthyl acetate was the most efficient methodology for the detection of stigma receptivity, and to identify the receptive areas of the stigma.
Studies on seed germination in Eugenia species after embryo fractionation have demonstrated that cotyledon cells have capacity for de-differentiation and consequent production of roots. However, ...there is no information about the origin of those new roots. Thus, the aim of this study was to characterize anatomically the cotyledon regions of seeds of five species of Eugenia to elucidate the tissue that originates such roots. Seeds were sectioned across the hillum region and immediately placed to germinate. As soon as the fractions of these cut seeds develop roots they were fixed and processed to the usual techniques for light microscopy. The adventitious roots originated only when the seed was fractioned, never occurring spontaneously in uninjured seeds. Adventitious roots were formed from perivascular parenchyma cells, located close to the injured region of the cotyledons. These cells divided periclinally and proliferated, giving rise to a root meristem. Therefore, new seedlings probably have a different genome than the mother plant, but they would be identical to the embryo that was a result of fertilization.
Resumo: Estudos de germinação de sementes em espécies de Eugenia após fracionamento de embriões demonstraram que as células dos cotilédones têm grande capacidade de desdiferenciação e consequente produção de raízes. No entanto, não há informações sobre a origem dessas novas raízes. Assim, o objetivo deste estudo foi caracterizar anatomicamente as regiões dos cotilédones de sementes de cinco espécies de Eugenia para elucidar o tecido que origina tais raízes. As sementes foram seccionadas na região do hilo e imediatamente colocadas para germinar. Assim que as frações desenvolveram raízes, elas foram fixadas e processadas com as técnicas usuais de microscopia de luz. As raízes adventícias originaram-se apenas quando a semente foi fracionada, nunca ocorrendo espontaneamente em sementes não danificadas. Raízes adventícias foram formadas a partir de células do parênquima perivascular, localizadas próximas à região lesada dos cotilédones. Essas células se dividiram periclinalmente e proliferaram, dando origem a um meristema radicular. Dessa forma, as novas mudas provavelmente têm genoma diferente da planta mãe, mas seriam idênticas ao embrião resultante da fecundação.
Dormancy is a physiological process that allows seeds to survive in unfavorable environments by preventing their germination. For a large number of species, seed desiccation at the end of maturation ...is common, and for some of these seeds, this includes seed coat water impermeability (SCWI). The environmental conditions in which the mother plant develops affect the seed maturation process, causing variations in both seed physiological quality and the onset of physical dormancy. In this study, we analyzed the induction of SCWI in immature seeds of Erythrina speciosa by artificial drying. Seeds at three stages of immaturity were dried gradually for subsequent evaluation of their germination. At each level of drying, the anatomical structure of the seed coat was also analyzed. Artificial drying was able to induce SCWI in immature seeds. Furthermore, environmental conditions affected at which stage of maturity SCWI began, and they affected development of desiccation tolerance. However, unlike other species, there were no anatomical differences related to this SCWI (whether by natural drying or artificial drying) and, therefore, in E. speciosa seeds, SCWI may be related to biochemical differences in the seed coat.
Resumo: A dormência é um processo fisiológico que permite que as sementes sobrevivam em ambientes desfavoráveis, impedindo sua germinação. Para grande número de espécies, a dessecação de sementes no final da maturação é comum e, em algumas delas, instala-se a impermeabilidade do tegumento à água (IT). As condições ambientais sob as quais a planta-mãe se desenvolve interferem no processo de maturação das sementes, causando variações tanto na qualidade fisiológica quanto na instalação da dormência física. Neste trabalho analisou-se a instalação de IT em sementes imaturas de Erythrina speciosa por secagem artificial. Sementes de três estádios imaturos foram secadas em intervalos graduais e sua germinação foi analisada. O tegumento das sementes de cada nível de secagem também foi analisado anatomicamente. Concluiu-se que a secagem artificial foi capaz de promover a instalação da IT em sementes imaturas. Além disso, as condições ambientais influenciaram o estádio de maturidade no qual a IT foi instalada, bem como o desenvolvimento da tolerância à dessecação. No entanto, diferente de outras espécies, não houve diferenças anatômicas relacionadas a essa IT (tanto pela secagem natural quanto pela artificial) e, portanto, em sementes de E. speciosa, a impermeabilidade pode estar relacionada a diferenças bioquímicas no tegumento da semente.
Sugarcane (Saccharum spp.) is currently one of the most efficient crops in the production of first-generation biofuels. However, the bagasse represents an additional abundant lignocellulosic resource ...that has the potential to increase the ethanol production per plant. To achieve a more efficient conversion of bagasse into ethanol, a better understanding of the main factors affecting biomass recalcitrance is needed. Because several studies have shown a negative effect of lignin on saccharification yield, the characterization of lignin biosynthesis, structure, and deposition in sugarcane is an important goal. Here, we present, to our knowledge, the first systematic study of lignin deposition during sugarcane stem development, using histological, biochemical, and transcriptional data derived from two sugarcane genotypes with contrasting lignin contents. Lignin amount and composition were determined in rind (outer) and pith (inner) tissues throughout stem development. In addition, the phenolic metabolome was analyzed by ultra-high-performance liquid chromatography-mass spectrometry, which allowed the identification of 35 compounds related to the phenylpropanoid pathway and monolignol biosynthesis. Furthermore, the Sugarcane EST Database was extensively surveyed to identify lignin biosynthetic gene homologs, and the expression of all identified genes during stem development was determined by quantitative reverse transcription-polymerase chain reaction. Our data provide, to our knowledge, the first in-depth characterization of lignin biosynthesis in sugarcane and form the baseline for the rational metabolic engineering of sugarcane feedstock for bioenergy purposes.
ABSTRACT Most species of Anacardiaceae have drupes containing secretory structures.. The substances produced by these structures may have importance to industry and folk medicine, and may even cause ...allergenic effects. This work describes the ontogeny of pericarp of Tapirira guianensis with an emphasis on the secretory structures present at different stages of development. Ovary and fruits in various stages of development were collected, fixed and processed for studies using light and scanning electron microscopy according to conventional techniques. Histochemical tests were employed to identify the major metabolites present in the tissues. The fruit is a drupe formed by exocarp, mesocarp containing secretory ducts and idioblasts, and endocarp with some lignified layers. Fruit growth occurs through the division and elongation of cells. The secretory ducts produce mainly phenols and lipids and are active during all stages of development. The secreted substances protect the fruit against pathogens and predators. In ripe fruits the cells of the mesocarp accumulate starch. This study is the first report of the presence of a secretory endocarp in young fruits of a species of Anacardiaceae. The substances produced by the endocarp in early developmental stages may play an important role in seed dispersal and germination.
Astronium
and
Myracrodruon
are small genera of Anacardiaceae characterized by having fruits with calycinal wings, which play an important role in dispersion. Molecular phylogenetic studies have ...indicated that both genera form a monophyletic clade, but the taxonomic circumscription remains controversial, with several discussions either recognizing
Myracrodruon
as a genus or an infrageneric category of
Astronium.
In this study, the fruit anatomy of both genera was reevaluated to further develop the understanding of their circumscription and taxonomic position. To this end, the morphoanatomy of the ripe fruits of
Myracrodruon balansae
and seven species of
Astronium
was analyzed using standard techniques of light microscopy. In addition, the fruit ontogeny in both genera was evaluated for distinguishable differences and similarities among them. As a result of the emanating study, it can be concluded that fruits of
Astronium
and
Myracrodruon
, previously classified as pseudosamara and drupe, respectively, should both be called pseudosamara. Findings such as uniseriate exocarp, parenchymatic mesocarp with large secretory ducts, endocarp organized in discrete layers, and similar development of the calycinal wings support the inclusion of
Myracrodruon
as a section of
Astronium
.
Presumed domatia are actually extrafloral nectaries on leaves ofAnacardium humile (Anacardiaceae), a species from the Brazilian savannah, is associated with foraging ants, which leads to the ...description of the structure of its leaves as domatia. However, the ants collect secretions on the leaves, a phenomenon that inspired us to elucidate this structure. To this end, we conducted an analysis of the distribution, micromorphology, anatomy and histochemistry of these supposed domatia. They are located in the axil of thicker leaf veins and are composed of glandular trichomes which exude glucose; they are, therefore, described here as extrafloral nectaries (EFNs). The nectariferous trichomes are located at the same level as the other epidermal cells on young leaves, while in mature leaves they were found in depressions of the leaf blade. The secretory activity of EFNs is limited to juvenile phases, becoming degenerated in mature leaves. Carbohydrates and lipophilic compounds were detected in the produced secretion. It can be concluded that the presence of ants foraging leaves to collect from EFNs indicates a mutualistic interaction, with the plant providing a sugar resource to the ants in return for protection against herbivory since they are present in developing leaves.
PDF
