RESUMO

A novel MADS-box transcription factor from Pinus radiata D. Don was characterized. PrMADS11 encodes a protein of 165 amino acids for a MADS-box transcription factor belonging to group II, related to the MIKC protein structure. PrMADS11 was differentially expressed in the stems of pine trees in response to 45° inclination at early times (1 h). Arabidopsis thaliana was stably transformed with a 35S::PrMADS11 construct in an effort to identify the putative targets of PrMADS11. A massive transcriptome analysis revealed 947 differentially expressed genes: 498 genes were up-regulated, and 449 genes were down-regulated due to the over-expression of PrMADS11. The gene ontology analysis highlighted a cell wall remodeling function among the differentially expressed genes, suggesting the active participation of cell wall modification required during the response to vertical stem loss. In addition, the phenylpropanoid pathway was also indicated as a PrMADS11 target, displaying a marked increment in the expression of the genes driven to the biosynthesis of monolignols. The EMSA assays confirmed that PrMADS11 interacts with CArG-box sequences. This TF modulates the gene expression of several molecular pathways, including other TFs, as well as the genes involved in cell wall remodeling. The increment in the lignin content and the genes involved in cell wall dynamics could be an indication of the key role of PrMADS11 in the response to trunk inclination.

Assuntos

RESUMO

The growth of international trade, coupled with an expansion of large-scale pine plantations in South America during the second half of the twentieth century, has significantly increased the opportunities for the invasion of forest insects. Bark beetles (Coleoptera: Curculionidae, Scolytinae) are a large and diverse group of insects, commonly recognized as one of the most important tree mortality agents in coniferous forests worldwide and an important group among invasive forest species. In this study, we combined data from field sampling with published records of established non-native pine bark beetles, to describe their distribution and invasion history in pine plantations across southern South America, reviewing the available information on their phenology and host range. We obtained records of established populations of six Eurasian species distributed in two major regions: the southwest region comprises plantations in Chile and the Argentine Patagonia, with four bark beetle species: Hylastes ater, Hylastes linearis, Hylurgus ligniperda, and Orthotomicus laricis; the northeastern zone includes northeastern Argentina, Uruguay, and southern Brazil, and includes three bark beetle species: Cyrtogenius luteus, H. ligniperda, and O. erosus. The establishment of non-native populations across the study area began in the 1950s, and from the 1980s onwards, there has been an exponential increase in introductions. We predict that several of these species will continue spreading across South America and that new species will continue arriving. We highlight the importance of international collaboration for early detection and management of non-native pine bark beetles.

Assuntos

RESUMO

This is the first report of Antiteuchus tripterus (Fabricius, 1787) (Heteroptera: Pentatomidae) damaging Araucaria angustifolia (Bertol.) Kuntze, 1898 (Pinales: Araucariaceae) plants in Brazil. This bug, native to the neotropical region, damaged this plant on fragments of mixed rain forest in Bueno Brandão, Minas Gerais state, Brazil. Araucaria angustifolia, native and with ecological and economic values, was widely used in the lumber market and, therefore, threatened with extinction. Nymphs and adults of A. tripterus were observed in March and April with a population reduction until June 2022. The bioecology and damage caused by A. tripterus on A. angustifolia are not known.

Assuntos

RESUMO

Purification methods such as membrane technology and adsorption have been studied for the purification of textile effluents. This article aimed to evaluate the membrane separation process and adsorption on pine nut shell, separately and sequentially, for reactive dye blue 5G removal from a synthetic effluent. The membrane separation process was carried out in a front filtration module using polymeric membranes. The maximum dye retention was 35.9% using a regenerated cellulose membrane, with agitation and a pressure of 0.5 bar. The permeate flux was fully restored after cleaning the membrane. In the adsorption using pine nut shell, the best results were at pH 2, 50°C, and 50 ppm, with 85% dye removal. The Freundlich isotherm showed the best fit to the data, as did the pseudo-second-order kinetic model. The thermodynamic parameters indicated that the adsorption is of the physical type, with the process being endothermic and spontaneous. In the combined process, the permeate from the membrane separation process was subjected to adsorption on pine nut shell, achieving a removal rate of 98.7 for the initial concentration of 50 ppm. Therefore, this work shows the potential of pine nut shell as an adsorbent, not only to purify textile effluents but also to add value to a waste product, indicating that the combination of membrane technology and adsorption on pine nut shell could be an alternative for the treatment of textile effluents containing the reactive dye 5G blue.

Assuntos

RESUMO

Prepregs are commonly fabricated with non-renewable petroleum-based materials. To reduce the impact of the manufacturing of these materials and to produce more sustainable prepregs, this research aims to manufacture poly(furfuryl alcohol)/wood veneer prepregs and their posterior molding in laminate composites. For this purpose, the vacuum infusion process was used to impregnate the wood veneers, and compression molding was applied to manufacture three- and four-layer laminate composites. Scanning electronic microscopy was used to evaluate the impregnation. the laminate manufacturing and differential scanning calorimetry were used to predict the shelf-life of the prepregs, Fourier-transform infrared was used to evaluate the induced hydrolysis resistance, and thermogravimetric analysis was used to determine the thermal degradation of the laminates. Moreover, water uptake and flexural, compressive, and tensile properties were evaluated. The kinetic models were effective and showed a shelf life for the laminates of approximately 30 days in storage at -7 °C, which is an interesting result for laminates with lignocellulosic materials. FTIR proved the laminates' excellent resistance to hydrolysis. The water absorption, thermal stability, and mechanical properties did not differ as the amount of wood veneer increased, but these results were up to ~40% higher compared with unidirectional wood laminates found in the literature, which is probably linked to the excellent interface observed with SEM.

RESUMO

We hypothesized that the age of loblolly pine stands influences soil methane (CH4) and nitrous oxide (N2O) emissions. This is a relevant topic to be studied in subtropical Brazil, where the pine plantation area is increasing considerably. We evaluated N2O and CH4 emissions for two years in a Ferralsol under loblolly pine (Pinus taeda L.) stands of 1, 9 and 18 year-olds and a native forest (NF). We calculated the net CO2eq emission by considering the N2O and CH4 emissions from soil and the carbon (C) accumulation as litter in the forest floor. The soil N2O emission reduced gradually over the loblolly pine cultivation years, whereas CH4 uptake rates showed no clear pattern. Soil N2O emission showed a positive relationship with soil temperature in NF, and with soil ammonium and nitrate intensities in the pine stands. Soil CH4 uptake was inversely related to water-filled pore space in the pine stands, but this relationship was not observed in NF. The soil CH4 uptake rate was 4.6 times higher (p < 0.10) in NF than the average uptake in loblolly pine stands. On the other hand, soil N2O emissions in 9 and 18-year-old stands were similar (p > 0.10) to those in NF (1.3 kg N ha-1 yr-1). Our results suggest that cultivation with loblolly pine for 18 years can reduce soil N2O emission, and the uptake of CH4 in this system offsets 17 % of N2O emissions. Furthermore, the C accumulation as litter in the forest floor of the mature pine stands (9- and 18-year-old) generated a net emission of -1.6 Mg CO2eq ha-1 yr-1, showing to be an expressive offsetting mechanism. Therefore, we conclude that aged loblolly forests can reach N2O emissions levels comparable to those of NF, and the C sequestration in these forests floor can significantly contribute to offset N2O emissions and act as sink for net atmospheric CO2eq.

RESUMO

Radiata pine bark is a widely available organic waste, requiring alternative uses due to its environmental impact on soil, fauna, and forest fires. Pine bark waxes could be used as cosmetic substitutes, but their toxicity requires evaluation since pine bark may contain toxic substances or xenobiotics, depending on the extraction process. This study evaluates the toxicity of radiata pine bark waxes obtained through various extraction methods on human skin cells grown in vitro. The assessment includes using XTT to evaluate mitochondrial activity, violet crystal dye to assess cell membrane integrity, and ApoTox-Glo triple assay to measure cytotoxicity, viability, and apoptosis signals. Pine bark waxes extracted via T3 (acid hydrolysis and petroleum ether incubation) and T9 (saturated steam cycle, alkaline hydrolysis, and petroleum ether incubation) exhibit non-toxicity up to 2% concentration, making them a potential substitute for petroleum-based cosmetic materials. Integrating the forestry and cosmetic industries through pine bark wax production under circular economy principles could promote development while replacing petroleum-based materials. Extraction methodology affects pine bark wax toxicity in human skin cells due to the retention of xenobiotic compounds including methyl 4-ketohex-5-enoate; 1-naphthalenol; dioctyl adipate; eicosanebioic acid dimethyl ester; among others. Future research will investigate whether the extraction methodology alters the molecular structure of the bark, affecting the release of toxic compounds in the wax mixture.

Assuntos

RESUMO

Pine seed shells and yerba mate are common wastes leftover from the food and beverage industry. This study presents the development of rigid polyurethane foams (RPUFs) filled with pine seed shells and yerba mate at 5, 10 and 15 wt%. The fillers were characterized for chemical properties using bench chemistry analyses, and the RPUFs were investigated in terms of chemical, morphological, mechanical, thermal and colorimetric characteristics. The main results indicated that yerba mate showed good compatibility with the polyurethane system, probably because its available hydroxyl groups reacted with isocyanate groups to form urethane bonds, producing increases in mechanical and thermal properties. However, pine seed shell did not appear to be compatible. Anisotropy increased slightly, as there was an increase in the percentage of reinforcement. The mechanical properties of the yerba mate reinforced foams proved stable, while there was a loss of overall up to ~50% for all mechanical properties in those reinforced with pine seed shell. Thermal properties were improved up to ~40% for the yerba mate reinforced foams, while those reinforced with pine nuts were stable. It was possible to observe a decrease in the glass transition temperature (Tg) of ~-5 °C for the yerba mate reinforced foams and ~-14 °C for the pine seed shell reinforced ones.

RESUMO

Every year more than 150,000 tons of resin used in a myriad of industrial applications are produced by Brazilian plantations of Pinus elliottii Engelm. (slash pine), which are also used for timber. A pine tree can be tapped for resin over a period of several years. Resin is a complex mixture of terpenes, which are carbon-rich molecules, presumably influencing pine plantation carbon budgets. A total of 270 trees (overall mean DBH of 22.93 ± 0.11 cm) of 14-, 24-, and 26-year-old stands had their C content measured. Three different treatments (intact, wounded panels, and wounded + chemically stimulated panels, 30 trees each) were applied per site. Above- and belowground biomass, as well as resin yield, were quantified for two consecutive years. Data were statistically evaluated using normality distribution tests, analyses of variance, and mean comparison tests (p ≤ 0.05). The highest resin production per tree was recorded in the chemically stimulated 14-year-old stand. Tree dry wood biomass, a major stock of carbon retained in cell wall polysaccharides, ranged from 245.69 ± 11.73 to 349.99 ± 16.73 kg among the plantations. Variations in carbon concentration ranged from 43% to 50% with the lowest percentages in underground biomass. There was no significant difference in lignin concentrations. Soils were acidic (pH 4.3 ± 0.10-5.83 ± 0.06) with low C (from 0.05% to 1.4%). Significantly higher C stock values were recorded in pine biomass compared to those reported for temperate zones. Resin-tapping biomass yielded considerable annual increments in C stocks and should be included as a relevant component in C sequestration assessments of planted pine forests.

RESUMO

Tars are one of the most effective, unknown, and oldest therapies for psoriasis. They include coal tar (CT) and biomass-derived products. These treatments, particularly the CT, have proven to be cost-effective with long remission times compared to other systemic or topical treatments. However, they have hardly evolved in recent years, as they are not well-embraced by clinicians or patients because of concerns regarding cosmesis and safety. This review summarizes current knowledge about the chemical characterization, mechanism of action, toxicity, and clinical studies supporting the use of tars for psoriasis over the last decade. Trends within these above aspects are reviewed, and avenues of research are identified. CT is rich in polycyclic aromatic hydrocarbons, whereas biomass-derived tars are rich in phenols. While the activation of the aryl hydrocarbon receptor is involved in the antipsoriatic effect of CT, the mechanism of action of biomass-derived products remains to be elucidated. No conclusive evidence exists about the risk of cancer in psoriasis patients under CT treatment. Large, randomized, double-blind, controlled clinical trials are necessary to promote the inclusion of tars as part of modern therapies for psoriasis.

Assuntos

RESUMO

Climatic factors play an essential role in the growth of tree ring width. In this study, we aimed to evaluate the correlation between climatic variables and tree-ring growth characteristics of Pinus sibirica in Altai mountains, northwestern China. This study being is first of its kind on climate growth analysis of Pinus sibirica in northwestern China. The study showed great potential to understand the species growing under the specific climatic conditions. Total of 70 tree cores collected from three sites in the sampling area, out of which 63 tree cores considered for this study. The effect of climatic variables which was studied include precipitation, temperature and PDSI. Our results showed that Tree Ring Width chronology has a significantly positive correlation with the late winter (March) temperature and significant negative correlation with the July temperatures. A significant correlation was observed with the late summer precipitation whereas no significant relation found with the Palmer Drought Severity Index. These significant correlations with temperature and precipitation suggested that this tree species had the potential for the reconstruction of the past climate in the area.

Fatores climáticos desempenham papel essencial no crescimento da largura dos anéis das árvores. Neste estudo, objetivou-se avaliar a correlação entre variáveis climáticas e características de crescimento de anéis de árvores de Pinus sibirica nas montanhas de Altai, noroeste da China. Este estudo é o primeiro desse tipo na análise do crescimento climático de Pinus sibirica no noroeste da China. O estudo mostrou grande potencial para entender as espécies que crescem sob as condições climáticas específicas. Total de 70 testemunhos coletados em três locais na área de amostragem, dos quais 63 testemunhos considerados para este estudo. O efeito das variáveis climáticas estudadas incluem precipitação, temperatura e PDSI. Nossos resultados mostraram que a cronologia da Largura do Anel da Árvore tem uma correlação significativamente positiva com a temperatura do final do inverno (março) e uma correlação negativa significativa com as temperaturas de julho. Uma correlação significativa foi observada com a precipitação do final do verão, enquanto nenhuma relação significativa foi encontrada com o Índice de Severidade de Seca de Palmer. Essas correlações significativas com a temperatura e precipitação sugeriram que esta espécie de árvore tinha o potencial para a reconstrução do clima passado na área.

Assuntos

RESUMO

Abstract Climatic factors play an essential role in the growth of tree ring width. In this study, we aimed to evaluate the correlation between climatic variables and tree-ring growth characteristics of Pinus sibirica in Altai mountains, northwestern China. This study being is first of its kind on climate growth analysis of Pinus sibirica in northwestern China. The study showed great potential to understand the species growing under the specific climatic conditions. Total of 70 tree cores collected from three sites in the sampling area, out of which 63 tree cores considered for this study. The effect of climatic variables which was studied include precipitation, temperature and PDSI. Our results showed that Tree Ring Width chronology has a significantly positive correlation with the late winter (March) temperature and significant negative correlation with the July temperatures. A significant correlation was observed with the late summer precipitation whereas no significant relation found with the Palmer Drought Severity Index. These significant correlations with temperature and precipitation suggested that this tree species had the potential for the reconstruction of the past climate in the area.

RESUMO Fatores climáticos desempenham papel essencial no crescimento da largura dos anéis das árvores. Neste estudo, objetivou-se avaliar a correlação entre variáveis climáticas e características de crescimento de anéis de árvores de Pinus sibirica nas montanhas de Altai, noroeste da China. Este estudo é o primeiro desse tipo na análise do crescimento climático de Pinus sibirica no noroeste da China. O estudo mostrou grande potencial para entender as espécies que crescem sob as condições climáticas específicas. Total de 70 testemunhos coletados em três locais na área de amostragem, dos quais 63 testemunhos considerados para este estudo. O efeito das variáveis climáticas estudadas incluem precipitação, temperatura e PDSI. Nossos resultados mostraram que a cronologia da Largura do Anel da Árvore tem uma correlação significativamente positiva com a temperatura do final do inverno (março) e uma correlação negativa significativa com as temperaturas de julho. Uma correlação significativa foi observada com a precipitação do final do verão, enquanto nenhuma relação significativa foi encontrada com o Índice de Severidade de Seca de Palmer. Essas correlações significativas com a temperatura e precipitação sugeriram que esta espécie de árvore tinha o potencial para a reconstrução do clima passado na área.

RESUMO

Climatic factors play an essential role in the growth of tree ring width. In this study, we aimed to evaluate the correlation between climatic variables and tree-ring growth characteristics of Pinus sibirica in Altai mountains, northwestern China. This study being is first of its kind on climate growth analysis of Pinus sibirica in northwestern China. The study showed great potential to understand the species growing under the specific climatic conditions. Total of 70 tree cores collected from three sites in the sampling area, out of which 63 tree cores considered for this study. The effect of climatic variables which was studied include precipitation, temperature and PDSI. Our results showed that Tree Ring Width chronology has a significantly positive correlation with the late winter (March) temperature and significant negative correlation with the July temperatures. A significant correlation was observed with the late summer precipitation whereas no significant relation found with the Palmer Drought Severity Index. These significant correlations with temperature and precipitation suggested that this tree species had the potential for the reconstruction of the past climate in the area.(AU)

Fatores climáticos desempenham papel essencial no crescimento da largura dos anéis das árvores. Neste estudo, objetivou-se avaliar a correlação entre variáveis climáticas e características de crescimento de anéis de árvores de Pinus sibirica nas montanhas de Altai, noroeste da China. Este estudo é o primeiro desse tipo na análise do crescimento climático de Pinus sibirica no noroeste da China. O estudo mostrou grande potencial para entender as espécies que crescem sob as condições climáticas específicas. Total de 70 testemunhos coletados em três locais na área de amostragem, dos quais 63 testemunhos considerados para este estudo. O efeito das variáveis climáticas estudadas incluem precipitação, temperatura e PDSI. Nossos resultados mostraram que a cronologia da Largura do Anel da Árvore tem uma correlação significativamente positiva com a temperatura do final do inverno (março) e uma correlação negativa significativa com as temperaturas de julho. Uma correlação significativa foi observada com a precipitação do final do verão, enquanto nenhuma relação significativa foi encontrada com o Índice de Severidade de Seca de Palmer. Essas correlações significativas com a temperatura e precipitação sugeriram que esta espécie de árvore tinha o potencial para a reconstrução do clima passado na área.(AU)

Assuntos

RESUMO

Sterile bracts can represent 80% of Araucaria angustifolia pinecone and are a rich source of phenolic compounds. This study aimed to optimize the extraction of the phenolic compounds from Araucaria angustifolia bracts using response surface methodology; the bioactivity properties were also investigated. The effects of the ethanol concentration, solute/solvent ratio, and temperature in relation to the phenolic composition and antioxidant activity were evaluated. The quantification and identification of the individual phenolic compounds (using high-performance liquid chromatography) and their bioactivity were evaluated. The optimized extraction conditions, which detected gallic acid, catechin, epicatechin, quercetin, and kaempferol, were obtained using 60% ethanol at a ratio of 1:38 (w/v) and a temperature of 80 °C. The extract showed high levels of phenolic classes and antioxidant activity. The extract also showed an inhibitory activity for pathogenic (approximately 80%, 10,000 µg/mL) and lactic acid (27.9%, 15,000 µg/mL) bacteria strains. The α-glucosidase inhibitory activity was approximately ten times greater than acarbose, demonstrating its high antiglycemic potential. No antioxidant and anti-inflammatory cellular activity were determined; however, a high cytotoxicity for non-tumor cells and the antiproliferative activity against the tumor cells were observed. Overall, the phenolic extract showed promising action in relation to the fight against the diseases related to oxidative stress and, hopefully, the application of the safe concentrations of the extract, based on bioavailability assays, can be verified.

RESUMO

Defense-related metabolome traits in pine species after infestation by Sirex noctilio are largely unknown, despite, in most cases, trees being overwhelmed. Using LC-MS-based untargeted metabolomics, we revealed the systemic metabolic changes induced by this insect in 14-year-old Pinus radiata trees, the most affected species worldwide. An immediate metabolome alteration was expressed in needles after infestation, including the up-regulation of flavonols, flavan-3-ols, oxyneolignans, auxins, proline, and tryptophan, among others. The flavan-3-ols (catechin and procyanidin B1) suggested a rapidly induced photoprotection mechanism aided by diverting proline as an alternative substrate for respiration to compensate for the progressive chlorosis that degrades photosystems. Meanwhile, glutathione, glutamate, and ascorbate levels significantly dropped in needles, which may indicate the critical oxidative stress that trees had to face since the onset of the infestation. They were not fully replenished after long-term infestation, and redox homeostasis was probably not achieved, compromising tree survival. Nevertheless, a huge auxins overexpression detected in needles throughout the infestation may reflect tolerance against the premature senescence caused by the woodwasp venom. In contrast, the metabolome of wood tissues remained initially unchanged, although it seems to collapse after three months. Overall, the metabolomics strategy adopted in this work evidenced its usefulness in uncovering the fundamental roles of plants' chemical defense that govern interactions with specific stressors.

Assuntos

RESUMO

BACKGROUND: Genomic prediction (GP) and genome-wide association (GWA) analyses are currently being employed to accelerate breeding cycles and to identify alleles or genomic regions of complex traits in forest trees species. Here, 1490 interior lodgepole pine (Pinus contorta Dougl. ex. Loud. var. latifolia Engelm) trees from four open-pollinated progeny trials were genotyped with 25,099 SNPs, and phenotyped for 15 growth, wood quality, pest resistance, drought tolerance, and defense chemical (monoterpenes) traits. The main objectives of this study were to: (1) identify genetic markers associated with these traits and determine their genetic architecture, and to compare the marker detected by single- (ST) and multiple-trait (MT) GWA models; (2) evaluate and compare the accuracy and control of bias of the genomic predictions for these traits underlying different ST and MT parametric and non-parametric GP methods. GWA, ST and MT analyses were compared using a linear transformation of genomic breeding values from the respective genomic best linear unbiased prediction (GBLUP) model. GP, ST and MT parametric and non-parametric (Reproducing Kernel Hilbert Spaces, RKHS) models were compared in terms of prediction accuracy (PA) and control of bias. RESULTS: MT-GWA analyses identified more significant associations than ST. Some SNPs showed potential pleiotropic effects. Averaging across traits, PA from the studied ST-GP models did not differ significantly from each other, with generally a slight superiority of the RKHS method. MT-GP models showed significantly higher PA (and lower bias) than the ST models, being generally the PA (bias) of the RKHS approach significantly higher (lower) than the GBLUP. CONCLUSIONS: The power of GWA and the accuracy of GP were improved when MT models were used in this lodgepole pine population. Given the number of GP and GWA models fitted and the traits assessed across four progeny trials, this work has produced the most comprehensive empirical genomic study across any lodgepole pine population to date.

Assuntos

RESUMO

The fungus Aspergillus flavus causes serious damage to maize grains and its by-products, such as tortilla. Currently, animal and plant derivatives, such as chitosan and propolis, and plant extract residues, respectively, are employed as alternatives of synthetic fungicides. The objective of this research was to evaluate the efficacy of several formulations based on propolis-chitosan-pine resin extract on the in vitro growth of A. flavus, the growth of maize grain plantlets and the quality of stored tortillas at 4 and 28 °C. The most outstanding formulation was that based on 59.7% chitosan + 20% propolis nanoparticles + 20% pine resin extract nanoparticles; since the in vitro conidia germination of A. flavus did not occur, disease incidence on grains was 25-30% and in tortillas, 0% infection was recorded, along with low aflatoxin production (1.0 ppb). The grain germination and seedling growth were markedly reduced by the nanocoating application. The percentage weight loss and color of tortillas were more affected by this coating compared to the control, and the rollability fell within the scale of non-ruptured at 4 °C and partially ruptured at 28 °C. The next step is to evaluate the toxicity of this formulation.

Assuntos

RESUMO

The influence of load on the cellulose microfibrils of single cells or thin wood foils is known. It can decrease the cellulose microfibril angles and, in turn, increase the stiffness. However, this modification of a piece of wood, which is made up of multiple cells, is unknown. The aim of this research was to study the effect of tensile creep on the longitudinal stiffness of radiata pine wood. The modulus of elasticity of each specimen was determined before and after being subjected to tensile creep. The samples were loaded at 1170 N and 1530 N for 20 min at 70 °C. The load was determined as a function of a percentage of the force at the proportional limit. The moduli of elasticity before and post-tensile creep showed no effect on the stiffness of wood at the macroscopic level, but neither were there damage to the cell structure. It can be assumed that there are changes at the microscopic level, but they are not enough to be reflected at the macro scale. It is also challenging to achieve the modifications that occur at the level of a single cell or in thin wood foils; however, the implications of this would be favorable for the development of stronger wood-based products.

RESUMO

Sugar pine, Pinus lambertiana Douglas, is a keystone species of montane forests from Baja California to southern Oregon. Like other North American white pines, populations of sugar pine have been greatly reduced by the disease white pine blister rust (WPBR) caused by a fungal pathogen, Cronartium ribicola, that was introduced into North America early in the twentieth century. Major gene resistance to WPBR segregating in natural populations has been documented in sugar pine. Indeed, the dominant resistance gene in this species, Cr1, was genetically mapped, although not precisely. Genomic single nucleotide polymorphisms (SNPs) placed in a large scaffold were reported to be associated with the allele for this major gene resistance (Cr1R). Forest restoration efforts often include sugar pine seed derived from the rare resistant individuals (typically Cr1R/Cr1r) identified through an expensive 2-year phenotypic testing program. To validate and geographically characterize the variation in this association and investigate its potential to expedite genetic improvement in forest restoration, we developed a simple PCR-based, diploid genotyping of DNA from needle tissue. By applying this to range-wide samples of susceptible and resistant (Cr1R) trees, we show that the SNPs exhibit a strong, though not complete, association with Cr1R. Paralleling earlier studies of the geographic distribution of Cr1R and the inferred demographic history of sugar pine, the resistance-associated SNPs are marginally more common in southern populations, as is the frequency of Cr1R. Although the strength of the association of the SNPs with Cr1R and thus, their predictive value, also varies with geography, the potential value of this new tool in quickly and efficiently identifying candidate WPBR-resistant seed trees is clear.

Assuntos

RESUMO

A 52-year-old pine forest is characterized as an environment with low plant diversity and large accumulation of allelopathic litter with poor nutrient content. Collembola is sensitive to environmental conditions and may have difficulties living in these forests. This study aimed (1) to evaluate the abundance and richness of Collembola in the soil of a 52-year-old pine afforestation with different moisture contents; and (2) to identify the landhopper sampled unintentionally. For sampling, pitfall traps were set up for four days, in areas of a Pinus elliottii afforestation with high and low soil moisture located at the Universidade Federal de Santa Maria. Collembola specimens were counted and identified to family and genus level. The total abundance of springtails was greater in the low soil moisture area. The genera Desoria and Lepidocyrtus, and specimens of the family Onychiuridae were more abundant in low soil moisture, meanwhile, the genus Ceratophysella was more abundant in the high soil moisture. The landhopper Talitroides sylvaticus was sampled unintentionally by traps set up in the soil with higher moisture and calcium content. Six genera of Collembola and the landhopper T. sylvaticus were identified in soil of a P. elliottii afforestation and their distribution is influenced by soil moisture.(AU)

Assuntos