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Percentage of positive amplifications per region (CD and ITS) of DNA extracted from cambium samples of three tree species under different treatments (Treat) of storage time (0, 7, 14, 21 days) and storage media (DTT = dithiothreitol transport buffer, AA = ascorbic acid transport buffer, SIL = silica gel beads).
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Many tropical trees have high canopies and their leaves are not accessible. Thus, the use of tissue from a more accessible organ (cambium) for DNA extraction may be an alternative for molecular studies. We adapted a feasible methodology for extracting genomic DNA from cambium tissue harvested in the field for the assessment with PCR. We tested thre...
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... SIL storage at room temperature (approximately 25 ºC instead of 4 ºC for the buffer samples) exhibited some DNA degradation, which was likely due to the temperature difference. However, several positive PCR amplifications were obtained ( Table 2). The SIL storage resulted in a higher amount of DNA compared to previous studies. ...Citations
... Tradicionalmente, as folhas são usadas como fonte principal de DNA genômico (Colpaert et al., 2005;Novaes et al., 2009;Aydin et al., 2020). Materiais alternativos, entretanto, como a casca e tecidos do caule, vêm sendo utilizados por serem mais fáceis de serem coletados, especialmente em espécies arbóreas onde a altura das folhas dificulta sua amostragem (Mangaravite et al., 2020). ...
Ferramentas de identificação baseadas em DNA são de suma importância em estudos genéticos de plantas, onde o isolamento e a purificação são passos cruciais. O objetivo do presente estudo foi testar a eficiência de métodos de conservação e de maceração de materiais biológicos na extração de DNA genômico de folha e estipe de x Butyagrus nabonnandii (Prosch.) Vorster. Os dados foram analisados com ajuda do software Genes via análise de variância, considerando o esquema fatorial 3x2x2x2, com três repetições (três espécimes do híbrido; dois tipos de material biológico, estipe e folha; dois tipos de conservação, fresco e desidratado; dois tipos de maceração, com e sem nitrogênio líquido). As médias foram analisadas pelo teste Tukey a 5% de probabilidade de erro. O DNA genômico foi avaliado por espectrofotometria para determinar a concentração. A integridade foi determinada por eletroforese em gel de agarose. Foram utilizados dois primers da família gênica WRKY para testar a qualidade do DNA obtido em reações de PCR. As análises estatísticas revelaram diferenças significativas nas concentrações de DNA entre os métodos avaliados. Obteve-se maiores quantidades de DNA a partir da extração de folhas frescas quando comparadas às folhas desidratadas. O rendimento do DNA a partir de estipe fresco e desidratado não variou entre os métodos testados. O uso de nitrogênio líquido pode ser dispensado, conforme resultado dos padrões das bandas nas reações de PCR. Foi possível extrair DNA de qualidade e quantidades suficientes dos materiais biológicos de x B. nabonnandii, que amplificaram as regiões genômicas de interesse.
Trees are integral to ecosystems and hold considerable economic importance. Their exceptional longevity and modular structure also make them valuable models for studying the long-term accumulation of somatic mutations and epimutations in plants. Empirical evidence indicates that the annual rate of these stochastic events correlates negatively with generation time, suggesting that species with long lifespans have evolved mechanisms to mitigate the build-up of deleterious somatic variants. It has been hypothesized that this reduction is achieved by slowing growth and minimizing the number of cell divisions per unit time, thereby reducing errors associated with DNA replication. However, a direct test of this “mitotic-rate hypothesis” remains technically challenging. Here we took advantage of a 150 year-old experiment in European beech to show that a thinning-induced growth acceleration increases the annual rate of somatic epimutations in main stems and lateral branches of trees. We demonstrate that this effect is accompanied by a proportional increase in the rate of cell divisions per unit time. These findings support the notation that life-history constraints on growth rates in trees are not merely a trade-off between resource allocation and structural stability but also a strategy to preserve genetic and epigenetic fidelity over extended lifespans. Keywords: Fagus sylvatica, DNA methylation, epimutation rate, somatic epigenetic drift, somatic evolution, somatic epimutation, tree epigenomics
We explored a 320-km transect in the Tumucumaque mountain range along the border between southern French Guiana and Brazil, sampling all trees and lianas with DBH ≥ 10 cm in seven 25 x 25-m plots installed near seven boundary milestones. We isolated DNA from cambium tissue and sequenced two DNA barcodes (rbcLa and matK) to aid in species identification. We also collected fertile herbarium specimens from other species (trees/shrubs/herbs) inside and outside the plots. The selected DNA barcodes were useful at the family level but failed to identify specimens at the species level. Based on DNA barcoding identification, the most abundant families in the plots were Burseraceae, Fabaceae, Meliaceae, Moraceae, Myristicaceae and Sapotaceae. One third of the images of sampled plants posted on the iNaturalist website were identified by the community to species level. New approaches, including the sequencing of the ITS region and fast evolving DNA plastid regions, remain to be tested for their utility in the identification of specimens at lower taxonomic levels in floristic inventories in the Amazon region.
KEYWORDS:
DNA barcoding; French Guiana-Brazil border; matK; rbcLa; tree inventory; Tumucumaque
