In silico characterization and expression analysis of a Selenium-Binding Protein gene from cacao : S01P01

Witches' broom disease, caused by the fungus Moniliophthora perniciosa, is one of the main diseases of cacao (Theobroma cacao L.) and is responsible to severe economic losses in the production areas. Recently, expressed sequence tags (ESTs) from cacao-M. perniciosa interaction were obtained and differentially defense-related genes expressed during the cacao-M. perniciosa interaction were identified. Among them, a Selenium-Binding Protein (TcSBP) was found. In other organisms, SBP genes are related to the increase of plant defenses against abiotic and biotic stresses; in rice the SBP gene was successfully used to increase the plant resistance to Magnaporthe grisea by plant transformation. Here, in silico characterization and expression analysis of TcSBP were developed. Search on the Cacao Genome Database revealed the presence of only one SBP sequence of 4774 pb in length located on the chromosome 4. The TcSBP ORF is 1431 bp in length and encodes a protein of 476 amino acids which does not contain any signal peptide. Prediction of possible post-translational events allowed the identification of several glycosylation, phosphorylation and acetylation sites. The comparison of TcSBP sequence with SBP from other organisms using the BLASTP tool revealed identity from 62% to 91% and allowed the identification of specific conserved regions. The expression analysis of TcSBP in meristems of cacao plantlets varieties Catongo (susceptible) and TSH1188 (resistant to M. perniciosa), inoculated or not with M. perniciosa, was obtained by RT-qPCR using 3 biological and 3 experimental replicates. qPCR analysis of TcSBP gene was conducted using the standard settings of the ABI PRISM 7500 and the System of Sequence Detection software. The TcSBP relative expression was analyzed with the comparative Ct method (2-??Ct) using malate dehydrogenase and actin as endogenous reference genes, and noninoculated plants (control) as calibrator. The relative expression of TcSBP was significantly increased 8 and 15 days after inoculation in the resistant variety TSH1188 compared to susceptible Catongo. These data suggest the possible role of TcSBP in cacao resistance to M. perniciosa. This study is the first step to better understand the role of TcSBP in cacao resistance as well as for the development of control strategies of the witches' broom disease (e.g. using plant transformation). Work supported by FAPESB, CAPES, EMBRAPA, CNPq, FINEP/Renorbio and CIRAD. (Texte intégral

The anatomy of the fruit in relation to the propensity of citrus species to split

The anatomy of the fruit has been compared in three prone-to-split mandarin hybrids (Nova, Ellendale and Murcott), several cultivars of clementine mandarin (Fino, Clementina de Nules and Orogrande), and in Owari satsuma mandarin. The fruit of the hybrids is oblate to subglobose and usually presents an open stylar end disrupted by a navel formed by the floral meristem, which is conserved near the apex of the fruit. In the non-prone-to-split clementines as well as in Owari satsuma, the floral axis protrudes inside the style, and the flower meristem is lost through abscission shortly after petal fall. The abaxial side of the carpels fuses with the flower axis forming at the stylar end of the fruit a solid tissue which externally has a small scar at the place of style abscission. Most of the fruits in these cultivars have no navel. In addition, the fruit of clementine is slightly oblate or globose. The relevance of these anatomical characteristics as regards to splitting is supported by the differences between the split and non-split fruits in Nova, the split fruit being more oblate in shape and having a bigger navel than non-split fruit. However, the effect of applied growth regulators on fruit splitting could not be correlated with their effect on the anatomy of the fruit. Additional factors not contemplated in the study also influence fruit splitting

Prioritizing Amazon Forest conservation: Assessing potential biomass under climate change

This study aims to identify the capacity of intact forests to maintain Above Ground Biomass (AGB) under new climate conditions. Using a predictive approach under different climate scenarios (SSP1–2.6 and SSP5–8.5), and considering the mean of General Circulation Models (GCMs) for the period (2021–2040), it was revealed that the regions with the greatest capacity for AGB in the optimistic scenario are concentrated in the northwest and southeast regions, covering the basins of the Negro, Xingu and Tapajós rivers. In the SSP5–8.5 scenario, although potential AGB gains are concentrated in the same regions, the spatial distribution is more restricted and dispersed. Indigenous Landsemerge as areas with the greatest potential AGB gains in both climate scenarios. However, these predictions do not include the impact of extreme climate events, such as storms, severe droughts, and wildfires, which could lead to an underestimation of actual biomass variations

Marked non-compliance with deforestation embargoes in the Brazilian Amazon

Advances in monitoring capacity and strengthened law enforcement have helped to reduce deforestation in the Brazilian Amazon since the early 2000s. Embargoes imposed on the use of deforested land are important instruments for deterring deforestation and enabling forest recovery. However, the extent to which landowners respect embargoes in the Brazilian Amazon is unknown. In this study, we evaluated the current recovery status of embargoes due to deforestation imposed between 2008 and 2017 to conduct the first large-scale assessment of compliance with embargo regulations. We observed forest recovery in only 13.1% (±1.1%) of embargoed polygons, while agriculture and pasture activities were maintained in 86.9% (±1.8%) of embargoed polygons. Thus, landowners openly continue to disrespect environmental legislation in the majority of embargoed areas. We attribute the marked non-compliance observed to limited monitoring of embargoed areas, as environmental agents seldom return to verify the status of embargoed lands after they have been imposed. Recent advances in remote sensing provide low-cost ways to monitor compliance and should form the basis of concerted efforts to ensure that the law is observed and that those responsible for illegal deforestation do not benefit from it