Abstract: South American leaf blight caused by the ascomycete Microcyclus Wei is the most harmful disease of the rubber tree in Latin America and a potential threat to Asiatic and African natural rubber production. Until now, the variability of this fungus was assessed through observation of pathogenicity of isolates on a range of rubber tree clones with known resistance reactions. The present study describes the process used to design 11 microsatellite markers and evaluates their usefulness in detecting genetic polymorphism. Nine of these markers were polymorphic among six isolates from Brazil (with two to three alleles per locus) and five markers were polymorphic among four isolates from French Guiana (with two to four alleles per locus).

Abstract: Near infrared (NIR) spectroscopy provides rapid and non-destructive analysis of wood properties and composition. In this study, we aimed to use NIR measurement for the prediction of teak phenolic compounds, which are chemical markers for natural durability of wood. Twenty-seven teak trees from two geographical zones (Malaysia and Ivory Coast) were used. On ground heartwood samples, the content of total phenolics and individual quinones (tectoquinone, 2-(hydroxymethyl)anthraquinone, 2-anthraquinone carboxylic acid, 1,4-naphthoquinoneand 4c,5c-dihydroxy-epiisocatalponol) were determined using high performance liquid chromatography (HPLC). Partial least squares (PLS) regression with NIR spectra on the same samples and phenolic data was used to build NIR models for phenolic contents. The PLS models for the total predicted phenolics and three quinone contents (tectoquinone, 2-(hydroxymethyl) anthraquinone, and 4¢,5¢-dihydroxy-epiisocatalponol) showed a good ratio of performance to deviation (RPD ≥ 2.5), strong coefficients of determination (r2 ≥ 0.8) and the prediction errors were consistent with the reference method. These results demonstrate that NIR spectroscopy can be reliable for the evaluation of total phenolics and individual quinones in teak heartwood wood meal. NIR spectroscopy is a promising technique for rapidly providing information on the quinone contents in teak wood and indirectly for knowing its natural durability. This finding leads to a precise, non-destructive tool for teak wood quality evaluation. © IM Publications LLP 2014.

Abstract: A combination of restriction associated DNA sequencing (RADSeq) and low coverage MiSeq genome sequencing was used for the development of single nucleotide polymorphisms (SNP) and INDEL (insertion/deletions) genetic markers for Ipe (Handroanthus sp.). Of the 402 putative loci identified, 389 SNPs and INDELs (315 nuclear SPNs, six chloroplast INDELs, 15 chloroplast SNPs, 12 mitochondrial INDELs and 41 mitochondrial SNPs) were successfully genotyped at 93 individuals from Brazil, Bolivia and French Guiana using a MassARRAY® iPLEX™ platform. This set of markers will be invaluable for population genetics, phylogeography and DNA fingerprinting studies. © 2017, Springer Science+Business Media B.V., part of Springer Nature.

Abstract: The mechanism for tree orientation in angiosperms is based on the production of high tensile stress on the upper side of the inclined axis. In many species, the stress level is strongly related to the presence of a peculiar layer, called the G-layer, in the fibre cell wall. The structure of the G-layer has recently been described as a hydrogel thanks to N-2 adsorption-desorption isotherms of supercritically dried samples showing a high mesoporosity (pores size from 2-50 nm). This led us to revisit the concept of the G-layer that had been, until now, only described from anatomical observation. Adsorption isotherms of both normal wood and tension wood have been measured on six tropical species. Measurements show that mesoporosity is high in tension wood with a typical thick G-layer while it is much less with a thinner G-layer, sometimes no more than normal wood. The mesoporosity of tension wood species without a G-layer is as low as in normal wood. Not depending on the amount of pores, the pore size distribution is always centred around 6-12 nm. These results suggest that, among species producing fibres with a G-layer, large structural differences of the G-layer exist between species.

Abstract: Using an integrated transcriptomic and proteomic approach, we characterized the venom peptidome of the European red ant, Manica rubida. We identified 13 “myrmicitoxins” that share sequence similarities with previously identified ant venom peptides, one of them being identified as an EGF-like toxin likely resulting from a threonine residue modified by O-fucosylation. Furthermore, we conducted insecticidal assays of reversed-phase HPLC venom fractions on the blowfly Lucilia caesar, permitting us to identify six myrmicitoxins (i.e., U3-, U10-, U13-, U20-MYRTX-Mri1a, U10-MYRTX-Mri1b, and U10-MYRTX-Mri1c) with an insecticidal activity. Chemically synthesized U10-MYRTX-Mri1a, -Mri1b, -Mri1c, and U20-MYRTX-Mri1a irreversibly paralyzed blowflies at the highest doses tested (30-125 nmol·g-1). U13-MYRTX-Mri1a, the most potent neurotoxic peptide at 1 h, had reversible effects after 24 h (150 nmol·g-1). Finally, U3-MYRTX-Mri1a has no insecticidal activity, even at up to 55 nmol·g-1. Thus, M. rubida employs a paralytic venom rich in linear insecticidal peptides, which likely act by disrupting cell membranes.