The ecdysteroid 20-hydroxyecdysone (20E) is a steroid hormone found in arthropods and plants. It is suspected to have agrochemical, biotechnological, medicinal, and pharmaceutical applicability. In insects, 20E controls or elicits molting and other developmental processes, and several characterized P450 enzymes are involved in its biosynthesis. In plants, it may act as a defensive substance against insects and nematodes. It is suspected that 20E, being a physiologically active compound, may affect morphological and physiological processes in plants and that C 27 phytosterols may be its precursors. However, neither its precise function nor its mechanism of biosynthesis in plants is fully understood. Here, the importance of 20E and current understanding of its structure, potential functions, and biosynthesis in both plants and insects are reviewed.Résumé : L'ecdysteroïde, le stéroïde hormonal 20-hydroxyecdysone (20E), se retrouve chez les arthropodes et les plantes. On croit qu'il aurait des applications agrochimiques, biotechnologiques, médicinales et pharmaceutiques. Chez les insectes, le 20E contrôle ou induit la mue et autres processus morphogénétiques, et on compte plusieurs enzymes P450 caractérisées impliquées dans sa biosynthèse. Chez les plantes, il peut agir comme substance de défense contre les insectes et les néma-todes. On croit que le 20E, une substance physiologiquement active, pourrait affecter des processus morphologiques et physiologiques chez les plantes et que des phytostérols en C27 pourraient en être les précurseurs. Cependant, on ne comprend pas complètement sa fonction précise ni le mécanisme de sa biosynthèse. Les auteurs passent en revue la compré-hension actuelle de sa structure, de ses fonctions potentielles et de sa biosynthèse, chez les plantes et chez les insectes.

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-This study aimed to characterize the genetic diversity of buriti populations by AFLP (Amplified Fragment Length

The sucrose binding protein (SBP) from soybean has been implicated as an important component of the sucrose uptake system. Two SBP genomic clones, gsS641.1 and gsS641.2, which correspond to allelic forms of the GmSBP2/S64 gene, have been isolated and characterized. As a member of the seed storage protein superfamily, it has been shown that the SBP gene structure is similar to vicilin genes with intron/exon boundaries at conserved positions. Fluores cence in situ hybridization (FISH) suggested that the soybean SBP gene family is represented by at least two non-allelic genes corresponding to the previously isolated GmSBP1 and GmSBP2/S64 cDNAs. These two cDNAs share extensive sequence similarity but are located at different loci in the soybean genome. To investigate transcriptional activation of the GmSBP2 gene, 2 kb 5'-flanking sequences of gsS641.1 and gsS641.2 were fused to the beta-glucuronidase (GUS) reporter gene and to the green fluorescent protein (GFP) reporter gene and inde pendently introduced into Nicotiana tabacum by Agrobacterium tumefaciens-mediated transformation. The SBP2 promoter directed expression of both GUS and GFP reporter genes with high specificity to the phloem of leaves, stems and roots. Thus, the overall pattern of SBP-GUS or SBP-GFP expression is consistent with the involvement of SBP in sucrose translocation-dependent physiological processes.