SUMMARYFruit ripening in tomato (Solanum lycopersicum L.) is well understood at the molecular level. However, information regarding genetic pathways associated with tomato ovary and early fruit development is still lacking. Here, we investigate the possible role(s) of the microRNA156/SQUAMOSA promoter-binding protein-like (SPL or SBP box) module (miR156 node) in tomato ovary development. miR156-targeted S. lycopersicum SBP genes were dynamically expressed in developing flowers and ovaries, and miR156 was mainly expressed in meristematic tissues of the ovary, including placenta and ovules. Transgenic tomato cv. MicroTom plants over-expressing the AtMIR156b precursor exhibited abnormal flower and fruit morphology, with fruits characterized by growth of extra carpels and ectopic structures. Scanning electron microscopy and histological analyses showed the presence of meristem-like structures inside the ovaries, which are probably responsible for the ectopic organs. Interestingly, expression of genes associated with meristem maintenance and formation of new organs, such as LeT6/TKN2 (a KNOX-like class I gene) and GOBLET (a NAM/ CUC-like gene), was induced in developing ovaries of transgenic plants as well as in the ovaries of the natural mutant Mouse ear (Me), which also displays fruits with extra carpels. Conversely, expression of the MADS box genes MACROCALYX (MC) and FUL1/TDR4, and the LEAFY ortholog FALSIFLORA, was repressed in the developing ovaries of miR156 over-expressors, suggesting similarities with Arabidopsis at this point of the miR156/SPL pathway but with distinct functional consequences in reproductive development. Altogether, these observations suggest that the miR156 node is involved in maintenance of the meristematic state of ovary tissues, thereby controlling initial steps of fleshy fruit development and determinacy.

This study aimed to fingerprint 36 water yam (Dioscorea alata) accessions using microsatellite markers. Ten accessions were collected in local markets from several municipalities in Brazil, eight were obtained from the 'Instituto Agronômico de Campinas' (IAC) germplasm collection and eighteen were collected directly from growers from São Paulo state. A total of nine microsatellite loci were used in the analysis. Loci revealed high polymorphism verified by elevated PIC values (0.57-0.77), and by high gene diversity and Shannon-Wiener indices (0.69 and 1.29 on average, respectively). The accessions were classified into two groups based on clustering analysis. One group contained mostly accessions from the IAC collection, including a commercial cultivar acquired in a market in the city of Cuiabá, Mato Grosso state. The second group was composed of most accessions, including those collected directly from growers and markets in São Paulo, a few accessions from the IAC collection, and an accession from Puerto Rico, named 'Florida', which is the most cultivated in Brazil. Several duplicates were identified in this study, including accessions obtained from two farmers in Mogi Guaçu and Mogi Mirim, São Paulo state. However, some of these accessions were allocated in different sub-groups, within this second group. Results suggested the hypothesis of different origins for accessions currently cultivated in Brazil. Similar accessions obtained from different municipalities revealed the commercialization of the same accessions at different locations.

IntroducciónLa diversidad de pisos ecológicos presentes en la Amazonía peruana, ha permitido a través de los siglos, la domesticación de numerosas especies de plantas nativas con una alta variabilidad genética (Zapata 2003). La impresionante diversidad biológica hace que muchas de estas especies no hayan sido estudiadas en profundidad, desconociendo aún muchas características biológicas, genéticas y fitoquímicas. Plukenetia volubilis L., sacha inchi es una planta nativa de la Amazonía peruana, cuyas semillas presentan altos contenidos de proteínas, ácidos grasos (esenciales: omegas 3, 6; omega 9) y vitamina E (tocoferoles y tocotrienoles) en cantidades significativamente mayores que otras semillas de oleaginosas como el maní, palma, soya, maíz, colza y girasol (Hamaker 1992).El valor del sacha inchi radica no sólo en los aspectos alimenticios, culturales e históricos, sino también en su rentabilidad económica. Siendo un cultivo con potencial rendimiento económico y grandes posibilidades de industrialización (Arévalo 1995), viene siendo intensamente cultivado; sin embargo, se observa una alta variabilidad genética, morfológica y fitoquímica, lo que ha generado que en el proceso de expansión del cultivo se hayan llegado a confundir especies del género Plukenetia. Hasta el año 2008 fueron descritas para la Amazonía peruana, cuatro especies en base a caracteres morfológicos: P. volubilis L., P. brachybotrya Müll. Arg., P. loretensis Ule, y P. polyadenia Müll. Arg. Recientemente fue descrita, para la región Amazonas, P. huayllabambana Bussmann, C. Téllez & A. Glenn. Nuestras observaciones en la morfología de algunas colecciones biológicas del Herbarium Amazonense (AMAZ) indican cierta sobreposición en algunos de los caracteres de estas especies, lo que podría dificultar su correcta determinación.Los marcadores moleculares constituyen poderosas herramientas para esclarecer cuestiones no resueltas mediante la taxonomía morfológica y para determinar los límites taxonómicos. Así, el ADN han sido utilizado para comprobar la sistemática morfológica o para cuestionarla (Judd et al. 1999). La litera- ResumenEn el presente trabajo se estudian cinco especies del género Plukenetia de la Amazonía peruana: P. brachybotrya, P. loretensis, P. polyadenia, P. huayllabambana, P. volubilis (procedencia San Martín); y de un supuesto morfotipo (P. volubilis, procedencia Cusco). Los 126 especímenes estudiados fueron identificados mediante claves de caracteres morfológicos (formas de hojas, tallos y semilla; posición de glándulas basilaminares) y posteriormente mediante marcadores moleculares ISSR (CAA, CAG, GACA). Los análisis morfológicos permitieron separar las cinco especies descritas: P. brachybotrya, P. loretensis, P. polyadenia, P. volubilis y P. huayllabambana. Los dos supuestos morfotipos de P. volubilis fueron discriminados por la posición de las glándulas, tamaño de semillas y forma del tallo. Los resultados proporcionados por el Análisis Factorial de Correspondencia (AFC) y corroborados por el Índice de fijación (F ST ), distan...

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