Abstract Proteins of the Split ends (Spen) family are characterized by an N-terminal domain, with one or more RNA recognition motifs and a SPOC domain. In Arabidopsis thaliana, the Spen protein FPA is involved in the control of flowering time as a component of an autonomous pathway independent of photoperiod. The A. thaliana genome encodes another gene for a putative Spen protein at the locus At4g12640, herein named AtSpen2. Bioinformatics analysis of the AtSPEN2 SPOC domain revealed low sequence similarity with the FPA SPOC domain, which was markedly lower than that found in other Spen proteins from unrelated plant species. To provide experimental information about the function of AtSpen2, A. thaliana plants were transformed with gene constructs of its promoter region with uidA::gfp reporter genes; the expression was observed in vascular tissues of leaves and roots, as well as in ovules and developing embryos. There was absence of a notable phenotype in knockout and overexpressing lines, suggesting that its function in plants might be specific to certain endogenous or environmental conditions. Our results suggest that the function of Atspen2 diverged from that of fpa due in part to their different transcription expression pattern and divergence of the regulatory SPOC domain.

Abstract Molecular techniques such as PCR and RFLP allowed the isolation and identification of complete A component sequences of two begomoviruses from soybean plants with virus symptoms in the state of Sinaloa, Mexico. Both genomes were analyzed by comparison of their nucleotide sequences with those available in the NCBI database. The first isolate corresponded to Rhynchosia golden mosaic virus (RhGMV), while the second corresponded to the Chino del tomate virus (CdTV) which showed a 92.3% overall identity with its closest relatives, CdTV-[8[ and CdTV-[RK[. Plant extracts of symptomatic soybean were analyzed by PCR using a pair of universal primers that allowed to amplify and confirm the presence of the CdTV B component, therefore the second isolate identified in this work is proposed as a new CdTV strain called "Chino del tomate virus - Soybean" (Mexico: Sinaloa: 2005). The presence of this new CdTV strain isolated from soybean is important because to date virus infection was naturally restricted to plants of the Solanaceae family.

Resumen Mediante el uso de técnicas moleculares como la PCR y los RFLPS se logró aislar e identificar a partir de plantas de soya con síntomas de virosis las secuencias completas del componente A de dos begomovirus en el estado de Sinaloa, México. Ambos genomas fueron analizados mediante la comparación de sus secuencias nucleotídicas con las disponibles en la base de datos del NCBI. El primer aislado correspondió a Rhynchosia golden mosaic virus (RhGMV), mientras que el segundo corresponde a la especie Chino del tomato virus (CdTV) el cuál mostró 92.3% de identidad global con sus parientes más cercanos, CdTV-[8] y CdTV-[RK]. Los extractos de plantas de soya sintomáticas fueron analizados mediante PCR utilizando un par de iniciadores universales que permitieron amplificar y confirmar la presencia del componente B de CdTV, por lo que se propone al segundo aislado identificado en este trabajo como una nueva cepa de CdTV denominada "Chino del tomato virus- Soybean'" (México: Sinaloa: 2005). La presencia de esta nueva cepa de CdTV aislada de soya es importante ya que hasta la fecha la infección del virus había sido restringida en forma natural a plantas de la familia Solanaceae.