Transportability of Conclusions From Confined Field Trials: A Case Study Using the Virus Resistant Transgenic Bean Developed in Brazil.

The conceptual framework for Data Transportability, builds on the premise that well-designed studies conducted for the environmental and food/feed risk assessment of transgenic crops may be transportable across geographies. Beyond individual data, provided that certain criteria are met, the general conclusions of comparative assessments of a transgenic crop with its conventional counterpart would also be transportable. In spite of this, many regulatory agencies still require in-country field trials to complete risk assessments of transgenic crops. A sub-team from ILSI Argentina's (International Life Sciences Institute, Argentina. www.ilsi.org.ar) Biotechnology Working Group tested the applicability of the transportability concept to the case of the golden mosaic virus-resistant transgenic bean, developed by EMBRAPA (EMBRAPA: Brazilian Agricultural Research Corporation). To this end, regulatory confined field trials (CFTs) carried out in Brazil to gather agro-phenotypic and compositional data were analyzed. The transportability of the conclusions of these studies to the bean cropping areas in Argentina was assessed as a conceptual exercise (with no intention to conclude on the biosafety of the common bean event). Comparative studies included the transgenic bean and its conventional parental line and were run in different agroecological environments so that any relevant differences could be observed. The main criteria to enable transportability were set by the sub-team and found to be met by the CFTs carried out in Brazil to inform a potential risk evaluation for Argentina.

Phosphorylation of the TGBp1 movement protein of Potato virus X by a Nicotiana tabacum CK2-like activity.

The movement protein (MP) TGBp1 of the potexvirus Potato virus X (PVX) is a multifunctional protein required for cell-to-cell movement within the host plant. Recent work on other plant viruses has indicated that MP phosphorylation by host kinases can regulate MP function. In this study, we demonstrate that recombinant and native TGBp1 are phosphorylated by Nicotiana tabacum extracts from both PVX-infected and non-infected leaves. The phosphorylation activity present in plant extracts has distinctive characteristics of casein kinase 2 (CK2): it is inhibited by heparin, stimulated by polylysine, and uses either ATP or GTP as phosphoryl donors. We also demonstrate that TGBp1 is efficiently phosphorylated by recombinant tobacco CK2 alpha subunit and by partially purified tobacco CK2. Phosphopeptide mass mapping reveals that TGBp1 is phosphorylated in Ser-165, which is localized within a CK2 consensus sequence. Our results strongly suggest that a N. tabacum kinase of the CK2 family is involved in TBGp1 phosphorylation during the course of viral infection.