How to Analyze Transgenic Lines Resulting from (Salinity) Stress Engineering

Apart from satisfying scientific curiosity, what is the value that can be associated with knowledge about plant reactions, leading to tolerance or sensitivity, to high salinity? The major incentive is the agronomical value that crops might acquire if they could be made tolerant to high salinity because most crops are glycophytes, whose metabolism and growth are affected at low concentrations of sodium, well below 100 mM that would not pose problems for halophytes, in the soil. It seems possible to engineer tolerance at this level and at even higher NaCl concentrations, yet productivity might well be compromised (Apse et al., 1999; Kasuga et al., 1999; Mckersie et al., 1996; Romero et al., 1997; Roxas et al., 1997; Tarczynski et al., 1993; Van Camp et al., 1996; Zhifang and Loescher, 2003). Providing additional credibility to claims of engineered tolerance to a particular stress condition, it seems appropriate to establish rules about the experimental design of abiotic stress engineering, and how the results should be reported. The text box added below includes a suggestion for such rules. They were established by the attendees of a conference on salinity stress responses in plants in 2001. These recommendations (compiled by A. D. Hanson, University of Florida) describe what the participants considered essential and sufficient experimental process for the analysis and description of the effect of single transgenes on engineering or altering complex genetic and physiological traits, such as tolerance to salinity stress, drought, low temperature, or freezing (Serrano and Rodriguez-Navarro, 2002).