An In Vivo Perspective of the Role(s) of the Alternative Oxidase Pathway

Despite intense research on the in vitro characterization of regulatory factors modulating the alternative oxidase(AOX) pathway, the regulation of its activity in vivois still not fully understood. Advances concerning in vivoregulation of AOX based on the oxygen- isotope fractionationtechnique are reviewed, and regulatory factors that merit future research are highlighted. In addition, we review and discuss the main biological functionsassigned to the plant AOX, and suggest future experiments involving in vivoactivity measurements to test different hypothesized physiological roles.