Effect of 24-epibrassinolide on Arabidopsis thaliana alternative respiratory pathway under salt stress

Using wild-type (WT) Arabidopsis thaliana plants and two transgenic lines—overexpressing alternative oxidase AOX1a (AOX1a-OE) and antisense AOX1a (AOX1a-AS)—it was observed that brassinosteroids (BRs) are involved in regulation of respiration in A. thaliana leaf, particularly alternative respiratory pathway, under salt stress conditions. This study demonstrates that BRs stimulate total respiration rate, alternative respiratory pathway, and shift capacity of alternative respiratory pathway comparing to cyanide-sensitive pathway. Lowering the level of endogenous BRs with the specific inhibitor of BRs biosynthesis—brassinazole—caused the decrease of alternative respiratory pathway activity in WT plants and transgenic AOX1a-OE and AOX1a-AS lines.