Reverse genetic analysis of myosin XI homologues of Arabidopsis thaliana

Abstract

The continuous and rapid movement of organelles and endosomal vesicles, which is termed cytoplasmic streaming, is found within plant cells. The cytoplasmic streaming has been studied for two centuries and is believed to be driven by the acto-myosin cytoskeleton. However, the molecular mechanism underlying the cytoplasmic streaming in plants is unknown. In order to elucidate the mechanism and physiological function of the cytoplasmic streaming, we performed reverse genetics by focusing on myosin XI Arabidopsis thaliana, which has 13 myosin XI homologues. We established a single knockout mutant of each of 13 myosin XI genes and then generated many kinds of double and triple mutants. We found that one of the myosin double mutants exhibited a defect of cytoplasmic streaming in the cells where the respective myosin genes expressed. The double mutants grew normally. No other double mutants showed were defective in cytoplasmic streaming in the cells.