Genome-wide functional analysis in Arabidopsis with the mechanical properties as a measure

点击翻译按钮获取中文摘要

To identify the function of every gene in Arabidopsis, it is required to develop the systematic genome-wide screening method with a suitable phenotype as a measure. For this purpose, we established the efficient procedures and conditions for analyzing the mechanical properties of Arabidopsis hypocotyls. To accurately measure the mechanical properties of tiny hypocotyls, we introduced a new tensile tester and developed feasible software and interface. The newly developed rheological method, in which the load-strain analysis and the stress-relaxation analysis are successively applied to a common sample, enabled the efficient analysis of the mechanical properties of hypocotyls. We also determined cultivation conditions of Arabidopsis seedlings suitable for effective sample preparation.We applied the method established in such a way to the analysis of the mechanical properties of Arabidopsis mutants defective in formation, metabolism, or function of the cell wall, the plasma membrane, and cortical microtubules. Out of various mutants examined, the mechanical properties of the knockout and over-expressed mutants in certain xyloglucan endotransglucosylase/hydrolase (XTH) genes were shown to be modified, the degree of which matched with the degrees of modifications in growth phenotype or xyloglucan metabolism. Moreover, α- and β-tubulin, MAPs (mor1, spr1, spr2, MAP65, katanin) and hmg mutants showed disordered growth pattern, such as dwarfism and helical growth, and also the corresponding changes in the mechanical properties. These results indicate the effectiveness of the method established in the present study for genome-wide functional analysis in Arabidopsis.