Abstract
To elucidate the molecular mechanism of gravitropism, we have isolated and analyzed Arabidopsis shoot gravitropism (sgr) mutants. However, further conventional mutant screening mayn't be efficient way to obtain new mutants. Then, we attempted to screen novel genes involved in shoot-gravitropism with DNA microarray analysis comparing gene expression profiles between wild type and several mutants.
Major site for gravity sensing is the endodermis in Arabidopsis shoot. sgr1/scarcrow (scr) and sgr7/short-root (shr) mutant failed to form the endodermis. In addition, our recent study demonstrated that eal1(endodermal-amyloplast less 1), which exhibits no-gravitropism in inflorescence stem but retains ability to form endodermis, is a hypomorphic allele of sgr7/shr.
Take advantage of these mutants, we performed DNA microarray analysis. We found that 29 genes were commonly down-regulated in these mutants. A T-DNA insertion mutant of one gene among them showed reduced shoot gravitropism. Now we are carring out functional analysis of the gene.
