AtMTM2 histochemical analysis and generation of AtMTM1-miRNA mutants
The 2-kb potential AtMTM2 promoter activity during plant development was analyzed by GUS staining (Weigel & Glazebrook, 2002). The 21mer artificial microRNA (miRNA) of AtMTM1 was cloned into pRS300 vector which contains the miR319a precursor (Schwab, Ossowski, Riester, Warthmann, & Weigel, 2006). The automated design of artificial miRNAs was according to the Web app (http://wmd3.weigelworld.org/cgi-bin/webapp.cgi). The final PCR fragment was subcloned into pPZP200GB vector for constructing microRNA-mediated AtMTM1 suppression lines.