Expressions of AtMTM1, AtMTM2, and AtMSD1 during development
The expression of AtMTM1 was previously analyzed in transgenicAtMTM1 -promoter::GUS plants (Su et al., 2007). In this study, we generated AtMTM2 -promoter::GUS plants to establish AtMTM2 expression profile (Supplemental Figure S6) , and clarified AtMTM1 , AtMTM2 , and AtMSD1 mRNA expressions by qPCR (Figure 4) .
The 2-kb potential AtMTM2 promoter region was fused with the reporter gene GUS , and transgenic plants were stained for GUS activity (Supplemental Figure S6) . AtMTM2 expression was clear in hypocotyl, root, and cotyledon in 5-d-old young seedlings(Supplemental Figure S6A to C) . AtMTM2 expression was also detected in 15-d-old trichomes, rosette leaf, cauline leaf(Supplemental Figure S6D to F) , and flower organs of sepal, petal, anther, pollen, stigma, and embryo in siliques(Supplemental Figure S6G to I) .
We further compared the gene expression levels of AtMTM1 ,AtMTM2 , and AtMSD1 in root, rosette leaf, cauline leaf, flower stem, flower, and silique by qPCR (Figure 4) .AtMTM2 had higher expression than AtMTM1 in rosette and cauline leaves. AtMSD1 expression was ubiquitously higher, but lower in flower and silique. Notably, both AtMTM1 andAtMTM2 had profound expressions in flower.