Abstract
Our previously studies revealed that the cell death regulator LSD1 interacts with some Aux/IAAs in Arabidopsis. We suggested that the function of LSD1 is involved in auxin-responsive transcriptional regulation via interaction with Aux/IAA as well as in the regulation of cell death since LSD1 has a function as retention protein to interfere the nuclear import of transcription factors into cytosol. To clarify the function of LSD1 on auxin response, at first we examined the auxin-related phenotype in an overexpressor of LSD1 (LSD1-ox) and LSD1 mutant (lsd1-2). The analysis of the auxin-related phenotype in roots demonstrated that the primary root growth is promoted in LSD1-ox, whereas reduced in lsd1-2. In addition, the quantification of endogenous IAA in roots using LC-MS/MS indicated that the level of endogenous IAA is significantly altered in both LSD1-ox and lsd1-2. The microarray analysis showed that various auxin-responsive genes are up-regulated in lsd1-2. These results suggest that the function of LSD1 is also involved in the regulation of endogenous IAA level in roots by the transcriptional regulation via interaction with Aux/IAAs.
